Bio Lect 22 Flashcards
1
Q
who was the first to set up the idea of genetics?
A
Gregor Mendel and the rules of inheritance in diploid organisms 1822 to 1884
2
Q
What organism did Gregor Mendel use for his experiments?
A
Pea plants
Mendel focused on characteristics controlled by individual genes in pea plants.
3
Q
What are the characteristics of the parental generation (P) in Mendel’s experiment?
A
One plant with round seeds (RR) and one with wrinkled seeds (rr)
The round seeds are homozygous dominant and the wrinkled seeds are homozygous recessive.
4
Q
What genotype represents the round seeds in Mendel’s experiment?
A
RR
This indicates that round seeds are homozygous dominant.
5
Q
What genotype represents the wrinkled seeds in Mendel’s experiment?
A
rr
This indicates that wrinkled seeds are homozygous recessive.
6
Q
What was the result of crossing the parental generation in Mendel’s experiment?
A
All F1 generation plants had round seeds
This occurred because the round seed allele (R) is dominant over the wrinkled seed allele (r).
7
Q
What is the genotype of all F1 generation plants?
A
Rr
All F1 plants were heterozygous, expressing the round seed trait.
8
Q
What was the observed ratio of round to wrinkled seeds in the F2 generation?
A
3:1
This indicates that three-fourths of the seeds were round and one-fourth were wrinkled.
9
Q
What does the 3:1 ratio in the F2 generation indicate about the round seed allele?
A
It is dominant over the wrinkled seed allele
The wrinkled seed phenotype appears only when both alleles are recessive (rr).
10
Q
Fill in the blank: The round seed allele is _______ over the wrinkled seed allele.
A
dominant
This dominance explains the appearance of traits in the F1 and F2 generations.
11
Q
True or False: The wrinkled seed phenotype can appear in the F1 generation.
A
False
All F1 plants exhibited the round seed trait due to the dominance of the round seed allele.
12
Q
label the diagram:
A
13
Q
Who developed the Punnett square?
A
Reginald C. Punnett
The Punnett square is a diagram used to predict the outcome of a particular cross or breeding experiment.
14
Q
What is the main purpose of the Punnett square?
A
To predict genetic outcomes
The Punnett square is used in genetics to determine the probability of an offspring inheriting particular traits.
15
Q
Which genetics did Reginald C. Punnett expand upon?
A
Mendelian genetics
Mendelian genetics is based on the principles of inheritance first described by Gregor Mendel.
16
Q
What types of organisms did Punnett study inheritance in?
A
Animals and plants
Punnett’s work included a variety of species, emphasizing both animal and plant genetics.
17
Q
why is the R allele dominant?
A
the more dominant allele can make starch branching enzyme, which gives the starch 3 dimensional complex shape. And so results in a round robust shape and the less dominant allele can’t make this starch branching enzyme so it will have a linear molecule and so a less robust shape which will be collapsed into a kind of wrinkled shape.
18
Q
What is starch?
A
A polymer made up of smaller sugar molecules.
19
Q
How does the complexity of starch affect its strength?
A
The more complicated the starch, the stronger the molecule.
20
Q
What is the function of starch synthase?
A
It links sugar/glucose molecules together to make starch.
Starch synthase is responsible for creating linear molecules of sugar.
21
Q
What is the role of starch branching enzymes?
A
They are responsible for creating branches of sugar molecules in starch.
Branching is necessary to form more complex starch structures.
22
Q
What is the cause of the white phenotype in tigers?
A
A recessive 1 bp mutation in SLC45A2
SLC45A2 is a gene associated with pigmentation in various species.
23
Q
What does the term ‘phenotype’ refer to?
A
The observable characteristics of an organism
Phenotype can be influenced by both genetic and environmental factors.
24
Q
Is the white phenotype in tigers dominant or recessive?
A
Recessive
Recessive traits require two copies of the mutated gene to be expressed.
25
explain phenotypic variation in snapdragons
26
Explain the white hair mutation in white lion, snow leopard etc and explain why the mutation leads to white hair
27
what is the CW allele in snapdragons?
CW is a null allele of a gene required for producing red pigment, it means that this allele disrupts the production of the enzyme or protein responsible for synthesizing the red pigment. As a result, organisms carrying the CW null allele would likely lack red pigmentation, or their red pigment synthesis would be severely reduced or absent.
28
What are the possible coat colors of American Black Bears?
