Chapter 9

Question 1

The scientific study of heredity.

Answer 1

Genetics

Question 2

The transmission of traits from one generation to the next.

Answer 2

Heredity

Question 3

Who was the first to study genetics?

Answer 3

Gregor Mendel

Question 4

Gregor Mendel

Answer 4

was the first to study genetics, and did this by observing patterns of inheritance in pea plants

Question 5

Organisms are composed of combination of many different _____.

Answer 5

traits

Question 6

Some traits are common, and are referred to as ____________, while others may be rare or unusual.

Answer 6

wild type trait

Question 7

The reason why we see such differences is because____________________________.

Answer 7

individuals may posses variation of each gene

Question 8

Offspring inherit these genetic variations from their parents, incorporating their parents genetic information in the offspring ________.

Answer 8

Genome

Question 9

The overall appearance of an organism is called its __________.

Answer 9

Phenotype

Question 10

The phenotype includes.

Answer 10

all visible characteristics of an organism, including its physiology

Question 11

An organisms genetic makeup is called.

Answer 11

Genotype

Question 12

The genotype is all of the organisms.

Answer 12

genes and their exact DNA composition

Question 13

Genes exit at specific position on the chromosomes called?

Answer 13

Gene locus (pl.loci)

Question 14

Mendal studied __________.

Answer 14

Garden peas

Question 15

Pea plants

Answer 15

have variety of easily observed traits
they are easily manipulated
they are normally self fertillized

Question 16

Mendals experimental treatments consisted of ____-______ plants with different traits.

Answer 16

Cross-fertilizing

Question 17

Mendals found true-breeding (purebred) individuals and crossed them to create________.

Answer 17

hybrids

Question 18

Genes have different versions, which we call _____.

Answer 18

Alleles

Question 19

Diploid organisms have __ pair (_) alleles for a given gene.

Answer 19

1

2

Question 20

Each egg carries __ copy of each _____. and each sperm also carriers____ copy of each _____.

Answer 20

1 allele

1 allele

Question 21

Once sperm and egg fuse, the newly fertilized egg (zygote) has 2 copies of each allele and is therefore called?

Answer 21

Diploid

Question 22

What is a diploid?

Answer 22

has 2 copies of each allele. these copies can be identical or different verison of each allele

Question 23

If an allele is different what happens?

Answer 23

the dominant allele masks the the recessive allele and is expressed.

Question 24

A ________ is a cross between organisms that differ in only 1 trait.

Answer 24

Monohybrid cross

Question 25

An explanation of a monohybrid cross using a __________.

Answer 25

punnet square

Question 26

a upper case letter is used to express what?

Answer 26

dominant traits

Question 27

When eggs and sperm form, allele pairs separate from the parent cells to make _________.

Answer 27

haploid cells

Question 28

What is the law of independent assortment?

Answer 28

Alleles also typically separate independently of other alleles.

Question 29

A chromosome pair consist of two__________.

Answer 29

Homologous chromosomes

Question 30

if the alleles on two homologous chromosomes are identical this is called_________.

Answer 30

homozygous

Question 31

if the alleles are different this is called________.

Answer 31

Heterozygous

Question 32

An example of homozygous recessive.

Answer 32

pp

Question 33

example of homozygous dominant

Answer 33

PP

Question 34

Example of heterozygous

Answer 34

Pp

Question 35

A_________ looks at organisms with an organism with 2 traits of interest(crossing 2 traits at once)

Answer 35

dihybrid cross

Question 36

Because alleles assort independently of other alleles during gamate formation,

Answer 36

this results in all possible combination

Question 37

Mendels principles apply to all organisms, including the inhertiance of thousands of ________.

Answer 37

human traits

Question 38

To determine the pattern of inheritance among families, geneticists draw__________.

Answer 38

pedigrees.

Question 39

these illustrate the history of a trait in a family

Answer 39

pedigree

Question 40

since most of these genetic disorders are fairly rare, we can conclude that they are __________

Answer 40

recessive

Question 41

______________ is dominant disorder known as dwarfism.

Answer 41

Achondroplasia

Question 42

Dwarfism is found in _____________.

Answer 42

heterozygotes

Question 43

in Dwarfism with DD is a ____________.

Answer 43

lethal combination

Question 44

When F1 offspring have appearance is an intermediate between two extreme parental phenotypes, this is the result of allelic __________________.

Answer 44

incomplete dominance

Question 45

The human disease hypercholesterolemia is another example of

Answer 45

incomplete dominance

Question 46

Blood type O is the

Answer 46

recessive phenotype

Question 47

A and B are two _________alleles.

Answer 47

dominance

Question 48

If you are homozygous for the A (IAIA) allele or are heterozygous (IAi) you blood type is __.

Answer 48

A

Question 49

If you are homozygous for the B (IBIB) allele or are heterozygous (IBi) your blood type is____.

Answer 49

B

Question 50

If you are heterozygous with both dominant alleles present you have blood type___.

Answer 50

AB

Question 51

If a single gene affect more than one trait, this is called__________.

Answer 51

Pleiotrophy

Question 52

If two or more genes have combined effects on the phenotype, this is called____________.

Answer 52

polygenic inheritance

Question 53

Polygenic inheritance occurs because_______________________________.

Answer 53

more then 1 gene influence the phenotype expressed.

Question 54

Linked genes are located close together on a chromosome, therefore during crossing over they are__________________.

Answer 54

often linked together

Question 55

To determine how crossing over worked, scientist used the fruit fly ___________________.

Answer 55

Drosophila melanogaster

Question 56

Using Drosophila, frequencies of gene inheritance (from crossing over) were determined. Based the frequent genes were inherited together, the more likely they are located _______________________________.

Answer 56

closer together on the same chromosomes

Question 57

This allowed us to determine the order and spacing of genes on a chromosome, resulting in a ___________.

Answer 57

linkage map

Question 58

Among the chromosome pairs of organisms, one pair may be the one carrying the genes to determine the sex of an individual these are called _______________.

Answer 58

sex chromosomes

Question 59

humans have an ____ sex determination system.

Answer 59

XY

Question 60

males are___.

Answer 60

XY

Question 61

females are ____.

Answer 61

XX

Question 62

genes located on the sex chromosomes are called_________________.

Answer 62

Sex-linked genes

Question 63

the inheritance of ________________ in the fruit fly illustrates an X-linked recessive trait in the fruit fly drosophila melanoganaster.

Answer 63

white eye color

Question 64

Among humans, a common type of sex-linked disorder is ________________________.

Answer 64

red-green color blindness

Question 65

red-green color blindness is linked to the ___ chromosome.

Answer 65

X

Question 66

Another sex-linked disease is ________ a bloodclotting disease.

Answer 66

Hemophilia