Inheritance, Variation And Evolution Flashcards
1
Q
What does DNA stand for?
A
Deoxyribonucleic acid
2
Q
What is the primary function of DNA?
A
Contains coded information for organism construction and function
3
Q
What are chromosomes made of?
A
Long molecules of DNA
4
Q
What is the structure of a DNA molecule?
A
Double helix structure
5
Q
What is a gene?
A
A small section of DNA found on a chromosome
6
Q
What does a gene code for?
A
A particular sequence of amino acids to make a specific protein
7
Q
How many amino acids are used to make proteins?
A
20 amino acids
8
Q
What determines the type of cell produced?
A
The proteins that the cell produces
9
Q
What is a genome?
A
The entire set of genetic material in an organism
10
Q
Why is understanding the human genome important?
A
It helps identify genes linked to diseases and aids in developing treatments
11
Q
What can scientists trace using genomes?
A
Migration patterns of human populations
12
Q
What type of reproduction combines genetic information from two organisms?
A
Sexual reproduction
13
Q
What are gametes?
A
Reproductive cells produced by meiosis (e.g., egg and sperm cells)
14
Q
How many chromosomes do human gametes contain?
A
23 chromosomes
15
Q
What is fertilization?
A
The fusion of egg and sperm cells
16
Q
What type of reproduction involves only one parent?
A
Asexual reproduction
17
Q
What is the cell division process involved in asexual reproduction?
A
Mitosis
18
Q
What are offspring produced by asexual reproduction called?
A
Clones
19
Q
What is the main difference between sexual and asexual reproduction?
A
Sexual reproduction involves two parents and genetic variation, while asexual reproduction involves one parent and produces genetically identical offspring
20
Q
Fill in the blank: In sexual reproduction, offspring inherit features from both parents because they receive a mixture of _______.
A
chromosomes
21
Q
True or False: Asexual reproduction results in offspring that are genetically different from the parent.
A
False
22
Q
What process produces gametes with half the number of chromosomes?
A
Meiosis
23
Q
How many divisions occur during meiosis?
A
Two divisions
24
Q
In which organs does meiosis occur in humans?
A
Ovaries in females and testes in males
25
What happens to chromosomes before the first division in meiosis?
They duplicate their genetic information, forming two armed chromosomes
26
What is the outcome of the first division in meiosis?
Each new cell has one copy of each chromosome
27
What is the significance of chromosome shuffling during meiosis?
Each gamete is genetically different
28
What is the result of the second division in meiosis?
Four gametes, each with a single set of chromosomes
29
What occurs after two gametes fuse during fertilization?
The resulting cell divides by mitosis
30
How many chromosomes are present in each human body cell?
46 chromosomes
31
What are the X and Y chromosomes responsible for?
Determining sex (male or female)
32
What is the chromosome combination for males?
XY
33
What is the chromosome combination for females?
XX
34
What is the probability of each sperm cell getting an X or Y chromosome?
50% for X-chromosome and 50% for Y-chromosome
35
What type of genetic diagram shows possible gamete combinations?
Punnett square
36
What do the letters in a Punnett square represent?
Possible combinations of gametes
37
What is the expected ratio of boys to girls from the Punnett square?
50:50 ratio
38
What does a more complicated genetic diagram show?
Possible gametes from parents and combinations of offspring
39
What combination of sex chromosomes do human females have?
XX
40
What do genetic diagrams help to illustrate?
The possible alleles of offspring
## Footnote
Genetic diagrams represent the inheritance patterns of traits based on parental genotypes.
41
What controls the characteristics you develop?
What genes you inherit
## Footnote
Characteristics are influenced by the specific genes passed down from parents.
42
What is a homozygous trait?
When an organism has two identical alleles for a particular gene
## Footnote
Homozygous traits can be either dominant (e.g. AA) or recessive (e.g. aa).
43
What is a heterozygous trait?
When an organism has two different alleles for a particular gene
## Footnote
Heterozygous traits are expressed as Aa, where A is dominant and a is recessive.
44
What is the dominant allele represented by?
A capital letter
## Footnote
For example, 'C' represents a dominant allele.
45
What is the recessive allele represented by?
A lowercase letter
## Footnote
For example, 'c' represents a recessive allele.
46
What must be true for an organism to display a recessive characteristic?
Both alleles must be recessive
## Footnote
For example, the genotype must be 'cc' to show the recessive trait.
47
What is the genotype?
The combination of alleles an organism has
## Footnote
Genotype determines the genetic makeup and potential traits of the organism.
48
What is the phenotype?
The observable characteristics of an organism
## Footnote
Phenotype is influenced by the genotype and environmental factors.
49
In the breeding example, what allele causes hamsters to have superpowers?
The recessive allele 'b'
## Footnote
Normal behavior in hamsters is due to the dominant allele 'B'.
50
What is the expected phenotype ratio of normal to superpowered offspring when breeding two heterozygous hamsters?
