Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology 1406 > Chapter 13 > Flashcards

Chapter 13 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Living organisms are distinguished by

A

their ability to reproduce their own kind

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

Genetics is the

A

scientific study of heredity and variation

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

Heredity is the

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
4
Q

Variation is

A

demonstrated by the differences in appearance that offspring show from parents and siblings

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

Offspring acquire genes from parents by

A

inheriting chromosomes

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

In a literal sense, children do not

A

inherit particular physical traits from their parents

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

It is

A

genes that are actually inherited

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

Genes are the

A

units of heredity, and are made up of segments of DNA

Genes are generic categories, but they have specific locations

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

Genes are passed to the next generation via reproductive cells called

A

gametes (sperm and eggs)

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

Each gene has a specific location called a

A

locus, on a certain chromosome

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

Most DNA is packaged into

A

chromosomes

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

One set of chromosomes is inherited from

A

each parent

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

Every person has

A

specific details (alleles)

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

In asexual reproduction (mitosis),

A

a single individual passes genes to its offspring without the fusion of gametes

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

A clone is

A

a group of genetically identical individuals from the same parent

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

In sexual reproduction,

A

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

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

Fertilization and Meiosis alternate in

A

sexual life cycles

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

A life cycle is the

A

generation-to-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
19
Q

Human somatic cells (any cell other than a gamete) have

A

23 pairs of chromosomes.

have 2 of every chromosome

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

A karyotype is an

A

ordered display of the pairs of chromosomes from a cell

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

The two chromosomes in each pair are called

A

homologous chromosomes, or homologs

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

Chromosomes in a homologous pair are the

A

same length and shape and carry genes controlling the same inherited characters ((but slightly different information??))

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

The sex chromosome, which determine the sex of the individual, are called

A

X and Y

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

Human females have a

A

homologous pair of X chromosomes (XX)

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

Human males have

A

one X and one Y chromosome (XY)

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

The remaining 22 pairs of chromosomes are called

A

autosomes

not a sex chromosome

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

Each pair of homologous chromosomes includes

A

one chromosome from each parent

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

The 46 chromosomes in a human somatic cell are

A

two sets of 23: one from the mother and one from the father

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

A diploid cell (2n) has

A

two sets of chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

For humans, the diploid number is

A

46 (2n = 46)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

In a cell in which DNA synthesis has occurred,

A

each chromosome is replicated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Each replicated chromosome consists of

A

two identical sister chromatids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

A gamete (sperm or egg) contains a

A

single set of chromosomes, and is haploid (n)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

For humans, the haploid number is

A

23 (n = 23)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Each set of 23 consists of

A

22 autosomes and a single sex chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

In an unfertilized egg (ovum),

A

the sex chromosome is X

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

In a sperm cell,

A

the sex chromosome may be either X or Y

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Fertilization is the

A

union of gametes (the sperm and the egg)

when the egg and sperm come together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

The fertilized egg is called a

A

zygote and has one set of chromosomes from each parent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

The zygote produces

A

somatic cells by mitosis and develops into an adult

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

At sexual maturity,

A

the ovaries and testes produce haploid gametes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Gametes are the only types of human cells produced by

A

meiosis, rather than mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Meiosis results in

A

one set of chromosomes in each gamete

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Fertilization and meiosis alternate in

A

sexual life cycles to maintain chromosome number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

The alternation of meiosis and fertilization is common to

A

all organisms that produce sexually

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

The three main types of sexual life cycles differ in

A

the timing of meiosis and fertilization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Gametes are the only haploid cells in

A

animals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

The gametes are produced by meiosis and undergo no further

A

cell division before fertilization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Gametes fuse to form a diploid zygote that

A

divides by mitosis to develop into a multicellular organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Plants and some algae exhibit an

