Ch. 8 Genetics

Question 1

heredity

Answer 1

the passing of traits from parent to offspring

Question 2

Why were pea plants easy to study?

Answer 2

1. Many traits in two forms
2. Easy subject to control mating.
3. Grow fast & produce many offspring.

Question 3

What are monohybrid crosses?

Answer 3

punnett squares that involve only one pair of contrasting traits

Question 4

What is the first step in mendels experiment?

Answer 4

Mendel allowed each variety of pea plants to self-pollinate for several generations to ensure that each variety was true-breeding for a particular trait

Question 5

what are the true breeding plants called?

Answer 5

parental generation, P generation

Question 6

What is the second step in mendels experiment?

Answer 6

mendel then crossed-pollinated two parental plants

Question 7

What is the name of the offspring of the P generation?

Answer 7

f1 generation, f1= first filial

Question 8

What is the third step in mendels experiment?

Answer 8

mendel then allowed for the F1 generation to self-pollinate

Question 9

what is the name of the F1 generation offspring?

Answer 9

F2 generation

Question 10

What are the different versions of a gene called?

Answer 10

allele

Question 11

Dominant allele

Answer 11

is when the allele is expressed

Question 12

Recessive allele

Answer 12

the allele that is hidden

Question 13

what is an allele?

Answer 13

a different version of a gene

Question 14

How are dominant allele shown?

Answer 14

writing the first letter of the trait as a capital letter

Question 15

How are recessive alleles indicated?

Answer 15

by writing the first letter of the dominant as a capital

Question 16

if two alleles of a particular gene are the same it is

Answer 16

Homozygous

Question 17

if two alleles of a particular gene are different it is

Answer 17

heterozygous

Question 18

define genotype

Answer 18

the set of alleles that an individual has

Question 19

define phenotype

Answer 19

the physical appearance of a trait

Question 20

what are the two laws that mendel created?

Answer 20

The law of segregation and the law of independent assortment

Question 21

What is the law of segregation?

Answer 21

a pair of genes separate during gamete formation

Question 22

What is the Law of Independent Assortment?

Answer 22

genes for different characteristics if found on different chromosomes are distributed to gametes independently

Question 23

what is probability?

Answer 23

the likelihood that a specific event will occur

Question 24

what is the diagram called

Answer 24

a punnett square.

Question 25

when is a test cross done

Answer 25

it is done to find out the genotype of any individual whose phenotype is dominant

Question 26

what is a sex-linked trait

Answer 26

a trait whose allele is located on a sex chromosome

Question 27

what is hemophilia

Answer 27

blood that cannot clot. A mutated allele produces defective blood clotting proteins

Question 28

is hemophilia recessive or dominant

Answer 28

recessive

Question 29

sex-linked equals

Answer 29

x-linked

Question 30

color blindness is a recessive or dominant disorder

Answer 30

recessive x^n

Question 31

what is polygenic inheritance?

Answer 31

when several genes influence a question

Question 32

is genes with 2 alleles considered as a multiple allele?

Answer 32

no it has to be 3 or more

Question 33

what is codominace?

Answer 33

when both alleles for a gene are expressed in a heterozygous offspring

Question 34

what is incomplete dominance?

Answer 34

when the F1 offspring has a phenotype in between that of the offspring. Note: think of it like mixing colors

Question 35

what is a dihybrid cross?

Answer 35

a large punnett square crossing two different traits at once

Question 36

what is the magic ratio for the dihybrid cross when they are all heterozygous?

Answer 36

9:3:3:1

Question 37

what is a pedigree?

Answer 37

a family history that shows how a trait is inherited over several generations

Question 38

what is a genetic disorder?

Answer 38

mutations in genetic material that are passed on

Question 39

what is sickle cell anemia?

Answer 39

a recessive genetic disorder caused by a mutated allele that produces a defective hemoglobin protein

Question 40

In sickle cell anemia red blood cells are

Answer 40

deformed

Question 41

what is cystic fibrosis?

Answer 41

mutated allele produces defective chloride ion channel. The thick mucus blocks airways and organ ducts

Question 42

is Huntington's disease recessive or dominant

Answer 42

dominant

Question 43

when do the symptoms appear for Huntington?

Answer 43

30's or 40's

Question 44

What are the Huntington's symptoms?

Answer 44

the brain degenerates and causes loss of muscle control, uncontrollable muscle spasms, severe mental illness, and eventually death

Question 45

Gene Therapy may be used for what

Answer 45

correct certain recessive genetic disorders by replacing defective genes with copies of healthy genes