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BIOL 107 > Chapter 6: Reproduction at the Cellular Level > Flashcards

Chapter 6: Reproduction at the Cellular Level Flashcards

1
Q

define genome

A

complete set of genes or genetic material in a cell

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2
Q

define histones

A
  • proteins
  • DNA folds around them to create chromatin
  • helps package DNA and control gene expression
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3
Q

define nucleosomes

A
  • structural unit consisting of a length of DNA wrapped around a histone
  • cube of 8 histones with DNA wrapped around
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4
Q

define chromatin

A
  • complex made of DNA and proteins to form chromosomes
  • condenses during cell division
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5
Q

define chromatid

A

an entire DNA molecule

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6
Q

define sister chromatids

A
  • two identical copies of a chromosomes
  • formed after DNA replication
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7
Q

define chromosome

A
  • each protein bound DNA molecule
  • chromatin condenses into chromosomes
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8
Q

define centromere

A

where two sister chromatids are connected

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9
Q

define centrosome

A
  • organelle found near the nucleus
  • made of centrioles and a dense protein
  • microtubule organizing center
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10
Q

define centriole

A
  • pair of cylindrical-shaped structure of microtubules
  • made of tubulin protein
  • located in the centrosome
  • organize microtubules to form the cytoskeleton
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11
Q

define kinetochore

A
  • proteins
  • at centromere
  • what microtubules attach to on the sister chromatids to pull them apart during division
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12
Q

define spindle apparatus

A
  • collection of all spindle fibers during cell division
  • includes astral microtubules, kinetochore microtubules, and polar microtubules
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13
Q

define astral microtubules

A
  • extend from centrioles to plasma membrane
  • anchor to cell membrane
  • keep mitotic spindle in place
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14
Q

define kinetochore microtubules

A
  • extend from centrioles to kinetochores on sister chromatids
  • bind to chromosomes and pull them apart during cell division
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15
Q

define polar micortubules

A
  • extend from centrioles to middle of the cell
  • push single poles apart during division
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16
Q

define somatic cells

A
  • body cells
  • soma means body
  • diploid (2n)
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17
Q

define gametes

A
  • sex cells (egg and sperm)
  • haploid (1n)
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18
Q

define karyotype

A
  • number and visual appearance of chromosomes in a cell
  • picture of all the chromosomes paired up
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19
Q

what is the purpose of cell division in single celled organisms

A

reproduction

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20
Q

what is the purpose of cell division in multicellular organisms

A
  • reproduction
  • growth and development
  • tissue repair
  • tissue maintenance
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21
Q

is cell division the only part of the cell cycle

A
  • no
  • is integral part but not only part
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22
Q

what two major things happen during cell division

A
  • duplication of genetic material
  • cell physically divides
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23
Q

what does mitosis cell division result in

A
  • genetically identical daughter cells
  • ensures each daughter cell receives an exact copy of DNA
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24
Q

what are the similarities between prokaryote and eukaryote DNA

A
  • double stranded; form double helix
  • same nucleotides
  • same genetic code; combinations of nucleotides code for amino acids
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25
Q

differences between prokaryote and eukaryote DNA

A
  • prokaryote: in nucleoid region; 1 circular chromosome; have plasmids (small circular pieces of DNA)
  • eukaryote: in nucleus; several linear chromosomes; have histones (protein DNA folds around to make chromatin)
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26
Q

what is the only part of eukaryotic cells that has circular DNA

A

mitochondria

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27
Q

how many chromosomes are in a cells nucleus

A
  • varies among species
  • chromosome number is consistent within a species
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28
Q

which human cells don’t contain DNA

A
  • red blood cells
  • allows for more room to carry oxygen
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29
Q

are chromosomes always x-shaped

A
  • no
  • only after condensing during cell division
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30
Q

why are centrioles important in cell division

A
  • migrate to opposite sides of the nucleus before cell divides
  • form mitotic spindle which attaches to chromosomes to pull them apart
  • form microtubules for cilia and flagella
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31
Q

define diploid

A

2 matching sets of chromosomes

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32
Q

define haploid

A

1 set of chromosomes

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33
Q

how many chromosomes are in human somatic cells

A
  • 46 total
  • 2 pairs: 1 from mom and 1 from dad
34
Q

how many chromosomes are in human gamete cells

A

23

35
Q

define homologous chromosomes

A

chromosomes that pair in reproduction of diploid cells

36
Q

define heterologous chromosomes

A
  • pairs of chromosomes that don’t match
  • example: X and Y chromosomes in humans
37
Q

define interphase

A
  • consists of G1, S, and G2 phase
  • time for growth and preparation for cell division
  • takes up most of the cell cycle
38
Q

define mitotic phase

A
  • includes mitosis and cytokinesis
  • replicated DNA and cytoplasm are split and the cell divides
39
Q

define mitosis/karyokinesis

A
  • nuclear division
  • 5 steps: prophase, prometaphase, metaphase, anaphase, telophase
40
Q

define cytokinesis

A
  • cytoplasmic division
  • cell physically separates
41
Q

define G1 phase

A
  • first phase of interphase
  • change is not obvious
  • cell is very biochemically active
42
Q

define S phase

A
  • second phase of interphase
  • DNA synthesis
  • chromosomes are replicated
  • centrosomes produce mitotic spindles to move chromosomes
43
Q

define G2 phase

A
  • third phase of interphase
  • energy replenished
  • organelles reproduce
  • cytoskeleton breaks down
  • visible cell growth
44
Q

define G0 phase

A
  • cellular state outside of replicative cell cycle
  • when cells are not actively dividing
  • can be reversible or irreversible
45
Q

