Brainscape's Knowledge GenomeTM

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


See full index

A-Level Biology > Inheritance > Flashcards

Inheritance Flashcards

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

What are the rules for monohybrid crosses?

A 
Upper case = dominant
Lower case = recessive
Label parents + their phenotype
Label parental gametes (circle them)
Draw punnet square
Always write dominate allele first
State phenotypes
Ratio
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a monohybrid cross?

A

A cross in which alleles of only one gene are involved

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

What is monohybrid inheritance?

A

Inheritance of single genes

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

What are monohybrid crosses used to do?

A

To determine dominant relationship between two alleles

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

What will be the phenotype of offspring with parents with Rr?
R = orange skin
r = blue skin

A 
3:1
RR
Rr
Rr
rr
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are diploid organisms characteristics determined by?

A

Alleles in pairs

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

What is pure-breeding?

A

When both homologous organisms are bred

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

What does pure-breeding result in?

A

1st filial (F1) generation

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

How many alleles can be present in a single gene?

A

Only one of each pair

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

Can pure-breeding varieties be crossed with other pure-breeding varieties?

A

YES

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

What is dihybrid inheritance?

A

Inheritance of 2 characteristics at the same time

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

What does dihybrid crosses/inheritance show?

A

Shows how 2 characteristics, determined by 2 different genes, located on different chromosomes are inherited

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

What did Mendel discover about peas?

A

Round + yellow = dominant

Wrinkled + green = recessive

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

What phenotypes would be produced if you crossed yellow + round peas?
Genotype = RrYy

A 
9:3:3:1
Yellow + round
Round + green
Yellow + wrinkled
Wrinkled + green
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why does F2 in dihybrid inheritance have 4 types of gametes?

A

As gene for colour + gene for shape are on separate chromosomes

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

What does it mean their is random assortment in meiosis?

A

There can be either shape allele

+ either colour allele

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

What does it mean that fertilisation is random?

Dihybrid inheritance

A

So any 4 gametes with one parent can mix with any 4 gametes from another parent

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

How many gametes should dihybrid have?

A

4

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

What is the Law of Independent Assortment?

A

Each member of a pair of alleles may combine randomly with either of another pair

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

What is codominance?

A

When both alleles are expressed in the phenotype; neither are dominant or recessive - they are equally dominant

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

What are the rules to consider with codominance crosses?

A

Can’t use upper + lower case
Use different letters in stead
Subscript = gene in question

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

What is an example of codominant?

A

CR CR
CW CW
CR CW

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

What is the genotype for a red flower in codominance?

A

CR CR

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

What is the genotype for a white flower in codominance?

A

CW CW

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

What is the genotype for a pink flower in codominance?

A

CR CW

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

Why is a pink flower produced when there it is heterozygous codominant?

A

As single functioning allele only produces enough pigment for pink

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

What phenotype would be produced if you crosses a codominant white and red flower?

A

Pink flowers 1:1:1:1

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

What phenotype would be produced if you crossed the codominant F1 generation?
Pink flowers

A 
1:2:1
C*R C*R
C*W C*W
C*R C*W
C*R C*W
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are multiple alleles?

A

When alleles have more than 2 alternative forms of a single gene, located at the same loci of homologous chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is an example of a polygenetic phenotype?

A

Eye colour

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

What is polygenetic determined by?

A

Several genes at different loci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are the three human blood group alleles associated with?

A

Immunoglobulin gene (I)

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

What are the three human blood group alleles?

A

IA
IB
I*o

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

What does gene I dictate?

A

The presence of certain antigens on the cell surface of a RBC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What antigen does I*A present?

A

A

Round-shaped

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

What antigen does I*B present?

A

B

Pointy triangular-shape

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

What antigen does I*o present?

A

Neither

No antigen present on RBC

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

Even though there is 3 blood group alleles how many are present in one individual?

A

2

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

Why are only 2 blood group ales only present in one individual?

A

As only 2 homologous chromosomes, so only 2 gene loci

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

What are IA + IB?

A

Codominant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is I*o?

A

Recessive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

How many possible blood groups is there?

A

4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What are the four different blood groups

A

A
B
AB
O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What are the possible genotypes of blood group A?

