Chapter 13 Meiosis And Sexual Life Cycle Flashcards

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1
Q

What do children inherit from their parents?

A

Just the DNA

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2
Q

Transformation of traits from one generation to the next

A

Heredity

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3
Q

Same trait but expressed differently. Ex. Eye color

Similar characteristics but not identical

A

Variation

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4
Q

…..

A

Genetics

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5
Q

Basic units of heredity

Made up of segments of DNA

A

Genes

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6
Q

Gametes

A

Sperm and egg

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7
Q

?The location for a specific trait?

A

Gene locus

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8
Q

Most DNA is packed into ______________

A

Chromosomes

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9
Q

Human somatic cells have _____ pairs of chromosomes

A

23

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10
Q

Homologous chromosome pairs are the same __________ and _____________

A

Length and centromere placement

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11
Q

Homologous chromosome pairs carry genes controlling the ________ inherited characters

Ex eye close

A

Same

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12
Q

Humans have _____ set of sex chromosomes and _____ pairs of autosome chromosomes

A

1, 22

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13
Q

2n is ….

A

Diploid -two sets

2n= 46 chromosomes total

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14
Q

n is …..

A

Haploid

Single set of chromosomes

n=23

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15
Q

Zygote…

A

One set of chromosomes from each parent

I cell

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16
Q

Each replicated chromosome consists of …..

A

Two identical sister chromatids

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17
Q

Meiosis starts with a _________ cell and ends with _________ cells

A

Diploid, haploid

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18
Q

Meiosis results in four daughter cells with only ____ as many chromosomes as the parent cell

A

Half

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19
Q

I’m meiosis 1 ____________ chromosomes separate and in meiosis 2 ____________ spectate

A

Homologous, sister

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20
Q

Two key differences from mitosis to meiosis

A
  • homologous pairs form a bivalent or tetrad

- crossing over

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21
Q

Meiosis 1 and meiosis 2

A

Meiosis 1 (reductions division): homologous pair up and separate, resulting in two haploid daughter cells with replicated chromosomes

Meiosis 2 (equational division) sister chromatids separate

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22
Q

What is the spot on a chromosome called where crossing over happens?

A

Chiasma

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23
Q

Physical exchange between chromosomes prices of the crossing bivalent

A

Crossing over

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24
Q

What phase does crossing over take place?

A

Prophase 1

25
Q

After interphase the sister chromatids are held together by proteins called

A

Cohesions

26
Q

A zipper like structure called the ________________ holds the homologs together tightly

A

Synaptoneal complex

27
Q

In meiosis are sister chromatids identical after crossing over takes place?

A

No

28
Q

Meiosis 1

A

Homologoues line up side by side at the equator- synapsis

When pairs spectate, each daughter cell receives one member of the pair

Cells are now haploid

29
Q

How the chromosomes line up in metaphase 1 is ___________

A

Random

30
Q

I’m prophase 1, replicated homologous chromosomes loosely pair up, aligned gene by gene

(This happens prior to their segregation and crossing over)

A

Synapsis

31
Q

In prophase 1
Nuclear membrane …….
Replicated chromosomes……

What is formed?

A

Breaks down
Condense
Bivalents

32
Q

Non sister chromosomes reciprocally exchange DNA segments

A

Crossing over

33
Q

Each pair of chromosomes forms a __________, a group of four chromatids

A

Tetrad

34
Q

Each tetrad usually has one or more ___________, X-shaped regions where crossing over occurred

A

Chiasmata

35
Q

A spindle forms from each centrosome and spindle fibers attached to kinetochores and chromosomes

This happens in what phase?

A

Prophase 1

36
Q

In what phase does the spindle apparatus complete, and the chromatids are attached to kinetochore microtubules

Pairs of sister chromatids attached to ____ pole

A

Prometaphase 1

1

37
Q

In what phase are bivalents organized along metaphase plate as double row such that maternal or paternal members may be oriented toward either pole

A

Metaphase 1

38
Q

Homologous pairs separate maternal and paternal homologue into daughter cells independently of other pairs
Promotes gentility diversity

A

Independent assortment

39
Q

In anaphase 1 segregation of _________________ occurs

Connection between __________ break, but not the connections that hold ________________ together

Each joined pair of chromatids migrates to one pole, and the homologous pair of chromatids moves to the opposite pole

A

Homologue

Bivalent

Sister chromatids

40
Q

In telophase 1
Sister chromatids ____________
And the nuclear membranes ___________

A

Decondense

Reforms

41
Q

I’m the beginning of Telophase 1, each half of the cell has a ___________ set of chromosomes; each chromosome still consists of ______sister chromatids

A

Diploid

2

42
Q

No chromosome replication occurs between the end meiosis I and the beginning of meiosis II because the chromosomes are already replicated

True or false?

A

True

43
Q

In anaphase 1

__________________ get pulled to opposite ends

A

Homologous chromosomes

44
Q

What is the period of time between meiosis 1 and meiosis II?

A

Interkinesis

45
Q

There is a S phase between meiosis 1 and meiosis 2

True or false?

A

False

There is no S phase in between

46
Q

Sorting events of meiosis 2 are similar to those of _________

A

Mitosis

47
Q

Sister chromatids are separated during …..

A

Anaphase 2

Unlike anaphase 1

48
Q

In meiosis 2 each of the four daughter cells produced has the haploid chromosome number and each chromosome is composed of ___________

A

One chromatid

49
Q

Meiosis 2 is very similar to _______

A

Mitosis

50
Q

What happens in Prophase 2?

A

Spindle apparatus forms

In late prophase, chromosomes (each still composed of two chromatids) move toward the metaphase plate

51
Q

Are the sister chromatids of each chromosomes in meiosis 2 genetically identical?

A

No,

because of crossing over In meiosis 1

52
Q

Metaphase 2

A

The sister chromatids are arranged at the metaphase plate (sister tids are not identical)

The kinetochores of sister chromatids attach to microtubules extending from opposite poles

53
Q

In what phase do sister chromatids separate

The sister chromatids of each chromosome now move as two newly individual chromosomes toward opposite poles

A

Anaphase 2

54
Q

Telophase 2….

A

The chromosomes arrive at opposite poles

Nuclei form, and the chromosomes define decondensing

55
Q

At the end of meiosis, there are four daughter cells, each with a haploid set of _____________ chromosomes

Each daughter cell is genetically __________ from the other and form the parent cell

A

Unreplicated

Distinct

56
Q

What three mechanisms contribute to genetic variation?

A
  • independent assortment of chromosomes
  • crossing over
  • random fertilization
57
Q

Crossing over begins very early in _______________, as homologous chromosomes pair up gene by gene

A

Prophase 1

58
Q

Crossing over produces __________________, which combine DNA inherited form each parent

A

Recombinant chromosomes