topic 6 - inheritance, variation and evolution Flashcards
1
Q
What is meiosis?
A
Meiosis is the formation of four non-identical cells from one original cell. It is the process that produces gametes which are used in sexual reproduction.
2
Q
What is mitosis?
A
Mitosis is the process of forming two identical cells from one original cell. It is used for growth maintenance and repair of tissues.
3
Q
What are gametes in animals?
A
In animals gametes are male and female sex cells: sperm (male) and egg (female) cells each carrying genetic information.
4
Q
What are gametes in flowering plants?
A
In flowering plants gametes are produced as pollen (male) and egg cells (female) which carry genetic information for reproduction.
5
Q
How are gametes formed?
A
Gametes are formed by the process of meiosis which results in non-identical cells that contain half the number of chromosomes of the original cell.
6
Q
How many chromosomes are in a normal human cell?
A
A normal human cell has 46 chromosomes organized into 23 pairs.
7
Q
From where do the two sets of chromosomes in a normal cell originate?
A
In each pair of chromosomes one chromosome comes from the mother and the other comes from the father.
8
Q
How many chromosomes are present in each gamete?
A
Each gamete contains 23 chromosomes which is half the number of chromosomes found in a normal somatic cell.
9
Q
What is the significance of sexual reproduction?
A
Sexual reproduction allows for genetic variation through the combination of genetic material from two parents contributing to diversity in the offspring.
10
Q
What is the difference between sexual and asexual reproduction?
A
Sexual reproduction involves the combination of genetic information from two parents (involves gametes) while asexual reproduction produces offspring from a single parent without the fusion of gametes.
11
Q
What is meant by ‘non-identical cells’ in the context of meiosis?
A
‘Non-identical cells’ refers to the gametes produced by meiosis which have different genetic combinations compared to each other and the parent cell leading to genetic diversity.
12
Q
What is the role of meiosis in evolution?
A
Meiosis introduces genetic variation through recombination and independent assortment of chromosomes which is crucial for evolution as it provides a diverse gene pool for natural selection.
13
Q
Define gamete fusion in sexual reproduction.
A
Gamete fusion is the process where male and female gametes join together during fertilization leading to the formation of a zygote which will develop into a new organism.
14
Q
Explain the term ‘chromosome pairs.’
A
Chromosome pairs consist of two homologous chromosomes one inherited from each parent that carry the same genes but may have different alleles.
15
Q
What is genetic variation and why is it important?
A
Genetic variation refers to the differences in DNA among individuals. It is important for the survival of species as it enhances adaptability to changing environments and survivability.
16
Q
What is the role of chromosomes in fertilization?
A
Chromosomes carry genetic information from each parent that fuse during fertilization mixing the genetic material and producing variation in the offspring.
17
Q
What is asexual reproduction?
A
Asexual reproduction involves one parent and does not involve the joining of gametes. It occurs through the process of mitosis resulting in two identical cells formed from one parent cell.
18
Q
What are the characteristics of offspring produced by asexual reproduction?
A
Offspring produced through asexual reproduction are clones meaning they are genetically identical to each other and to the parent organism.
19
Q
Give examples of organisms that reproduce asexually.
A
Examples of organisms that reproduce asexually include bacteria some plants like spider plants and potato tubers and some animals like starfish and certain types of worms.
20
Q
What is meiosis?
A
Meiosis is the process of cell division that results in the formation of four non-identical gametes from one initial cell typically occurring in reproductive organs.
21
Q
How does meiosis differ from mitosis?
A
Meiosis produces four non-identical cells with half the chromosome number while mitosis produces two identical cells with the same chromosome number as the parent cell.
22
Q
What happens to the chromosome number during meiosis?
A
In meiosis the initial cell makes copies of its chromosomes doubling the genetic information. It then undergoes two rounds of divisions resulting in gametes with half the chromosome number (23 chromosomes) from the original cell (46 chromosomes).
23
Q
What are the final products of meiosis?
A
The final products of meiosis are four gametes each containing a quarter the number of chromosomes specifically 23 chromosomes.
24
Q
What are gametes and how many chromosomes do they contain?
A
Gametes are reproductive cells formed through meiosis and they contain one copy of each chromosome totaling 23 chromosomes in humans.
25
Explain the significance of genetic variation in offspring produced through fertilization.
Genetic variation in offspring is significant because it increases the potential for adaptation survival and evolution in changing environments as offspring inherit a mix of traits from both parents.
26
What processes result in clones during asexual reproduction?
In asexual reproduction the process of mitosis leads to the formation of clones as cells divide to produce identical copies without genetic mixing.
27
What are gametes?
Gametes are reproductive cells that carry half the genetic information of an organism. In humans they are sperm and egg cells each containing 23 chromosomes.
28
Why are gametes genetically different from each other?
Gametes are genetically different due to the process of meiosis where chromosomes are shuffled and randomly distributed into four daughter cells resulting in unique combinations of chromosomes in each gamete.
29
What happens during fertilization?
During fertilization two gametes (sperm and egg) combine to form a zygote which contains a complete set of chromosomes (46 in humans) restoring the diploid number.
30
What is mitosis and its role in embryonic development?
Mitosis is the process of cell division that results in two identical daughter cells. After fertilization the zygote undergoes mitosis to produce many copies of cells leading to the formation of an embryo.
31
What is cell differentiation?
Cell differentiation is the process by which unspecialized cells in the developing embryo take on specific roles or functions resulting in the formation of various cell types in the body.
32
List the advantages of sexual reproduction.
1. Produces variation in offspring which enhances survival in changing environments.
33
2. Increases genetic diversity within a species allowing for adaptation and evolution.
34
List the disadvantages of sexual reproduction.
1. Requires more time and energy to find mates and engage in mating.
35
2. Generally produces fewer offspring compared to asexual reproduction.
36
List the advantages of asexual reproduction.
1. Allows for rapid population growth since one organism can produce many offspring.
37
2. Offspring are genetically identical to the parent ensuring successful traits are passed on.
38
List the disadvantages of asexual reproduction.
1. Lack of genetic variation making the population more susceptible to environmental changes or diseases.
39
2. If the parent possesses unfavorable traits all offspring may inherit them.
40
What is meant by 'survival advantage'?
Survival advantage refers to a beneficial characteristic that improves an organism's ability to survive in its environment especially when conditions change.
41
How does sexual reproduction contribute to evolutionary processes?
Sexual reproduction contributes to evolutionary processes by creating genetic diversity among offspring increasing the chances that some individuals will possess traits suited for survival and reproduction in changing environments.
42
What is the outcome of the meiotic process?
The meiotic process results in four genetically diverse haploid gametes each containing half the number of chromosomes of the original diploid cell.
43
What are the advantages of variation in a species?
Variation decreases the chance of the whole species becoming extinct. It allows for selective breeding which enhances traits desirable for survival.
44
What is the main feature of asexual reproduction?
Only one parent is needed allowing for quicker reproduction and less energy expended since organisms do not need to find a mate.
45
What is the significance of selective breeding?
Selective breeding involves mixing genetic information from two organisms to produce offspring with even more desirable characteristics thereby speeding up natural selection.
46
How does selective breeding impact food production?
Selective breeding can be used to increase food production by breeding animals with a high yield of meat or crops with better growth traits.
47
How do malarial parasites reproduce?
Malarial parasites reproduce sexually in the mosquito host and asexually in the human host within the liver and blood cells.
48
What are the two methods of reproduction mentioned for organisms?
The two methods of reproduction are sexual reproduction and asexual reproduction.
49
In what conditions can asexual reproduction be most advantageous?
In favorable conditions asexual reproduction can lead to the production of many identical offspring quickly.
50
What is a downside of sexual reproduction?
Sexual reproduction while promoting genetic diversity can be slower and requires two parents to contribute genetic material.
51
What is natural selection?
Natural selection is the process through which species evolve as advantageous traits become more common in successive generations often influenced by variations in sexual and asexual reproduction.
52
How do fungi typically reproduce?
Many species of fungi can reproduce both sexually and asexually often depending on environmental conditions.
53
What is one example of an organism that reproduces both sexually and asexually given in the text?
Malarial parasites are one example reproducing sexually in mosquitoes and asexually in humans.
54
What is the efficiency of asexual reproduction regarding energy and time?
Asexual reproduction is generally more efficient as it uses less energy and is faster enabling rapid population growth under ideal conditions.
55
What are the two types of reproduction in fungi?
Fungi undergo asexual reproduction and sexual reproduction. Asexual reproduction involves the release of spores that are genetically identical to the parent. Sexual reproduction occurs when conditions change producing spores that lead to increased genetic variation.
56
What is the purpose of sexual reproduction in fungi?
The purpose of sexual reproduction in fungi is to increase genetic variation which helps to avoid extinction in changing environmental conditions.