3:1
## Footnote
This means for every three normal hamsters, there is one superpowered hamster.
51
What is the result of crossing a homozygous dominant hamster (BB) with a homozygous recessive hamster (bb)?
All offspring are normal (boring)
## Footnote
The genotypes of the offspring will all be Bb.
52
What ratio of offspring is expected when a heterozygous cat (Hh) is crossed with a homozygous recessive cat (hh)?
1:1 ratio
## Footnote
This results in half the kittens having long hair and half having short hair.
53
What can be inferred from a family tree that shows cystic fibrosis?
The allele for cystic fibrosis isn't dominant
## Footnote
Carriers can exist without showing the disorder.
54
What is the probability that a new baby will have cystic fibrosis if both parents are carriers?
25%
## Footnote
There is also a 50% chance the baby will be a carrier.
55
What is the dominant allele for round peas represented by?
The letter R
## Footnote
The recessive allele for wrinkly peas is represented by 'r'.
56
Fill in the blank: An organism can display a dominant characteristic if it has the genotypes _____ or _____.
CC or Co
## Footnote
Dominant traits can be expressed in homozygous or heterozygous forms.
57
True or False: Genetic diagrams can predict the exact outcome of offspring.
False
## Footnote
Genetic diagrams provide probabilities, not certainties.
58
What are inherited disorders?
Disorders that can be passed from parents to offspring, often screened for in embryos.
59
What causes cystic fibrosis?
A recessive allele, 'f', carried by about 1 in 25 people.
60
What is the probability of a child having cystic fibrosis if both parents are carriers?
1 in 4 chance.
61
What is polydactyly?
A genetic disorder where a baby is born with extra fingers or toes.
62
What causes polydactyly?
A dominant allele, 'D'.
63
What is the probability of a child having polydactyly if one parent has the D allele?
50% chance.
64
What is embryonic screening?
A process during IVF where embryos are tested for genetic disorders before implantation.
65
What are some ethical concerns regarding embryonic screening?
Could imply genetic problems are undesirable, may lead to selecting traits, and is expensive.
66
What are some arguments for embryonic screening?
* Helps stop suffering
* Reduces government healthcare costs
* Laws prevent extreme selection
67
Why won't someone heterozygous for the cystic fibrosis allele have the disorder?
Because cystic fibrosis is caused by a recessive allele.
68
What is variation within a species?
Differences among organisms of the same species, such as hair color and height.
69
What is genotype?
All of the genes and alleles that an organism has.
70
How does genotype affect phenotype?
Genotype influences the characteristics displayed by an organism.
71
What is environmental variation?
Differences in phenotype caused by interactions with the environment.
72
What is a mutation?
A rare, random change in an organism's DNA that can be inherited.
73
What are genetic variants?
Different forms of a gene caused by mutations.
74
Do most mutations affect an organism's phenotype?
Most have little or no effect on phenotype.
75
What can happen if a mutation dramatically affects a protein?
It can lead to significant changes in the organism's phenotype.
76
What is natural selection?
The process where advantageous traits become common in a population.
77
Fill in the blank: Most variation in phenotype is determined by a mixture of _______ and environmental factors.
genetic
78
True or False: Cystic fibrosis is a dominant genetic disorder.
False
79
What is the theory of evolution?
All of today's species have evolved from simple life forms that first started to develop over three billion years ago.
## Footnote
This theory explains the diversity of life on Earth.
80
Who proposed the theory of evolution by natural selection?
Charles Darwin
## Footnote
Darwin's work laid the foundation for modern evolutionary biology.
81
What is phenotypic variation?
Wide variation in characteristics among organisms in a species.
82
What does 'survival of the fittest' refer to?
The idea that organisms with the most suitable characteristics for the environment are more likely to survive and reproduce.
83
What happens to successful organisms in terms of reproduction?
They are more likely to reproduce and pass on their beneficial genes to their offspring.
84
What is speciation?
The development of a new species over time due to significant changes in phenotype.
85
What leads to reproductive isolation in speciation?
Populations of the same species change enough that they cannot interbreed to produce fertile offspring.
86
What is extinction?
When no individuals of a species remain.
87
List some reasons why species become extinct.
* Environment changes too quickly
* New predator kills them
* New disease kills them
* Competition with another species for food
* Catastrophic events
88
What is selective breeding?
Humans artificially select plants or animals for breeding to maintain specific characteristics in the population.
89
Give examples of traits targeted in selective breeding.
* Animals that produce more meat or milk
* Crops with disease resistance
* Dogs with a gentle temperament
* Decorative plants with large flowers
90
What is the basic process of selective breeding?
* Select existing stock with desired characteristics
* Breed them together
* Select the best offspring and breed them
* Repeat over several generations
91
What is the main drawback of selective breeding?
Reduction in the gene pool, leading to increased inbreeding.
92
What health issues can arise from inbreeding?
Increased chance of inheriting harmful genetic defects.
