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Biology 1 > Ch. 12 and 13 Review > Flashcards

Ch. 12 and 13 Review Flashcards

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1
Q

Where do cells come from?

A

Other cells via cell division

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2
Q

Do all cells divide?

A

No, BUT all cells are produced via cell division

ex. nerve cells

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3
Q

Why do cells divide (3)? What is special about the third reason

A
  1. Growth/development
  2. Repair/regeneration
  3. Reproduction
    • this is the ONLY reason single-celled organisms divide!
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4
Q

Prokaryotes go through what type of cell division?

A

Binary fission
Single circular chromosome copies DNA, the cell elongates and divides

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5
Q

Why is eukaryotic cell division more complex?

A
  1. membrane bound organelles
    ex. mitochondria and chloroplasts- replicate similarly to binary fission
    ex. ER, Golgi- nuclear envelope disintegrates during division
    small pieces remain in daughter cells and are REBUILT
  2. multiple chromosomes
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6
Q

What are the two types of eukaryotic cell division?

A

mitosis and meiosis

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7
Q

Compare and contrast mitosis and meiosis

A

mitosis
-produces 2 identical daughter cells
- used for growth and repair
-somatic cells

meiosis
-produces daughter cells with 1/2 the number of chromosomes
-exclusively for reproduction
-cells differ
-occurs in gonads

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8
Q

The cell cycle is…

A

a series of tightly regulated events unique to eukaryotes

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9
Q

What controls the cell cycle

A

The cycle is controlled by many enzymes

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10
Q

Why is the cell cycle studied so intensely?

A

For the treatment of diseases like cancer or autoimmune disease

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11
Q

What are the steps of mitosis?

A

prophase
prometaphase
metaphase
anaphase
telophase

cytokinesis after

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12
Q

Define interphase

A

interphase
- 90% of cell cycle
- has three phases G1, S, and G2

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13
Q

Define the G1, S, and G2 phases

A

G1
- growth occurs
- prepare for S phase
- DNA inspected for mutations
- G1 will make more enzymes and nucleotides for S phase

S phase
- chromosome duplication
-DNA synthesis

G2
-growth occurs
- prepare for M phase
- DNA inspected for mutations
-G2 will make spindle fibers for M phase

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14
Q

Why is DNA inspected?

A

to fix DNA damage
inspects to PREVENT mutation, recognizing it and fixing it or undergoing apoptosis

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15
Q

What are the two phases of M phase

A

mitosis, cytokinesis

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16
Q

What is mitosis?

A

division of the content of the nucleus, separation of chromosomes

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17
Q

What is cytokinesis?

A

separation of the cytoplasm

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18
Q

The cell can _____ the cell cycle and exist in….

A

exit, exist in a non dividing cell state

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19
Q

Where do cells exit the cell cycle?

A

During G1
Daughter cells are only 1/2 as big after M phase, they need to grow in order to exit cell cycle
Exiting cell cycle is called G0

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20
Q

How often do cells do the cell cycle?

A

It depends on the cell type

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21
Q

What are the three frequencies of mitosis?

A
  1. Continuous- skin, G.I. cells, blood cells
  2. Based on need- liver cells
    ex. and alcoholic will have a larger need for liver cells than a nonalcoholic
  3. Rare/never- nervous and muscle cells
    -growth only occurs in gestation

only 2 and 3 are in G0, most cells are in G0

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22
Q

How do eukaryotes become more/less compact, why do they do this?

A

-nuclear DNA is wrapped around protein
-this complexed material is known as chromatin

Why- so it can fit into the cell

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23
Q

One human cell contains how many feet of DNA?

A

6 feet

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24
Q

When is the chromatin more or less compact in the cell cycle?

A

Interphase- less compact, not visible
M phase- prophase and prometaphase compacts, visible
After cytokinesis- less compact, not visible

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25
Q

Eukaryotic chromosome is?

A

one DNA molecule plus associated proteins
long linear DNA molecules
100s-1000s of genes

26
Q

How many chromosomes do humans have

A

46

27
Q

A replicated chromosome contains _____ its joined by a

A

2 sister chromatids, centromere

28
Q

In interphase, what does the nucleus usually contain?

