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Summer Bio Final - All Notes > Chapter 9 > Flashcards

Chapter 9 Flashcards

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Biology 101 flashcards
1
Q

Define genetics

A

Discrete heriable factors

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2
Q

define true breeding

A

PP + pp

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3
Q

What are mendels 4 hypotheses

A

1.) Alleles are alt forms of genes
2.) 2 alleles for each characteristics, 1 from each parent
3.) when 2 alleles of a pair are diff, 1 is fuly expressed (Pp)
4.) law of segregation: alleles separate from eachother in meiosis

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4
Q

What is meant by dominant and recessive alleles

A

Dom: expressed (D)
Recss: not expressed unless homozygous recessive (d)

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5
Q

Define Homozygous

A

2 identical alleles (DD)

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6
Q

Define heterzygous

A

2 diff alleles (Dd)

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7
Q

What is genotype? Phenotype?

A

Geno: genetic makeup
Pheno: physical expression

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8
Q

What 3 combos can a pair of allels be found

A

Homo Dom: DD
Homo Recessive:dd
Hetero: Dd

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9
Q

What is a dihybrid cross

A

mating parents w 2 characteristics

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10
Q

Identify gametes of TtYy

A

TY, Ty, tY, ty

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11
Q

What is meant by the principle of independent assortment

A

alleles f genes are distributed to gametes randomly, genes are inherited independently from eachother, random orientation on metaphase plate in meta 1

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12
Q

What is a carrier? how can 2 hearing parents have a deaf child

A

Carrier: Popele who carry one copy of the allele for a recessive disorder (Dd)
If both parents are carriers they have a 25% chance of having a deaf child

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13
Q

When are recesisve disorders expressed?

A

Homozygous recessive for the trait

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14
Q

what are examples of recessive disorders?

A

Deafness, Cistic fibrosis, albanism, tay-sachs, sickle cell

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15
Q

What is a dominant disorder? Why are they less common?

A

Disorders carried in dom alleles. Only happens if heterozygous

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16
Q

What are examples of dominant disorders?

A

Achroplasia (dwarfism), Alzheimers, huntingtons

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17
Q

Describe incomplete dominance

A

Inbtw pheontype where one allele is not completly expresed over the other (not the same as blending)

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18
Q

Define and give examples of polygenetic inheritance

A

2+ genes control one pehnotype trait
Ex: Skin color, height, weight, eyecolor, herat disease

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19
Q

Explain pleitropy and give an example

A

One gene controls multiple charcateristics
Ex: Sickle cell

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20
Q

Define sex-linked traits. give some examples

A

Gene located on either sex chrom (usually X)
Ex: Red/Green colorblindness, Hemophilia, dachenae-muscular dystrophy

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21
Q

Who was the father of genetics?

A

Gregor Mendel

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22
Q

What did mendel study?

A

Variation among garden pea plants.

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23
Q

What was Mendel’s 4 Principles?

A

1) Each individual has at least two alleles for each trair, one from each parent.
2) The different versions of a trait are contained by the two inhereted alleles. (Homo or hetero)
3) Expression of trait physically is determined by the genetic information from both parents. An individual contains one allele from one parent, and one allele from the other.
4) The alleles may be dominant or recessive.

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24
Q

Which type of allele is expressed?

A

Dominant

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25
Q

What is an allele?

A

A different version of a gene

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26
Q

What does locus mean?

A

Location of genes on chromosomes.

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27
Q

What does genotype mean?

A

Genetic makeup of individual. Allele makeup (Hh, HH, hh)

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28
Q

What does phenotype mean?

A

The trait that is shown, actual physical makeup.

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29
Q

What is a monohybrid cross?

A

Crossing one character. Two alleles on a single locus are studied.

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30
Q

What does homozygous dominant mean?

A

It means both alleles are dominant. Both capitalized letters.

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31
Q

What does heterozygous dominant mean?

A

It means that you have one dominant allele and one recessive. One uppercase, one lowercase letter.

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32
Q

What does homozygous recessive mean?

A

It means that both alleles are recessive. Both lowercase letters.

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33
Q

What does true breeding mean?

A

It means that both parents only have 1 type of allele. (HH and hh)

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34
Q

If a parent plant is homozygous dominant, or true breeding purple, and the other is homozygous recessive, or true breeding white, what would the genotype look like?

A

0% PP, 100% Pp, 0% pp

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35
Q

What is a punnett square?

A

A grid of boxes used to determine all possible outcomes of alleles from genetic crossing.

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36
Q

What is the P generation?

A

The parental generation.

