biology final Flashcards
(96 cards)
1
Q
What is blending inheritance?
A
The hypothesis that traits are handed down from one generation to the next by the parent’s traits being blended in the offspring.
2
Q
How do we know blending inheritance does not work?
A
Being taller than both of your parents or being shorter than both of your parents.
3
Q
Who was Gregor Mendel?
A
An Austrian man who was born into a poor family. He wanted to go to college but he couldn’t because his family was poor. He signed up to be a monk just so he could go to college. He studied botany and physics.
4
Q
Explain Gregor Mendel’s experiment.
A
Gregor Mendel looked at 7 different traits of pea plants and bred the plants with the same allele fro true breeding. Mendel was lucky that all traits of the pea plants followed simple dominance and were all separate chromosomes.
5
Q
What plant did Mendel use for his experiments?
A
Pea Plants.
6
Q
Why was it a good idea for Mendel to use pea plants in his experiment?
A
Luckily, all of the traits of the pea plants followed simple dominance and were all on separate chromosomes.
7
Q
What are alleles?
A
One of two or more alternative versions of a particular gene. Some genes have many, each of which contains slightly different instructions for building a protein.
8
Q
What are dominant alleles?
A
Alleles which are always expressed if present, even if the individual only has one copy.
9
Q
What are recessive alleles?
A
Alleles which are only expressed if the individual has two copies, the individual must be homozygous for the allele.
10
Q
Explain the shorthand we use to designate allele pairs.
A
Genotypes. Genotypes are the arrangement of alleles that a person has.
11
Q
What does “homozygous” mean?
A
Refers to an individual which has two of the same alleles at a particular locus.
12
Q
What does “heterozygous” mean?
A
Refers to an individual which has two different alleles at a particular locus.
13
Q
What is Mendel’s Law of Segregation?
A
States that diploid organisms inherit 2 genes per trait during meiosis. The genes separate so there is 1 gene per section. He demonstrated this with a Punnet Square.
14
Q
What is Mendel’s Law of Independent Assortment? How did he demonstrate it?
A
States that gene pairs segregate during gamete production independently of other gene pairs located on non-homologous chromosomes. He demonstrated this using the pea plants.
15
Q
What is complete dominance?
A
When there are two alleles, one is dominant and the other is recessive.
16
Q
How is complete dominance different from incomplete dominance?
A
Incomplete dominance is one dominant allele and one recessive allele and the dormant allele does not completely mask the recessive allele.
17
Q
What is codominance?
A
A situation in which two different alleles are completely expressed in heterozygotes. The ABO blood typing system in humans is an example.
18
Q
What is pleiotropy?
A
A situation in which one gene controls two seemingly unrelated aspects of the phenotype. EX: Sickle Cell Syndrome
19
Q
What is epistasis?
A
A situation in which one gene pair may block the expression of a different gene pair.
20
Q
Give an example of each type of inheritance.
A
Autosomal Recessive - Sickle Cell Syndrome, Galactosemia.
Autosomal Dominant - Achondroplasia, Huntington’s Disease.
X-Linked Recessive - Colorblindness, Hemophilia.
21
Q
What is discontinuous variation?
A
When there are two or more separate phenotypes. Examples are tall or short plants and purple or white flowers.
22
Q
What is quantitative inheritance?
A
A situation in which a single phenotypic trait is controlled by several gene pairs, resulting in continuous variation. Example of this would be skin color.
23
Q
What are some examples of how genetic inheritance interacts with the environment?
A
When your skin color changes because of the sun providing more melanin to appear.
24
Q
How is sex determine in humans and other mammals?
A
SRY gene. If SRY is found in a human, that human is a male.
25
What are some examples of animals in which sex is not genetically determined?
Alligators and Turtles.
26
What is linkage?
The property of genes located on the same chromosome, which tend to be transmitted together.
27
How can linkage be disrupted?
Crossing over.
28
What are difficulties involved in studying human genetics?
Difficulties involved in studying human genetics include small family sizes, long generation times, and privacy concerns and other ethical questions.
29
What is pedigree analysis?
Pedigree Analysis is when you use a family tree with known individuals to determine the traits that will be passed down.
30
What is the difference between an abnormality, a disorder, a syndrome, and a disease?
An abnormality refers to a genetic condition that is deviated from normal but it is not life threatening and does not cause any symptoms. A disorder refers to a genetic abnormality that causes medical symptoms. A syndrome refers to a genetic disorder that has a recognizable set of symptoms that comes with it. A disease refers to a medical problem that is caused by an infection, a toxin, or a lack of a certain nutrient. This is not a genetically caused problem.
31
What are the three main patterns of inheritance?
The three main patterns of inheritance are Autosomal Recessive, Autosomal Dominant, and X-Linked Recessive.