57
How do many plants reproduce sexually?
Many plants reproduce sexually using pollen which must reach the egg cells in the female parts of another flower. This process is called pollination and it leads to the formation of seeds.
58
Describe asexual reproduction in strawberry plants.
Strawberry plants reproduce asexually by producing runners. New identical plants grow off these runners.
59
Explain how daffodils reproduce asexually.
Daffodils reproduce asexually by growing from bulbs. New bulbs can grow from the main bulb resulting in new plants that are genetically identical to the parent.
60
What is an advantage of asexual reproduction in plants like daffodils?
An advantage of asexual reproduction in plants is that they can reproduce even if their flowers are destroyed by frost or other animals allowing for survival and continued propagation.
61
What is DNA?
DNA or deoxyribonucleic acid is the genetic material in the nucleus of a cell. It is a polymer made up of two strands that wrap around each other forming a double helix structure.
62
Describe the structure of DNA.
DNA is structured as a double helix consisting of two long strands that coil around each other. Each strand is made up of a sequence of nucleotides which include a sugar a phosphate group and a nitrogenous base.
63
What is the role of DNA in cells?
DNA stores genetic information that guides the development functioning growth and reproduction of all living organisms.
64
What is the structure of DNA?
DNA is structured as a double helix which consists of two strands that twist around each other.
65
What are chromosomes?
Chromosomes are structures found in the nucleus that contain DNA.
66
What are the four nitrogenous bases in DNA and how do they pair?
The four nitrogenous bases in DNA are adenine (A) thymine (T) cytosine (C) and guanine (G). Adenine pairs with thymine (A-T) and cytosine pairs with guanine (C-G).
67
What is a gene?
A gene is a small section of DNA on a chromosome that consists of a triplet of bases. It codes for a specific protein.
68
How do genes relate to proteins?
Each gene codes for a specific sequence of amino acids. When amino acids link together they form a protein.
69
What is a genome?
The genome is the complete set of genes coding for all proteins within an organism.
70
What advancements have been made in studying the human genome?
Studying the human genome has improved understanding of the genes linked to various diseases treatments for inherited disorders and tracing human migration patterns.
71
Why is understanding the human genome important for the future of medicine?
Understanding the human genome is crucial for developing targeted treatments for diseases and improving personalized medicine approaches.
72
What does DNA stand for?
DNA stands for deoxyribonucleic acid.
73
What is the significance of DNA as a polymer?
DNA as a polymer contains the biological instructions necessary for the growth development functioning and reproduction of living organisms.
74
What are chromosomes made of?
Chromosomes are structures made up of long molecules of DNA.
75
Where are chromosomes found in a cell?
Chromosomes are found in the nucleus of a cell.
76
What is DNA composed of?
DNA is composed of many small parts called nucleotides.
77
What are the components of a nucleotide?
Each nucleotide is made up of one sugar molecule one phosphate molecule (which form the backbone) and one of the four types of organic bases.
78
What are the four types of organic bases in DNA?
The four types of organic bases in DNA are Adenine (A) Cytosine (C) Guanine (G) and Thymine (T).
79
How are the DNA strands structured?
Each DNA molecule is made up of two DNA strands that are twisted together in a double helix structure.
80
What is complementary base pairing?
Complementary base pairing is when A bases connect to T bases and C bases connect to G bases.
81
What does the sequence of bases in DNA code for?
The sequence of different bases in DNA forms a code that determines the order of amino acids in a protein.
82
How many bases form a code for an amino acid?
Each group of three bases codes for one amino acid.
83
How many different types of amino acids are there?
There are 20 different types of amino acids.
84
What determines what type of protein is formed?
The different types and order of amino acids determine which type of protein is formed.
85
Explain the importance of the order of bases in DNA.
The order of bases in DNA is crucial as it dictates the order of amino acids in a protein ultimately determining the protein's structure and function.
86
What is the primary function of DNA in the context of protein production?
DNA contains the genetic code for making proteins which is essential for protein synthesis.
87
What are non-coding regions of DNA?
Non-coding regions of DNA do not code for proteins but some are involved in regulating gene expression by switching genes on or off.
88
Describe the process of protein synthesis.
Protein synthesis is the process of producing a protein from DNA involving the transcription of DNA into mRNA followed by the translation of mRNA into an amino acid sequence.
89
Why can't DNA move out of the nucleus?
DNA cannot move out of the nucleus because it is too large to pass through the nuclear pores.
90
What happens to the DNA strands during transcription?
During transcription the two strands of DNA pull apart from each other.
91
What role do mRNA nucleotides play in protein synthesis?
mRNA nucleotides match to their complementary bases on the DNA strand to form a new mRNA strand.
92
What is created after the mRNA nucleotides are joined together?
A new strand called the mRNA strand is created which serves as a template of the original DNA.
93
Where does mRNA go after it is synthesized?
After synthesis the mRNA moves out of the nucleus to the cytoplasm and onto ribosomes.
94
What is the significance of ribosomes in protein synthesis?
Ribosomes read the bases on the mRNA in groups of three (codons) to code for specific amino acids.
95
How are amino acids coded for during translation?
The first three bases on the mRNA (a codon) correspond to one specific amino acid determining the order of amino acids in the protein.
96
What is the structure that mRNA binds to in order to begin the process of translation?
mRNA binds to ribosomes in the cytoplasm to start translation.
97
What is meant by a gene being 'expressed'?
A gene is said to be expressed when it is successfully transcribed into mRNA and subsequently translated into a protein.
98
Explain the role of complementary base pairing in mRNA synthesis.
During mRNA synthesis complementary base pairing ensures that the correct mRNA nucleotides align with the corresponding DNA bases forming an accurate mRNA copy.
99
What does mRNA stand for and what is its purpose?
mRNA stands for messenger RNA and its purpose is to carry the genetic information from the DNA in the nucleus to the ribosomes in the cytoplasm for protein synthesis.
100
What are the three main stages of protein synthesis?
The three main stages of protein synthesis are transcription mRNA processing (in eukaryotes) and translation.
101
What is a codon?
A codon is a sequence of three nucleotides on the mRNA that specifies a particular amino acid in a protein.
102
What is the significance of the ribosome reading mRNA in threes?
Reading mRNA in threes allows for the correct amino acid to be added to the growing polypeptide chain ensuring proper translation of the genetic code.
103
What is the role of amino acids in protein synthesis?
Amino acids are the building blocks of proteins. They are linked together in a chain by peptide bonds as specified by the sequence of codons (triplets of bases) in mRNA. Each set of three nucleotides in mRNA corresponds to a specific amino acid.
104
How do amino acids reach the ribosome during protein synthesis?
The corresponding amino acids are brought to the ribosomes by transfer RNA (tRNA) molecules. Each tRNA has an attached amino acid and an anticodon that pairs with the codon in mRNA to ensure the correct amino acid is added to the growing polypeptide chain.
105
What happens to a protein once it is synthesized?
Once the polypeptide chain is complete it folds into a specific three-dimensional structure which is essential for its functionality. This structure is determined by the sequence of amino acids in the protein.
106
Why is the specific shape of a protein important?
The specific shape of a protein is critical because it determines the protein's function. A protein's structure allows it to interact with other molecules which is necessary for performing its role such as catalyzing reactions or signaling.
107
What are the different types of proteins and their functions?
1. Enzymes: Biological catalysts that speed up the rate of chemical reactions. \n2. Hormones: Chemical messengers that send signals throughout the body. \n3. Structural proteins: Strong proteins that form structures such as collagen.
108
What is a mutation in the context of DNA and protein synthesis?
A mutation is a change in the sequence of bases in DNA that can affect the coding for amino acids. Mutations can disrupt the normal function of proteins by altering their amino acid sequence.
109
What are the effects of base insertions in DNA?
A base insertion adds an extra base into the DNA sequence. Since bases are read in triplets this insertion alters the reading frame potentially changing all the subsequent amino acids coded for after the point of insertion which can change the protein significantly.
110
What are the effects of base deletions in DNA?
A base deletion removes a base from the DNA sequence. Like insertions deletions affect the reading frame of the sequence which may change all the resulting amino acids coded for after the deletion. This can lead to nonfunctional proteins.
111
How are codons related to amino acids?
Codons are sequences of three nucleotide bases in mRNA that correspond to specific amino acids in a protein. Each codon specifies one amino acid to be added to the polypeptide chain during translation.
112
What is the role of ribosomes in protein synthesis?
Ribosomes are the cellular machinery that facilitates the translation of mRNA into proteins. They read the codons on the mRNA and help assemble amino acids into the correct sequence to form a polypeptide chain.
113
Describe the process of protein folding. Why is it important?
Protein folding is the process wherein a newly synthesized polypeptide chain assumes its functional three-dimensional structure. This is crucial because the folded shape determines the protein's specific function including its ability to interact with other molecules.
