Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOLOGY STRUCTURED > 06. Genetics > Flashcards

06. Genetics Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is the phenotype ratio of the monohybrid cross?

A

3:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the phenotype ratio of dihybrid cross?(in independent assortment)

A

9:3:3:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the conditions we can apply the laws of independant assortment to?

A
  1. Genes located on different chromosomes
  2. genes located far apart on the same chromosome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Name the success of the Mendel’s experiments

A
  1. Mendel carried out thousands of genetic crosses of any given kind, closely resembling the
    probability predictions . Usually, larger the sample size, closer the results are to the value predicted based on probability.
  2. He kept an accurate record of his results. These records help him to trace the patterns which otherwise would go unnoticed.
  3. He usually followed up each cross for at least two offspring generation (F1 and F2) helped him to uncover some of the traits hidden in the F1 generation.
  4. He did a quantitative analysis of the phenotypes of the resulting offsprings.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the desirable properties of garden pea plants for the genetic experiment?

A
  1. Pea plants are available in many varieties with contrasting traits
  2. The generation time is short.
    ‘
  3. A large number of offspring is produced from each cross.
  4. Crossing between plants could be strictly controlled (by self/ cross pollination)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What kind of trait is attached/detached ear lobe?

A

both copies in recessive would result in the attached ear lobe.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What kind of trait is widow’s peak?

A

This occurs as a result of the recessive allele (ww)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What kind of trait is dimples on cheek?

A

It is a dominant trait
It often occurs in both of the cheeks
dimple occurring in one cheek is a rare phenomenon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What kind of trait is bent thumb?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What kind of trait is bent thumb?

A

Having a dominant S would produce the dominant phenotype of the straight thumb

Absence of dominant allele will allow the thumb to bend

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What kind of trait is rolling or non rolling of the tongue?

A

Rolling the tongue into a tube shape is a dominant trait

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does the intrinsic muscles of the tongue allow?

A

people to fold the tongue into specific shapes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Give an example for incomplete dominance

A

Mirabilis jalapa ( four’o clock plant)
when red is crossed with white plants, pink plants would be obtained.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the crossing of incomplete dominance?

A

CrCr x CwCw

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the gentype ratio for incomplete dominance?

A

1: 2: 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the phenotypic ratio for incomplete dominance?

A

1:2:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the phenotypic ratio for codominance?

A

Red:pink:white
1:2:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is an example for codominance?

A

AB blood group system; based on the type of carbohydrate present on the RBC surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the cross of codominance?

A

IaIa x IbIb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the genotype ratio for codominance?

A

1:2:3
IaIa:IaIb:IbIb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the phenotypic ratio of codominance?

A

1:2:1
A:AB:B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do we differentiate incomplete dominance from codominance?

A

incomplete dominance show a different phenotype than both of the parents whereas in codominance, F1 generation shows both the parental traits together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Name an example for Polyallelism?

A

ABO blood group system in humans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How is Polyallelism different from codominance?

A
  • IA and IB codes for enzymes that add A and B carbohydrates to the RBC surfaces. The two alleles are further in a codominant relationship

-However, ‘i’ allele results in the lack of these carbohydrates on the RBC surface.

  • It is recessive to both of the Ia and Ib alleles.

-Thus, ii would result in a recessive trait of not having either A or B on carbohydrates.

-Iai and Ibi genotypes would result in a dominant phenotype.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the cross in Polyallelism?

A

IaIa x ii = Iai (F1 generation)

IbIb x ii = Ibi (F1 generation)

Then:

Iai x Ibi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the genotype ratio of Polyallelism?

A

IaIb : Iai : Ibi: ii

1: 1: 1: 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the phenotype ratio of the F2 generation in Polyallelism ?

A

AB : A : B: O
1: 1: 1: 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the blood groups based on the presence of two carbohydrates?

A

Type A ( Carbohydrate A is present)
Type B ( Carbihydrate B is present)
Type AB ( Both A and B carbohydrates are present)
Type O ( Neither of the two carbohydrates are present)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are the two main types of epistasis based on the nature of the gene interaction?

A
  1. Dominant epistasis
  2. Recessive epistasis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is an example of the dominant epistasis?

A

Plumage colour of the house fowls

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the nature of the feather colors of the house fowls in the F1 generation?
What is the ratio of the dominant epistasis in the F2 generation?

