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Genetics > Ch.1 Mitosis and Meiosis > Flashcards

Ch.1 Mitosis and Meiosis Flashcards

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1
Q

Mitosis

A

Partitions chromosomes into dividing cells
Creates identical daughter cells
No genetic variation

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2
Q

Meiosis

A

Creates haploid gametes
Creates non-identical daughter cells
Genetic variation

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3
Q

All organisms are made of what?

A

Cells- one of the properties of living organisms

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4
Q

Multicellular organisms

A

consist of more than one cell

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5
Q

Unicellular organisms

A

consist of only one cell

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6
Q

Living things can only arise from?

A

Can only arise from living things

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7
Q

The cellular environment

A

Cytoplasm-the inside of the cell; water; hydrophilic and hydrophobic molecules; carbohydrates; lipids; proteins including enzymes; membrane- made of lipids and proteins; organelles

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8
Q

Prokaryotic

A

(bacteria, archaea) no cell nucleus

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9
Q

Eukaryotic

A

(protists, plants, fungi, animals) cell nucleus

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10
Q

In both unicellular and multicellular organisms, prokaryotic and eukaryotic cells, where is the genetic material located?

A

It is organized into chromosomes

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11
Q

All cells share some common features, what are they?

A

DNA organized in chromosomes; plasma membrane; ribosomes

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12
Q

Nucleus

A

Found in eukaryotes
Membrane bound
Houses genetic material (DNA)
Nucleolus- where ribosomal RNA (rRNA) is synthesized

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13
Q

Nucleoid

A

Found in Bacteria and Archaea (prokaryotes)
Nucleoid region
NOT membrane bound
Area of DNA

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14
Q

Chromosomes

A

Double-stranded DNA with associated proteins and sometimes RNA
Unit of DNA molecule which is passes on to the next generation

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15
Q

What kind of chromosome is in prokaryotic cells?

A

Contains 1 circular chromosome plus smaller plasmids (ring shaped DNA molecules)

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16
Q

What kind of chromosome is in eukaryotic cells?

A

Most eukaryotic cells contain several large linear chromosomes

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17
Q

Chromatin

A

association of double stranded DNA and proteins

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18
Q

Chromosomes are the condensed form of what?

A

Chromatin. (Discrete units)

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19
Q

Why does DNA have to be organized in discrete unites before the cell can divide?

A

It makes it easier to distribute DNA molecules evenly to daughter cells

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20
Q

Order of condensing

A

Double helix DNA, “Beads on a string” DNA wound on nucleosomes, chromatin fiber, chromosomes

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21
Q

How is chromosome shape determined?

A

Location of centromere determines appearance of chromosome

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22
Q

Metacentric chromosome

A

centromere is in the middle

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23
Q

Submetacentric chromosome

A

centromere is in between middle and end

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24
Q

Acrocentric chromosome

A

centromere is close to the end

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25
Q

Telocentric chromosome

A

centromere is at the end

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26
Q

Karyogram

A

chromosomes sorted into homologous pairs, organized and labeled by size

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27
Q

Metaphase chromosomes

A

chromosomes are fully condensed into X shape

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28
Q

How many chromosomes in a human?

A

22 pairs of autosomes and 1 pair of sex chromosomes
XY- male
XX- female

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29
Q

Diploid cells (2n)

A

have 2 sets of homologous chromosomes (maternal/paternal)

Human 2n=46

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30
Q

Haploid cells (n)

A

have 1 set of chromosomes

human n=23

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31
Q

Somatic cells

A

nonreproductive cells in the body of a eukaryote

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32
Q

Are somatic cells diploid or haploid?

A

Diploid (2n)

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33
Q

Sex cells (gametes)

A

reproductive cells: sperm and egg cells produced by diploid cells of the germ line

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34
Q

Germ line

A

tissue that produces reproductive cells

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35
Q

Are sex cells diploid or haploid?

A

Haploid (n)

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36
Q

Human sexual life cycle

A

Germ line (reproductive tissue) - ovary and testis
Meiosis- produces sex cells (n state)
Egg and sperm - each is in the haploid state (one set of chromosomes)
Fertilization results in zygote (2n)- 1st diploid state of human
Mitosis and development into human - body is 2n

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37
Q

Homologous chromosomes

A

the 2 chromosomes in a pair: one maternally, one paternally derived

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38
Q

Are homologous chromosomes identical?

A

They are identical in size and shape. They contain the same information (genes) but in variants (alleles)

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39
Q

Sister chromatids

A

arms of the chromosome which consist of identical copies of DNA

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40
Q

Eye color on homologous chromosomes

A

Eye color gene is located at a specific site (locus). Both chromosomes in a homologous pair have the same genes at the same loci. One chromosome carries the allele for brown eyes (B) at the eye color gene locus, the other chromosome carries the blue eye allele (b)

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41
Q

Eye color on sister chromatids

A

the sister chromatids within one chromosome are identical. They both have BB or both have bb

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42
Q

MTOCs

A

microtubule organizing center - differentiated into centrosomes which each contain 2 centrioles

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43
Q

Where do microtubules start to form?

A

From the centrosomes

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44
Q

Microtubules

A

protein fibers, attach to the centrosome of the chromosomes and move them

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45
Q

What do the microtubules make up?

A

The mitotic spindle (spindle apparatus)

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46
Q

How do microtubules move the chromosomes?

A

Protein fibers start to degrade and get shorter which causes movement of the chromosomes

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47
Q

Mitosis (2n -> 2n)

A

cell division that creates 2 daughter cells identical to the parent cell (bc the sister chromatids get separated and divided onto the daughter cells)

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48
Q

Meiosis (2n -> n)

A

Cell division that creates sperm and egg cells. The sperm cells and the egg cells created are NOT identical to each other (bc the homologous chromosomes get separated and divided)
Ovaries/testes are diploid -> sperm and egg are haploi

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49
Q

Mitosis - when eukaryotic cells divide, how do that distribute their genetic material?

A

They distribute their genetic material equally and exactly to their offspring.

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50
Q

Ex of mitosis: tissue renewel

A

all of your skin cells are identical clones: they carry identical DNA molecules

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51
Q

Mitosis steps

A 
Interphase
Prophase
Metaphase
Anaphase
Telophase
52
Q

Mitosis step 1 (interphase to prophase)

A

Chromosomes duplicate to produce sister chromatids

53
Q

Mitosis step 2 (prophase)

A

Duplicated chromosomes condense

54
Q

Mitosis step 3 (metaphase)

A

Duplicated chromosomes migrate to the equatorial plane of the cell and nuclear membranes breaks down

55
Q

Mitosis step 4 (anaphase)

A

Sister chromatids of each duplicated chromosome move to opposite poles of the cell (microtubule fibers in contact w/centromere)

56
Q

Mitosis step 5 (anaphase to telophase)

A

chromosomes decondense and new nuclear membranes form

57
Q

Mitosis step 6 (cytokinesis)

A

membrane forms between daughter cells

58
Q

What forms during cytokinesis in animal cells?

A

Cleavage furrow

59
Q

What forms during cytokinesis in plant cells?

A

Formation of a cell plate

60
Q

What gets separated during mitosis?

A

Sister chromatids (which contain identical DNA molecules)

61
Q

Do all cells within one organism carry identical DNA molecules?

A

Yes - but they can be specialized in their form and function (RBCs, skin cells, neurons)

62
Q

What are the 2 phases of the cell cycle?

A

Interphase and mitosis

63
Q

Steps in interphase

A

G1, G0 (non dividing) S phase, G2

64
Q

What happens in the S phase of the cell cycle?

A

DNA synthesis: sister chromatid form

65
Q

What happens during the G phases of the cell cycle?

A

GAP - DNA molecules are not active. Synthesis of proteins required for mitosis.

66
Q

How often and how fast cell divides depends on what?

A

The type of cell

67
Q

The cell cycle passes several checkpoints and gets signal to proceed.

A

TRUE

68
Q

What happens during cancer?

A

Cells divide uncontrolled and tumor grows

69
Q

Reduction division

A

2n -> n (meiosis

70
Q

Family and meiosis

A

Family members look similar to each other. Family members are not genetic identical clones

71
Q

What type of cells does meiosis produce?

A

haploid gametes (reduction division)

72
Q

What type of cells can undergo meiosis?

A

Only diploid cells

73
Q

What are haploid cells (gametes) produced by in meiosis?

A

They are produced by the diploid cells of the germ line (tissue in ovaries and testes)

74
Q

Are somatic cells diploid or haploid?

A

Diploid (2n) - one set of chromosomes from mom and one set of chromosomes from dad

75
Q

Are gametes diploid or haploid?

A

Haploid (n) - one set of chromosomes

76
Q

Meiosis interphase overview

A

Pair of homologous chromosomes in diploid parent cell -> Chromosomes duplicate -> end with diploid cell with duplicated chromosomes

77
Q

Meiosis 1 overview

A

Homologous chromosomes separate. End with 2 haploid cells with duplicated chromosomes

78
Q

Meiosis 2 overview

A

Sister chromatids separate. End with 4 haploid cells with unduplicated chromosomes

79
Q

Meiosis - Prophase 1

A

5 substages: leptonema, zygonema, pachynema, diplonema, diakinesis. End - centromeres are present on the equatorial plate

80
Q

Leptonema

A

chromosomes condense, visible as long thin threads

81
Q

Zygonema

A

synapsis (pairing) of each pair of homologous chromosomes (bivalent) (chromosomes have 1 chromatid)

82
Q

Pachynema

A

more condensation, splits into 2 sister chromatids (tetrads) crossing over
Tetrads- 4 chromosomes each pair

83
Q

Diplonema

A

within tetrads, sister chromatids separate. Chiasma-where chromatids are still intertwined

84
Q

Diakinesis

A

Nucleus and envelope break down; centromeres attach to spindle fibers

85
Q

Chiasmata (chiasma)

A

Homologous chromosomes exchange pieces with each other (non-sister chromatids). The inner non sister chromatids exchange pieces.

86
Q

Resulting chromosomes of crossing over

A

still homologous, but they are now mixtures of maternal and paternal pieces - recombinant chromatids

87
Q

Recombinant chromatids

A

sister chromatids, not identical anymore

88
Q

Meiosis - Metaphase 1

A

Paired chromosomes align on the equatorial plane. Paired chromosomes are oriented toward opposite poles. Terminalisation

89
Q

Terminalisation

A

chiasmata move toward telomeres (end of the chromosome arms)

90
Q

Meiosis - Anaphase 1

A

Homologous chromosomes disjoin and move to opposite poles of the cell. Chromosome disjunction. Separated homologues move toward opposite poles

91
Q

Chromosome disjunction

A

separation of paired chromosomes

92
Q

Meiosis - Telophase 1

A 
Chromosomes reach the new poles; nuclei forms
Spindle apparatus disassembled
Daughter cells separated by membranes
Chromosomes decondense
Each chromosome still has 2 chromatids
93
Q

Meiosis II is similar to what?

A

Mitosis

94
Q

Meiosis - Prophase II

A

(Chromosomes, each consisting of 2 sister chromatids, condense and become attach to spindle fibers)
Chromosomes condense
Chromosomes attach to a new spindle apparatus
Chromatids are attached to spindle fibers from opposite poles

95
Q

Meiosis - Metaphase II

A

Chromosomes align at equatorial plane in each cell

96
Q

Meiosis - Anaphase II

A

(Sister chromatids disjoin and move to opposite poles in each cell)
Centromeres split
Chromatid disjunction

97
Q

Chromatid disjunction

A

chromatids move toward opposite poles

98
Q

Meiosis - Telophase II

A

(Chromosomes decondense and new nuclei begin to form)
Separated chromatids gather at poles; daughter nuclei form
Each chromatid is now called a chromosome
Each daughter nucleus contains a haploid set of chromosomes

99
Q

Cytokinesis

A

The haploid daughter cells are separated by cytoplasmic membranes

100
Q

Meiosis results in

A

4 haploid daughter cells. Not identical to mother cell and not identical to each other

101
Q

Gametogenesis

A

process of the formation of gametes (occurs in the gonads)

102
Q

Oogenesis definition

A

Formation of eggs. Takes place in the ovaries

103
Q

Spermatogenesis definition

A

Formation of sperm. Takes place in the testis

104
Q

Spermatogenesis overview

A

Spermatogonia (undifferentiated diploid cells) produce haploid cells through meiosis
Haploid cells differentiate into mature gametes
All of the 4 cells develop into sperm cells

105
Q

Spermatogenesis detailed

A

Spermatogonia (2n) -> primary spermatocyte (undergo meiosis 1) - secondary spermatocyte (n). Eventually form 4 spermatids that mature into 4 sperm cells

106
Q

Oogenesis overview

A

oogonia (undifferentiated diploid cells) produce haploid cells through meiosis
Haploid cells differentiate into mature gametes
Only 1 of the 4 cells becomes an egg (ovum), other 3 degenerate (polar bodies)

107
Q

Oogenesis detailed

A

Oogonium (2n) -> primary oocyte (undergo meiosis 1) -> divides uneven to produce a polar body and a secondary oocyte (undergo meiosis 2). Eventually produces 1 haploid egg cell and 3 haploid polar bodies

108
Q

What 3 mechanisms contribute to genetic variation?

A

Crossing over, independent assortment of chromosomes, random fertilization

109
Q

What is responsible for most of the variation that arises in each generation?

A

Behavior of chromosomes during meiosis and fertilization

110
Q

How do homologous pairs of chromosomes orient at metaphase 1 of meiosis?

A

Randomly

111
Q

Independent assortment

A

Each pair of chromosomes sorts maternal and paternal homologs into daughter cells independently of the other pairs. Partners in a homologous pair (and chromatids) end up randomly in the daughter cells

112
Q

Number of combinations in independent assortment

A

2^n where n is the haploid number. For humans (n=23) there are more than 8 million (2^23) possible combos of chromosomes

113
Q

Why does random fertilization add to genetic variation?

A

Because and sperm can fuse with any egg cell

114
Q

How many combinations can the fusion of 2 gametes produce?

A

8.4 million chromosome combinations from independent assortment. Women and men produce this many so 70 trillion diploid combos possible. Crossing over adds even more variation

115
Q

Each zygote has a unique genetic identity

A

TRUE

116
Q
  1. Living organisms are are categorized into 2 major groups based on the presence or absence of a nucleus. What group is defined by the presence of a nucleus?
A

Eukaryotic organism

117
Q

2.The diploid chromosome number of an organism is usually represented as 2n. Humans have a diploid chromosome number of 46. What would be the expected haploid number?

A

23

118
Q
  1. What occurs in meiosis but not in mitosis?
A

synapsis of chromosomes

119
Q
  1. What significant mechanism happens in S phase of the cell cycle?
A

DNA synthesis

120
Q
  1. Fly has a haploid chromosome number of 6. How many chromatids should be present in a diploid, somatic, metaphase cell?
A

24

121
Q
  1. The centromere of a chromosome separates during?
A

Anaphase

122
Q
  1. If a typical somatic cell has has 64 chromosomes, how many chromosomes are expected in each gamete of that organsism?
A

32

123
Q
  1. What is true about the second meiotic division?
A

Sister chromatids are pulling apart

124
Q
  1. During meiosis chromosome number reduction takes place in?
A

Anaphase 1

125
Q
  1. What happens during early metaphase of of mitosis?
A

Chromosomes align at metaphase plate

Genetics (15 decks)

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