A

IA IA

IA Io

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are the possible genotypes of blood group B?

A

IB IB

IB Io

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What are the possible genotypes of blood group AB?

A

IA IB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What are the possible genotypes of blood group O?

A

Io Io

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Why can I*o be present in blood group A + B?

A

Because I*o is recessive so doesn’t change phenotype

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What antigens will blood group AB have present?

A

Rounded + pointy triangular

50
Q

What antigens will blood group A have present?

A

Rounded

51
Q

What antigens will blood group B have present?

A

Point-triangular

52
Q

What antigens will blood group O have present?

A

NONE

53
Q

What phenotype is produced when you cross
IA IB
Io Io

A 
2:2
I*A I*o
I*B I*o
Blood group A + B
Offspring don't have same blood group as parents
54
Q

What phenotypes would be produced if you crossed F1 blood group generations?
IA Io
IB Io

A

1:1:1:1

55
Q

What should you get if you cross heterozygous blood groups?

A

1:1:1:1

56
Q

What is one chromosome composed of before replication?

A

One DNA molecule

57
Q

What is one chromosome composed of after replication?

A

Two identical DNA molecules

58
Q

What does it mean about the chromosome after replication?

A

Amount of DNA increases but no. of chromosomes stay the same

59
Q

How many chromosomes is there?

A

46

60
Q

How many pairs of chromosomes is there?

A

23

61
Q

How many out of the 23 are homologous pairs?

A

22

62
Q

Why is the 23rd pair no homologous?

A

Because it is the sex cells

X and Y

63
Q

What are genes located on X or Y?

A

Sex-linked

64
Q

What is the difference between the structure of X and Y?

A

X is longer than Y

65
Q

What does it mean that X is longer than Y?

A

Genes found on X do not have a homologous equivalent on Y

66
Q

What are males?

A

XY

67
Q

What are females?

A

XX

68
Q

Why are recessive characteristics more common in males?

A

As no homologous section on Y that could carry dominant allele

69
Q

What is haemophilia?

A

Blood doesn’t clot correctly
So leads to excessive bleeding following a cut or internal bleeding
Fatal is not treated

70
Q

What sex cell is haemophilia linked to?

A

X

71
Q

What type of genetic disorder is it?

A

Recessive

72
Q

What does the haemophilia genes code for?

A

Alternative base sequence = faulty protein

73
Q

What can the healthy protein to treat haemophilia be produced by?

A

GM organisms

74
Q

What phenotype would be produced if a carrier female was crossed with a normal male?

A

1:1:1:1

75
Q

When doing a sex linage cross what must you include?

A

The X and Y

So you can see which gender has what alleles

76
Q

When doing sec linkage cross what must you always say as well as the phenotypes?

A

Genders

77
Q

What is a carrier?

A

Someone who has the genotype to pass on the genetic disorder but it is not expressed in their phenotype

78
Q

What does it mean if any 2 genes are found on the same chromosome?

A

They are linked

79
Q

What is formed when all genes are on a single chromosome?

A

Linkage group

80
Q

What is autosomal linkage?

A

When 2 or more genes are carried on the same autosome

81
Q

What happens to all linked genes in meiosis?

A

They all stay together

82
Q

What does it mean that all linked genes stay together during meiosis?

A

They will pass on into gametes together

So will pass into offspring together

83
Q

Does autosomal linkage follow Mendel’s Law of Independent Assortment?

A

NO

84
Q

Why doesn’t autosomal linkage follow Mendel’s Law of Independent Assortment?

A

Since each allele is not free to mix with either allele from another pair

85
Q

Which cross produces the ratio 3:1?

A

Monohybrid - 2 heterozygous

86
Q

Which cross produces the ratio 9:3:3:1?

A

Dihybrid - 2 heterozygous

87
Q

Which cross produces the ratio 1:1:1:1?

A

Blood group - heterozygous A + B

Sex linkage - carrier female, normal male

88
Q

Which cross produces the ratio 1:2:1?

A

Codominance - heterozygous

89
Q

What is epistasis?