Black, brown and creamy
## Footnote
Some American Black Bears exhibit a variety of coat colors, including brown and creamy.
29
What mutation causes the brown coat color in the 'cinnamon' morph of the American black bear?
TYRP1 mutation
## Footnote
The TYRP1 mutation is responsible for the brown coat color in certain morphs of American black bears.
30
Which mutation is also responsible for the brown coat color in American brown bears?
TYRP1 mutation
## Footnote
The same TYRP1 mutation that affects American black bears also influences coat color in American brown 'grizzly' bears.
31
What type of genetic dominance do the two alleles for coat color exhibit?
Semi-dominant
## Footnote
The alleles for coat color in these bears show semi-dominance with respect to one another.
32
In which region is there selection for the brown allele in American black bears?
South western USA
## Footnote
There is evidence of selection favoring the brown allele in the southwestern United States.
33
What are the possible reasons for selection of the brown allele in certain regions?
Thermoregulatory adaptation or selection for the black allele
## Footnote
The selection for the brown allele may be related to thermoregulation or competition with brown grizzly bears in northern areas.
34
In which climates is there selection for the black allele in American black bears?
More northern climes
## Footnote
The black allele is favored in northern climates where American black bears coexist with brown grizzly bears.
35
What is Mendel's Second Law also known as?
The Law of Independent Assortment
36
What does Mendel's Second Law state?
Alleles for different traits are inherited independently of one another.
37
Which two traits did Mendel study in his experiments with pea plants?
Pea color and pea shape
38
What are the possible colors of peas studied by Mendel?
* Yellow (dominant)
* Green (recessive)
39
What are the possible shapes of peas studied by Mendel?
* Round (dominant)
* Wrinkled (recessive)
40
What was the phenotypic ratio observed in Mendel's experiments with heterozygous plants?
9:3:3:1
41
In the 9:3:3:1 ratio, how many offspring are yellow and round?
9
42
In the 9:3:3:1 ratio, how many offspring are green and wrinkled?
1
43
How does the inheritance of one trait affect the inheritance of another trait according to Mendel's findings?
It does not affect it.
44
What does independent assortment lead to in offspring?
Genetic diversity
45
Fill in the blank: Mendel's Second Law leads to _______ during gamete formation.
genetic diversity
46
Who studied fruit flies Drosophila melanogaster?
Thomas Hunt Morgan
47
Fill in the blank: Thomas Hunt Morgan studied fruit flies _______.
Drosophila melanogaster
48
explain the number of chromosomes in drosophila fruit flies and their sizes
Drosophila has 4 pairs of chromosomes, 2 and 3 are very big, 4 is very small and then an x and a y to determine what the genetic sex is.
49
What is the sex chromosome combination for female fruit flies?
XX
50
What is the sex chromosome combination for male fruit flies?
XY
51
What determines the sex of fruit flies?
The X-to-autosome ratio
52
What X-to-autosome ratio results in a female fruit fly?
1.0
53
What X-to-autosome ratio results in a male fruit fly?
0.5
54
In fruit flies, which chromosome primarily influences sex determination?
X chromosome
55
True or False: In fruit flies, the Y chromosome is the main factor in determining male development.
False
56
Fill in the blank: Females have _______ chromosomes in fruit flies.
two X
57
Fill in the blank: Males have _______ chromosomes in fruit flies.
one X and one Y
58
What role does the Y chromosome play in Drosophila melanogaster?
Allows spermatogenesis to occur
## Footnote
Spermatogenesis is the process of sperm cell development.
59
How do the X and Y chromosomes act in Drosophila melanogaster regarding sex determination?
In a cell-autonomous manner
## Footnote
This indicates that the chromosomes themselves drive the determination.
60
What is the primary factor in the sex determination mechanism of Drosophila melanogaster?
The number of X chromosomes relative to the number of sets of autosomes
## Footnote
This relationship is crucial for determining the organism's sex.
61
True or False: Hormones are directly involved in the sex determination process of Drosophila melanogaster.
False
## Footnote
The sex determination is driven by chromosomes, not hormones.
62
What organism is mentioned as being able to exhibit both male and female characteristics?
Drosophila melanogaster
## Footnote
Commonly known as the fruit fly, a model organism in genetics.
63
What is required to create a Drosophila melanogaster with both male and female characteristics?
Certain genetic manipulations
## Footnote
This involves specific alterations in the genetic makeup of the organism.
64
If a Drosophila melanogaster is genetically male but has a female brain, to whom would it be attracted?
