Chapter 2 a

Question 1

autosomal variation

Answer 1

the phenotypic variation arising from the genes located on regular chromosomes (autosomes)

Question 2

sex-linked inheritance

Answer 2

the phenotypic variation arising from the genes located on sex-determining chromosomes

Question 3

cytoplasmic inheritance

Answer 3

the phenotypic variation arising from the genes located on organellar chromosomes

Question 4

characteristics of a model organism

Answer 4

small size

easily maintained

short generation time

small genome

representative

large numbers of progeny

diploid
varieties with varying traits available

Question 5

pure-breeding lines/ pure lines

Answer 5

the lines which do not show variation in a particular phenotype over generations

Question 6

crosses

Answer 6

a cross is a way to introduce traits/genes from one variety or line into a new genetic background

Question 7

characters

Answer 7

different phenotypes

Question 8

a hereditary factor (gene) is responsible for-

Answer 8

each phenotypic character

Question 9

each parent contains 2 -

Answer 9

Alleles of each other

Question 10

each parent contributes 1 copy of each factor to offspring with equal frequency

Answer 10

gametes are haploid (one allele from each gene) and fuse to form diploid (2 alleles of each gene) offspring

Question 11

monohybrid crosses

Answer 11

a cross between two organisms with variations at one genetic locus pf interest

Question 12

a test cross

Answer 12

a cross between an unknown genotype and homozygous recessive parent for the same locus

Question 13

what would be the phenotypic and genotypic ratio for a monohybrid test cross

Answer 13

both would be 1:1

Question 14

if an individual heterozygous for one gene (A/a) is selfed (A/a x A/a), a-

Answer 14

3:1 phenotypic ratio and 1 (AA) : 2 (A/a) : 1 (aa) genotypic ratio will result

Question 15

if an individual heterozygous for one gene is testcrossed (A/a x a/a), a -

Answer 15

1:1 phenotypic and genotypic ratio will result

Question 16

Probability - product AND rule

Answer 16

the probability of independent events occurring together is equal to the product of their indivudal probabilities

Question 17

if you tossed 2 coins, what is the probability of getting 2 heads?

Answer 17

getting heads on coin 1 = 1/2

on coin 2 = 1/2

getting head on BOTH coin 1 AND coin 2 = 1/2 x 1/2 = 1/4

Question 18

probability Sum OR rule

Answer 18

the probility of either one OR the other mutually exclusive events occuring is equal to the sum of their individual probabilities

Question 19

if you tossed 2 coins, what is the probability of getting 2 heads or 2 tails?

Answer 19

heads coin 1 and coin 2 =1/2 x 1/2 = 1/4

tails coin 1 AND coin 2- 1/2 x 1/2 = 1/4

getting 2 heads OR 2 tails 1/4 + 1/4 = 1/2

Question 20

mendel concept ploidy

Answer 20

each individual has 2 copies of each factor and passes one copy to their offspring with equal frequency

(diploid -> haploid)

Question 21

diploid cells =

Answer 21

2n

Question 22

haploid cells =

Answer 22

n

Question 23

what are the two types of cell divistion

Answer 23

mitosis (making cell copies)

meiosis (reductional cell division to make gametes)

Question 24

S(synthesis) phase:

Answer 24

DNA synthesis generates indentical DNA molecules = sister chromatids

Question 25

S phase key point

Answer 25

- DNA synthesis -DNA content is doubled -each DNA molecule (chromosome) is copied to make 2 daughter DNA molecules chromosome number stays the same each chromosome has 2 chromatids called dyads

Question 26

different alleles result from changes to-

Answer 26

DNA sequence -single nucleotide polymorphism

Question 27

Ill Pass My Amazing Taco Chief (mitosis)

Answer 27

interphase prophase metaphase Anaphase Telophase =daughter cells

Question 28

M phase =

Answer 28

mitosis and meiosis

Question 29

prophase in mitosis early stage

Answer 29

chromosomes condense, and shorten

Question 30

prophase in mitosis late stage

Answer 30

sister chromatids joined at the centromere visible nuclear membrane breaks down, spindle fibers attach to the kinetochore of the centromere

Question 31

prophase 1in meiosis

Answer 31

leptotene zygotene pachytene diplotene

Question 32

leptotene

Answer 32

chromosomes condense, and shorten

Question 33

zygotene

Answer 33

chromosomes starts to align with the homolougous partner

Question 34

pachytene

Answer 34

chromosomes are fully synapsed (aligned)

Question 35

Diplotene

Answer 35

crossing over occurs between the non-sister chromatids

Question 36

what is crossing over

Answer 36

the exchange of genetic material between the non-sister chromatids to introduces new allelic combinations

Question 37

in mitosis metaphase is

Answer 37

side by side

Question 38

in meiosis metaphase is

Answer 38

on top of each other

Question 39

anaphase and telophase in mitosis

Answer 39

they take one half of each dyads (take one sister chromatid)

Question 40

anaphase and telophase in meiosis

Answer 40

they take the pair (the whole dyad)

Question 41

what is a kinetochore

Answer 41

a multiprotein complex that binds to centromere site of attachement for microtubules after anaphase (when chromosomes are attached) microtubules depolymerize at kinetochore, drawing chromatids apart

Question 42

meiosis

Answer 42

after telophase, it restarts from prophase ang goes through it a second time so that the product is haploid

Question 43

In an organism with a haploid life cycle, haploid phase is-

Answer 43

predominant (undergoes mitotic divisions) and so, phenotype of the products of meiosis (n) can be directly scored

Question 44

Ascus heterozygote demonstrates what ratio?

Answer 44

1:1

Question 45

how do allleles result in different phenotypes

Answer 45

alleles are variants of the genes sequence resulting from mutation

Question 46

a gene may have many-

Answer 46

different variants or alleles

Question 47

null alleles

Answer 47

no functional gene product formed

Question 48

leaky alleles

Answer 48

some functional gene product

Question 49

silent allele

Answer 49

no change in gene product function

Question 50

mutant alleles may be-

Answer 50

recessive (more common) dominant (less common)

Question 51

dominance and recessivness is defined based on the-

Answer 51

phenotype of the heterozygous indivudals

Question 52

haplosuffient

Answer 52

one wild-type gene copy is sufficient to confer the wild type phenotype (wild type = 12, 10 are needed, so 2 wild type = 24, one wild, one mutant = 12, two mutants = 0)

Question 53

loss of function mutations of haplosufficient genes are-

Answer 53

recessive

Question 54

haploinsuffient

Answer 54

one wild type gene copy is not enough to confer the wild type phenotype (wild type = 12, 20 are needed. 2 wildtype = 24, one wild/ one muatnt = 12, 2 mutants = 0 )

Question 55

loss of function mutations of haploinsufficeint genes may be-

Answer 55

dominant

Question 56

Upper case letters =

Answer 56

Wild type (or *)

Question 57

lower case letters =

Answer 57

mutant alleles