genetics reveiw

Question 1

what name did Mendel give to the characteristic that seemingly disappeared from the generation?

Answer 1

recessive

Question 2

A gene exists in two different forms (A and a). With respect to the allele present, which type of gamete can a homozygous recessive individual produce?

Answer 2

a

Question 3

The gene makeup of an organism for a particular trait is its:

Answer 3

genotype

Question 4

The physical appearance of an organism for a particular trait is its

Answer 4

phenotype

Question 5

in the cross of Tt x Tt,
the proportion of the offspring that will have the same genotype as the parents is

Answer 5

50%

Question 6

If an organism of genotype AA
mates with an organism of genotype Aa and 150 offspring are produced, the number of offspring with genotype Aa will most probably be close to:

Answer 6

70

Question 7

Two parents were known to be right-handed. Assuming that right-handed (R) is dominant to left-handed (r), what would be the genotypes of the parents if their son is left-handed

Answer 7

Rr x Rr

Question 8

The alleles for blood types A and B are codominant but are dominant over the allele for blood type O. Answer the following question. A female with AB blood type and a male with O blood type have several children. The phenotypic ratio for these children would be:

Answer 8

1/2 type A and 1/2 type B

Question 9

I^i represents the blood group phenotype.

Answer 9

A

Question 10

If a human zygote has an X and a Y chromosome, it will normally produce a:

Answer 10

male

Question 11

A man with red-green colour blindness marries a woman who has normal colour vision and is not a carrier of the gene for this trait. Which of the following statements would best describe their offspring?

Answer 11

no children will be colourblind but daughters will be carriers

Question 12

color blindness is a sex-linked characteristic because the gene is

Answer 12

carried on a sex chromosome

Question 13

the rare trait called ocular albinism, an almost complete absence of I pigment, is inherited as a sex-linked recessive trait. If a man with the condition marries a woman who is a carrier of this condition, their offspring will result..

Answer 13

about half the sons and half the daughters will have ocular albinism the other half will just be carriers

Question 14

a man is a hemophiliac, this indicates that he:

Answer 14

inherited the condition from his mother

Question 15

an x-linked dominant allele is inherited from a heterozygous female

Answer 15

equally male and female

Question 16

what is the law of segregation

Answer 16

the separation of paired alleles during meiosis

Question 17

what is the law of independent assortment

Answer 17

If genes are located on separate chromosomes, they are inherited independently of each other.

Question 18

what are hybrids

Answer 18

offspring that differ in one or more traits

Question 19

genes are….

Answer 19

a unit of instruction located on a chromosome, which produces or influences a specific trait in the offspring.

Question 20

recessive

Answer 20

alleles of this type are overruled when the genotype is not homozygous

Question 21

inheritance is..

Answer 21

the process of recciving traits from previous generations

Question 22

what are alleles

Answer 22

two or more alternate forms of a gene

Question 23

dominant alleles determine the

Answer 23

determine the expression of the genetic trait

Question 24

a phenotype is..

Answer 24

a type of cross that involves two genes, each consisting of nonidentical alleles.

Question 25

a Punnett square is

Answer 25

a chart used by geneticists to show the possible combinations of alleles in offspring

Question 26

a genotype is

Answer 26

the alleles an organism contains

Question 27

alleles are…

Answer 27

two or more alternate forms of a gene

Question 28

homozygous is…

Answer 28

a genotype in which both alleles of a pair are the same

Question 29

what is a monohybrid cross

Answer 29

a cross that involves one allele pair of contrasting traits

Question 30

heterozygous is

Answer 30

a genotype in which the alleles of a pair are different

Question 31

a phenotype is

Answer 31

the observable traits of an organism

Question 32

recessive lethal is

Answer 32

A small, dark spot of chromatin located in the nucleus of a female mammalian cell

Question 33

mutation means

Answer 33

a heritable change in the molecular structure of DNA

Question 34

haemophilia is

Answer 34

an example of a sex-linked trait

Question 35

XX refers to

Answer 35

female sex chromosomes

Question 36

XY refers to

Answer 36

male sex chromosomes

Question 37

somatic means

Answer 37

all the cells of an organism other than sex cells

Question 38

As a result of a mutation, the allele for hemophilia is believed to have been present in Queen Victoria. Hemophilia is a sex-linked trait that affects males more often than females. Leopold, Duke of Albany, one of Victoria’s children, was a hemophiliac. He had two children, one male and one female.

Answer 38

the probability that has brother was also a hemophiliac

Question 39

If a normal man marries a normal woman whose father was colourblind, what are the chances that their sons and daughters will be colourblind?
Colourblindness is a sex-linked trait that affects males more often than females.

Answer 39

their sons will have a high chance of being color blind while their daughter is will be unaffected but be carriers