Chapter two test one

Question 1

what is a gene

Answer 1

basic unit of biological info

Question 2

what is heredity

Answer 2

the way genes transmit physiological, anatomical and behavioral traits from parents to offspring

Question 3

what is genetics

Answer 3

the science of heredity

Question 4

what is artificial selection

Answer 4

the purposeful control of mating by choice of parents for the next generation

Question 5

what were the ideas of heredity before mendel

Answer 5

one parent (male) contributes most to an offsprings inherited features
blended inheritance: parental traits become mixed and forever changed

Question 6

why did mendel choose the pea plant

Answer 6

female and male organs in same plant (self-fertilizing)
easy to breed
large numbers, short period of time

Question 7

what are discrete traits

Answer 7

an inherited trait that clearly exhibits an either/or status

Question 8

what are continuous traits

Answer 8

an inherited trait that exhibits many intermediate forms

such as skin color or height

Question 9

what are hybrids

Answer 9

offspring of genetically dissimilar parents

Question 10

what are reciprocal crosses

Answer 10

crosses performed in two directions, with the traits in the males and females reversed relative to each other, thereby controlling whether a particular trait is transmitted by the male or female gamete

Question 11

what crosses reveal the law of segregation

Answer 11

monohybrid crosses

Question 12

what do F1 generations look like in a monohybrid cross

Answer 12

all one phenotype

Question 13

what are monohybrid crosses

Answer 13

crosses between parents that differ in only one trait

Question 14

what is the ratio for a F2 monohybrid cross

Answer 14

3:1

Question 15

what was evidence in monohybrid crosses that showed blending did not occur

Answer 15

green reappeared in the F2 generation

Question 16

what is an allele

Answer 16

alternative forms of a single gene

Question 17

what are gametes

Answer 17

eggs or sperms that carry genes between generations

Question 18

what is a zygote

Answer 18

fertilized egg

Question 19

what is mendels law of segregation

Answer 19

two alleles for each trait segregate during gamete formation, and then unite at random, one from each parent, at fertilization

Question 20

purpose of punnett square

Answer 20

visualize the fertilization events possible in a give cross

Question 21

what is the product rule

Answer 21

the probability of two or more independent events occurring together is the product of the probabilities that each event will occur by itself

Question 22

what is the key word to look for in product rule

Answer 22

AND

Question 23

what is the sum rule

Answer 23

the probability that any of two or more mutually exclusive events will occur is the sum of their individual probabilities

Question 24

what is the key word to look for in the sum rule

Answer 24

OR

Question 25

what is the ratio of a specific yellow genotype for a monohybrid

Answer 25

1 YY ; 2 Yy

Question 26

purpose of a testcross

Answer 26

determine phenotype

Question 27

if phenotype shows one color in testcross what is the genotype

Answer 27

YY

Question 28

if phenotype shows two colors in testcross what is the genotype

Answer 28

Yy

Question 29

what kind of crosses shows the law of independent assortment

Answer 29

dihybrid crosses

Question 30

what is a dihybrid

Answer 30

an individual that is heterozygous at different genes

Question 31

how many phenotypes produced in F1 generation for a dihybrid cross

Answer 31

1

Question 32

what is a parental type

Answer 32

phenotypes that reflect a previously existing parental combination of alleles that is retained during gamete formation

Question 33

what is a recombinant type

Answer 33

phenotypes reflecting a new combination of genes that occurs during gamete formation

Question 34

what is the phenotypic ratio of a f2 generation for a dihybrid cross

Answer 34

9:3:3:1

Question 35

each individual trait in a dihybrid f2 generation has what phenotypic ratio

Answer 35

3:1

Question 36

what is the law of independent assortment

Answer 36

alleles of different genes segregate into gametes independently of each other

Question 37

what is the possible allele combination ratio in gametes for dihybrid cross

Answer 37

1:1:1:1

Question 38

what is a pedigree

Answer 38

an orderly diagram of a family's relevant genetic features, extending through as many generations as possible

Question 39

what is a late onset genetic trait

Answer 39

symptoms not present at birth and manifest later in life

Question 40

what disease is an example of a late onset genetic trait

Answer 40

huntingtons disease

Question 41

what is a vertical pattern in pedigrees

Answer 41

at least one person is affected in each generation

Question 42

what genotype is the diseased huntington

Answer 42

Hd HD+, HD HD

Question 43

a vertical pattern of inheritance indicates what

Answer 43

a rare dominant trait

Question 44

a horizontal pattern of inheritance indicates what

Answer 44

rare recessive trait

Question 45

what is a common rare recessive disease

Answer 45

cystic fibrosis

Question 46

what is a trait of horizontal pattern in pedigrees

Answer 46

unaffected parents can have affected children