93
Why is a limited gene pool problematic for new diseases?
If one organism is susceptible, closely related organisms are likely to be affected as well.
94
Fill in the blank: Selective breeding is also known as _______.
artificial selection.
95
Explain how natural selection could lead to the development of long-tongued moths.
Moths with longer tongues can access nectar in flowers, improving their survival and reproductive success.
96
How did humans contribute to the extinction of the dodo?
Hunted them and introduced other animals that ate their eggs and destroyed their habitat.
97
What is a key component of Darwin's theory that genetics helped to explain?
How organisms with beneficial characteristics can pass them on to their offspring via genes.
98
What is genetic engineering?
Genetic engineering is the transfer of genes between organisms to introduce desirable characteristics.
99
What is a vector in genetic engineering?
A vector is usually a virus or a bacterial plasmid used to introduce a gene into a target organism.
100
Name one application of genetic engineering in bacteria.
Bacteria have been genetically modified to produce human insulin for diabetes treatment.
101
What are genetically modified (GM) crops designed to improve?
GM crops are designed to improve the size and quality of fruit and to provide resistance to disease, insects, and herbicides.
102
What is gene therapy?
Gene therapy involves inserting working genes into individuals with inherited diseases caused by faulty genes.
103
When is the gene transfer carried out in some organisms?
Gene transfer can be carried out when the organism is at an early stage of development, such as in the egg or embryo.
104
True or False: Genetic engineering is universally accepted as a beneficial practice.
False.
105
What is one concern about GM crops?
One concern is that growing GM crops may reduce farmland biodiversity.
106
What is a potential health risk associated with GM crops?
There are concerns that people may develop allergies to GM foods.
107
What could happen if transplanted genes escape into the natural environment?
Transplanted genes could create 'superweeds' that are resistant to herbicides.
108
What is one benefit of GM crops for developing nations?
GM crops can be engineered to contain essential nutrients missing from diets.
109
What is 'golden rice'?
'Golden rice' is a GM rice crop that contains beta-carotene, which prevents blindness.
110
What are fossils?
Fossils are the remains of organisms from many thousands of years ago found in rocks.
111
What are the three ways fossils can form?
1) Gradual replacement by minerals 2) Casts and impressions 3) Preservation in environments with no decay.
112
What forms the majority of fossils?
Most fossils form through gradual replacement by minerals.
113
How can casts and impressions form?
Casts and impressions can form when an organism is buried in soft material like clay that hardens around it.
114
What type of environments are suitable for fossil preservation?
Low-oxygen environments such as amber, peat bogs, and glaciers.
115
What is a challenge in studying the origin of life?
There is a lack of good, valid evidence to support hypotheses about how life began.
116
What geological activity can destroy fossils?
Movement of tectonic plates can crush fossils already formed in rock.
117
Fill in the blank: Fossils provide evidence that organisms _______.
lived ages ago.
118
What is one hypothesis about the origin of life?
Life may have originated in a primordial swamp or under the sea.
119
What was the impact of the discovery of antibiotics like penicillin?
Bacterial infections that had often been fatal could be cured
120
How do bacteria develop antibiotic resistance?
Through random mutations in their DNA that can lead to less susceptibility to antibiotics
121
What is a consequence of rapid bacterial reproduction?
Bacteria can evolve quickly, leading to increased antibiotic-resistant strains
122
Why is antibiotic resistance advantageous for bacteria?
It allows them to survive and reproduce even in treated hosts
123
What is a 'superbug'?
A strain of bacteria that is resistant to most known antibiotics
124
Give an example of a common superbug.
MRSA (Methicillin-resistant Staphylococcus aureus)
125
What has contributed to the worsening problem of antibiotic resistance?
Overuse and inappropriate use of antibiotics
126
Complete the statement: Antibiotics don't kill _______.
viruses
127
Why is it important to take the full course of antibiotics?
To ensure all bacteria are destroyed and prevent the development of resistant strains
128
How can antibiotics in farming contribute to antibiotic resistance?
They can lead to the development of resistant bacteria in animals that can spread to humans
129
What is the impact of antibiotic resistance on drug development?
It encourages drug companies to develop new antibiotics, but the process is slow and costly
130
What was Carl Woese's contribution to classification systems?
He proposed the three-domain system based on RNA sequence analysis
131
List the three domains in Woese's classification system.
* Archaea
* Bacteria
* Eukaryota
132
What does the binomial system of naming organisms consist of?
A two-part Latin name: genus and species
133
What is the genus in the binomial name 'Homo sapiens'?
Homo
134
What is the significance of evolutionary trees?
They show how different species are related and their common ancestors
135
How do scientists determine evolutionary relationships?
By analyzing DNA, structural similarities, and fossil records
136
Complete the statement: The more recent the common ancestor, the more _______.
closely related the two species are
137
What is the purpose of the binomial system in scientific naming?
To ensure consistent naming across different languages and countries
