Chapter 5: the mitotic cell cycle Flashcards

1
Q

what is the centromere?

A

the section of the chromosome that holds the two chromatids together

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2
Q

why is mitosis important for growth?

A
  • the two daughter cells are CLONES of the parent cells

- this allows the growth of multicellular organisms from unicellular zygotes

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3
Q

why is mitosis important for cell replacement?

A

cells that die are able to be replaced by identical cells

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4
Q

why is mitosis important for asexual reproduction?

A
  • genetically identical offspring

- budding can occur

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5
Q

what does interphase consist of?

A

G1, S and G2 phases

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6
Q

what happens during the S stage?

A

DNA replication

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7
Q

what happens during the G1 stage?

A

growth and normal metabolic roles

-RNA, enzymes and other proteins needed for growth are made

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8
Q

what happens during the M stage?

A

mitosis

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9
Q

what happens during the G2 stage

A

growth and preparation for mitosis

  • new DNA is checked and any errors usually repaired
  • increase in the protein tubulin which is needed to make microtubules for the mitotic spindle
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10
Q

what happens during prophase?

A
  • chromosomes appear
  • chromatin coils up
  • centrosomes replicate before prophase
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11
Q

what happens during the second stage of prophase?

A
  • nuclear envelope breaks up
  • nucleolus disappears
  • chromosomes seen to contain two identical chromatids
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12
Q

what happens during metaphase?

A
  • each centrosome reaches a pole
  • chromosomes line up along equator of spindle
  • they are attached to the spindle by their centromeres
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13
Q

what happens during anaphase?

A
  • chromatids move to opposite poles

- they are pulled by microtubules

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14
Q

what happens during telophase/ cytokinesis?

A
  • chromatids uncoil
  • cytoplasm and cell divide into two by constriction from the edges of the cell
  • nucleolus reforms
  • nuclear envelope reforms
  • centrosome will replicate again during interphase
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15
Q

what are telomeres?

A
  • short DNA base sequences that are repeated

- lots of G and C

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16
Q

what is the function of telomeres?

A
  • they ‘seal’ the DNA

- they make sure that the ends of the molecule are included when DNA replicates

17
Q

how do telomeres work?

A
  • they add more bases using a copying enzyme called telomerase
  • the extra DNA that the telomerase adds are the telomeres
18
Q

what is the potency of a cell?

A

the extent of the power of a stem cell to produce different cell types

19
Q

what is the definition of multipotent?

A

can only produce a few types of cell

20
Q

what is a mutation?

A

a change in any gene

21
Q

what is an oncogene?

A

a mutated gene that causes cancer

22
Q

what is the definition of a malignant tumour?

A

a tumour that interferes with the normal functioning of the area where it has started to grow

23
Q

what are secondary growths?

A

cells that break off and spread to other parts of the body

24
Q

what is metastasis?

A

the spread of cancers

25
Q

how is mitosis different in plant cells?

A
  • do not contain centrosomes

- after nuclear division, a new cell wall must form between the daughter nuclei