A

chromatin

29
Q

What is a genome?

A

total genetic information possessed by an organism

30
Q

How does the cell distribute the sister chromatids to the daughter cells?

A

using the CYTOSKELETON
microtubules and mitotic spindles

31
Q

Is mitosis a continuous process?

A

YES

32
Q

Define prophase

A

prophase
-chromosomes condense
-centrosomes begin moving to opposite ends
-spindle begins to form

33
Q

Define prometaphase

A

prometaphase
-nuclear envelope DISINTEGRATES
-microtubules grab chromosomes by their centromeres

34
Q

Define metaphase

A

metaphase
-chromosomes aligned in the middle
-chromosomes pulled to opposite poles

35
Q

Define anaphase

A

anaphase
-chromosomes pulled apart
-cell elongates

36
Q

Define telophase

A

telophase
-two nuclear envelopes reform
- chromosomes decondense

37
Q

Define cytokinesis

A

cytokinesis
-pinches the cell
-contractile ring of microfilaments

38
Q

How is the cytoskeleton used?

A

-pulls chromosomes apart with spindles of microtubules by attaching to kinetochore protein complex on centromeres
-contractile ring of microfilaments pinching the cell in cytokinesis

39
Q

What advantage does meiosis have?

A

Combing chromosomes makes offspring diverse, more variation allows for greater survival

40
Q

Define a karyotype for a human

A

-contents of a single human nucleus
-46 chromosomes
-comes from a mitotic cell

displays # of chromosomes
replicated and paired

41
Q

Define a cells chromosomes when viewing on a karyotype?

A

-different sizes
-have different centromere positions
-stain differently

42
Q

What are homologous chromosomes, where do they come from?

A

chromosome pairs that carry the SAME genes
one pair is inherited from each parent
homologous chromosomes separated by meiosis

43
Q

Are genes on homologous chromosomes identical?

A

NO

44
Q

Any gene can have multiple _______, this is called ______

A

variation, alleles

45
Q

What do alleles mean chemically?

A

They have slightly different nucleotide sequences

46
Q

Compare homologous chromosomes and sister chromatids

A

homologous chromosomes
-present throughout the cell cycle
-not identical
-come from parents

sister chromatids
-identical
-created in S phase for M phase (mitosis)
-separate in the cell cycle

47
Q

Humans have how many autosomes, sex chromosomes?

A

44 autosomes, 2 sex chromosomes

48
Q

Males and females have what sex chromosomes

A

Male- XY
Female- XX

49
Q

Are X and Y homologous chromosomes?

A

NO they carry different genes

50
Q

Males have how many homologous chromosomes, females?

A

Males- 22
Females- 23

51
Q

Somatic cells have ______ sets of chromosomes, gametes have ______ set of chromosomes

A

two, one
somatic cells- diploid 2n, contain homologous chromosomes
gametes- haploid n, meiosis separates the homologous chromosomes

52
Q

How many rounds of cell division are in meiosis?

A

2 (I and II)

53
Q

Meiosis I does what? Meiosis II?

A

Meiosis I- separates homologous chromosomes (diploid to haploid)
Meiosis II- separates sister chromatids

54
Q

How does meiosis I separate homologous chromosomes?

A

Pair in prophase I, align in metaphase I, separate in anaphase I

55
Q

What are the three mechanisms that generate variation?

A
  1. independent assortment
  2. crossing over
  3. random fertilization

all occur in meiosis and is the reason siblings differ

56
Q

What is the fourth mechanism that generates variation

A
  1. mutation creates new alleles
57
Q

Define independent assortment

A

Chromosomes in gametes are a random mix of maternal and paternal chromosomes

“gonads forget” randomly segregate chromosomes

humans= diploid^chromosome pairs= 2^23= 8 million possibilities

58
Q

Define random fertilization

A

Any sperm can fertilize any ova

humans= 8 million x 8 million= 70 trillion

59
Q

Define crossing over

A

Occurs in prophase 1
-homologous chromosomes are physically broken and rejoined
-leads to chromosomes with new combinations of the gene versions (alleles)

DNA recombination

60
Q

What do histones do

A

package DNA and control gene expression

Biology 1 (9 decks)

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