Chapter 13 (Inheritance/Meiosis) Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is heredity?

A

transmission of traits from one generation to the next

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is variation?

A

demonstrated by differences in appearance that offspring show from parents and springs (each offspring has different combo)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is genetics?

A

the scientific study of heredity and variation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are genes?

A

units of heredity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are genes made of?

A

segments of DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How are genes passed to the next generation?

A

gametes (reproductive cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How many chromosomes do humans have in the somatic cells?

A

46 chromosomes (46 of these X)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What cells of the body have 46 chromosomes?

A

somatic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a locus?

A

a gene’s specific position along a chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens to genes in asexual reproduction?

A

single individual passed all genes to offspring without fusion of gametes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the offspring of an asexual reproductive organism called?

A

clones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens to genes in sexual reproduction?

A

two parents give rise to offspring that have a unique combo of genes inherited from parents of the parents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a life cycle?

A

generation sequence of stages in the reproductive history of an organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How many pairs of chromosomes do humans have?

A

23 pairs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a karyotype?

A

ordered display of pairs of chromosomes from a cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are homologous chromosomes?

A

one of a pair of chromosomes with the same gene sequence, loci, chromosomal length, and centromere location (X)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are homologous pairs?

A

consists of one paternal and one maternal chromosome (X X) consisting of the genes controlling the same inherited characters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are sex chromosomes?

A

23rd pair of chromosomes that determines gender (X and Y)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the homologous pair of females?

A

XX (FEMALES ONLY HAVE THE HOMOLGOUS SEX CHROMOSOME)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the chromosomal pair of males?

A

XY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the remaining 22 pairs of chromosomes called?

A

autosomal chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is a diploid cell?

A

represented by 2n, has two sets of chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the diploid number for humans?

A

46

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a haploid cell?

A

gametes, represented by n (n=23)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the sex chromosome in an ovum?

A

X

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the sex chromosome in a sperm?

A

can be either X or Y

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is fertilization?

A

union of gametes (sperm and egg)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is a fertilized egg called?

A

zygote

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How many sets of chromosomes does a zygote have?

A

2 sets, one from each parent

30
Q

What type of cell does the zygote produce?

A

somatic cells by mitosis and develops into an adult

31
Q

At sexual maturity, the ovaries and testes produce what?

A

haploid gametes

32
Q

What process produces gametes?

A

meiosis

33
Q

What is the result of meiosis?

A

4 gamete cells that contain a half set of chromosomes in each as compared to the parent cell

34
Q

How is mitosis and meiosis similar?

A

replication of chromosomes

35
Q

How is meiosis different from meiosis?

A

meiosis occurs in two stages (meiosis I and meiosis II), reduces the number of chromosomes sets from two diploids to one haploid to produce genetically different cells

36
Q

What are the phases of mitosis I?

A

prophase I, metaphase I, anaphase I, telekinesis I, cytokinesis

37
Q

What happens in prophase I?

A

each chromosome pairs with its homolog and crossing over occur via synapsis, spindle formed, nuclear envelope disappears

38
Q

What is a synapsis?

A

the pairing of two chromosomes that occurs during meiosis, DNA breaks are repaired, joining corresponding nonsister chromatids to the other corresponding segment, paternal segment goes to maternal side and vice versa

39
Q

What is the chiasmata?

A

two chromosomes have contact during the state of crossover, point of crossover

40
Q

What happens in crossing over?

A

breaking of DNA and pairing with the homologous chromosome

41
Q

What happens in metaphase I?

A

pairs of homologs line at metaphase plate, one chromosome facing each plate
microtubulues from each pole are attached to kinetochore of one chromosome of each pair

42
Q

What happens in anaphase I?

A

pairs of homologs chromosomes separate via spindle apparatus and move towards opposite poles
sister chromatids remain attached at the centromere and move as one until towards the pole

43
Q

What happens in telophase I and cytokinesis?

A

each half of cell has a haploid set of chromosomes, still has two sister chromatids
cytokinesis forms two haploid daughter cells and cleavage

44
Q

What forms as cytokinesis happen in plants?

A

cell plate forms

45
Q

When does chromosomal replication end in mitosis?

A

end of mitosis I because chromosomes have already replicated at that point

46
Q

What are the phases of meiosis II?

A

prophase II, metaphase II, anaphase II, telophase II, cytokinesis

47
Q

What happens in prophase II?

A

spindle apparatus forms, chromosomes (still containing two chromatids) move towards metaphase plate

48
Q

What happens in metaphase II?

A

sister chromatids (not identical anymore because of crossing over in prophase I) arranged at the metaphase plate, kinetochores of sister chromatids attach to microtubules at opposite poles

49
Q

What happens in anaphase II?

A

sister chromatids separate and move as individual chromosomes towards opposite poles

50
Q

What happens in telophase II and cytokinesis?

A

chromosomes arrive at opposite poles, nuclei form, chromosomes become less dense
cytokinesis separates cytoplasm and creates 4 daughter cells with each having a haploid set of unreplicated chromosomes

51
Q

Are the four daughter cells at the end of meiosis genetically identical?

A

NO

52
Q

How is mitosis different that meiosis?

A

conserves a number of chromosome sets and produces cells that are genetically identical

53
Q

What stages are unique to meiosis?

A

synapsis and crossing over in prophase I, homologous pairs line up at metaphase plate, separation of homologous pairs at anaphase I, separation of chromatids

54
Q

What does genetic variation do?

A

contribute to evolution

55
Q

What is a big source of genetic diversity?

A

mutation, the behavior of chromosomes during meiosis and fertilization

56
Q

What do mutations create?

A

different versions of genes called alleles

57
Q

What process in sexual reproduction contributes to genetic variation?

A

reshuffling of alleles

58
Q

What mechanisms contribute to genetic variation?

A

independent assortment of chromosomes, crossing over, random fertilization

59
Q

What happens in the independent assortment?

A

homologous pairs of chromosomes orient randomly at metaphase I of meiosis, maternal and paternal homologs orient differently in daughter cells independent of other pairs

60
Q

How does crossing over contribute to genetic diversity?

A

combine DNA from each parent into a single chromosome

61
Q

How many crossing overs does the average human cell go through?

A

one to three

62
Q

How does random fertilization contribute to genetic variation?

A

any sperm can fuse with any ovum, each zygote has a unique genetic identity

63
Q

What is the significance of variation in natural selection?

A

accumulation of genetic variation that is favored by the environment

64
Q

when do the chromosomes duplicate?

A

interphase

65
Q

What do offspring inherit from parents in mitosis?

A

chromosomes

66
Q

Which type of reproduction gives exact replicas of offspring?

A

asexual reproduction

67
Q

At what point does a haploid cell become a diploid cell?

A

during fertilization

68
Q

What cells are gametes produced from?

A

germ cells in the gonads (ovaries/testes)

69
Q

What is an allele?

A

different version of genes at the same loci

70
Q

What forms at the end of meiosis I?

A

2 haploid cells consisting of 2 sister chromatids in each of the chromosomes

71
Q

How many divisions happen in meiosis?

A

2