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Bio 20–Lassiter > Chapter 8 > Flashcards

Chapter 8 Flashcards

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Biology 101 flashcards
1
Q

parent–offspring relationship in a/sexual reproduction

A
  • asexual reproduction: produces offspring that are identical to the original cell or organism; involves inheritance of all genes from one parent
  • sexual reproduction: produces offspring that are similar to the parents, but show variations in traits; involves inheritance of unique sets of genes from two parents
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2
Q

cell division in prok. & euk. cells

A
  • prok. cells reproduce by binary fission (dividing in half)

* euk. cells reproduce by mitosis and cytokinesis

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3
Q

stages of the cell cycle

A 
the cell cycle consists of two stages:
• Interphase: duplication of cell contents
G1—growth, increase in cytoplasm
S—duplication of chromosomes
G2—growth, preparation for division
• Mitotic phase: division
mitosis—division of the nucleus
cytokinesis—division of cytoplasm cell contents
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4
Q

phases of mitosis

A
  • prophase
  • prometaphase
  • metaphase
  • anaphase
  • telophase
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5
Q

interphase

A
  • the cytoplasmic contents double
  • two centrosomes form
  • chromosomes duplicate in the nucleus during the S phase
  • nucleoli, sites of ribosome assembly, are visible
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6
Q

prophase

A
  • in the cytoplasm, microtubules emerge from centrosomes, forming the spindle
  • in the nucleus, chromosomes coil & become compact & nucleoli disappear.
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7
Q

prometaphase

A
  • spindle microtubules reach chromosomes, where they attach at kinetochore
  • centrosomes move to opposite poles
  • nuclear envelope disappears.
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8
Q

metaphase

A
  • mitotic spindle is fully formed.

* sister chromatids align at the cell equator.

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9
Q

anaphase

A
  • sister chromatids separate at the centromeres.
  • daughter chromosomes are moved to opposite poles
  • cell elongate
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10
Q

telophase

A
  • cell continues to elongate
  • nuclear envelope forms around chromosomes at each pole, establishing daughter nuclei
  • chromatin uncoils & nucleoli reappear
  • spindle disappears
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11
Q

cytokinesis in animal vs. plant cells

A

• animal cells:
cytokinesis occurs as a cleavage furrow forms from a contracting ring of microfilaments
• plant cells:
a cell plate forms in the middle, from vesicles containing cell wall material

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12
Q

cancerous cells

A

• cancer cells escape controls of cell cycle:

  • start out as normal body cells
  • undergo genetic mutations
  • lose ability to control tempo of their own division and divide rapidly, often in absence of growth factors
  • spread to other tissues through circulatory system
  • grow w/out being inhibited by other cells
  • creating chaos causing disease
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13
Q

functions of mitosis

A
  • cell repair and replacement
  • growth
  • sperm and egg production
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14
Q

somatic cells

A
  • 23 pairs of homologous chromosomes

* one from each parent

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15
Q

gametes

diploid cells vs. haploid cells

A
  • sperm and egg cells (occurs in meiosis)
  • diploid cells: have 2 homologous chromosomes
  • haploid cells: have 1 set of chromosomes
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16
Q

meiosis

A
  • a process that converts diploid nuclei to haploid nuclei

* 2 haploid gametes combine in fertilization to restore diploid state in zygote

17
Q

why sexual reproduction requires meiosis

A
  • offspring would have twice as many chromosomes as parents

* no genetic variation

18
Q

meiosis I

A

• prophase I:
- homologous chromosomes come together in pairs
- site of crossing over between homologous (non sister) chromatids
• metaphase I:
- tetrads (pairs of homologous chromosomes) line up at metaphase plate
• anaphase I/telophase I:
- homologous chromosomes separate during ana I
- sister chromatids remain attached

19
Q

meiosis II

A

• sister chromatids separate during anaphase II

20
Q

similarities & differences btwn mitosis and meiosis

A

• similarities:
- begin with diploid parent cell
- have chromosomes duplicated during the previous interphase
• differences:
- mitosis: produces 2 genetically identical diploid somatic daughter cells
- meiosis: produces 4 genetically unique haploid gametes

21
Q 
genetic variation
 (produced in sexual reproduction)
A
  • independent orientation at metaphase I
  • random fertilization
  • crossing over
22
Q

karyotyping

A 
• an ordered display of magnified images of an individual's chromosomes arranged in pairs
• allows for observation of...
- homologous chromosome pair
- chromosome #
- chromosome structure
23
Q

nondisjunction

A

• the failure of chromosomes or chromatids to separate normally during meiosis.
• can happen during:
- meiosis I: if both members of a homologous pair go to 1 pole
- meiosis II: if both sister chromatids go to one pole
• fertilization after nondisjunction creates zygotes with altered #s of chromosomes

Bio 20–Lassiter (4 decks)

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