Mendelian Genetics

Question 1

What are the four types of inheritance?

Answer 1

1. Autosomal recessive
2. Autosomal dominant
3. X-linked recessive
4. X-linked dominant

Question 2

What are the two degrees of dominance?

Answer 2

1. Incomplete
2. Co-dominance

Question 3

What are the three forms of gene interactions?

Answer 3

1. Pleiotropy
2. Polygenic
3. Epistasis

Question 4

How many gene loci does a monohybrid cross represent?

Answer 4

One gene loci

Question 5

How does the dominant allele effect one’s appearance?

Answer 5

The dominant allele determines the organism’s appearance

Question 6

How does the recessive allele effect one’s appearance?

Answer 6

The recessive allele has no noticeable effect on the organism’s appearance

Question 7

What is a genotype?

Answer 7

The genetic make up

Question 8

What is a phenotype?

Answer 8

An organism’s appearance or an observable trait

Question 9

What type of cross tests for independent assortment?

Answer 9

A dihybrid cross

Question 10

What are the two Mendel’s laws of inheritance?

Answer 10

1. The law of segregation
2. The law of independent assortment

Question 11

What does Mendel’s law of segregation state?

Answer 11

The two alleles for a heritable character segregate during gamete formation and end up in different gametes

Question 12

What does Mendel’s law of independent assortment state?

Answer 12

Genes are inherited independently of each other. They do not influence each other when sorting of alleles into gametes

Question 13

What are alleles?

Answer 13

Alternative versions of genes that account for variations in inherited characteristics

Question 14

What is incomplete dominance?

Answer 14

Neither allele is completely dominant over the other, which results in a third phenotype which is a combination of the two phenotypes of both alleles

Question 15

What is co-dominance?

Answer 15

A form of dominance wherein the alleles of a gene pair in a heterozygote are fully expressed, and the offspring has a phenotype which is neither dominant or recessive

Question 16

The ABO blood group system is an example of what type of dominance?

Answer 16

Co-dominance

Question 17

What is pleiotropy?

Answer 17

When one gene influences two or more phenotypic traits

Question 18

What is epistasis?

Answer 18

Phenotypic expression of a gene at one locus that alters the phenotypic expression of a gene at a second locus

Question 19

Are polygenic gene interactions qualitative or quantitative?

Answer 19

Quantitative

Question 20

What are polygenic gene interactions?

Answer 20

The additive effect of two or more genes on a single phenotypic character

Question 21

Conditions involving genes on chromosomes 1-22 are what?

Answer 21

Autosomal (dominant/recessive)

Question 22

Conditions involving genes on the sex chromosomes (pair 23) are what?

Answer 22

X-linked (dominant recessive)

Question 23

What percentage risk is there of having an affected child in each pregnancy in autosomal dominant inheritance?

Answer 23

50%

Question 24

What percentage risk is there of having an affected child in each pregnancy in autosomal recessive inheritance?

Answer 24

25%

Question 25

What percentage risk is there of having an affected child in each pregnancy in X-linked recessive inheritance, from the mother?

Answer 25

25%

Question 26

What percentage risk is there of having an affected child in each pregnancy in X-linked recessive inheritance, from the father?

Answer 26

0%

Question 27

There is no male-to-male transmission in what type of inheritance?

Answer 27

X-linked dominant inheritance

Question 28

Huntington’s disease and dwarfism are example conditions of what type of inheritance?

Answer 28

Autosomal dominant inheritance

Question 29

Three example conditions of autosomal recessive inheritance are?

Answer 29

1. Cystic fibrosis
2. Sickle cell anaemia
3. Albinism

Question 30

Only sons will suffer from what type of inheritance?

Answer 30

X-linked recessive inheritance from the mother

Question 31

Haemophilia, red-green colour blinds, and Duchenne muscular dystrophy are example conditions of what type of inheritance?

Answer 31

X-linked recessive inheritance from the mother

Question 32

From what type of inheritance will all daughters be heterozygote carriers?

Answer 32

X-linked recessive inheritance from the father

Question 33

What syndrome is an example condition of X-linked dominant inheritance?

Answer 33

Fragile X syndrome