1.2. Physical Basis of Heredity Flashcards

• Cell Structure and Genetic Function • Chromosomes • Major Processes Involved in the Genetic Continuity of Nucleated Cells

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1
Q

cell structure that houses the dna

A

nucleus

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2
Q

site of rRNA synthesis and the initial stages of ribosome assembly

A

nucleolus

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3
Q

site of translation

A

ribosome

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4
Q

site of atp synthesis; contains dna

A

mitochondria

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5
Q

site of photosynthesis; contains dna

A

chloroplast

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6
Q

coiled chromatin fibers

A

chromosome

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7
Q

extended form of the chromosome

A

chromatin fiber

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8
Q

centromere in the middle

A

metacentric

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9
Q

centromere between middle and end

A

submetacentric

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10
Q

centromere is close to end

A

acrocentric

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11
Q

centromere is at the end portion

A

telocentric

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12
Q

chromosomes that have the same size, shape, position of centromere, gene sites along their lengths, and characteristics

A

homologous chromosomes

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13
Q

homologous chromosomes all carry the same information. true or false?

A

false; not necessarily the same

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14
Q

major process in genetic continuity that leads to the production of two cells with the same number of chromosomes as the parent cells; involves somatic cells

A

mitosis

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15
Q

what are the roles of mitosis?

A

(1) growth and development
(2) regeneration and repair
(3) basis for asexual reproduction for unicellular organisms (i.e., protozoa, fungi, algae)

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16
Q

constitutes the events that occur from the completion of one division until the completion of the next division

A

cell cycle

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17
Q

what happens in the g0 stage?

A

cells are dormant; cells are viable and metabolically active but do not proliferate; reversible or irreversible

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18
Q

cells spend most of their time in interphase. true or false?

A

true. they spend 15 hours in interphase(5 for g1, 7 for s phase, and 3 for g2 phase. only one hour is spent for mitosis

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19
Q

g1/s checkpoint checks for

A

cell size and dna quality

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20
Q

g2/m checkpoint checks for

A

dna replication and quality

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21
Q

m checkpoint checks for

A

spindle assembly checkpoint

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22
Q

no visible chromosomes but visible nucleolus; nuclear membrane starts to disintegrate

A

interphase

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23
Q

interphase
(1) chromatin number
(2) chromosome number
(3) chromatid number

A

(1) 92 chromatins/cell
(2) 0 chromosome/cell
(3) 0 chromatid/cell

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24
Q

visible chromosomes; complete disintegration of nuclear membrane; asters/star-like arrangement of microtubules; spindle fiber assembly

A

prophase

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25
Q

cohesin is formed during what stage?

A

interphase

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26
Q

prophase
(1) chromatin number
(2) chromosome number
(3) chromatid number

A

(1) 0/cell
(2) 46/cell
(3) 92/cell

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27
Q

period of chromosome migration to the equatorial plane called the metaphase plate; migration is facilitated by the binding of spindle fibers to the chromosome’s kinetochore

A

prometaphase

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28
Q

an assembly of multilayered plates of proteins; associated with the centromere

A

kinetochore

29
Q

degrades cohesin

A

separase

30
Q

protects cohesin from degradation at the centromeric region

A

shugoshin

31
Q

prometaphase
(1) chromatin number
(2) chromosome number
(3) chromatid number

A

(1) 0/cell
(2) 46/cell
(3) 92/cell

32
Q

chromosome configuration following migration

A

metaphase

33
Q

metaphase
(1) chromatin number
(2) chromosome number
(3) chromatid number

A

(1) 0/cell
(2) 46/cell
(3) 92/cell

34
Q

degradation of shugoshin and cohesin; sister chromatids separate (disjunction)

A

anaphase

35
Q

after anaphase, each migrating chromatid is referred to as ____.

A

daughter chromosome

36
Q

anaphase
(1) chromatin number
(2) chromosome number
(3) chromatid number

A

(1) 0/cell
(2) 46 choromosomes/pole
(3) 0 chromatids/cell

37
Q

final stage wherein there is one complete chromosome set per pole

A

telophase

38
Q

chromosomes begin to uncoil; reformation of the nuclear envelope; spindle fibers disappear; nucleolus gradually reforms but not visible

A

late telophase

39
Q

telophase + cytokinesis
(1) chromatin number
(2) chromosome number
(3) chromatid number

A

(1) 0 chromatin/cell
(2) 46 chromosomes/cell
(3) 0 chromatid/cell

40
Q

cell division by which gametes or spores are produced; haploid set of chromosomes

A

meiosis

41
Q

in meiosis, each haploid cell contain precisely one member of each homologous pair of chromosomes. true or false?

