Ch 20 Practice Flashcards Preview

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Flashcards in Ch 20 Practice Deck (25):
1

A diagram that uses sperms genotypes on one side and egg genotypes on the other side to predict the genotypes of offspring is called a ______ ______.

Punnett square

2

If a male exhibits a sex-linked trait, the allele for the trait came from the mother and resides on the ______.

X chromosome

3

Phenotype

The physical appearance of a trait (e.g., blue eyes)

4

Genotype

The specific combination of alleles an individual is born with

5

Alternate forms of a gene are called ______.

Allele

6

______ alleles require two copies to be present in order to exert their effect.

Recessive

7

An organism with a ______ genotype carries two identical alleles for a given gene.

Homozygous

8

For each gene, an individual inherits ______ allele(s) with ______ being contained in the sperm and ______ being contained in the egg.

2, 1, 1

9

If neither parent is affected by an autosomal dominant disorder, what percentage of their children will be affected?

0; Both parents possess the recessive traits.

10

What are the characteristics of polygenic phenotype?

• Alleles have additive effects on phenotype
• Phenotype variation appears continuous
• The phenotype can be influenced by the environment

11

How many copies of a damaged allele must be present for a recessive genetic disease to be expressed?

2

12

The specific genes or combination of alleles for a trait is called an individual's ______.

Genotype

13

A person who is heterozygous for an autosomal recessive disorder and shows the dominant phenotype is called a(n) ______.

Carrier

14

All combinations of alleles are possible in the gametes because the ______ align independently during meiosis.

Chromosomes

15

How many traits are being considered in a dihybrid cross?

2

16

The position of a gene on a chromosome is called its ______.

Locus

17

______ occurs when one gene affects multiple, seemingly unrelated traits.

Pleiotropy

18

An individual with one recessive allele and one ______ allele has a heterozygous genotype.

Dominant

19

An individual hat inherits two copies of the same form of a gene from his or her two parents has a ______ genotype.

Homozygous

20

A genetic system in which alleles are equally expressed in a heterozygote is called ______.

Codominance

21

Sickle-cell disease is an example of which type of condition?

Autosomal recessive disorder

22

A genetic system in which a heterozygous individual displays a phenotype intermediate between that of an individual homozygotic for either allele is called ______ ______.

Incomplete dominance

23

In simple one-trait crosses, one gene affects one trait. In ______ inheritance, multiple genes govern a trait, and in ______, one gene affects many traits.

Polygenic, pleiotropy

24

The ______ allele of a gene is represented with an uppercase letter.

Dominant

25

An Ff x Ff cross is an example of:

A monohybrid cross