chapter 10

Question 1

euchromatin

Answer 1

• open regions of DNA
• more available DNA
• regions that actively expressed

Question 2

heterochromatin

Answer 2

area of DNA that is tightly bound

Question 3

what is nondisjunction

Answer 3

when chromosomes do not separate correctly

Question 4

euploid number

Answer 4

number of chromosomes you are supposed to have

Question 5

aneuploid

Answer 5

at diploid state, but different +1 or =1 chromosome

Question 6

what happens during nondisjunction in meiosis 1

Answer 6

chromosomes enter only 1 cell (n+1), and the other cell has none (n-1)

Question 7

in meiosis 2, what occurs during nondisjunction

Answer 7

only half of the gametes are affected
- 2 will be affected and 2 will be nonaffected

Question 8

can human adjust to aneuploidy

Answer 8

no
- very sensitive to gene dosage changes

Question 9

what are the only chromosomes that can be trisomy

Answer 9

13
18
21

Question 10

trisomy 21

Answer 10

linked to older maternal and paternal age

Question 11

turner syndrome

Answer 11

• monosomy of x chromosome
• XO
• start out with correct number of chromosomes
• mitotic issue (nondisjunction)

Question 12

mosaicism

Answer 12

not all of your cells match

Question 13

what is uniparental disomy

Answer 13

2 copies of chromosome but came from one parent

Question 14

what are 2 ways uniparental disomy can occur

Answer 14

1. nondisjunction in both egg and sperm at same time
2. nondisjunction only occurs to one of cells, and when zygote forms, randomly kicks out the extra copy

Question 15

polyploidy

Answer 15

extra sets of chromosomes
- occurs in plants

Question 16

turner syndrome

Answer 16

• monosomy of x chromosome
• no second sex chromosome

Question 17

how does mosaicism occur

Answer 17

nondisjunction early in embryo

Question 18

what is autopolyploid

Answer 18

result from duplication of chromosome sets within a species

Question 19

what is allopolyploidy

Answer 19

occur from combining chromosome sets of different species
- result of hybridization of 2 different species

Question 20

in ploidy, is even # copies better or worse than odd # copies

Answer 20

better

Question 21

what two mechanisms cause autopolyploidy

Answer 21

1. meiotic nondisjunction
2. mitotic nondisjunction

Question 22

meiotic nondisjunction leads to what

Answer 22

diploid rather than haploid gamate

Question 23

mitotic nondisjunction leads to what

Answer 23

doubling of chromosome number

Question 24

what type of cells will move towards the nucleus

Answer 24

active and large genes

Question 25

what type of cells will be found outside of the cell

Answer 25

small and les active genes

Question 26

what are regions between territories

Answer 26

interchromosomal domains

Question 27

what are the four chromosome shapes

Answer 27

metacentric submetacentric acrocentric telocentric

Question 28

metacentric shape

Answer 28

centromere near the middle of chromosome - short and long are the same

Question 29

p is the

Answer 29

short arm

Question 30

q is the

Answer 30

long arm

Question 31

submetacentric shape

Answer 31

centromere between center and tip

Question 32

acrocentric shape

Answer 32

centromere close to one end

Question 33

telocentric shape

Answer 33

centromere at tip of chromosome and no p arm present

Question 34

what kind of shape allows for chromosomes to break more easily

Answer 34

longer chromosomes

Question 35

what is the satellite on the chromosome

Answer 35

repetitive sequences that don't hold genes

Question 36

how does fluorescent in situ hybridization work (FISH)

Answer 36

molecular probes that are labeled with compounds that emit fluorescent light will detect a target sequence

Question 37

what is the purpose of FISH

Answer 37

way of flagging a particular area of your chromosome

Question 38

what is chromosome banding

Answer 38

identify each chromosome in karyotype based on size, shape, and banding pattern

Question 39

what is the standard for human chromosome banding

Answer 39

Giemsa (G) banding

Question 40

why does G banding work better for humans

Answer 40

binds to phosphate a more readily to AT rich areas

Question 41

what are the regions that contain actively expressed genes and are less condensed

Answer 41

euchromatin

Question 42

area of DNA that is tightly bound have fewer expressed genes

Answer 42

heterochromatin

Question 43

what is hybrid vigor

Answer 43

- rapid growth - increased fruit and flower production - improved resistance to genes

Question 44

what can cause a change in chromosome structure

Answer 44

chromosome breakage

Question 45

what is the chromosome break point

Answer 45

where both DNA strands are severed at

Question 46

terminal deletion

Answer 46

detachment of all or part of one chromsome

Question 47

what does the terminal deletion contain

Answer 47

broken fragment of telomere and additional genetic material

Question 48

acentric

Answer 48

- lacks a centromere - may be lost during cell division

Question 49

what is an interstitial deletion

Answer 49

loss of an internal portion of a chromosome that results from two chromosome breaks

Question 50

unequal crossover

Answer 50

- rare - takes place between two homologs

Question 51

what can result in an unequal crossover

Answer 51

partial duplication on one homolog and partial deletion on the other

Question 52

partial duplication heterozygote

Answer 52

one normal and one duplication homolog

Question 53

partial deletion heterozygote

Answer 53

one normal and one deleted homolog

Question 54

what kind of deletions can be detected by microscopy

Answer 54

large deletions or duplications

Question 55

what is not easily detected by microscopy

Answer 55

microdeletions or microduplications

Question 56

chromosome inversion

Answer 56

- flipping and then re-flipping chromosome back - reattachment in the wrong orientation - 3 types

Question 57

chromosome translocation

Answer 57

attachment to nonhomologous chromosomes

Question 58

paracentric inversion

Answer 58

centromere outside of inverted region

Question 59

pericentric inversion

Answer 59

centromere within inverted region

Question 60

inversion heterozygotes

Answer 60

one normal and one inverted homolog

Question 61

what causes dicentric chromosomes

Answer 61

crossing over within paracentric inversion

Question 62

dicentric bridge

Answer 62

dicentric chromosome pulled toward both poles

Question 63

what are the 3 genetic implications of recombination in inversion heterozygotes

Answer 63

1. probability of crossover within inversion loop is proportional to size of loop 2. suppresses production of recombinant chromosomes 3. fertility may be altered if there is a very large inversion

Question 64

how are eukaryotic chromosomes organized

Answer 64

into chromatin

Question 65

why are chromatin important

Answer 65

- proper function and distribution of chromosomes in cell division - regulation of gene expression

Question 66

histone proteins

Answer 66

- half of DNA - small - basic - tightly bind DNA

Question 67

nonhistone proteins

Answer 67

- other half of DNA - very diverse - perform variety of tasks in nucleus

Question 68

how many histones are there

Answer 68

5 - H1 - H2A - H2B - H3 - H4

Question 69

H1

Answer 69

- help stabilize linker DNA - located on linker DNA in between each nucleosome

Question 70

H2A, H2B, H3, H4

Answer 70

come together to form nucleosome

Question 71

what are the nucleosome core particles

Answer 71

fundamental units of histone protein organization

Question 72

solenoid structure

Answer 72

- 30nm fiber - 6 to 8 nucleosomes per turn - H1 stabilizing

Question 73

why is there condensing of the nuclear material

Answer 73

trying to condense further and further

Question 74

when is the chromosome most compact

Answer 74

during metaphase

Question 75

what can happen when a chromosome is more tightly compacted

Answer 75

more difficult it can be to transcribe certain genes