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37
Q

What is the F1 generation?

A

The offspring produced from crossing of 2 parents.

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38
Q

Given the previous example, what is the F1 generation genotype?

A

25% PP, 50% Pp, 25% pp

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39
Q

Given the previous example, what is the F1 generation phenotype?

A

75% purple, 25% white

40
Q

You do a monohybrid cross of a male (XY) and a female (XX) and get XX, XX, XY, and XY. What percent of offspring will be male? Female?

A

50% and 50%

41
Q

What is a dihybrid cross?

A

A two trait test cross to determine the genotype for two traits.

42
Q

YY = yellow seeds. Yy = yellow seeds. yy = green seeds. RR = smooth seeds. Rr = smooth seeds. rr = smooth seeds. What would the PHENOTYPE be for YYRR and Yyrr?

A

YYRR = Yellow and smooth. Yyrr = yellow and wrinkled.

43
Q

What method do you use to set up a dihybrid cross?

A

FOIL method.

44
Q

Tongue rollers (T) can roll the edges of their tongue up to form a U shape. The inability to roll one’s tongue is recessive (t). Both Tony and his wife Tonya are heterozygous for tongue rolling. A widow’s peak hairline (H) is dominant over a straight hairline (h). Tony is hererozygous for a widow’s peak, but Tonya has a straight hairline. What are their GENOTYPES?

A

Tony: TtHh
Tonya: Tthh

45
Q

Tony’s genotype is TtHh. Tonya’s genotype is Tthh. What are their possible gametes?

A

Tony: TH, Th, tH, th.
Tonya: Th, Th, th, th

46
Q

What is a test cross?

A

It is performed to determine the genptypes of two parents. It is working backwards to use the offspring phenotype to determine the genotypes of the parents.

47
Q

Give an example of a test cross.

A

Black fur is the dominant color in labrador retrievers, so a black lab could have either genotype Bb or BB. Chocolate labs are recessive, so all chocolate labs must be bb. If you have black and chocolate puppies, you would have had to cross a bb (chocolate lab) with a Bb (black lab).

48
Q

What are recessive disorders?

A

They are disorders located on autosomal chromsomes. People with these are often born to normal parents.

49
Q

If a parent is ____ for a disorder, then they are a carrier.

A

Hererozygous

50
Q

How many alleles for the disorder must the offspring receive in order to express the recessive disorder?

A

2, homozygous recessive.

51
Q

Recessive disorders include:

A

Cystic fibrosis, Albinism, Tay-Sachs, and Sickle Cell Anemia. (CATS)

52
Q

Most disorders are autosomal recessive. What does that mean? Would the carrier likely show the signs of the disorder?

A

It means that the disorder shows up on a heterozygous recessive offspring. Carrier wouldn’t show signs of it, but it means that their parents were carriers also.

53
Q

Define pedigree. When might a pedigree be useful?

A

Pedigree is a chart that diagrams inheritance of health conditions. It can be used to see if parents are carriers.

54
Q

What is a dominant disorder?

A

When the dominant allele causes the disorder to express phenotypically. Offspring will exhibit the disorder if only one allele is inherited.

55
Q

Dominant recessive disorders include:

A

Huntington’s, Alzheimers, Achondroplasia, and Polydactylism.

56
Q

Why are dominant disorders less common than recessive disorders?

A

Because if they are homozygous, the embryo dies before it can even be born.

57
Q

What is incomplete dominance?

A

When the dominant allele(s) are not fully dominant and a small percent of the recessive allele expresses phenotypically.

58
Q

If an allele shows incomplete dominance, what will occur phenotypically when it pairs with a recessive allele?

A

You will see a mixture of both dominant and recessive.

59
Q

What is a common example for incomplete dominance?

A

Snapdragons. RR is a homozygous dominant red, and rr is homozygous recessive. The offspring will all be pink.

60
Q

How do you know genes aren’t ‘blended’ together?

A

Because the heterozygote contains both distinct alleles in their phenotype.

61
Q

What is codominance?

A

When there is more than one dominant allele.

62
Q

What is a common example of codominance?

A

Blood type in humans.

63
Q

What are the 4 possible phenotypes for blood type?

A

A, B, AB, or O

64
Q

What is the genotype for A?

A

AA or AO.

65
Q

What is the genotype for B?

A

BB or BO.

66
Q

What is the genotype for AB?

A

AB

67
Q

What is the genotype for O?

A

OO

68
Q

What blood type is the universal donor?

A

O blood

69
Q

What blood type is the universal recipient?

A

AB

70
Q

How are incomplete dominance and co-dominance different?