Males
65
Fill in the blank: A genetically male Drosophila melanogaster with a female brain would be attracted to _______.
males
66
True or False: A Drosophila melanogaster with an XY genotype and a female brain exhibits male attraction.
True
67
What determines the eye color in Drosophila melanogaster?
A gene located on the X chromosome
68
What is the typical eye color in wild-type Drosophila melanogaster?
Red
69
What type of allele causes the red-eye color in Drosophila melanogaster?
Dominant allele
70
What is the result of a recessive mutation in the eye color gene of Drosophila melanogaster?
White-eye color
71
True or False: The white-eye color in Drosophila melanogaster is a dominant trait.
False
72
What type of eye color is dominant in fruit flies?
Red eye colour
73
What were the eye colors of the F1 flies resulting from a wild type red eyed female crossed with a white eyed male?
All F1 flies had red eyes
74
Fill in the blank: A wild type red eyed female crossed with a white eyed male produces _______ in the F1 generation.
red eyes
75
True or False: The white eyed male contributes to the dominant red eye color in the F1 generation.
False
76
What is the eye color of Drosophila melanogaster?
Red
## Footnote
Drosophila melanogaster is commonly known as the fruit fly.
77
What causes the red eye color in Drosophila melanogaster, protein or enzyme?
A protein involved in pigment transport into the eye cells
## Footnote
The red eye color is not caused directly by an enzyme that produces pigment.
78
True or False: The red eye color in Drosophila melanogaster is caused by an enzyme that produces pigment.
False
## Footnote
The cause is related to a protein for pigment transport, not pigment production.
79
Fill in the blank: In Drosophila melanogaster, red eye color is due to a protein involved in _______ transport into the eye cells.
pigment
80
describe the results of crossing F1 male white eye and females red eyed fruit flies
81
Who was the first to provide strong evidence that genes are located on chromosomes?
Thomas Hunt Morgan
82
What chromosome combination do males have?
XY
83
How many copies of genes located on the X chromosome do males have?
One
84
What does having a single X chromosome imply for males regarding X-linked traits?
Males have only one chance to inherit the allele for that gene
85
True or False: Males have two copies of any gene located on the X chromosome.
False
86
Fill in the blank: Since males have only one X chromosome (XY), they only have a single copy of any gene that is located on the _______.
X chromosome
87
What organism did Thomas Hunt Morgan use in his classic experiment?
Drosophila melanogaster
## Footnote
Commonly known as the fruit fly, it is a model organism in genetics.
88
What two traits did Morgan investigate in his experiment?
Eye color and wing shape
## Footnote
These traits were chosen to study inheritance patterns.
89
What is the dominant allele for eye color in Morgan's experiment?
Red-eye (wild-type, w+)
## Footnote
The red-eye trait is dominant over the white-eye trait.
90
What is the dominant allele for wing shape in Morgan's experiment?
Normal wing (wild-type, V+)
## Footnote
The normal wing trait is dominant over the vestigial wing trait.
91
What was the genotype of the red-eyed, normal-winged female Morgan crossed?
W+ W+ V+ V+
## Footnote
This genotype represents homozygous dominant for both traits.
92
What was the genotype of the white-eyed, vestigial-winged male Morgan crossed?
w w V V
## Footnote
This genotype represents homozygous recessive for both traits.
93
What was the phenotype of the F1 generation in Morgan's experiment?
Red eyes and normal wings
## Footnote
This phenotype reflects the dominance of the alleles from the parent generation.
94
What ratio did the F2 generation display in Morgan's experiment?
3:0:0:1
## Footnote
Indicates the presence of parental combinations and recombinant traits.
95
What did the 3:0:0:1 ratio in the F2 generation suggest about the genes?
The genes for eye color and wing shape were linked on the same chromosome
## Footnote
This implies that independent assortment did not occur.
96
What phenomenon was observed less frequently during Morgan's experiment?
Recombination (crossing over)
## Footnote
This refers to the exchange of genetic material between homologous chromosomes.
97
What theory of inheritance was supported by Morgan's findings?
The chromosomal theory of inheritance
## Footnote
This theory posits that genes are located on chromosomes and that these chromosomes segregate during meiosis.
98
True or False: Independent assortment occurred in Morgan's experiment.
False
## Footnote
The results indicated that the genes were inherited together more often than expected.
99
What is Mendel’s Law of Independent Assortment?
Genes on different chromosomes are inherited independently
## Footnote
This law leads to a variety of combinations in the offspring.