A
  1. All of the feather colors would be white
  2. The white: coloured fowl ratio would be 13: 3
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the ratio of the dominant epistasis?

A

13:3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How is it crossed for the dominant epistasis?

A

A homozygous, double dominant white house fowl and a homozygous double recessive white house fowl are crossed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

How is the colour of the two fowl varieties are determined by?

A
  1. Gene C/c is responsible for producing the colour in the feathers. The dominant C produces colour while the recessive c results in the absence of pigmentation.
  2. Gene I is epistatic to the gene C and it suppresses the expression of the colour. Dominant I allele prevents the production of pigmentation. recessive i is unable to prevent colouration.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the cross used in the dominant epistasis?

A

CCII x ccii - CcIi

then CcIi x CcIi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What makes a species white in dominant epistais?

A

presence of both C and I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Name an example for recessive epistasis?

A

Lathyrus (sweet pea) plant containing purple and white coloured flowers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is the cross used in recessive epistasis?

A

Purple flower (AABB) x heterozygous recessive flower (aabb)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is the result of the recessive epistasis?

A

F1 generation- AABB and aabb produces all purple coloured plants.

F2 generation phenotype ratio- purple: white = 9:7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is the purple colour of the sweet pea plant in recessive epistasis governed by?

A
  • 2 dominant A and B genes code for the purple colour of sweet pea plants
  • A and B alleles code for compounds that are necessary of purple colour. Purple colour will only be present with A and B.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are the traits involved in polygenic inheritance?

A
  1. Height
  2. skin colour (A, B and C contribute to the dark skin allele contributing 1 unit of phenotype. It is incompletely dominant to a, b and c alleles)
  3. IQ
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Based on the number of genes in determining a polygenic character , what might vary?

A
  1. Phenotype combinations
  2. Genotype combinations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What kind of phenotypes do majority of offspring have?

A
  • Intermediate phenotypes
44
Q

Give an example genetic linkage?

A

Inheritance of body colour and wing size of Drosophila flies- wild type flies are found to have gray bodies and normal sized wings.

45
Q

How is both of the characters determined in gene linkage?

A

By the genes of autosomal characters

46
Q

In gene linkage, why does it escape from crossing over and independent assortment?

A
  1. That is because some genes coding for a particular character are located on the same chromosome.

2.They are also at a closer distance.

47
Q

In gene linkage, due to mutation, what happens to the traits?

A

The body colour of the above traits which are of gray bodies and normal sized wings of wild type become black and wings become vestigial.

48
Q

What are recessive alleles to the wild type alleles in gene linkage?

A

Mutant alleles of gene linkage.

Body colour alleles

G- gray
g- black

Wing size alleles

N- normal
n- Vestigial

49
Q

What was the cross conducted during gene linkage?

A

Crossing of the wild type alleles with the mutant alleles( to both body size and the wing size)

Followed by a dihybrid cross

50
Q

What was the cross conducted during gene linkage?

A

Crossing of the wild type alleles with the mutant alleles( to both body size and the wing size)

Followed by a dihybrid cross

51
Q

What is the phenotype and genotype ratio during gene linkage?

What kind of genotype did most offsprings have?

A

Genotype ratio : GgNn: Ggnn: ggNn: ggnn
1: 1 : 1: 1

Phenotype ratio : Gray body normal: Gray body vestigial wings: Black body normal wings: Black vestigial wings
1: 1: 1 : 1

52
Q

During gene linkage, what happens in some occasions?

A

They get assorted independently due to crossing over.

The above gene linkage test-cross results in recombinant offsprings in lower frequency.

53
Q

What is the genotype ratio of monohybrid cross?

A

1:2:1

54
Q

What are the examples for human sex linked diseases?

A

Red-Green color blindness
Hemophilia

55
Q

Red-Green colour blindness is caused as a result of . . .?

A

X-linked recessive gene

56
Q

What is red-green color blindness characterized by?

A

By the difficulty in perceiving differences between red and green colors

57
Q

Hemophilia is resulted by…?

A

X-linked recessive gene

58
Q

What happens in hemophilia?

A

One or more proteins required for blood clotting are absent.

59
Q

Name a risk factor of hemophilia

A

Severe bleeding during injuries due to delay in clot formation

60
Q

What are pleiotropic alleles responsible for?