A

alternation of generations

51
Q

This life cycle (plants) includes both a

A

diploid and haploid multicellular stage

52
Q

The diploid organism, called the

A

sporophyte, makes haploid spores by meiosis

53
Q

Each spore grows by mitosis into a

A

haploid organism called a gametophyte

54
Q

A gametophyte makes

A

haploid gametes by mitosis

55
Q

Fertilization of gametes results in a

A

diploid sporophyte

56
Q

In most fungi and some protists,

A

the only diploid stage is the single-celled zygote; there is no multicellular diploid stage

57
Q

In most fungi, the zygote produces haploid cells by

A

meiosis

58
Q

Each haploid cell grows by

A

mitosis into a haploid multicellular organism

59
Q

The haploid adult produces gametes by

A

mitosis

60
Q

Depending on the type of life cycle,

A

either haploid or diploid cells can divide by mitosis

61
Q

However, only diploid cells can

A

undergo meiosis

62
Q

In all three life cycles,

A

the halving and doubling of chromosomes contributes to genetic variation in offspring

63
Q

Meiosis reduces the

A

number of chromosome sets from diploid to haploid

64
Q

Like mitosis, meiosis is preceded by

A

the replication of chromosomes

65
Q

Meiosis takes place in two sets of cell divisions, called

A

meiosis I and meiosis II

66
Q

The two cell divisions result in

A

four daughter cells, rather than the two daughter cells in mitosis

67
Q

Each daughter cell has only

A

half as many chromosomes as the parent cell

68
Q

Meiosis Stages

A
  1. Replicate DNA (DNA synthesis)
  2. meiosis I
    P-prophase I
    M- metaphase I
    A- anaphase I
    T- telophase I and cytokinesis
  3. meiosis II
    P-prophase I
    M- metaphase I
    A- anaphase I
    T- telophase I and cytokinesis
69
Q

After chromosomes duplicate, two divisions follow

A
  • Meiosis I (reductional division: homologs pair up and separate, resulting in two haploid daughter cells with replicated chromosomes
  • Meiosis II (equational division): sister chromatids separate

-The result is four haploid daughter cells with unreplicated chromosomes

70
Q

Meiosis I is preceded by

A

interphase, when the chromosomes are duplicated to form sister chromatids

71
Q

The sister chromatids are

A

genetically identical and joined at the centromere

72
Q

The single centrosome replicates, forming

A

two centrosomes

73
Q

Division in meiosis I occurs in four phases

A

P-prophase I
M- metaphase I
A- anaphase I
T- telophase I and cytokinesis

((they are generally the same as in Mitosis, but there are a few differences))

74
Q

Prophase I typically occupies more than

A

90% of the time required for meiosis.

75
Q

In prophase I,

A

chromosomes begin to condense

76
Q

In synapsis,

A

homologous chromosomes loosely pair up, aligned gene by gene

77
Q

In crossing over,

A

nonsister chromatids exchange DNA segments

78
Q

Each pair of chromosomes forms a

A

tetrad, a group of four chromatids

79
Q

Each tetrad usually has one or more

A

chiasmata, X-shaped regions where crossing over occurred

80
Q

3 things that make meiosis different/unique from mitosis

A
  1. prophase I- synapsis/crossing over
  2. metaphase I- homologs line up
  3. Anaphase I- homologs separate
81
Q

In metaphase I,

A

tetrads line up at the metaphase plate, with one chromosome facing each pole

82
Q

Microtubules from one pole are attached to the

A

kinetochore of one chromosome of each tetrad

83
Q

Microtubules from the other pole are attached to

A

the kinetochore of the other chromosome

84
Q

In anaphase I,

A

pairs of homologous chromosomes separate

85
Q

One chromosome moves toward

A

each pole, guided by the spindle apparatus

86
Q

Sister chromatids remain attached at the

A

centromere and move as one unit toward the pole

87
Q

In the beginning of telophase I,

A

each half of the cell has a haploid set of chromosomes; each chromosome still consists of two sister chromatids

88
Q

Cytokinesis usually occurs

A

simultaneously, forming two haploid daughter cells

  • In animal cells, a cleavage furrow forms
  • In plant cells, a cell plate forms
89
Q