32
What are examples of genetic disorders that are transmitted in each pattern?
Examples of Autosomal Recessive are Sickle Cell and Galactosemia. Examples of Autosomal Dominant are Achondroplasia and Huntington’s Disease. Examples of X-Linked Recessive are Colorblindness and Hemophilia.
33
What are the different types of changes in chromosome structure?
The different types of changes in chromosome structure are:
- Duplication: a copied chromosome has 2 copies of itself.
- Inversion: break off part of a chromosome and when it is reassembled, it has turned itself backwards.
- Translocation: Break off part of one chromosome and attach it to part of another chromosome.
Deletion: Part of a chromosome is destroyed or lost.
34
What are the different types of changes in chromosome number? What are the various examples of aneuploidies in human sex chromosomes?
The different types of changes in chromosome number are called Aneuploidy. Aneuploidy is broken down into Monosomy and Trisomy.
Monosomy is if there is one chromosome.
YO – fatal
XO – survivable (Turner Syndrome)
Trisomy is if there are three chromosomes in one set.
XXY – Klinefelter Syndrome
XYY – Extra-Y Syndrome
XXX – Super Female
35
What did Fred Griffith discover? How did his experiment work?
Fred Griffith discovered that there was something in the bacteria that could turn R strain into S strain which was called the transforming substance. In his experiment, he took S strain, heated them up to kill them but they stayed alive and he injected them into mice. He mixed dead S strain and live R strain and injected them into the mice and that killed them.
36
What did Alfred Hershey discover? How did he know that the genetic substance was DNA instead of protein?
Alfred Hershey discovered the DNA, not proteins, was the genetic material of the cell. He knew that the genetic substance was DNA instead of protein because he used viruses and viruses are made of DNA and proteins. If sulfur was passed along, it would have been proteins, but since it was phosphorus passed along, Hershey knew it was DNA.
37
What are Chargaff’s Rules? Why are they important to the structure of DNA?
Chargaff’s Rules are that cytosine is equal to guanine and adenine is equal to thymine. Chargaff’s rules are important to the structure of DNA because of the way the nucleotides are aligned in the DNA molecule.
38
What did Watson and Crick discover? How was the work of Franklin and Wilkins critical to this discovery?
Watson and Crick discovered the structure of DNA. The work of Franklin and Wilkins was critical to this because of their conduction of X-ray diffraction experiments on DNA which helped to discover its basic double helix structure.
39
What is the overall structure of DNA?
The overall structure of DNA is a double helix made of the nucleotides adenine, guanine, cytosine, and thymine, with two sugar-phosphate backbones.
40
How does this structure all DNA to be replicated? What does it mean to say that DNA replication is semi-conservative? Can you describe the process of DNA replication? What enzymes are important to this process?
DNA is replicated easily because the double helix can be stripped into two complementary strands, and each strand can be used as a template to build the corresponding strand, so that you end up with two identical DNA molecules, each one consisting of one old strand and one new complementary strand. This is what “semi-conservative” means.
41
How does the structure of DNA transmit information?
DNA contains information in the order of the nucleotides that make it up – they act like letters in words (the codons correspond to words in a languageDNA contains information in the order of the nucleotides that make it up – they act like letters in words (the codons correspond to words in a languageDNA contains information in the order of the nucleotides that make it up – they act like letters in words (the codons correspond to words in a language.)
42
What is the “Central Dogma” of molecular biology?
DNA --> RNA --> proteins.
43
What are the three main types of RNA?
The three main types of RNA are:
Messenger RNA (mRNA)
Ribosomal RNA (rRNA)
Transfer RNA (tRNA)
44
How is RNA different from DNA?
DNA is composed of adenine, guanine, cytosine, and THYMINE. RNA is composed of adenine, guanine, cytosine, and URACIL.
45
How does the process of transcription work?
Transcription is when an RNA polymerase reads a specific gene and builds a complementary strand of mRNA by assembling the appropriate nucleotides.
46
How are mRNA transcripts edited before use?
The mRNA transcript is edited by addition of a cap and a poly-A tail, and the removal of introns.
47
What are introns and exons?
Introns are sections removed from an mRNA transcript before it is used for translation. “Intron” is short for “Intragenic Region”. Exons are sections of an mRNA transcript that remain after editing. “Exon” is short for “Expressed Region”.
48
How does the process of translation work? What are the three stages of translation, and what happens in each?
The three stages of translation are:
- Initiation: The ribosomal complex is assembled in this order – initiator, small ribosomal subunit, mRNA transcript, large ribosomal complex.
- Elongation: tRNA molecules bring the appropriate nucleotides to the ribosome where they are connected in order.
- Termination: The stop codon of the mRNA transcript is reached and the complete polypeptide chain is released.
49
What is a mutation?
Any change in the order of nucleotides in a DNA molecule.
50
What are some different types and causes of mutations?
Point mutations, frameshift mutations, base-pair substitutions, insertions, and deletions.
51
Are most mutations harmful, neutral, or beneficial?
Most mutations are neutral, and most of the rest are harmful.
52
Who are some of the ancient Greek philosophers who had some ideas related to evolutionary thought? What were their ideas?
Ancient Greek Philosophers and their ideas:
- Anaximander: proposed the idea that the earth was originally in a fluid state and when it dried, fish-like people adapted to the dry land.
- Xenophanes: Recognized that a fossil was the remains of a long-dead organism.
- Empedocles: Believed that every thing was made up of the 4 elements (earth, air, fire, and water)
- Aristotle: Believed in the fixity of species (organisms cannot change over time.) Observed nature and developed a chain to be compatible with the fixity of species.
- St. Augustine: took the ideas of St. Gregory and applied them to living things. He said the God would not make nuisance animals, so they have to have mutated from other organisms.
- Leonardo Da Vinci: invented the hot air balloon. Among one of the first to recognize that fossils are remains of long-dead individuals. Fossils are almost always found in sedimentary rock. He demonstrated organisms do change over time.
- Carolus Linnaeus: invented the “Systems Naturae” which is the classification system of living things. HE Realized it looks like a family tree.
53
Who were the early leaders of the Christian Church who had some ideas related to evolutionary thought? What were their ideas? Why were the ideas of St. Augustine so important?
- St. Gregory of Nyssa believed that all of nature might form as basic materials followed God's natural laws, so that every individual thing wasn't specifically created by Him.
- St. Augustine's ideas were important because they said that the Scriptures didn't need to be interpreted literally, and that to insist on a literal interpretation would make Christians look foolish when they contradicted obvious reality.
54
What is fixity of species? How is this related to the Chain of Being?
The fixity of species is that there is no such thing as extinction. Fixity of species says that organisms don't change over time or become extinct. This is approximately the same thing as the Chain of Being.
55
What is mutability of species?
Mutability of species is organisms DO change over time.
56
What did early people think about fossils?
People use to think that fossils did not come from long-dead animals and plants, but were instead naturally forming crystals or the results of the flood of Noah in the Bible.
57
How did the work of Leonardo daVinci demonstrate that these ideas were wrong?
Leonardo demonstrated that fossils found high in the mountains could not have been washed there by floodwaters.
58
Who was Carolus Linnaeus? What was his most famous work, and how did it lead him to question the idea of fixity of species?
Carolus Linnaeus was a Swedish Botanist. He developed the nomenclature and classification system we used today. He published this in the 10th edition of Systema Naturae. He originally believed in the fixity of species, but during his work of naming organisms, he was convinced that mutability may be possible
59
Who were some of the early geologists who contributed ideas to evolutionary thought? What are Catastrophism and Uniformitarianism?
Early geologists included Cuvier, who formulated catastrophism, the idea that the earth is subject to a series of giant catastrophes that explain changes in the fossil record, and Lyell, who formulated Uniformitarianism, the idea that changed in the earth’s surfaces are caused by slow, constant forces that have remained the same throughout its history.
60
Who was Jean Baptiste de Lamarck? What was his famous theory? What were the four main components of this theory? How do we know he was wrong?
He was a French Scientist.
He originated the Theory of Acquired Characteristics.
The four main components were as follows:
- Living organisms and their components parts tend to continually increase in size.
- Production of a new organ results from a new need and associated movements.
- If an organ is used constantly, it will become highly developed and little-used organs will degenerate.
- Modifications thus produced during an individuals lifetime are inherited by its offspring.
We knew he was wrong because his ideas are not borne out by observation and experimentation – for instance changes to an organism during it’s life are not passed down to offspring.
61
Describe the early life of Charles Darwin. How did his journey on the H.M.S. Beagle, contribute to his evolutionary ideas?
Charles Darwin was a British Scientist who traveled around the world on the HMS Beagle and explored much of South America and the Galapagos Islands. He set out his Theory of Natural Selection in his book On the Origin of Species.
62
How did the work of Thomas Malthus and Charles Lyell influence his ideas?
Malthus influenced Darwin by his idea about overpopulation – populations can increase exponentially, but resources increase in a linear fashion, if at all. Lyell’s ideas about Uniformitarianism implied that the earth is very old, giving enough time for evolution to occur.
63
Who was Alfred Russel Wallace? How did his work spur Darwin to finish On the Origin of Species?
Wallace was a British scientist who say the Theory of Natural Selection in a fevered dream while suffering from malaria. Wallace sent his version of the Theory to Darwin in a letter which spurred Darwin to complete and publish On the Origin of Species.
64
What are the five components of the Theory of Natural Selection as we discussed them in class? Can you explain each in some detail?
The five components of the Theory of Natural Selection are:
- Variation: All populations vary naturally.
- Overpopulation: All populations produce more offspring than can survive.
- Competition: Resources are limited, so there is competition within species.
- Differential Reproductive Success: Variation allows some individuals to survive and reproduce better than others.
- Heritability: Favorable Traits are passed down from generation to generation.
65
What is an adaptation in an evolutionary sense?
any trait which allows those individuals that possess it to out-compete other members of the population which do not have it.
66
What is the definition of selection?
any non-random force which causes differential reproductive success among different genetic types.
67
What are the three different ways that selection can affect a population? Can you give an example of each?
Three different ways that selection can affect a population are:
- Directional Selection – Example: Peppered-Moth, increased resistance of pests ot pesticides, and increased immunity of germs to antibiotics.
- Stabilizing Selection – Example: Birth weight of human babies.
- Disruptive/Balancing Selection – Example: Birds Beak or Color of Field Mice.
68
Is it possible for a trait to completely lack selection? Can you give an example of such a trait?
It is possible for a trait to completely lack selection. This is called No Selection. An example of this would be bad vs. good eyesight.
69
What is sexual selection?
Selection which gives some individuals within a population an advantage during mating. IT can result in highly exaggerated versions of time traits. Sexual selection may be a way for females to judge the genetic quality of males.
70
What is the Biological Species Concept? What is the most important determinant of what makes a species separate from others?
The biological species concept is that natural groups of organisms that breed naturally and successfully with organisms that are within the group and unsuccessfully with organisms that are outside of the group.
71
What is a reproductive isolation mechanism?
Something that keeps members of different species from mating.
72
What are the two main types of reproductive isolation mechanisms?
Prezygotic and Postzygotic.
73
What are some various subtypes?
Subtypes of prezygotic are behavioral isolation, temporal isolation, ecological isolation, pollination isolation, mechanical isolation, and gametic mortality isolation. Subtypes of postzygotic are zygote mortality, hybrid sterility, and hybrid unviability.
74
What is speciation?
the evolution of new species.
75
What are the two main types of speciation?
Allopatric/Geographic speciation and Sympatric Speciation.
76
Can you describe how geographic (allopatric) speciation works?
a population that is divided into two when split by some new geographic barrier.
77
What are some types of sympatric speciation?
occurs without a geographic barrier blocking gene flow within the population.
78
What is the difference between cladogenesis and anagenesis?
Cladogenesis is when one species splits into two species and the parent species still exist and Anagenesis is when evolution takes place and the parent species become extinct.
79
What are the two models regarding the speed of speciation?
Gradual Model of Speciation and Punctuation Model of Speciation.
80
What is an adaptive radiation?
Adaptive Radiation is a sudden burst of speciation that occurs in a new habitat.
81
What is extinction?
the complete disappearance of a species without descendants.
82
What is background extinction?
The normal, natural, slow rate of extinction.
83
What is mass extinction?
when almost all of the species begin to disappear at the same time.
84
What are the various forms of evidence for evolutionary change?
The various forms of evidence for evolutionary change are fossils.
85
What is a fossil?
any preserved remains of a formerly living thing.
86
How are fossils made?
Fossils are made when a form of life passes and their body become preserved in sedimentary rock.
87
What is the Geologic Time Scale?
A chart which depicts the history of the earth as shown in the fossil record, divided into eons, eras, periods, and epochs by changes in the rock strata.
88
What are the three eras in the history of multicellular life?
Paleozoic, Mesozoic, and Cenozoic.
89
What is biogeography?
Biogeography is the study of the distribution of plants and animals.
90
What is the theory of plate tectonics?
The theory of plate tectonics is the theory which explains the movement and current positions of the continents. Land masses and ocean floors are situated on plates which move around the surface of the earth in response to currents of magma in the earth’s mantle.
91
What are homologous structures?
Refer to structures on different organisms which have similar evolutionary origins. Homologous structures are evidence of common ancestry.
92
What are analogous structures?
Refer to structures on different organisms which are similar due to similar selection pressures rather than due to a common evolutionary origin. Analogous Structures are not evidence of common ancestry.
93
Out of homologous structures and analogous structures, which one of these is useful for understanding evolutionary relationships?
Homologous Structures.
94
What are the levels of biological classification?
Kingdom, Phylum, Class, Order, Family, Genus, Species.
95
What is the proper format for a scientific name?
Genus follows by the specific epithet. The genus is always capitalized and the specific epithet is not.
96
What are the kingdoms of the six-kingdom system?
Eubacteria, Protista, Fungi, Plantae, Archaebacteria, Animalia.