define quiescent

A
  • reversible G0 phase
  • where cells reside before entering the cell cycle
46
Q

define senescent

A
  • irreversible G0 phase
  • in response of DNA damage or degradation
  • cells don’t replicate but still perform normal functions
  • alternative to apoptosis
47
Q

define differentiated

A
  • irreversible G0 phase
  • stem cells that have terminally differentiated
  • perform main functions indefinitely
  • example: neurons
48
Q

define prophase; what happens

A
  • chromosomes condense and become visible
  • nuclear envelope breaks down
  • nucleolus disappears
  • centrosomes migrate to opposite poles
  • microtubules of the spindle begin to form
  • organelles move towards the edge of the cell
49
Q

define prometaphase; what happens

A
  • chromosomes continue to condense
  • kinetochores appear at the centromere
  • mitotic spindle microtubules attach to kinetochores
  • centrosomes move towards opposite poles
50
Q

define metaphase; what happens

A
  • chromosomes line up at metaphase plate by movement of microtubules attached to their kinetochores
  • sister chromatids remain attached by cohesion proteins
51
Q

define anaphase; what happens

A
  • cohesion proteins degenerate to allow sister chromatids to separate
  • separated sister chromatids (now called chromosomes) move to opposite poles; pulled by microtubules to centrosomes
  • cell elongates
52
Q

define telophase; what happens

A
  • chromosomes reach opposite ends of the cell and start to decondense
  • spindles depolymerize to tubulin monomers that will make cytoskeleton
  • nuclear envelope forms around chromosomes
  • nucleosomes appear within nuclear areas
53
Q

define condensin proteins

A

aids chromosomes condensing during prophase

54
Q

define cohesion proteins

A
  • keep sister chromatids attached before they divide
  • disintegrate during anaphase
55
Q

define cleavage

A
  • process by which animal cells undergo cytokinesis
  • cleavage furrow forms and cell divides
56
Q

what are the two major phases of the cell cycle (mitosis)

A
  • interphase
  • mitotic phase
57
Q

what are the two major phases of the mitotic phase

A
  • mitosis: division of the nucleus
  • cytokinesis: division of the cytoplasm
58
Q

how does cytokinesis occur in animal cells

A
  • process known as cleavage
  • cleavage furrow forms
  • plasma membrane drawn in by ring of actin fibers
  • furrow deepens until cell is pinched in two
59
Q

how does cytokinesis occur in plant cells

A
  • vesicles were formed in interphase from golgi apparatus with enzymes and glucose
  • vesicles combine to form cell plate in old metaphase plate
  • cell plate strengthens and becomes cell wall
60
Q

how do cells control the cell cycle

A
  • through checkpoints
  • external and internal signals
61
Q

what external signals initiate or inhibit the cell cycle

A
  • death of nearby cells
  • release of growth hormones
  • cell crowding
62
Q

what internal factors regulate the cell cycle

A
  • G1 checkpoint
  • G2 checkpoint
  • M checkpoint
63
Q

why are internal checkpoints (the molecular control system) important

A
  • ensure new cell is an exact duplicate of the original
  • doesn’t let any mistakes throughout the cycle continue into daughter cells
64
Q

when does the G1 checkpoint take place

A

end of G1 phase

65
Q

when does the G2 checkpoint take place

A

at G2 and mitosis transition

66
Q

when does the M checkpoint take place

A

during metaphase in mitosis

67
Q

what checkpoint is the primary decision point for the cell

A

G1 checkpoint

68
Q

what does the G1 checkpoint check for

A
  • cell size
  • enough nutrients
  • growth factors
  • no DNA damage
69
Q

what options does a cell that didn’t pass the G1 checkpoint have

A
  • stop the cycle and try to fix the issue
  • enter G0 and wait for signs that conditions are better
70
Q

what does the G2 checkpoint check for

A
  • DNA replication complete
  • DNA damage in replicated DNA
71
Q

what options does a cell that didn’t pass the G2 checkpoint have

A
  • attempt to complete DNA replication
  • attempt to repair damaged DNA
72
Q

what does the M checkpoint check for

A
  • chromosomes lined up in metaphase plate correctly
  • spindle fibers are attached to both sister chromatid kinetochores
73
Q

what happens if a cell doesn’t pass the M checkpoint

A
  • cell cycle will halt until kinetochores of each sister chromatid are anchored
  • failure to correct it could lead to non-disjunction of chromatids; genetic abnormalities
74
Q

define cancer

A
  • many disorders characterized by uncontrolled cell growth
  • caused by problems with genes regulating checkpoints; usually after multiple divisions mutations build up
75
Q

define protooncogenes

A
  • normal genes that code for positive cell regulators (tell cell when to go)
  • becomes oncogene when mutated
  • example: Cdk
76
Q

define oncogenes

A
  • mutated versions of protooncogenes
  • leads to accelerated cell division
  • genes telling cells when to go override everything to cell division accelerates
77
Q

define tumor suppressor genes

A
  • normal genes that code for negative cell regulators (tell cell when to stop)
  • prevent cell from dividing if there is a problem
  • can’t stop the cell when mutated causing uncontrolled cell division
  • example: P53
78
Q

define binary fission

A
  • how prokaryotes reproduce/divide
  • only way they can reproduce
79
Q

do prokaryotes go through mitosis

A

no

80
Q

explain the process of binary fission

A
  • bacterial chromosomes replicate
  • 2 daughter chromosomes move apart
  • septum forms and divides the cell

BIOL 107 (18 decks)

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