No chromosome replication occurs between the

A

end of meiosis I and the beginning of meiosis II because the chromosomes are already replicated

90
Q

Division in meiosis II also occurs in four phases

A

P- prophase II
M- metaphase II
A- anaphase II
T- telophase II and cytokinesis

91
Q

Meiosis II is very similar to

A

mitosis

92
Q

In prophase II,

A

a spindle apparatus forms

93
Q

In late prophase II,

A

chromosomes (each still composed of two chromatids) move toward the metaphase plate

94
Q

In metaphase II,

A

the sister chromatids are arranged at the metaphase plate

95
Q

Because of the crossing over in meiosis I,

A

the two sister chromatids of each chromosome are no longer genetically identical

96
Q

The kinetochores of sister chromatids attach to

A

microtubules extending from opposite poles

97
Q

In anaphase II,

A

the sister chromatids separate

98
Q

The sister chromatids of each chromosome now move as

A

two newly individual chromosomes toward opposite poles

99
Q

In telophase II,

A

the chromosomes arrive at opposite poles

100
Q

Then in telophase II,

A

nuclei form, and the chromosomes begin decondensing

101
Q

Cytokinesis separates the

A

cytoplasm

102
Q

At the end of meiosis,

A

there are four daughter cells, each with a haploid set of unreplicated chromosomes

103
Q

Each daughter cell is genetically distinct from

A

the others and from the parent cell

104
Q

Mitosis conserves the number of

A

chromosome sets, producing cells that are genetically identical to the parent cell

105
Q

Meiosis reduces the number of

A

chromosomes sets from two (diploid) to one (haploid), producing cells that differ genetically from each other and from the parent cell

106
Q

Three events are unique to meiosis, and all three occur in meiosis I

A
  • synapsis and crossing over in prophase I: Homologous chromosomes physically connect and exchange genetic information
  • At the metaphase plate, there are paired homologous chromosomes (tetrads), instead of individual replicated chromosomes
  • At anaphase I, it is homologous chromosomes, instead of sister chromatids, that separate
107
Q

Genetic variation produced in sexual life cycles contributes to

A

evolution

108
Q

Mutations (changes in an organism’s DNA) are the

A

original source of genetic diversity

109
Q

Mutations create

A

different versions of genes called alleles

110
Q

Reshuffling of alleles during sexual reproduction produces

A

genetic variation

111
Q

The behavior of chromosomes (DNA) during meiosis and fertilization is responsible for

A

most of the variation that arises in each generation

112
Q

Three mechanisms contribute to genetic variation

reasons why kids look different from parents and other siblings

A
  1. independent assortment of chromosomes
  2. crossing over
  3. random fertilization
113
Q

Homologous pairs of chromosomes orient

A

randomly at metaphase I of meiosis

114
Q

In independent assortment,

A

each pair of chromosomes sorts maternal and paternal homologs into daughter cells independently (differently) of the other pairs

(chromosomes can line up differently)

115
Q

The number of combinations possible when chromosomes assort independently into gametes is

A

2^n, where n is the haploid number

116
Q

For humans (n = 23), there are more than

A

8 million (2^23) possible combinations of chromosomes

117
Q

Crossing over produces

A

recombinant chromosomes, which combine DNA inherited from each parent

118
Q

Crossing over beings very early in prophase I, as

A

homologous chromosomes pair up gene by gene

119
Q

In crossing over,

A

homologous portions of two nonsister chromatids trade places

120
Q

Crossing over contributes to

A

genetic variation by combining DNA from two parents into a single chromosome

121
Q

Random fertilization adds to

A

genetic variation because any sperm can fuse with any ovum (unfertilized egg)

122
Q

The fusion of two gametes (each with 8.4 million chromosome combinations from independent assortment) produces a

A

zygote with any of about 70 trillion diploid combinations

123
Q

Each zygote has a

A

unique genetic identity

Biology 1406 (53 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions