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Genetics > Lecture 2a and b: Chromosomes > Flashcards

Lecture 2a and b: Chromosomes Flashcards

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1
Q

Simple Mendelian Inheritance involves what gene to allele ratio

A

1 single gene with 2 different alleles

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2
Q

When studying human traits, it’s not ethical to control parental crosses (like Mendel and pea). Rather we rely on information from…

A

Pedigrees

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3
Q

Used to determine the pattern of inheritance of traits in humans

A

Pedigree analysis

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4
Q

For something to be autosomal recessive disease, it must be…

A

homozygous

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5
Q

Examples of an autosomal recessive disease?

A

Sickle cell anemia, CF

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6
Q

A minority of human diseases are causes by….

A

dominant mutations

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7
Q

For something to be a dominant mutation, an affected individual needs to have…

A

only inherited one copy of the mutant gene from an affected parent

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8
Q

Dominant mutations cause a ___ pattern of inheritance

A

dominant

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9
Q

Example of an autosomal dominant disease

A

Huntingtons disease (neurodegenerative disease)

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10
Q

p53 is a ____, if ___ or more units are mutated—the protein doesn’t work

A

tetramer, 1

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11
Q

Dominant negative mutation example

A

p53 is a protein that prevents cancer, but in more than 50% of cancers, it is mutated

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12
Q

Most p53 mutations are…

A

simple loss of function (both copies of gene deleted)

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13
Q

Gain of function mutation example

A

Ras promotes cell division. Mutated in 20% of cancers and is overactive

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14
Q

The common explanations for dominant disorders are…

A
  1. Haploinsufficiency
  2. Gain of function mutations
  3. Dominant negative mutations
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15
Q

The heterozygote has 50% of the normal protein in _____. However, you need the total protein to be fine.

A

Haploinsufficiency

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16
Q

Mutation changes the protein so it gains a new function

A

gain of function mutation

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17
Q

the altered gene product acts antagonistically to the normal product

A

dominant negative mutations

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18
Q

Many genetic diseases are inherited as ____, where the mutant genes responsible have been cloned and mapped.

A

autosomal dominants

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19
Q

Female is the carrier but the male gets the disease

A

X linked genes

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20
Q

A ____ for an X linked disease shows mostly ___ affected with their mothers as carriers

A

pedigree, males

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21
Q

Example of an X linked gene

A

Muscular dystrophy and hemophilia

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22
Q

Traits where one allele is dominant in one sex but recessive in the opposite sex

A

Sex influenced traits

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23
Q

Sex influence is a phenomenon of

A

heterozygotes

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24
Q

Most sex influenced traits are….

A

autosomal

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25
Q

Ex. of sex influenced traits

A

baldness

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26
Q

Bb and BB mean there will be balding, but bb means there will not. Allele B behaves ___ in males and ___ in females.

A

dominant, recessive

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27
Q

Pattern baldness results from the expression level of a gene that converts….

A

testosterone to 5-DHT

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28
Q

Testosterone levels are ___x more in males than females

A

5

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29
Q

The heterozygous exhibits a phenotype that is intermediate between the corresponding homozygotes.

A

Incomplete dominance

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30
Q

Example of incomplete dominance

A

A red homogenous flower and white homogenous flower make a pink heterozygous flower

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31
Q

An allele is dominant in some heterozygous individuals but not in others

A

Incomplete penetrance

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32
Q

Example of incomplete penetrance

A

polydactyly

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33
Q

polydactyly is what kind of trait

A

autosomal dominant (only need one mutant copy)

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34
Q

The measure of penetrance is described at what levek?

A

population

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35
Q

In incomplete penetrance, if 60% of heterozygotes are carrying a dominant allele exhibit the alleles trait, the trait is ___ penetrant

A

60%

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36
Q

In most cases with incomplete penetrance, the range of phenotypes is thought to be due to influences of the…

A

environment and/or genes

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37
Q

Phenomenon where a heterozygote is more vigorous than either of the corresponding homozygote

A

Overdominance

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38
Q

Sickle cell anemia is what kind of disorder

A

Autosomal recessive

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39
Q

Ex. of overdominance

A

Sickle cell anemia. If you are heterozygote you are resistant but if you are homozygote—you get it.

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40
Q

Over dominance is due to, at the molecular level…

A

to two alleles that produce slightly different proteins

41
Q

Enviornmental conditions may have a great impact on the ___ of the individual

A

phenotype

42
Q

By geneticists examining a range of conditions in regards to environmental conditions, this allows them to see the ____ of the environmental influence on phenotypic range.

A

norm of reaction

43
Q

There are multiple alleles that exhibit a…

A

dominance hierarchy

44
Q

Coat colors in rabbits is an example of…

A

4 dif alleles that exhibit dominance hierarchy

45
Q

Himalayan pattern of coat color in rabbits is an example of a….

A

temperature sensitive conditional allele

46
Q

Produced by the immune system that bind to things that are foreign to the body. The binding signals WBC to destroy the foreign thing

A

Antibody

47
Q

Something that is recognized by the immune system antibodies

A

antigen

48
Q

Example of multiple alleles with co-dominance

A

ABO blood group (A and B dominant over O)

49
Q

The ABO blood group is determined by the…

A

type of antigen present on the surface of RBC

50
Q

AB blood groups are expressed in a ____ person

A

heterozygous

51
Q

O blood group represents a…

A

loss of function

52
Q

Determined by the type of carb antigen (sugar) recognized on the surface of….

A

ABO blood group, RBC

53
Q

Antigens ___ arises when a sugar is added to a sugar chain already in the surface of the RBC by an enzyme controlled by the allele of the I gene

A

A and B

54
Q

Allele i is a __allele that is ___ to both IA and IB in ABO blood group

A

null, recessive

55
Q

An allele that has the potential to cause the death of an organism

A

lethal

56
Q

Lethal alleles are typically the result of mutations in….

A

essential genes

57
Q

Many lethal alleles prevent ____.

A

cell division

58
Q

May kill an organism only when certain environmental conditions prevail

A

conditional lethal alleles

59
Q

The situation where the alleles of one gene can mask the phenotypic effects of the alleles of another gene

A

Epistasis

60
Q

When genes in the same pathway, but one gene comes before the other and masks the effects of the gene after it

A

epistasis

61
Q

Plays a role in coat color in rodents, two true breeding parents are crossed and become ____. The F1 ____ is crossed and produces what ratio?

A

epistasis, agouti animals, 9:3:4

62
Q

At least one copy of each dominant results in ____ color

A

agouti

63
Q

Refers to one gene influencing 2 or more seemingly unrelated phenotypic traits

A

Pleiotropy

64
Q

Occurs when both parents express the same, or similar recessive phenotypes but produce offspring with a wild-type phenotype

A

complementation

65
Q

Example of complementation

A

White flowers homozygous (CCpp) and (ccPP) are crossed to make a purple heterozygous flower (CcPp)

66
Q

Occurs when one gene can compensate for the loss of function of another

A

Gene redundancy

67
Q

Gene redundancy can be due to…

A

gene duplication

68
Q

Duplicate genes are called

A

paralogs (not always the same)

69
Q

Example of gene redundancy

A

seed shape, 15:1 ratio, dominant allele will give triangle

70
Q

Refers to a pattern in which modification occurs to a nuclear gene or chromosome that alters gene expression

A

epigentic inheritance

71
Q

What does not change over many generations

A

DNA sequence

72
Q

Two ways to obtain epigenetic inheriteance

A
  1. chromosomal dna is not naked in cell but covered in proteins that stick to it. gene copies are expressed different because proteins are binding the copies of the gene different.
  2. chromosomal dna can be chemically modified by added methyl group
73
Q

Adding a methyl group onto chromosomal dna has what effect?

A

cause genes to be less expressed or turned off

74
Q

Phenomenon in which expression of a gene depends on whether it is inherited from the mom OR dad

A

Genomic imprinting

75
Q

Genomic imprinting is another example of…

A

monoallelic expression

76
Q

The slient allele in genomic imprinting is known as

A

imprinted allele

77
Q

Random X inactivation is an example of

A

monoallelic expression

78
Q

Epigenetic inheritance allele is expressed in euchromatin

A

monoallelic expression

79
Q

In random x inactivation, the chromosomes become….

A

more condensed and a barr body is formed

80
Q

Imprinting results in the expression of the ___ but not the ___ allele

A

paternal, maternal

81
Q

The imprinted allele is the silent one so that Igf2 gene is…

A

maternally imprinted

82
Q

Dosage compensation occurs when ___ is not expressed

A

X in males

83
Q

Dosage compensation is only epigenetic inheritance in…

A

marsupials

84
Q

X inactivation brings about….

A

Dosage compensation

85
Q

The purpose of Dosage compensation is to….

A

offset the differences in the number of genes on the sex chromosomes

86
Q

X-linked gene dosage compensation in human females occurs by:

A

condensation throughout one of the two X chromosomes in females to form a ‘Barr Body’

87
Q

Klinefelters syndrome

A

male XXY

88
Q

Turner syndrome

A

X0, female

89
Q

Triple X syndrome

A

XXX, female

90
Q

The ____ it the thing that binds the sister chromatids of a chromosome originally inherited from mom to the sister chromatids of a homologous chromosome inherited from dad

A

synaptonemal complex

91
Q

Cell not in cell cycle is in

A

G0

92
Q

Incomplete dominance occurs because
A. a gene is found on the X chromosome
B. the dominant allele is not expressed due to environmental effects
C. 50% of the normal protein is not enough to produce the same phenotype as 100% of the protein.
D. the recessive allele inhibits the expression of the dominant allele

A

C

93
Q

Chloroplasts originated as

A

cyanobacteria

94
Q

mitochondria originated as

A

nonsulfer purple bacteria

95
Q

The endosymbiotic origin of organelles is supported by what observations?

A

organelles have circular chromosomes (like bacteria)

Organelle genes are more similar to bacterial genes than to those in the nucleus.

96
Q

Chloroplasts are only inherited from the ___. What kind of leaves?

A

mother, white or variegated

97
Q

Mitochondria are inherited from

A

mom

98
Q

Mitochondrial mutations may occur in ____cells. Why?

A

somatic; they are susceptible to DNA damage

99
Q

protein recruits proteins to create a new bacterial cell wall

A

FtsZ protein

Genetics (11 decks)

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