Males and females have different chromosomes.Â
What is the correct combination of chromosomes to determine male or female sex?
Male XY
Female YY
Male YX
Female XY
Male XY
Female XX
Male XX
Female XY
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Males and females have different chromosomes.Â
What is the correct combination of chromosomes to determine male or female sex?
Male XY
Female YY
Male YX
Female XY
Male XY
Female XX
Male XX
Female XY
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A tall pea plant is crossed with a short pea plant.
Which is the correct genetic diagram for this cross?
 | t | t |
T | Tt | Tt |
T | Tt | Tt |
 | t | t |
T | Tt | Tt |
t | tt | tt |
 | T | t |
T | TT | Tt |
t | Tt | tt |
 | T | T |
t | Tt | Tt |
t | Tt | Tt |
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What is a mutation?
A change in the DNA base sequence that occurs in response to an environmental factor
A type of continuous variation
A condition caused by a dominant allele
A random change in the DNA base sequence
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Chromosomes, DNA molecules and genes are pieces of inherited material with different sizes.Â
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Which statement describes the relationship between these pieces of inherited material?
A chromosome is larger than a gene.
A gene is larger than a chromosome.
Multiple chromosomes make up a DNA molecule.
Multiple DNA molecules make up a gene.
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Which statements about genes and chromosomes are correct?
 | A chromosome contains DNA | A gene is a section of DNA |
A | true | true |
B | true | false |
C | false | true |
D | false | false |
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Albinism is a condition where the pigment melanin does not get produced in the skin, hair and eyes. This is an inherited condition that is caused by a recessive allele.
If both parents have albinism, what is the probability of the offspring inheriting albinism?
0 %
25 %
75 %
100 %
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Two individuals are crossed. One is homozygous dominant (TT), the other is heterozygous.
What will the genotypes of the offspring be?
All Tt
50 % TT, 50 % Tt
50 % TT, 50 % tt
25 % TT, 50 % Tt, 25 % tt
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The diagram shows how the sex of offspring can be determined.
What are the sex chromosomes in gamete Q and the son's cells R?
 | Q | R |
A | X | XY |
B | X | XX |
C | Y | XY |
D | Y | XX |
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A farmer is growing pea plants; the allele for tall plants is T and is dominant to the allele for dwarf plants, t.
Which cross would she need to carry out to produce a ratio of 1:1 tall to dwarf plants?
tt x tt
Tt x Tt
TT x Tt
Tt x tt
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ABO blood groups are an inherited characteristic.
Which of the following is the blood group of the offspring from two parents with the genotypes IAIA and IAIO?
Group O
Group B
Group AB
Group A
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Fruit flies can have orange or red eyes.
If two orange-eyed flies are crossed, all of the offspring will have orange eyes.
If two red-eyed fruit flies are crossed, the offspring have either orange or red eyes.
What can be concluded from these observations?
The allele for orange eyes is dominant
Crossing an orange-eyed fly with a red-eyed fly will give a 1:1 ratio
The allele for red eyes is dominant
We could determine which allele is dominant only if we did further crosses that produced a 3:1 ratio
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The inheritance of Huntington's disease is determined by a single gene. This gene has a dominant allele and a recessive allele. The allele for Huntington’s is dominant to the allele for non-sufferers of the condition.
The diagram shows the inheritance of Huntington’s in a family.
What is the probability that the next child from the same parents will have Huntington’s?
0 %
25 %
50 %
75 %
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The diagram shows the inheritance of ABO blood groups in a family.
Which of the following correctly identifies Jignasha’s genotype?
IAIO
IOIO
IBIB
IBIO
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Earlobes can either be attached to the cheek or be ‘free’ (unattached). This characteristic is controlled by a single gene.Â
The allele for attached earlobes is recessive.Â
The diagram shows the inheritance of attached earlobes in one family.
Which two individuals must be heterozygous for earlobe attachment?
1 and 7
3 and 4
 5 and 8
6 and 9
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The diagram shows a family in which some members suffer from a disease caused by a recessive allele.
Identify two members of the family who must be heterozygous for the gene?
5 and 7Â
3 and 6
2 and 5Â
1 and 4
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