A

Multiple symptoms associated with certain hereditary symptoms in humans such as cystic fibrosis and sickle cell disease.

61
Q

sickle cell disease cause?

A

Alteration in the hemoglobin protein of RBC is the cause for the sickle cell disease. A single gene mutation is responsible for the above condition.

62
Q

What are the types of individuals of sickle cell variety?

A

Homozygous recessive individuals

63
Q

What kind of people experience a low oxygen content in blood?

A

People living in high altitudes and under higher physical stress

64
Q

What takes place during sickle cell disease?

A

Low oxygen content in the blood may induce the sickle cell hemoglobin to get accumulated. It then results in sickle shape in red blood cells.

65
Q

In sickle cell disease, what takes place?

A

Sickle cells may clump and clog small blood vessels causing tissue and organ damage in several body parts.

66
Q

What is cystic fibrosis?

A

A disease condition causing thicker and stickier mucus than its normal structure

67
Q

Where does mucus get accumulated in cystic fibrosis?

A

Pancreas
Lungs
Digestive Tract
Reproductive Organs

68
Q

what does the accumulation of mucus result in cystic fibrosis?

A

Lung infections
Respiratory failure
Poor digestion
Infertility

69
Q

Why does the thickening of mucus occur?

A

due to excess chlorine secretion of defected chlorine channels of the plasma membrane

70
Q

why does the defect in the transmembrane chlorine channels occur?

A

As a result of cystic fibrosis regulator protein (CFTR).

71
Q

What is the cause for altered CFTR protein?

A

The mutation of the CFTR gene

72
Q

What kind of disease is cystic fibrosis?

A

Autosomal recessive disorder

73
Q

What is epigenetics caused by?

A

As a result of switching on and switching off of certain genes by modifying nucleotides of a DNA sequence by methylation and demethylation

74
Q

What is epigenetics resulted from?

A

Epigenetics results due to either inherited signals from parents

Due to the environmental factors

75
Q

How can epigenetics be reversed?

A

by various external stimuli from the environment

76
Q

What do some epigenetic influences result in?

A

Some epigenetic influences result in inappropriate gene expressions leading to cancers.

77
Q

What is schizophrenia?

A

Schizophrenia is a mental disorder that occurs due to the genetic defects

78
Q

What happens during schizophrenia in identical twins?

A

In some identical twins, only one of them gets schizophrenia and the other does not get it. This is due to two types of expressions for same DNA sequence, called epigenetics.

79
Q

What is Hardy-Weinberg equilibrium used for?

A

Hardy-Weinberg Equilibrium is used to assess whether a population is evolving with respect to a particular characteristic/ genetic locus

80
Q

If the population isn’t evolving, what would the genetic makeup of a trait be like according to Hardy-Weinberg equilibrium?

A

In 1908 British mathematician G.H. Hardy and German physician W. Weinberg, independently showed that, in a population that is not evolving, allele and genotype frequencies will remain constant from generation to generation.

The genetic makeup of a trait in a population would remain unchanged, if they are not evolving at that genetic locus.

81
Q

To determine allele and genotype frequency change in consecutive generations what can be drawn according to Hardy-Weinberg equilibrium?

A

A Punnett-square!

82
Q

What does P squared determined in Hardy-Weinberg equilibrium?

A

Frequency of dominant homozygotes

83
Q

What is denoted by Q squared?

A

Frequency of

84
Q

What are the factors affecting Hardy-Weinberg Equilibrium?

A
  1. Absence of mutations:
  2. Occurrence of random mating
  3. Absence of natural selection
  4. Size of the population is extremely large

5.Absence of immigration or emigration

85
Q

What is the importance of plant and animal breeding?

A

Addressing world food and feed quality needs

Addressing food supply needs for a growing world population

Need to adapt to environmental stresses

Satisfying industrial and other end-use requirements

Developing animal and plant varieties with aesthetic values

86
Q

What are breeding techniques?

A

Artificial selection

Inbreeding and out breeding

Hybrid breeding

Interspecific breeding

87
Q

Give examples for artificial selection

A

Corn

88
Q

Give examples for inbreeding

A

Plants:
Wheat
Oats
Barley
Tobacco

Animals:
Mating of father and daughter, brother and sister or cousins

89
Q

Give examples for outbreeding

A

In India zebu breeds of cows and nondescript cows are crossed with exotic breeds like Holstein Fresian, Brown Swiss and Jersey bulls or their semen.