114
What is a substitution mutation?
A substitution mutation is a type of mutation that changes one amino acid in the protein sequence. This change may or may not affect the overall protein depending on whether the new codon still codes for the same amino acid.
115
How can substitution mutations affect protein structure?
Substitution mutations can affect the way a protein folds and therefore its structure. Changes in the sequence of amino acids can lead to a different three-dimensional shape of the protein which can impact its functionality.
116
What is the general impact of most mutations on proteins?
Most mutations either do not alter the protein at all or only cause slight changes. However some mutations can have significant effects potentially altering protein shape and function.
117
What is the role of a substrate in enzyme activity?
A substrate is a molecule upon which an enzyme acts. If mutations change the shape of the enzyme's active site the appropriate substrate may no longer fit inhibiting the enzyme's ability to catalyze reactions.
118
What is the importance of structural proteins?
Structural proteins are crucial for maintaining the integrity and shape of cells and tissues. If these proteins lose their shape due to mutations it can lead to defects and malfunctions in the organism.
119
What are non-coding parts of DNA and their significance?
Non-coding parts of DNA do not code for proteins but play important roles in regulating gene expression. Mutations in these regions can affect whether certain genes are expressed or not.
120
What are the two main sources of variation between organisms?
Variation between two organisms primarily arises from two sources: 1. The coding DNA that determines the proteins and their activity and 2. The non-coding DNA that regulates gene expression.
121
Define gametes in the context of genetic inheritance.
Gametes are the reproductive cells of an organism. In females they are called eggs while in males they are called sperm. Gametes are haploid cells that contain half the genetic material required to form a new organism.
122
Why is it important to understand genetic mutations in terms of inheritance?
Understanding genetic mutations is crucial for grasping concepts of inheritance as mutations can be passed on to offspring potentially affecting their traits and health. This knowledge is fundamental in genetics medicine and evolutionary biology.
123
What is the connection between coding DNA and protein activity?
Coding DNA contains the sequences that dictate the synthesis of proteins. Variations in these sequences can lead to differences in protein structure and function which ultimately affect the organism's biochemical activities.
124
How do mutations in non-coding DNA influence gene expression?
Mutations in non-coding regions can affect the binding of transcription factors or other regulatory elements altering the level and timing of gene expression. This can have significant biological consequences for the organism.
125
What is the number of chromosomes in haploid human cells?
Half the number of chromosomes in humans is 23 representing the haploid number (n=23). This includes one of each type of chromosome as opposed to the diploid number (2n=46) found in somatic cells.
126
Define the structure and function of chromosomes. Where are they located in the cell?
Chromosomes are thread-like structures found in the nucleus of eukaryotic cells. They are made up of long strands of DNA wrapped around proteins called histones. Their primary function is to carry genetic information.
127
What is a gene? What role does it play in an organism's characteristics?
A gene is a short section of DNA that codes for a specific protein which contributes to an organism's characteristics. While some traits are controlled by a single gene (like fur color in mice or red-green color blindness in humans) most characteristics are influenced by the interaction of multiple genes.
128
What are alleles? How are they related to genes?
Alleles are different forms of a gene that may exist at a given locus on a chromosome. Humans typically have two alleles for each gene one inherited from each parent.
129
What is a dominant allele? How does it affect the phenotype?
A dominant allele is a version of a gene that only requires one copy to be expressed in the phenotype. This means if an individual has at least one dominant allele the trait associated with it will be exhibited.
130
What is a recessive allele? What is required for it to be expressed in the phenotype?
A recessive allele requires two copies (one from each parent) to be expressed in the phenotype. Only when an individual is homozygous for the recessive allele will the trait associated with it be observed.
131
What does homozygous mean in genetics?
Homozygous refers to an organism that has two identical alleles for a specific gene meaning they could have either two dominant alleles or two recessive alleles.
132
What does heterozygous mean? How does it differ from homozygous?
Heterozygous refers to an organism that has two different alleles for a specific gene one inherited from each parent. This is in contrast to homozygous which involves having two identical alleles.
133
Explain the concept of genotype and phenotype in genetics. How are they different?
Genotype refers to the genetic makeup of an organism specifically the alleles present for a particular gene. Phenotype on the other hand is the observable physical or biochemical characteristics of that organism which result from the interaction of the genotype with the environment.
134
What is the significance of genetic interactions in determining characteristics?
Genetic interactions where multiple genes influence a single trait are significant because they contribute to the complexity of traits in organisms. For many characteristics the phenotype is a result of the combined effects of multiple genes rather than any single gene alone.
135
What is the relationship between chromosomes genes and alleles?
Chromosomes are structures in the nucleus that contain DNA which is organized into genes. Each gene can have different forms known as alleles and these alleles determine the variants of traits that can be expressed in an organism.
136
How does inheritance work in terms of alleles from parents to offspring?
During reproduction each parent contributes one allele for each gene to their offspring. The combination of these alleles determines the offspring's genotype and consequently their phenotype through dominant and recessive interactions.
137
What is an allele?
An allele is a variant form of a gene that can exist in different versions; one allele may be dominant while another is recessive.
138
What is the difference between genotype and phenotype?
Genotype refers to the genetic makeup of an organism represented by the combination of alleles such as Aa. Phenotype refers to the observable physical characteristics of an organism such as eye color.
139
What is a Punnett square and how is it used?
A Punnett square is a diagram used to predict the genotype and phenotype distribution of offspring based on the alleles of the parents. It visually represents all possible combinations of alleles in the offspring.
140
How do you represent dominant and recessive alleles in genetics?
Uppercase letters are used to represent dominant alleles while lowercase letters are used for recessive alleles. Typically letters like A or B are chosen to represent specific traits.
141
What does a single gene cross study?
A single gene cross studies the inheritance of a single trait by observing the probability of offspring inheriting certain genotypes and phenotypes based on the alleles of the two parent organisms.
142
What is polydactyly and how is it inherited?
Polydactyly is a genetic disorder characterized by the presence of extra fingers or toes caused by a dominant allele.
143
What is cystic fibrosis?
Cystic fibrosis is a genetic disorder caused by inheriting two recessive alleles. It affects the respiratory and digestive systems leading to severe respiratory problems and difficulty in digesting food.
144
Explain how family trees are used in genetics.
Family trees or pedigrees are diagrams that track the inheritance of specific traits (phenotypes) across generations within a family allowing for the analysis of how genetic traits are passed down.
145
What is the significance of upper and lowercase letters in genetics?
Uppercase letters denote dominant traits (alleles) which will express themselves in the phenotype if present while lowercase letters denote recessive traits (alleles) that will only express themselves phenotypically when two recessive alleles are present.
146
How do you draw a Punnett square?
To draw a Punnett square first create a grid. Label the rows with one parent's alleles and the columns with the other parent's alleles. Fill in the grid with the combination of alleles from both parents to show the possible genotypes of their offspring.
147
What is Cystic Fibrosis (CF)?
Cystic Fibrosis is a genetic disorder that affects the cell membranes leading to the production of thick mucus in the airways and pancreas.
148
How is Cystic Fibrosis caused genetically?
Cystic Fibrosis is caused by a recessive allele meaning both parents must either be carriers of the recessive allele or one parent must have the disorder while the other is a carrier.
149
What is embryonic screening?
Embryonic screening is a process that allows scientists to observe whether an embryo will have a genetic condition by analyzing cells taken from the embryo or extracting DNA from embryos in the womb.
150
What are the two main methods of embryonic screening?
The two main methods are: 1) Taking cells from an embryo developed in the lab and analyzing them and 2) Extracting DNA from embryos in the womb for analysis.
151
What are the economic arguments for embryonic screening?
1) Reduces the number of people suffering from genetic disorders potentially lowering healthcare costs long-term. 2) Could lead to more informed family planning choices.
152
What are the ethical arguments against embryonic screening?
1) Could encourage the selection of specific traits leading to 'designer babies.' 2) It raises moral concerns about playing God and the value of human life.
153
What are the economic arguments against embryonic screening?
1) Treating genetic disorders is very expensive drawing resources from healthcare systems. 2) The cost of carrying out screening can also be substantial.
154
What social concerns exist around embryonic screening?
1) There may be regulations in place to prevent misuse but concerns remain about the potential for prejudice against those with genetic disorders.
155
What is the role of carriers in the inheritance of Cystic Fibrosis?
Carriers of the CF allele do not show symptoms of the disorder but can pass the recessive allele to their offspring potentially resulting in the child having Cystic Fibrosis if both parents are carriers.
156
What types of regulations exist regarding embryonic screening?
Regulations are designed to prevent abuse or 'designer baby' scenarios ensuring that screening is conducted ethically and responsibly.
157
What is the significance of the 23rd pair of chromosomes in human body cells?
