Review

Question 1

Why study genetics?

Answer 1

Critical role in understanding disease, improving agricultural practices, and biotechnology industry.

Question 2

What is a gene?

Answer 2

Fundamental unit of heredity

Question 3

What is an allele?

Answer 3

Multiple forms of genes

Question 4

Where is genetic information carried?

Answer 4

DNA

Question 5

Where are genes located?

Answer 5

On chromosomes

Question 6

How is genetic information transferred?

Answer 6

From DNA to RNA to protein

Question 7

What is a locus?

Answer 7

A specific place on a chromosome occupied by an allele

Question 8

What is a genotype?

Answer 8

Set of alleles possessed by an individual organism

Question 9

What is a heterozygote?

Answer 9

An individual organism possessing two different alleles at a locus

Question 10

What is a homozygote?

Answer 10

An individual organism possessing two of the same alleles at a locus

Question 11

What is a phenotype or trait?

Answer 11

The appearance or manifestation of a character

Question 12

Who discovered the basic principles of heredity?

Answer 12

Gregor Johann Mendel

Question 13

What is a monohybrid cross?

Answer 13

Cross of a single gene (ex. round x wrinkled)

Question 14

What is Mendel’s law of segregation?

Answer 14

3:1 ratio of dominant:recessive

Question 15

If an F1 plant (heterozygous) is backcrossed to the parent with round (dominant) seeds, what proportion of the progeny will have wrinkled seeds?

Answer 15

0

Question 16

What are dihybrid crosses? What is the approximate ratio of phenotypes?

Answer 16

Cross of 2 genes. Approximately 9:3:3:1 (DD:Dr:rD:rr)

Question 17

How is an affected person represented in a pedigree?

Answer 17

Shaded

Question 18

How is a male represented in a pedigree?

Answer 18

Square

Question 19

How is a female represented in a pedigree?

Answer 19

Circle

Question 20

What is the shape on a pedigree when the gender is unknown?

Answer 20

Diamond

Question 21

What is a generation line on a pedigree?

Answer 21

A vertical line = offspring.

Question 22

What is a sibship line on a pedigree?

Answer 22

Horizontal line (above) = siblings

Question 23

What do we assume for a pedigree?

Answer 23

If the trait is rare and autosomal recessive, then individuals who marry/mate into the pedigree are not carriers, but are homozygous for the normal allele unless there is evidence to the contrary.

Question 24

What are null/amorphic alleles?

Answer 24

• A nonfunctional protein is produced
  OR
• No protein is produced

Question 25

What are hypomorphic alleles?

Answer 25

- A poorly functioning protein is produced OR - Reduced amounts of a normally functioning protein is produced

Question 26

If the probability of being blood-type A is 1/8 and the probability of blood-type O is 1/2, what is the probability of being either blood-type A or O?

Answer 26

5/8

Question 27

What type of alleles usually result in loss of function?

Answer 27

Recessive

Question 28

What type of allele often involve gain/change of gene function?

Answer 28

Dominant

Question 29

What are dominant hypermorphic alleles?

Answer 29

- Negative phenotypic consequences due to the overproduction of a normal protein OR - Negative phenotypic consequences due to the production of a protein with increased activity levels

Question 30

What are neomorphic alleles?

Answer 30

- Negative phenotypic consequences due to the presence of an altered protein that has a new function OR - Negative phenotypic consequences when the altered protein interferes with the wildtype protein (Dominant-negative allele)

Question 31

For traits that are rare and dominant, affected individuals are most likely to be ____________. Why?

Answer 31

- Heterozygous - If the trait is rare, then matings between heterozygous individuals would be infrequent (you will see Bb x bb)

Question 32

Albinism is a recessive condition. A couple with normal skin want to have 2 children. The man has one albino parent; the woman has parents with normal skin, but an albino brother. What is the probability that their first child will be albino?

Answer 32

2/3 x 1 x 1/4 = 2/12 = 1/6