100
What happens when genes are on the same chromosome?
They tend to be co-inherited or linked
## Footnote
This means they are usually passed down together.
101
What is genetic linkage?
The tendency of genes on the same chromosome to be inherited together
## Footnote
This can result in fewer combinations in the offspring.
102
What can crossing over create?
New combinations of genes
## Footnote
This occurs during meiosis and can disrupt genetic linkage.
103
Who conducted experiments that demonstrated genetic linkage?
Thomas Hunt Morgan
## Footnote
His work with fruit flies showed that genes on the same chromosome are inherited together more often.
104
True or False: Genes on different chromosomes are usually passed down together.
False
## Footnote
They follow Mendel’s Law of Independent Assortment.
105
Fill in the blank: If genes are on the same chromosome, they tend to be ______.
co-inherited or linked
106
What is the consequence of genetic linkage in offspring?
Reduced variety of combinations
## Footnote
Genes that are linked are inherited together, limiting genetic diversity.
107
What does crossing over lead to?
Recombinant chromosomes
## Footnote
Crossing over is a process during meiosis where homologous chromosomes exchange genetic material.
108
What occurs during crossing over in terms of alleles and the relative ‘phase’?
The relative 'phase' of the different alleles is swapped
## Footnote
This swapping can result in new combinations of alleles in the offspring.
109
What occurs randomly along the chromosome?
Crossing over
## Footnote
Crossing over is a process that occurs during meiosis where homologous chromosomes exchange genetic material.
110
What is the relationship between gene proximity and recombination frequency?
Genes that are close together recombine less frequently.
111
What happens to recombination frequency as genes are further apart?
Genes that are further apart recombine more frequently.
112
True or False: Genes that are close together have a higher recombination frequency.
False
113
Fill in the blank: Genes that are _______ together recombine less frequently.
close
114
Fill in the blank: Genes that are _______ apart recombine more frequently.
further
115
What are the two main types of genetic variation?
Mutation and mixing up of variations
116
What processes can generate novel combinations?
Segregation and recombination
## Footnote
These processes are fundamental in genetics, contributing to genetic diversity.
117
What encodes the enzyme that adds carbohydrates onto proteins on the surface of red blood cells?
The haemagglutinin (H) gene
## Footnote
This enzyme is crucial for determining blood group types.
118
What is a null allele in the context of ABO blood grouping?
h allele (produces no functional protein)
## Footnote
This allele does not contribute to the formation of blood group antigens.
119
What does the A allele code for in ABO blood grouping?
An enzyme that synthesises the A carbohydrate
## Footnote
This carbohydrate is present on the surface of type A blood cells.
120
What does the B allele code for in ABO blood grouping?
An enzyme that synthesises the B carbohydrate
## Footnote
This carbohydrate is present on the surface of type B blood cells.
121
Which allele is recessive relative to the A and B alleles?
h
## Footnote
The presence of the h allele does not express any antigen, making it recessive.
122
How are the A and B alleles related to each other?
They are co-dominant with respect to each other
## Footnote
This means that both A and B carbohydrates can be expressed simultaneously in individuals with AB blood type.
123
What does HLA stand for?
Human Leukocyte Antigen
124
How many loci are in the HLA system?
11 loci
125
On which chromosome is the HLA system located?
Chromosome 6
126
What complex contains the HLA loci?
Major histocompatibility complex (MHC)
127
What is the role of HLA genes in the immune system?
Help the body recognize and respond to foreign substances
128
Each HLA locus contains multiple _______.
alleles
129
What type of breeding does Boris Feral Domestic Cat exhibit?
Boris Feral Domestic Cat is very outbred
## Footnote
Outbreeding refers to the mating of unrelated individuals, which can increase genetic diversity.
130
What is the breeding status of the Cinnamon Abyssinian Cat?
Cinnamon Abyssinian Cat is partially inbred
## Footnote
Inbreeding involves mating between closely related individuals, which can lead to a decrease in genetic diversity.
131
How is the Chewbacca Captive Cheetah categorized in terms of inbreeding?
Chewbacca Captive Cheetah is massively inbred
## Footnote
Massive inbreeding can significantly increase the risk of genetic disorders and reduce overall fitness.
132
draw what the phenotypes are
133
What is a notable characteristic of cheetahs related to inbreeding?
They do not reject skin grafts
## Footnote
This indicates a lack of genetic diversity among cheetahs, which can have significant implications for their health and survival.