The 23rd pair of chromosomes carries sex-determining genes which influence the sex of the individual. They consist of two types: X chromosomes and Y chromosomes. The combination of these chromosomes determines whether the offspring will be male or female.
158
What are the physical characteristics of X and Y chromosomes?
X chromosomes are larger than Y chromosomes. In humans females have two X chromosomes (XX) while males have one X and one Y chromosome (XY).
159
What is the process of meiosis and how does it relate to sex chromosome inheritance?
Meiosis is a type of cell division that reduces the chromosome number by half to form gametes (sperm and eggs). During meiosis one sex chromosome from each pair goes into each gamete. Females only produce X chromosomes in their eggs (XX) and males can produce either X or Y chromosomes in their sperm (XY).
160
How do Punnett squares illustrate sex inheritance?
Punnett squares can be used to predict the possible genetic combinations and outcomes of offspring based on the alleles contributed by both parents. For sex inheritance a Punnett square can show the likelihood of having male (XY) or female (XX) children based on the combinations of the parents' sex chromosomes.
161
What is the probability of a child being male or female if the parents are XX and XY?
There is a 50% chance of the child being female (XX) and a 50% chance of the child being male (XY). This is due to the fact that the mother can only pass on X chromosomes while the father can pass on either an X or a Y chromosome.
162
What social considerations can affect decisions regarding the termination of a pregnancy related to genetic disorders?
Decisions about terminating a pregnancy can involve complex social considerations including ethical beliefs about quality of life for individuals with genetic disorders potential societal stigma and personal circumstances of the parents. These factors contribute to the decision-making process surrounding the continuation or termination of a pregnancy.
163
What are some potential outcomes of procedures related to genetic screening and pregnancy?
Procedures related to genetic screening such as amniocentesis or chorionic villus sampling (CVS) can provide information about genetic disorders in a fetus. However these procedures carry risks including the potential for miscarriage. This highlights the importance of informed decision-making prior to undergoing such tests.
164
What is the role of chromosomes in determining human characteristics?
Chromosomes carry genes which are the basic units of heredity. The first 22 pairs of chromosomes (autosomes) control various characteristics in an individual while the 23rd pair (sex chromosomes) determines the biological sex and provides additional genetic traits specific to gender.
165
What ethical dilemmas may arise when considering genetic disorders and the decision to continue or terminate a pregnancy?
Ethical dilemmas may include concerns about the value of life in the context of disability the rights of the fetus versus the autonomy of the parent(s) societal views on disabilities and the implications of genetic screening and selective termination. These dilemmas often require a careful evaluation of moral social and individual considerations.
166
What is meant by 'phenotype' in an organism?
Phenotype refers to the observable physical and biochemical characteristics of an organism determined by both genetic makeup (genotype) and environmental influences.
167
What are the two main factors that determine an organism's phenotype?
1. Genotype - the genes inherited from the parents influencing characteristics like color size and susceptibility to diseases. 2. Environment - the surrounding conditions in which the organism grows and develops affecting its appearance and health.
168
What is genotype?
Genotype refers to the genetic constitution of an individual particularly in regard to a specific trait. It is the set of genes inherited from the parents.
169
How are genes passed from parents to offspring?
Genes are passed on from parents to offspring through sex cells (gametes) specifically through the combination of genes from the mother's egg and the father's sperm during fertilization.
170
Why do identical twins have the same genotype?
Identical twins originate from a single fertilized egg that splits into two embryos resulting in two individuals with the exact same genetic material thus sharing the same genotype.
171
What is genetic variation and why is it important in a population?
Genetic variation refers to the diversity in gene frequencies among individuals in a population which is important for the adaptability and survival of a species allowing it to cope with changing environments.
172
How does the environment contribute to the phenotype of an organism?
The environment can affect the appearance and behavior of an organism through various factors such as nutrition climate exposure to toxins and social interactions leading to traits such as scars in animals or leaf color in plants.
173
Give an example of a characteristic influenced by both genetics and the environment.
Weight is a characteristic influenced by both genetics (metabolism fat storage) and environment (diet physical activity) with its outcome being a result of the interplay between these factors.
174
What role do mutations play in genetic variation?
Mutations introduce genetic variation by altering the DNA sequence of an organism's genes. While most mutations may have no impact on phenotype some can influence traits although it is rare.
175
What is the likelihood that mutations will influence phenotype?
It is unlikely that mutations will significantly influence phenotype as most mutations have no effect at all on the observable characteristics of an organism.
176
What is evolution in biological terms?
Evolution is the change in the inherited characteristics of a population over time through a process of natural selection which may result in the formation of a new species.
177
What are the origins of all species according to the Theory of Evolution?
According to the Theory of Evolution all species have evolved from simple life forms that first developed more than three billion years ago.
178
What is the role of mutations in evolution?
Mutations introduce variation between organisms. If a mutation provides a survival advantage the organism is more likely to reach breeding age and pass that mutation onto its offspring.
179
How does natural selection lead to the prevalence of advantageous traits?
Natural selection leads to the prevalence of advantageous traits by increasing the likelihood that individuals with these traits will survive to reproductive age and pass on those traits to their offspring thus increasing the frequency of such mutations within the population over generations.
180
What happens when a population becomes genetically distinct due to evolution?
When a population of a species becomes genetically distinct due to evolution the changes may become so significant that individuals of the population can no longer interbreed with the original population potentially leading to the formation of a new species.
181
What triggers the process of natural selection?
Natural selection is triggered by environmental factors that favor certain traits over others leading to differential survival and reproduction among individuals.
182
What is an advantage of a mutation in the context of natural selection?
An advantage of a mutation in the context of natural selection is that it can enhance an organism's ability to survive and reproduce in its environment thereby increasing the chances that the mutation will be passed on to future generations.
183
What is meant by 'common phenotype'?
A common phenotype refers to a trait that becomes prevalent in a population due to natural selection favoring individuals with that trait particularly if it arises from a beneficial mutation.
184
What is a population in evolutionary biology?
In evolutionary biology a population is a group of individuals of the same species that live in a particular area and interbreed sharing a common gene pool.
185
What is the significance of variation among organisms?
Variation among organisms is significant as it provides the raw material for evolution; it allows for potential advantages to arise through mutations which can be subject to natural selection.
186
Define the term 'phenotype'.
Phenotype refers to the observable physical or biochemical characteristics of an organism determined by its genotype and environmental influences.
187
What is a speciation event?
A speciation event occurs when a population evolves to the point that it can no longer interbreed with the original population leading to the formation of a new species.
188
How do selective pressures affect a population over time?
Selective pressures such as predation climate and availability of resources affect a population over time by favoring certain traits that enhance survival and reproduction thereby shaping the evolutionary path of the population.
189
What is speciation?
Speciation is the process by which a new species is formed. It occurs when a group of organisms becomes sufficiently genetically distinct from its parent group and can produce fertile offspring that are also distinct.
190
What is selective breeding?
Selective breeding is a method used by humans to choose which organisms to breed in order to produce offspring with specific desirable characteristics such as animals with more meat plants with disease resistance or plants with larger flowers.
191
What types of characteristics are targeted in selective breeding?
Characteristics targeted in selective breeding can include increased yield in crops disease resistance in plants desirable physical traits in animals (like size or temperament) and enhanced productivity.
192
How does the process of selective breeding work?
The process of selective breeding involves selecting parent organisms with desired traits breeding them together and then from the resulting offspring selecting those that have the desired traits to breed again. This process is repeated over several generations.
193
What are some of the potential negative effects of selective breeding?
Selective breeding can lead to inbreeding which occurs when closely related individuals breed together. This leads to a reduced gene pool meaning there are fewer genetic variations. The reduction of different alleles can result in decreased resilience to diseases and environmental changes.
194
Why can inbreeding be problematic for a breeding program?
Inbreeding can be problematic because it increases the likelihood of offspring inheriting harmful genetic traits. It can also lead to genetic disorders reduced fertility and a lower overall fitness of the population due to lack of genetic diversity.
195
What is the gene pool?
The gene pool refers to the total collection of alleles within a population. A wide gene pool means there is a greater variation of genes which is beneficial for the adaptability and survival of the species.
196
What happens to the gene pool during selective breeding?
During selective breeding the gene pool can decrease as breeders often choose similar individuals with desirable traits leading to a reduction in genetic variation and the predominance of specific alleles.
197
What is an allele?
An allele is a variant form of a gene that can occur at a specific locus on a chromosome. Individuals can have two alleles for each gene one inherited from each parent.
198
What is one benefit of selective breeding?
One benefit of selective breeding is the ability to produce organisms with desirable traits such as higher yield in agriculture better taste in food or enhanced characteristics in pets thus improving human agricultural practices and food supply.
199
What is the impact of environmental changes or new diseases on species with low genetic diversity?