A

In incomplete dominance, there is expression from both the dominant and recessive alleles, so the offspring doesn’t display characteristics of its parents. In co-dominance, offspring exhibits both traits simotaniously.

71
Q

What is pleitropy and an example?

A

It is when one gene controls multiple characteristics. Ex) Sickle cell disease (homozygous recessive)

72
Q

What is polygenetic inheritance?

A

When many genes affect a single phenotype. Ex) eye color, skin color, hair type. (A, B, C alleles are incompletely dominant over a, b, c alleles).

73
Q

How are skin color and eye color examples of polygenetic inheritance?

A

Because they are controlled by many genes that are incompletely dominant. There is a spectrum/gradient of the phenotype.

74
Q

How are phenotypes a combination of genetics and environment?

A

Because someone can have the genetic makeup for a phenotype, but the environment can cause it to be something else. For example, someone could have the genetic makeup for a high IQ, but if they never are exposed to learning, then that environment causes them to remain with a low IQ.

75
Q

What are sex linked traits?

A

They are genes located on either sex chromosome.

76
Q

What is another name for sex linked traits?

A

X-linked

77
Q

Why are sex linked disorders more common in men than women?

A

Because males only have 1 copy of the X chromosome, whereas women have 2 copies. Males only need one defective allele to be affected.

78
Q

Are sex-linked disorders caused by dominant alleles or recessive alleles?

A

Recessive alleles. (XC = dominant and normal. Xc = recessive and defective).

79
Q

Define genetics, hybrids, and true breeding.

A

Genetics is the study of heredity. Passing of characteristics or traits to offspring. Hybrids are an organism that have 2 different alleles for a trait. True breeding is when an organism has both the same allele for a trait

80
Q

What are Mendel’s 4 hypothesis?

A

1) Each individual has at least two alleles for each trair, one from each parent.
2) The different versions of a trait are contained by the two inhereted alleles. (Homo or hetero)
3) Expression of trait physically is determined by the genetic information from both parents. An individual contains one allele from one parent, and one allele from the other.
4) The alleles may be dominant or recessive.

81
Q

What is meant by dominant and recessive alleles?

A

Dominant is what is expressed, recessive is the other trait.

82
Q

Define homozygous, heterozygous, P generation, F1 generation, F2 generation.

A

Homo: both alleles same. Hetero: one of each allele. P generation: parental generation. F1: offsprings made from breeding the parent generation. F2: offspring made from breeding the F1 generation.

83
Q

What is meant by genotype? Phenotype?

A

Genotype is the possible genetic makeup, and phenotype is what is actually expressed.

84
Q

In what three combinations can a pair of alleles be found?

A

Homozygous dominant, homozygous recessive, and heterozygous.

85
Q

What is a dihybrid cross?

A

When you cross 2 different characters on different genes.

86
Q

What is meant by the principle of independent assortment?

A

Genes for different traits can segregate independently during the formation of gametes

87
Q

When is making a pedigree beneficial?

A

When you are trying to see if a parent is a carrier.

88
Q

Describe a carrier. How can two parents with normal hearing produce a deaf child?

A

When a parent is heterozygous. They don’t express it, but they carry the allele for it.

89
Q

When are recesisve disorders expressed? Give some examples.

A

When you have a homozygous recessive offspring. An example is Cystic fibrosis, albinism, tay-sachs, and sickle cell anemia.

90
Q

Define dominant disorder. Why are they less common than recessive disorders? Give some examples.

A

It is when the dominant allele causes the disorder to express in the phenotype. They are less common because if you have a homozygous dominant offspring, they die right away. Examples are Huntington’s, alzheimers, achondroplasia, and polydactylism.

91
Q

Describe incomplete dominance

A

When the dominant trait doesn’t fully mask the recessive trait so both show up phenotypically.

92
Q

Define and give examples of polygenetic inheritance

A

Polygenetic inheritence is when multiple genes code for one characteristic, like hair color or eye color.

93
Q

Explain the inheritance of blood type. What are the posisble combos?

A

It is co-dominant. This means both dominant alleles are expressed.

94
Q

Explain pleitropy and give an example

A

It is when a single gene controls multiple characteristics. An example is sickle cell.

95
Q

List some benefits of genetic testing. Disscuss the dangers of genetic tesing

A

You will be able to tell if you are a carrier. It can be emotionally and socially dangerous.

96
Q

Define sex-linked traits. give some examples

A

Sex linked traits are ones that are located on either sex chromosome. Examples are color blindness and hemophilia.

Summer Bio Final - All Notes (11 decks)

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