Biology Chapter 7

Question 1

Any of the alternative forms of a gene

Answer 1

alleles

Question 2

Gene expression is often related to whether a gene is located on an ______ or a ____ ________

Answer 2

autosome, sex chromosome

Question 3

One of the factors that affect phenotype is which _________ a gene is located on

Answer 3

chromosome

Question 4

Why can the probability of autosomal disorders be predicted?

Answer 4

Each human autosome has 2 homologous chromosomes (X X), with one gene on each, M & F, that each influence phenotype

Question 5

Disorders can be caused by ______ or ______ alleles

Answer 5

Dominant, Recessive

Question 6

___ copies of a recessive allele must be present for a person to have the disorder

Answer 6

2

Question 7

A person who is ______ for a recessive disorder, does not have the disease but is a carrier

Answer 7

Heterozygous

Question 8

A person who does not show disease symptoms, but can pass on the disease-causing allele to offspring

Answer 8

Carrier

Question 9

_______ genetic disorders are far less common, but have greater chance of inheritance

Answer 9

Dominant

Question 10

Genes that are located on the sex chromosomes

Answer 10

Sex-linked genes

Question 11

Female genotype, male genotype

Answer 11

XX, XY

Question 12

Females can only pass on an x chromosome to offspring, but males can pass on an ___ or a ___, which determines the sex of the offspring

Answer 12

X,Y

Question 13

In the expression of sex-linked genes, a disease can be x-linked or y-linked, and dominant or recessive

Answer 13

Got it!

Question 14

In the expression of sex-linked genes, because males only have one copy of each sex chromosome, they express all of the alleles on both chromosomes (but if they donate a disease carrying Y chromosome to offspring, and the disease is X-linked, the offspring won’t have the disease)

Answer 14

Got it!

Question 15

Traits that are specifically on the sex chromosomes

Answer 15

Sex-linked traits

Question 16

In a sex-linked disease that is X-linked, males are more likely to inherit the disease because, __________

Answer 16

they only have one x chromosome

Question 17

A process that occurs in female sex cells, early in development, in which one x chromosome is randomly “turned off”

Answer 17

X chromosome-inactivation

Question 18

Why does X chromosome-inactivation occur?

Answer 18

If both x chromosomes continued to produce proteins normally, development of the embryo would be impaired; humans have evolved to develop with the aid of only one x chromosome

Question 19

Offspring which express a heterozygous phenotype that is somewhere between the two homozygous phenotypes of the parents; “mix”

Answer 19

Incomplete Dominance

Question 20

Both traits are fully and separately express- neither allele is dominant nor recessive

Answer 20

Codominance

Question 21

Traits produced by two or more genes

Answer 21

Polygenic Traits

Question 22

A gene that can interfere, or overpower, the expression of other genes, regardless of which other genes an organism has inerited

Answer 22

Epistatic Gene

Question 23

Phenotype is usually a mixture of genes AND _____

Answer 23

Environment

Question 24

What does Mendel’s Law of Independent assortment state?

Answer 24

During gamete formation, gametes inherit alleles randomly; No Pattern

Question 25

When is the Law of Independent Assortment NOT true?

Answer 25

With linked genes

Question 26

Traits that appear to be inherited together frequently

Answer 26

Linked Traits

Question 27

Where are linked traits/genes always found?

Answer 27

On the SAME chromosome

Question 28

The ______ two genes are on a chromosome, the more likely they will be inherited together in gametes

Answer 28

Closer

Question 29

The ______ two gametes are on a chromosome, the more likely they will be separated during meiosis

Answer 29

Farther

Question 30

What accounts for linked genes not being inherited together in the same gametes?

Answer 30

Homologous chromosomes Cross Over

Question 31

Maps of the relative locations of genes on a chromosome

Answer 31

Linkage Maps

Question 32

The likelihood of genes being separated during meiosis/gamete formation, resulting in allele recombination

Answer 32

Recombination Frequency

Question 33

The ______ genes are on a chromosome, the higher recombination frequency they have

Answer 33

Farther

Question 34

How is recombination frequency found?

Answer 34

Crossing organisms with defined, linked traits: The % of times the phenotypes of the linked traits are NOT found together in the offspring is the recombination frequency

Question 35

On a linkage map, 1% recombination frequency is represented by ___ unit

Answer 35

1

Question 36

Only ______ can carry sex-linked genetic disorders

Answer 36

Females; males can't carry sex-linked genetic disorders because they only have one x, and if that x is affected, then they just have the disorder

Question 37

Both males and females can be carriers of a(n) ________ disorder

Answer 37

Autosomal

Question 38

Autosomal disorders are represented with _________, while sex-linked disorders are represented with _________

Answer 38

One letter (Dominant, Recessive); T t Xs and Ys with exponents, dominant or recessive letters can represent the disease causing allele, depending on the disease

Question 39

A chart that can help trace the phenotypes and genotypes in a family to determine whether people carry recessive alleles

Answer 39

Pedigree

Question 40

In a pedigree, if roughly the same number of males and females have the disorder, it is likely ______ If more males have the disorder, it is likely _______

Answer 40

Autosomal, Sex-Linked

Question 41

A picture of all of the chromosomes in a cell

Answer 41

Karyotype

Question 42

How can Karyotypes be used to find chromosomal disorders?

Answer 42

Karyotypes show changes in chromosomes, by revealing their patterns/bands with a stain

Question 43

What did Morgan's research with crossovers indicate to Mendel's Law of Independent Assortment?

Answer 43

Chromosomes, not genes, assort independently