Species with low genetic diversity may face higher extinction risks during environmental changes or new disease outbreaks because all individuals share the same genetic make-up. This reduces the likelihood of some organisms possessing a survival advantage since they are all similarly susceptible.
200
What is meant by a 'small gene pool' and what are its consequences?
A small gene pool refers to a limited variety of genes in a population often resulting from inbreeding. The consequences include an increased likelihood of genetic defects in offspring as recessive traits are more likely to manifest when there are fewer genetic variations.
201
Define genetic engineering. What is its primary purpose?
Genetic engineering is the modification of an organism's genome by introducing a gene from another organism to obtain a desired characteristic. Its primary purpose is to enhance certain traits or introduce new traits to the organism.
202
Give examples of genetic engineering applications in plants and bacteria. What are the desired characteristics?
In plants genetic engineering is applied to develop disease-resistant varieties or to produce larger fruits. In bacteria genetic engineering is used to produce valuable substances for humans such as human insulin for diabetes treatment.
203
Describe the steps involved in genetic engineering. What is the role of restriction enzymes?
1. Genes are cut out from chromosomes using restriction enzymes which create 'sticky ends'—short sections of exposed unpaired DNA bases. 2. A virus or bacterial plasmid is cut using the same restriction enzymes ensuring complementary sticky ends for gene insertion. This facilitates the incorporation of the desired gene into the target organism.
204
What are 'sticky ends' in genetic engineering and why are they important?
Sticky ends are short sections of unpaired bases created when restriction enzymes cut DNA. They are important because they allow for the joining of DNA fragments from different sources to facilitate gene transfer ensuring the DNA can be inserted into a target genome effectively.
205
What is the role of a bacterial plasmid in genetic engineering?
A bacterial plasmid acts as a vector to transfer genetic material into a target organism. It carries the gene of interest and can replicate independently within the host cell allowing for the expression of the introduced gene.
206
What is the relationship between inbreeding and genetic defects?
Inbreeding increases the likelihood of genetic defects as it limits genetic variation enabling recessive alleles to manifest more frequently in the offspring. This can lead to a higher incidence of inherited disorders.
207
How can genetic engineering contribute to agriculture?
Genetic engineering can contribute to agriculture by creating crops that are resistant to pests diseases or environmental stresses ultimately leading to increased yields reduced reliance on chemical pesticides and improved nutritional content.
208
What is a possible ethical concern regarding genetic engineering?
Ethical concerns related to genetic engineering include the potential for unintended consequences in ecosystems the impact on genetic diversity issues of food safety and the moral implications of modifying living organisms particularly in human applications.
209
What is the function of restriction enzymes in genetic engineering?
Restriction enzymes are proteins that cut DNA at specific sequences. They create sticky ends which are short single-stranded overhangs on either side of the DNA. These sticky ends facilitate the ligation (joining) of DNA fragments from different sources.
210
How do sticky ends contribute to DNA recombination?
Sticky ends enhance the likelihood of DNA fragments joining together because they can base pair with complementary sticky ends from another DNA fragment. This increases the specificity and efficiency of DNA recombination.
211
What role does DNA ligase play in genetic engineering?
DNA ligase is an enzyme that joins the sugar-phosphate backbones of adjacent DNA strands sealing the nicks in the DNA to form a continuous double-stranded molecule. It is essential for combining the loop of DNA with the gene of interest.
212
What is a vector in the context of genetic engineering?
A vector is a vehicle often a plasmid or virus used to transfer a gene of interest into a host organism. In genetic engineering vectors carry modified genes into bacterial cells or other organisms where they can be expressed and multiplied.
213
What is an antibiotic marker gene and its purpose in genetic engineering?
An antibiotic marker gene provides a way to identify cells that have successfully incorporated a desired gene. Cells that possess the marker gene will survive in the presence of the antibiotic allowing researchers to isolate and select for those cells that have been genetically modified.
214
What does it mean when bacteria are resistant to antibiotics in genetic engineering?
When bacteria are resistant to antibiotics it means they possess a genetic modification (often through the incorporation of an antibiotic resistance marker) that allows them to survive in environments where antibiotics are present. This allows for the selection of successfully modified bacterial colonies.
215
Describe the process of creating genetically modified plants using vectors.
In genetically modified plants a vector is introduced into meristematic cells which are unspecialized and can differentiate into various cell types. The vector contains the modified gene and the cells can multiply producing identical copies of the modified plant through tissue culture techniques.
216
What are genetically modified crops engineered for?
Genetically modified crops are primarily engineered for resistance to insects and herbicides. This modification aims to reduce crop loss and increase agricultural yields by allowing plants to survive pest attacks and tolerate herbicide applications.
217
What is gene therapy and how does it relate to genetic engineering?
Gene therapy is a treatment methodology aimed at curing inherited disorders by transferring normal genes into patients. This approach involves replacing faulty genes with functional ones potentially correcting genetic defects that cause diseases.
218
What are the ethical considerations associated with genetic engineering and genetically modified organisms (GMOs)?
Ethical considerations include potential impacts on biodiversity the environment and human health. There are also concerns about corporate control of food production the right to know about GMOs in food and the implications of altering natural genetic structures.
219
What are perceived benefits of genetic engineering in medicine?
Genetic engineering allows for the mass production of certain hormones and proteins using microorganisms like bacteria and fungi improving medical treatments and accessibility.
220
What are perceived risks of genetic engineering related to GM crops?
GM crops may negatively impact wild flowers and insects leading to reduced biodiversity and ecological imbalance.
221
What is a potential ecological consequence of GM crops being infertile?
Infertile GM crop genes could potentially spread into wild plants leading to infertility in other species and affecting the entire environment.
222
How can the use of herbicides and pesticides in GM crops affect the environment?
The use of herbicides and pesticides can kill not only target pests but also beneficial insects and other plants which contributes to a decrease in biodiversity.
223
What agricultural benefits do GM crops offer?
GM crops can improve yields by enhancing growth rates modifying crops to thrive in various conditions (e.g. hotter drier climates) and allowing plants to produce their own pesticides or herbicides.
224
What health concerns have been raised regarding GM crops?
There is concern that the long-term effects of GM crops on human health are not fully understood generating worry among consumers and health experts.
225
What is the role of genetic engineering in improving crop resistance?
Genetic engineering can introduce traits into crops that enable them to resist pests and diseases as well as tolerate harsh environmental conditions.
226
How can genetic engineering contribute to food security?
By improving crop yields disease resistance and tolerance to climate extremes genetic engineering has the potential to enhance food security in a changing climate.
227
What is the significance of vitamin-enhanced GM crops?
Crops genetically modified to contain extra vitamins can potentially improve nutritional outcomes and address deficiencies in populations relying on staple foods.
228
What ethical concerns are associated with genetic engineering and GM crops?
Ethical concerns include the long-term environmental impacts potential health risks and the implications of altering natural ecosystems and food sources.
229
What regulatory measures are in place for GM crops?
Regulatory measures for GM crops typically include safety assessments monitoring of environmental impacts and evaluations of potential health effects before they are approved for commercial use.
230
What is genetic engineering in agriculture?
Genetic engineering in agriculture refers to the manipulation of an organism's genetic material to achieve desired traits or characteristics such as increased yield pest resistance or improved nutritional content. It involves techniques that allow scientists to alter the DNA of crops to enhance their productivity and resilience.
231
What potential future applications of genetic engineering in humans can arise from advancements in genetic engineering in agriculture?
Advancements in genetic engineering in agriculture could lead to genetic engineering in humans particularly in creating 'designer babies'—children whose genetic traits are chosen by their parents potentially enhancing desired characteristics such as intelligence physical appearance or resistance to diseases.
232
How could greater agricultural yields contribute to solving world hunger?
Greater agricultural yields could help alleviate world hunger by producing more food on the same amount of land thus increasing the overall food supply. This is especially important as the global population continues to grow leading to higher food demands.
233
What is 'selection pressure' in the context of genetic engineering in agriculture?
Selection pressure is an environmental factor that influences the survival and reproduction of organisms. In the context of genetic engineering in agriculture crops genetically modified to resist pests and herbicides can create a selection pressure on pest species and weeds leading to the evolution of resistant strains termed 'super weeds' and 'super pests'.
234
Define cloning in biological terms.
Cloning is the process of creating genetically identical copies of an organism. This can occur naturally (as in asexual reproduction) or artificially through techniques that replicate the genetic material of a parent organism.
235
What are the two primary methods of plant cloning mentioned?
1. Tissue Culture: A method where plant cells are taken and placed in a growth medium with nutrients and hormones allowing them to grow into new genetically identical plants. 2. Cuttings: An easier and older method where a section of the stem (or other parts) is taken from a plant with desirable traits planted and allowed to grow into a new plant.
236
What is the purpose of tissue culture in plant cloning?