A

true

42
Q

two sources of genetic variation

A

(1) many unique combinations of chromosomes from each parent
(2) crossing over

43
Q

genetic exchange between members of each homologous pair of chromosomes, creating intact chromosomes that are mosaics of the paternal and maternal homologs

A

crossing over

44
Q

how many rounds of dna replication take place in meiosis?

A

one; in meiosis I

45
Q

localized condensations that resemble beads on a string

A

chromomeres

46
Q

stage in prophase I wherein chromomeres appear and synapsis begins

A

leptonema

47
Q

what is synapsis?

A

pairing of homologs

48
Q

synapsed pair of homologs equal to the haploid number; what stage in prophase I do these appear?

A

bivalent; zygonema

49
Q

two pairs of sister chromatids; what stage in prophase I do they appear?

A

tetrad; pachynema

50
Q

stage in prophase I wherein crossing over happens

A

diplonema

51
Q

site of crossing over/point where non-sister chromatids have undergone genetic exchange

A

chiasma/chiasmata

52
Q

stage in prophase I wherein separation of chromosomes start; nucleolus and nuclear envelope break down; two centromeres of each tetrad attach to the recently formed spindle fibers

A

diakinesis

53
Q

during diakinesis, what happens to the chiasmata?

A

they move toward the ends of the tetrad

54
Q

prophase I
(1) chromatin number
(2) chromosome number
(3) chromatid number
(4) tetrad number
(5) bivalent number

A

(1) 0/cell
(2) 46/cell
(3) 92/cell
(4) 23/cell
(5) 23/cell

55
Q

what happens during metaphase I?

A

chromosome are maximally shortened and thickened; tetrads are randomly aligned

56
Q

metaphase I
(1) chromatin number
(2) chromosome number
(3) chromatid number
(4) tetrad number

A

(1) 0/cell
(2) 46/cell
(3) 92/cell
(4) 23/cell

57
Q

what happens in anaphase I?

A

the dyads are pulled toward each pole of the dividing cell; disjunction: separation of chromosomes from one another

58
Q

anaphase I
(1) chromatin number
(2) chromosome number
(3) chromatid number
(4) tetrad number
(5) dyad number

A

(1) 0/cell
(2) 23/pole
(3) 46/pole
(4) 0/pole
(5) 23/pole

59
Q

what happens in telophase I?

A

nuclear membrane forms around the dyads; nucleus enters into a short interphase period but no dna synthesis (absent in other organisms)

60
Q

telophase I
(1) chromatin number
(2) chromosome number
(3) chromatid number
(4) tetrad number
(5) dyad number

A

(1) 0/cell
(2) 23/pole
(3) 46/pole
(4) 0/pole
(5) 23/pole

61
Q

in prophase II, each dyad is composed of one pair of sister chromatids attached by a common centromere. true or false?

A

true

62
Q

prophase II
(1) chromatin number
(2) chromosome number
(3) chromatid number
(4) tetrad number
(5) dyad number

A

(1) 0/cell
(2) 23/pole
(3) 46/pole
(4) 0/pole
(5) 23/pole

63
Q

what happens in metaphase II?

A

chromosomes align at the metaphase plate

64
Q

metaphase II
(1) chromatin number
(2) chromosome number
(3) chromatid number
(4) tetrad number
(5) dyad number

A

(1) 0/cell
(2) 23/pole
(3) 46/pole
(4) 0/pole
(5) 23/pole

65
Q

what happens in anaphase II?

A

sister chromatids of dyads are pulled to opposite poles

66
Q

anaphase II
(1) chromatin number
(2) chromosome number
(3) chromatid number
(4) tetrad number
(5) dyad number

A

(1) 0/cell
(2) 23/pole
(3) 0/pole
(4) 0/pole
(5) 0/pole

67
Q

what happens in telophase II?

A

one member of each pair of homologous chromosomes at each pole; each chromosome is called monad

68
Q

telophase II
(1) chromatin number
(2) chromosome number
(3) chromatid number
(4) tetrad number
(5) dyad number
(6) monad numebr

A

(1) 0/cell
(2) 23/pole
(3) 0/pole
(4) 0/pole
(5) 0/pole
(6) 23/pole

69
Q

cytokinesis
(1) chromatin number
(2) chromosome number
(3) chromatid number
(4) tetrad number
(5) dyad number

A

(1) 0/cell
(2) 23/cell
(3) 0/cell
(4) 0/cell
(5) 0/cell