A

When the allele of one gene affects/masks the expression of another in the phenotype

90
Q

Describe agouti

A

Wild type
Grey/brown
Banded
AABB, AaBB, AABb, AaBb

91
Q

Describe albino

A

No melanin
Hs to have bb
AAbb, Aabb, aabb

92
Q

Describe black

A

Uniform black hairs
No banding
aaBb, aaBB

93
Q

What phenotypes are produced when two agouti (AaBb) mice are crossed?

A

9:4:3
Agouti: White : Black

94
Q

Why is an albino mouse produced when bb is present?

A

Because if there is no melanin = gene A cannot be expressed

95
Q

What is produced if a dominant allele is present in a biochemical pathway?

A

Functional enzyme

96
Q

What is produced if homozygous recessive is present in a biochemical pathway?

A

Non-functional enzyme

Disrupt pathway

97
Q

What is a biochemical pathway?

A

Some genes act in a sequence by coding for specific enzymes in pathway

98
Q

Explain how a mutation could cause an enzyme not to work

A

Mutation causes change in sequence (write where it changes)
= change in sequence of amino acids
= changes tertiary structure of protein
= active site no longer complementary

99
Q

Explain how it shows the man is heterozygous

A

Inherited recessive from mother
Normal allele from father
Father doesn’t have recessive allele or would have it

100
Q

Explain why Mendel’s work was not accepted

A

Wasn’t much scientific evidence about genetics yet

Already had pre-considered conditions

101
Q

Why might the prediction of fur type not be proved right?

A

Fertilisation is random

102
Q

Describe the difference between dominant + recessive alleles

A

Recessive not expressed in the presence of dominant alleles

103
Q

Describe the difference between alleles and genes

A

Gene is a section of DNA that codes for a specific sequence of amino acids
Allele is a version of a gene

104
Q

Describe the difference between homozygous + heterozygous chromosomes

A 
Homozygous = same alleles
Heterozygous = contain different alleles
105
Q

Explain how meiosis results in plants producing gametes with certain genotypes

A

Homologous pairs halved

Independent assortment

106
Q

What is a recessive allele?

A

An allele that mist be homozygous to produce a trait and won’t be expressed in the presence of a dominant allele

107
Q

What is a dominant allele?

A

The one that is always expressed

108
Q

Why would farmers only want calves of the same sex?

A

Females for milk

109
Q

How does the diagram show it is a recessive allele?

A

Unaffected parents have unaffected offspring

Give examples from diagram!

110
Q

Explain why observed ratios are often not the same as expected ratios

A

Fertilisation random

OR not large enough sample size

111
Q

Use gene linkage to explain results

A

All linked genes stay together during meiosis
GgNn individuals produce mainly GN + gn gametes
Gn + gN come from crossing over so fewer of them
USE EXAMPLES IN QUESTION

112
Q

What environmental factors affect egg production?

A

Temperature

Light intensity

113
Q

Explain why genes being close together on chromosome when identifying potential phenotype of offspring

A

Reduces chance of crossing over

If crossed over = mixture of gametes

114
Q

Explain how the genotype bbee produces yellow coat colour

A

All homozygous recessive = no enzyme produce

Stays yellow

115
Q

Explain how the genotype BbEe produces black coat

A

Two dominant = both enzymes produced

Two conversions take place

116
Q

Explain how to get white, red and purple flowers in this biochemical pathway

A

Both genes are involved in producing the different colours as one gene controls the expression of another - epistasis
White flower = Gene 1 + 2 both must have homozygous recessive alleles = neither enzyme produced = remain white
Red flower = Gene 1 must have at least one dominant allele so the 1st enzyme can be produced = convert pigment red. BUT gene 2 must have homozygous recessive alleles = enzyme 2 isn’t produced = no conversion from red to purple
Purple flower = Gene 1 + 2 must both have at least 1 dominant allele so both enzymes can be produced= 2 conversions of colour

117
Q

What is the loci?

A

Specific physical location of a gene on a chromosome

118
Q

What is a histone?

A

Protein that provides structural support to a chromosome

119
Q

What is a chromatid?

A

One of 2 identical halves of a replicated chromosome

120
Q

What is a chromosome?

A

A long, coiled molecule of DNA that carriers genetic information in the form of genes

A-Level Biology (21 decks)

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