Tissue culture is important for preserving rare plant species and is commercially used in plant nurseries to produce large quantities of clones efficiently. It ensures that the genetic identity of the desired plant is maintained.
237
What are some potential issues arising from genetic engineering in agriculture such as super weeds and pests?
Genetic engineering in agriculture can lead to the emergence of super weeds and pests due to selection pressure. When crops are engineered for pest and herbicide resistance the pests and weeds that survive may evolve resistance to these controls thereby creating more challenging agricultural problems and potential ecological imbalances.
238
What are 'designer babies'?
'Designer babies' refer to the concept of genetically engineered children whose genetic traits and characteristics are selected or altered through genetic engineering technologies allowing parents to choose desirable features before birth.
239
Why is cloning significant in preserving rare plant species?
Cloning is significant in preserving rare plant species because it allows for the propagation of plants that may be endangered or have limited populations. Through cloning genetic diversity can be maintained and these species can be saved from extinction.
240
What is cloning?
Cloning is the process of producing genetically identical organisms or cells which are known as clones. These clones are produced from a single organism ensuring they share the same genetic material.
241
What are the two main methods of cloning in animals?
The two main methods of cloning in animals are 1)Embryo Transplants and 2)Adult Cell Cloning.
242
What is the process of embryo transplant cloning?
In embryo transplant cloning sperm cells and egg cells from parents with desirable traits are collected. After fertilization in the lab the embryo is allowed to divide several times before being implanted into a host mother. The resulting offspring is genetically identical to the parents.
243
Explain the process of adult cell cloning.
In adult cell cloning the nucleus of an unfertilized egg cell is removed. The nucleus from an adult body cell is then inserted into the denucleated egg cell. An electric shock is applied to induce division of the egg cell leading to the formation of an embryo which is implanted into a female womb resulting in a clone of the adult body cell.
244
What are some benefits of cloning?
Cloning can produce many offspring with specific desirable traits which can be advantageous in agriculture research and conservation efforts.
245
What are the risks associated with cloning?
Cloning carries risks such as reduced genetic diversity (which can affect adaptability) potential for increased genetic defects ethical concerns and potential psychological impact on clones and surrogate mothers.
246
How does cloning affect the gene pool?
Cloning can negatively impact the gene pool by reducing genetic diversity since clones share identical genetic information. This can make a population more susceptible to diseases and environmental changes.
247
What ethical concerns are associated with cloning?
Ethical concerns surrounding cloning include issues of consent (especially in human cloning) the welfare of the clone and surrogate mothers potential exploitation of cloned organisms and the broader implications of 'playing God' with nature.
248
What is the role of electric shock in adult cell cloning?
Electric shock is used to stimulate the denucleated egg cell causing it to begin dividing and developing into an embryo after the introduction of the nucleus from the adult body cell.
249
Why is genetic diversity important in populations?
Genetic diversity is crucial for the adaptability and survival of populations. It enables species to adapt to changing environments resist diseases and maintain overall ecosystem health.
250
What is the primary difference between the two methods of cloning?
The primary difference is that embryo transplant cloning involves the fertilization of sperm and egg cells to create an embryo while adult cell cloning involves transferring the nucleus from a mature cell into a denucleated egg cell.
251
What is the implication of low genetic diversity in clones for population survival?
Low genetic diversity in clones means that the population is less likely to survive if a disease arises because there are fewer genetic variations that might confer resistance to that disease.
252
How can the study of clones contribute to research in biology?
The study of clones can enhance understanding of embryo development and help explore genetic issues despite the low survival rates and genetic problems often associated with cloning.
253
What potential benefits can cloning provide for endangered species?
Cloning can help extremely endangered species by boosting their population numbers and potentially bringing back species that have become extinct through the replication of existing genetic material.
254
What ethical concerns arise from cloning?
Cloning raises ethical concerns particularly regarding human cloning which involves moral considerations about identity genetic manipulation and the implications of creating human life.
255
Who is Charles Darwin and what was his contribution to biology?
Charles Darwin was a scientist and naturalist who put forward the theory of evolution supported by his extensive experimentation and geological knowledge from his round-the-world expedition.
256
What significant work did Darwin publish in 1859?
Charles Darwin published 'On the Origin of Species' in 1859 which outlined his theory of evolution based on natural selection.
257
What is the theory of evolution by natural selection?
The theory of evolution by natural selection posits that variation exists within species due to mutations in DNA and that organisms with traits best suited to their environment are more likely to survive and reproduce.
258
What is a mutation and how does it relate to evolution?
A mutation is a change in a DNA sequence that can result in new traits in an organism; these mutations contribute to variation within a species which is a fundamental aspect of the evolutionary process.
259
How do organisms with favorable characteristics impact the evolution of a species?
Organisms with favorable characteristics are more likely to survive and reproduce passing those advantageous traits on to future generations thus influencing the evolution of that species.
260
What role do fossils and geology play in understanding evolution?
Fossils and geological evidence provide insight into the history of life on Earth showing patterns of how species have evolved over time and supporting the theories of evolution proposed by scientists like Darwin.
261
Can cloning lead to advancements in human genetics?
Yes cloning may lead to advancements in human genetics by facilitating research into genetic diseases potentially allowing for therapies that could correct genetic problems.
262
What are the potential risks associated with cloning techniques?
Potential risks of cloning techniques include high failure rates the possibility of genetic abnormalities loss of biodiversity and ethical dilemmas surrounding the manipulation of life.
263
What is the definition of 'survival of the fittest' in the context of evolution?
'Survival of the fittest' refers to the process of natural selection where organisms with advantageous characteristics are more likely to survive and reproduce. These beneficial traits are then passed onto the next generation.
264
How does the frequency of alleles change in a population over generations?
Over many generations the frequency of alleles associated with advantageous characteristics increases within the population due to natural selection favoring those traits.
265
What were some reasons for the controversy surrounding Charles Darwin's ideas on evolution?
1. Darwin's ideas contradicted the belief that God was the creator of all species on Earth. 2. There was insufficient evidence at the time as few studies had been conducted on how organisms evolve. 3. The mechanisms of inheritance and variation were not understood during Darwin's time.
266
Who was Jean-Baptiste Lamarck and what was his theory of evolution?
Jean-Baptiste Lamarck was a French biologist who proposed that organisms could pass on traits acquired during their lifetime to their offspring a concept now known as Lamarckism. For instance he suggested that if a giraffe continuously stretched to reach higher leaves its neck would grow longer and this trait would be inherited by its offspring.
267
What is a key difference between Darwin's and Lamarck's theories of evolution?
A key difference is that Darwin's theory is based on natural selection where advantageous traits are inherited over generations while Lamarck's theory suggests that traits acquired during an organism's lifetime can be passed on to offspring.
268
What is natural selection and how does it work?
Natural selection is the process by which organisms better adapted to their environment tend to survive and produce more offspring. It works by favoring individuals with traits that provide a survival or reproductive advantage in a particular environment.
269
What is meant by 'advantageous characteristics' in the context of natural selection?
Advantageous characteristics are traits that enhance an organism's ability to survive and reproduce in its environment thus increasing the likelihood of those traits being passed on to future generations.
270
What evidence was lacking during the time of Darwin that contributed to controversy about his theory?
During Darwin's time there was a lack of comprehensive evidence from studies on how organisms change over time and a lack of understanding of the mechanisms of inheritance and genetic variation.
271
Explain the concept of inheritance of acquired characteristics as proposed by Lamarck. What is an example?
Lamarck's concept of inheritance of acquired characteristics suggests that traits developed through the actions of an individual during its lifetime can be transmitted to offspring. An example is the idea that if a giraffe stretches its neck to reach higher leaves its offspring would inherit a longer neck.
272
What was Lamarck's theory of evolution?
Lamarck's theory suggested that characteristics acquired by an organism during its lifetime could be passed on to its offspring. For example if an organism adapted to its environment in a specific way that adaptation would be inherited by its descendants.
273
What ultimately disproved Lamarck's theory?
Lamarck's theory was proven wrong when it was understood that changes caused by the environment cannot be inherited through the sex cells. Inheritance requires genetic changes which do not occur from acquired characteristics.
274
What is Darwin's theory of evolution?
Darwin's theory posits that evolution occurs through natural selection where advantageous traits that arise due to genetic mutations enhance survival and reproductive success thereby being passed on to future generations.
275
How does genetics support Darwin's theory?
Genetics supports Darwin's theory by providing a mechanism for hereditary transmission of advantageous mutations showing how these traits can persist and spread within a population over time.
276
What does fossil evidence indicate about the development of organisms?
Fossil evidence indicates that the development of organisms has been a gradual process demonstrating how species can evolve slowly over extended periods.
277
What is speciation?
Speciation is the process by which a new species develops through the selection of different alleles leading to increased genetic variation until the new population becomes unable to interbreed with the original population.
278
Who was Alfred Russel Wallace and what was his contribution to evolution?
Alfred Russel Wallace was a naturalist who independently developed the theory of speciation and evolution by natural selection. He proposed that individuals lacking advantageous traits would not survive environmental changes leading to a decline in their population.
279
What significant work did Wallace publish in support of evolutionary theory?
Wallace published joint studies with Darwin which provided supporting evidence for the theory of natural selection. One of their notable publications was of the 'On the Origin of Species.'
280
What is the significance of natural selection in the context of evolution?
Natural selection is significant because it is the mechanism by which certain traits become more common within a population as organisms with favorable traits are more likely to survive and reproduce influencing the genetic makeup of future generations.
281
What is the relationship between genetic variation and speciation?
Genetic variation is crucial for speciation as it provides the diverse traits needed for populations to adapt to different environments. As variations accumulate populations can diverge genetically eventually leading to the emergence of distinct species.
282
How do beneficial mutations contribute to evolution?
Beneficial mutations contribute to evolution by introducing new traits that enhance an organism's survival or reproductive success allowing those mutations to be passed on to subsequent generations and potentially leading to new species over time.
283
What was the significance of the publication 'On the Origin of Species' by Charles Darwin?
The publication 'On the Origin of Species' was significant as it established Charles Darwin as the key figure in the development of the theory of evolution by natural selection and provided a comprehensive explanation of how species evolve over time.
284
What field of study did Darwin contribute to through his research on warning coloration in animals?
Darwin contributed to the field of zoology and evolutionary biology through his research on warning coloration in animals which explored the adaptive significance of coloration patterns as a form of defense against predation.
285
What is the first step in the process of speciation?
The first step in the process of speciation is the existence of variation within a population which arises due to genetic mutations.
286
How do alleles that provide a survival advantage become prevalent in a population?
Alleles that provide a survival advantage become prevalent through the process of natural selection where individuals with those alleles are more likely to survive and reproduce.
287
What role do physical barriers play in speciation?
Physical barriers such as rock falls or rivers can isolate populations of a species preventing them from breeding together and leading to divergent evolution.
288
How can different environments affect allele selection in isolated populations?
In isolated populations different environmental conditions may favor different alleles leading to natural selection acting differently in each environment and promoting genetic divergence.
289
What is the outcome of the continued selection of different alleles in isolated populations?
The continued selection of different alleles in isolated populations increases the genetic variation between the two populations.
290
What marks the formation of a new species?
A new species is formed when populations are no longer able to interbreed and produce fertile offspring indicating reproductive isolation.
291
In the context of speciation what is reproductive isolation?
Reproductive isolation is a biological factor that prevents different species from interbreeding thereby leading to the emergence of new species over time.
292
What is genetic variation and why is it important in the process of evolution?
Genetic variation refers to the diversity of alleles within a population and it is important in evolution as it provides the raw material for natural selection to act upon enabling adaptation to changing environments.
293
What is natural selection and how does it relate to evolution?
Natural selection is the process by which organisms better adapted to their environment tend to survive and reproduce more than less adapted individuals driving the evolution of species.
294
Can you explain the concept of allele?
An allele is a variant form of a gene that arises by mutation and is located at a specific position (locus) on a chromosome. Different alleles can result in different traits or characteristics in an organism.
295
What is the significance of genetic mutations in the context of evolution?
Genetic mutations create new alleles which contribute to genetic diversity in a population; some of these mutations may confer survival advantages thus playing a crucial role in the process of evolution.
296
What evidence supports Darwin's theory of evolution by natural selection today?
Today evidence supporting Darwin's theory includes fossil records genetic studies comparative anatomy and observations of natural selection in action which together provide a comprehensive understanding of evolutionary processes.
297
How does speciation contribute to the diversity of life on Earth?
Speciation contributes to the diversity of life on Earth by creating new and distinct species that adapt to different environments thus expanding the variety of organisms and ecological niches.
298
What is the role of environmental pressures in evolutionary change?
Environmental pressures such as changes in climate availability of resources and predation influence which traits are advantageous for survival and reproduction directing the course of natural selection and evolution.
299
Who was Gregor Mendel?
Gregor Mendel was a scientist trained in mathematics and natural history in Vienna known for his foundational work in genetics.
300
What kind of experiments did Gregor Mendel conduct?
Mendel conducted breeding experiments on pea plants to observe the characteristics passed on to the next generations.
301
Which types of pea plants did Mendel use in his experiments?
Mendel used smooth peas wrinkled peas green peas and yellow peas in his experiments.
302
What conclusions did Mendel reach regarding inheritance?
Mendel concluded that offspring inherit characteristics from their parents through hereditary units with one unit received from each parent.
303
What are hereditary units?
Hereditary units later identified as genes can be dominant or recessive and cannot be mixed; they determine the traits that are inherited by offspring.
304
Did Mendel receive recognition during his lifetime for his work?
No Mendel was not recognized for his work until after his death because the concepts of genes and chromosomes had not yet been discovered.
305
What significant observation about chromosomes occurred in the late 19th century?
In the late 19th century chromosomes were observed as part of cell division.
306
What advancement was made concerning the understanding of chromosomes in the 20th century?
In the 20th century it was understood that chromosomes carry hereditary information and contain genes.
307
What are dominant and recessive traits?
Dominant traits are expressed in the phenotype even if only one copy of the gene is present while recessive traits require two copies of the gene to be expressed.
308
What was the publication year of Mendel's work?
Mendel published his work in 1866.
309
What was the significance of Mendel's work?
Mendel's work laid the foundation for the field of genetics by explaining how traits are inherited through discrete units.
310
How did Mendel keep track of his experiments?
Mendel meticulously kept records of all his breeding experiments and observations which contributed to his conclusions about inheritance.
311
How are traits inherited according to Mendel's findings?
Traits are inherited through specific hereditary units with each parent contributing one unit to the offspring.
312
What is the relationship between genes and chromosomes?
Genes are segments of DNA located on chromosomes which are structures that carry genetic information during cell division.
313
Are hereditary units mixed together?
No hereditary units (genes) cannot be mixed together; each parent contributes distinct units that determine traits.
314
What role did Mendel's background in mathematics play in his experiments?
Mendel's background in mathematics helped him analyze patterns and ratios in his genetic experiments allowing him to formulate his laws of inheritance.
315
What were the characteristics Mendel observed in pea plants?
Mendel observed traits such as seed shape (smooth and wrinkled) and seed color (green and yellow) among others.
316
What is the significance of the structure of DNA determined in 1953?
The determination of the structure of DNA in 1953 allowed scientists to understand how genes function including the mechanisms of heredity and genetic variation.
317
What are genes and where are they located?
Genes are units of heredity found on chromosomes. They are segments of DNA that contain the instructions for building proteins and determine traits in organisms.
318
What is the widely accepted theory regarding evolution?
The theory of evolution by natural selection is widely accepted. It posits that organisms evolve over time through a process where advantageous traits become more common in a population due to better survival and reproduction.
319
What are the two main types of evidence for evolution mentioned?
1. Fossils - remains of organisms found in rocks. 2. Antibiotic resistance in bacteria - advantageous mutations that help bacteria survive antibiotic exposure.
320
What are fossils and how are they formed?
Fossils are the preserved remains of organisms from millions of years ago found in rocks. They form when parts of organisms do not decay due to anoxic (absence of oxygen) or dry conditions that prevent the decay-causing microbes from surviving.
321
Describe how fossils provide evidence for evolution.
Fossils provide evidence for evolution by showing a historical record of past life forms and their progressive changes over time illustrating common ancestry and transitional forms.
322
What role does antibiotic resistance play in our understanding of evolution?
Antibiotic resistance exemplifies natural selection by demonstrating how bacteria can undergo advantageous mutations that allow them to survive and reproduce in the presence of antibiotics validating the mechanism of evolution.
323
What conditions are necessary for fossils to form?
Fossils typically form under conditions where oxygen and moisture are absent which inhibits the microbial decomposition of organic materials.
324
What types of organism parts can become fossils?
Parts of organisms that can become fossils include hard structures such as bones teeth shells and woody parts of plants that can withstand decay.
325
How do fossils contribute to our understanding of the timeline of life on Earth?
Fossils provide a chronological record that helps reconstruct the timeline of life on Earth showing how different species have emerged evolved and perished over geological periods.
326
Explain the connection between evolutionary theory and genetic mutations.
The theory of evolution is heavily reliant on genetic mutations that occur randomly. When these mutations provide a survival advantage in a given environment they are naturally selected for leading to evolution over time.
327
What happens to shells and bones as they decay?
Shells and bones are replaced by minerals as they decay forming a rock structure of the original part.
328
What are preserved traces in paleontology?
Preserved traces include footprints burrows and rootlet traces. These remain due to the ground hardening around them and forming a cast.
329
How are fossils used to show changes in anatomy over time?
Fossils are used to illustrate how the anatomy of organisms has changed over time providing evidence of evolutionary processes.
330
How can fossils be used to compare organisms?
Fossils can be compared by examining the number of similarities between the anatomy of two organisms which helps determine how closely related they are.
331
What is the purpose of creating evolutionary trees?
Evolutionary trees are created based on similarities found in fossils to illustrate the evolutionary relationships between different organisms.
332
Why can't fossils tell us how life started on Earth?
Fossils cannot indicate how life started on Earth because most early life forms were soft-bodied and decayed completely resulting in few fossils. Additionally traces left have often been destroyed by geological activity.
333
What is extinction in a biological context?
Extinction occurs when an entire species has died out.
334
What are some factors that contribute to extinction?
Factors contributing to extinction include: 1. Changes in the environment that a species cannot adapt to rapidly. 2. The evolution or migration of new predators to the area. 3. Other ecological changes that make survival impossible.
335
What happens to the fossilization process of soft-bodied organisms?
Soft-bodied organisms typically decay completely leaving little to no fossil record which limits our understanding of early life forms.
336
What geological activities can destroy potential fossil traces?
Geological activities such as erosion sedimentation and tectonic shifts can destroy potential fossil traces further complicating the fossil record.
337
What factors can lead to the extinction of a species?
1. Disease arises and there are no resistant alleles to it.
338
2. Competition with another species that has advantageous mutations for the same food source.
339
3. A catastrophic event wiping out a species.
340
4. Destruction of habitat.
341
What defines antibiotic-resistant bacteria?
Bacteria are defined as resistant when they are not killed by antibiotics that were previously used to treat infections caused by them.
342
How do bacteria reproduce and what is a consequence of this reproduction?
Bacteria reproduce at a fast rate and during this process mutations can occur that result in new genes including those that confer antibiotic resistance. This can lead to the creation of new strains of bacteria.
343
What is the selection pressure created by antibiotic exposure?
Exposure to antibiotics creates a selection pressure wherein bacteria with antibiotic-resistant genes survive while those without die. This leads to the increased reproduction of the antibiotic-resistant bacteria.
344
What is the consequence of the increase in antibiotic-resistant bacteria populations?
As antibiotic-resistant bacteria increase bacterial diseases can spread rapidly through populations because people do not have immunity to these new resistant strains.
345
How do mutations contribute to antibiotic resistance in bacteria?
Mutations during bacterial reproduction can introduce new genes such as those for antibiotic resistance which can then spread through the population when selective pressure is applied.
346
What role does reproduction speed play in the development of antibiotic-resistant bacteria?
The fast reproduction rate of bacteria allows for quick population turnover which facilitates the rapid spread of mutations including those that confer resistance to antibiotics.
347
Give an example of a catastrophic event that might lead to species extinction.
Natural disasters such as volcanic eruptions earthquakes tsunamis or human activities like deforestation and pollution can act as catastrophic events that lead to the extinction of species.
348
What is habitat destruction and how does it affect species survival?
Habitat destruction is the process by which natural habitat becomes incapable of supporting its native species. This can lead to loss of biodiversity and serve as a significant factor contributing to species extinction.
349
Explain how competition affects species survival in ecosystems.
Competition occurs when two or more species compete for the same resources such as food. Species that possess advantageous mutations may have a better chance of survival thereby affecting the population dynamics of both competing species.
350
What is MRSA and why is it called a superbug?
MRSA stands for Methicillin-resistant Staphylococcus aureus. It is called a superbug because it is resistant to many different types of antibiotics making it difficult to treat.
351
Where is MRSA commonly found?
MRSA is commonly found in hospitals where it can spread easily among patients and medical staff.
352
How does MRSA spread in hospitals?
MRSA spreads when doctors and nurses move from one patient to another potentially transferring the bacteria.
353
What are some strategies to slow the development of antibiotic resistance in bacteria?
1. Do not prescribe antibiotics for viral infections or non-serious bacterial infections.
354
2. Administer specific antibiotics targeted for specific bacteria.
355
3. Ensure patients complete their full course of antibiotics to eliminate bacteria and prevent mutation.
356
4. Reduce the use of antibiotics in agriculture to prevent the development of resistant strains.
357
Why should antibiotics not be given for viral infections or non-serious bacterial infections?
Giving antibiotics for viral infections or non-serious bacterial infections contributes to the development of antibiotic resistance because it exposes bacteria to the drugs unnecessarily.
358
Why is it important for patients to complete their course of antibiotics?
Completing the full course of antibiotics is crucial because if patients stop early some bacteria may survive and mutate leading to antibiotic-resistant strains.
359
How do agricultural practices contribute to antibiotic resistance?
Farmers often use antibiotics in livestock to prevent disease which can lead to the development of antibiotic-resistant bacteria that can be transferred to humans when they consume the meat.
360
What measures can be taken to slow the transmission of bacteria in hospitals?
1. Maintain high hygiene standards in hospitals.
361
2. Ensure medical staff and visitors wash their hands regularly.
362
3. Require medical staff to wear disposable or appropriately sanitized clothing.
363
What hygiene practices should medical staff and visitors follow to prevent the spread of MRSA?
Medical staff and visitors should wash their hands regularly and adhere to proper hygiene protocols when interacting with patients.
364
What is one major focus of preventing the transmission of MRSA in healthcare settings?
Maintaining high standards of hygiene in hospitals is a major focus for preventing the transmission of MRSA.
365
What is the challenge associated with the development of antibiotics?
The development of antibiotics is expensive and slow making it difficult to keep up with the emergence of resistant strains of bacteria.
366
What does classification of living organisms involve?
Classification involves organizing organisms into groups based on their structure and characteristics.
367
Who proposed the Linnaean system and when?
The Linnaean system was proposed by Carl Linnaeus in the 1700s.
368
What are the hierarchical ranks in the Linnaean classification system?
The hierarchical ranks in the Linnaean classification system are: kingdom phylum class order family genus and species.
369
What is the binomial nomenclature system?
The binomial nomenclature system assigns each organism a two-part name that includes its genus and species which is used worldwide to overcome language barriers.
370
Provide an example of binomial nomenclature for a ladybug. What is its genus and species?
The ladybug's scientific name in binomial nomenclature is Harmonia axyridis where Harmonia is the genus and axyridis is the species.
371
What significant developments in science contributed to a revised classification system?
Improvements in microscopy and increased knowledge in biochemistry such as RNA sequence analysis revealed that some species were more distantly related than previously thought.
372
Who added the three-domain system to the classification of living organisms?
Carl Woese added the three-domain system to the classification of living organisms.
373
What are the three domains in the three-domain system?
The three domains in the three-domain system are Archaea Bacteria and Eukarya.
374
Why is classification important in biology?
Classification is important in biology as it helps scientists organize and categorize living organisms making it easier to study their relationships similarities and differences.
375
How does the binomial system help overcome language barriers?
The binomial system provides a universal naming convention for organisms allowing scientists from different countries and languages to communicate clearly about species without confusion.
376
What are the three domains of life?
The three domains of life are Archaea Bacteria and Eukaryota.
377
What distinguishes the domain Archaea from Bacteria?
Archaea are primitive bacteria that often live in extreme environments such as hot springs unlike bacteria which can be found in a variety of environments.
378
What characterizes organisms in the domain Bacteria?
Bacteria also known as true bacteria are unicellular organisms that have a prokaryotic cell structure and are characterized by having a peptidoglycan cell wall.
379
What types of organisms are classified under the domain Eukaryota?
The domain Eukaryota includes organisms that have a nucleus enclosed in membranes and encompasses the kingdoms protists fungi plants and animals.
380
What is the purpose of evolutionary trees in biology?
Evolutionary trees are used to illustrate the evolutionary relationships among different species showing how closely related organisms are based on classification data and fossils of extinct species.
381
What are the benefits of using classification data in evolutionary studies?
Classification data helps in organizing organisms based on shared characteristics allows for the prediction of traits in related species and aids in understanding evolutionary history and relationships.
382
Why is fossil data important when studying evolutionary relationships?
Fossil data provides insights into extinct species helping scientists understand how organisms have evolved over time and allowing for a more complete evolutionary tree.
383
What are the four kingdoms included in the domain Eukaryota?
The four kingdoms included in the domain Eukaryota are Protista Fungi Plantae and Animalia.
384
Describe the cell structure of organisms in the domain Eukaryota.
Organisms in the domain Eukaryota possess a complex cell structure that includes a defined nucleus membrane-bound organelles and generally larger cell sizes compared to prokaryotes.
385
What is the significance of using an evolutionary tree diagram?
An evolutionary tree diagram visually represents the relationships between different species illustrating the concepts of common ancestry and divergent evolution making complex relationships easier to understand.