Corn and hemp are cross fertilized.

90
Q

Give examples for hybrid breeding

A

Nearly all corn and 50% of rice

91
Q

Give examples for interspecific breeding

A

plants :
bread wheats, boysenberries (Rubus ursinus x idaeus)
blackberries (Rubus fruticosus)
European raspberries (Rubus idaeus)
loganberries (Rubus × loganobaccus)
Malus × domestica from Malus × asiatica and Malus pumifolia.

animals:
Mule (male donkey x female horse)
Hinny (male horse x female donkey)
Liger (male lion x female tiger)
zebra/donkey cross called zonkey
zebra/ horse cross resulting in zorse.

92
Q

Name genetic principles of breeding techniques

A

Polyploidy
Mutation Breeding
Genetic Modification

93
Q

Give examples for polyploidy

A
94
Q

What is the prerequisite for artificial selection?

A

*availability of variation with respect to the desirable characters.

*Once a population with a desirable variation is recognized, the best
performing individuals for the desired feature are selected.

95
Q

What takes place during artificial selection?

A

*Once a population with a desirable variation is recognized, the best performing individuals for the desired feature are selected.

*The progeny of the selected individuals is
grown further and again screened for the desired feature. This process is repeated sometimes
for many generations, until a uniform plant population is attained *

96
Q

What are advantages of artificial selection?

A

*The advantage of selective breeding is that it uses the processes of natural selection, but under
direct supervision from carefully selected animals or plants with the desired traits.

*There are no genetic modifications or other forms of tampering that could potentially harm people and the risk
to the plant or animal is often minimum.

97
Q

What is a disadvantage of artificial selection?

A

However, selective breeding among animals can take a long time for the process to work.

98
Q

What are the disadvantages of inbreeding?

A
  • As a rule, inbreeding increases homozygosis and thus exposes harmful recessive genes which
    would have otherwise stay hidden among heterozygotes.
  • Continued inbreeding, therefore, reduces genetic fitness of the population. As a result, the growth and fertility of the inbred population would go down with adverse effect on their productivity.
  • Prevalence of genetic disorders might also increase among the inbred population.
99
Q

What are advantages of outbreeding?

A

This allows the desirable characters of the exotic parent, which the indigenous parent does not have, to be transmitted to the progeny.

100
Q

Name a disadvantage of interspecific breeding?

A

Often interspecific hybrids are sterile or for some other reason cannot interbreed with the parental
species.

101
Q

Name some examples for polyploidy

A

In plants : polyploidy can be induced artificially using antimitotic agent, colchicine.

(widely used principle in plant breeding.)

102
Q

What are advantages of polyploidy?

A

*Plant breeding are the increment in plant organs (‘‘gigas’’ effect) caused by the larger number of gene copies. Polyploid individuals may thus exhibit larger organs compared to their diploid counterparts, such as roots, leaves,
tubercles, fruits, flowers and seeds.

*Polyploid plants also have lower growth rates, and tend to
flower later or over a longer period of time than related diploids, which is a desirable feature for
ornamental breeding.

*On the other hand, when the crossing between two species is not possible because of differences in ploidy level, polyploids
can be used as a bridge for gene transferring between them.

*Similarly, the genome doubling in a newly formed sterile hybrid allows the restoration of its fertility.

*The increment in heterozygosity, leading to improving the product quality and increasing the tolerance to both biotic and abiotic stresses.

  • Genome redundancy promotes a ‘‘buffering’’ effect in which the deleterious alleles are masked by the extra
    copies of wild-type alleles.
103
Q

What are disadvantages of polyploidy?

A

*In addition, polyploidy often results in reduced fertility due to meiotic errors, allowing the production of seedless varieties such as the triploid watermelon.

*At the same time, genome redundancy allows functional diversification of redundant gene copies, in which one member of a duplicated gene pair mutates and acquires a novel function, without compromising essential functions.

104
Q

What are examples for polyploidy

A

maize, potato and alfalfa

improving the product quality and increasing the tolerance to both biotic and abiotic stresses.

105
Q

What are the agents that can cause mutations during mutation breeding?

A

ionizing radiation such as gamma rays, protons, neutrons, alpha and beta particles and chemicals such as sodium azide and ethyl
methanesulphonate.

BIOLOGY STRUCTURED (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions