Mitosis Flashcards

1
Q

Why does mitosis occur

A

Mitosis occurs because cells need to be produced for growth and repair of tissues, so the cells must divide as cells arise from pre-existing cells

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2
Q

Describe what is produced after mitosis

A

2 genetically identical daughter cells

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3
Q

Why is it important that the cells produced in mitosis are identical

A

So they have the same structure and function as the other cells, to replace the damaged cells

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4
Q

Before mitosis, what genetic material is present in the cell

A

Chromatin

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5
Q

Describe what is meant by chromatin

A

Long, thin threads of DNA

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6
Q

Describe what happens during interphase

A

DNA replicates, and the ell synthesises a lot of ATP

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7
Q

What are each ‘leg’ of a chromosome called

A

Chromatids

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8
Q

Why does a chromosome have 2 chromatids

A

DNA has replicated

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9
Q

Describe what is meant by sister chromatids

A

Chromatids that contain identical genetic material

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10
Q

What holds together the 2 chromatids in a chromosome

A

The centromere

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11
Q

What does the centromere do during mitosis. Explain why

A
  • The centromere wll divide, allowing the chromatids to be pulled apart into separate cells
  • This ensures hat each cell gets an identical copy of DNA
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12
Q

What happens to the separated chromatids at the end of mitosis

A

The separated chromatids become longer and thinner again, where each new cell has an identical copy of DNA

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13
Q

Describe what happens to the DNA during mitosis to ensure that both cells produced are identical

A
  • The DNA replicates during interphase prior to cell division
  • The DNA condenses becoming shorter and thicker
  • Chromosomes consisting of two identical chromatids held together by a centromere are formed
  • The centromere divides and the two chromatids are pulled apart
  • The chromatids becomes longer and thinner
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14
Q

What are 4 stages of mitosis

A
  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
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15
Q

Describe what happens during Prophase

A
  • The nuclear envelope breaks down
  • The chromosomes condense
  • The spindle fibres are formed by organelles called centrioles, which move to opposite poles (ends) of the cell
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16
Q

Describe what happens during metaphase

A
  • The chromosomes align in the middle of the cell
  • Spindle firbres attach to the centromere of each chromosome
17
Q

Describe what happens during Anaphase

A
  • The centromeres divide
  • The spindle fibres contract (which requires energy from ATP)
  • The chromatids separate and are pulled to opposite poles
18
Q

Describe what happens during Telophase

A
  • The spindle fibres disintergrate
  • The nuclear envelope begins to reform
  • The chromosomes become longer and thinner once more
19
Q

Describe birary fission in bacteria (3)

A
  • Circular DNA replicates
  • Plasmids replicate
  • Cytoplasm divides to produce daughter cells
20
Q

Suggest and explain how two environmental variables could be changed to increase the growth rate of these cells.

A
  • Increase concentration of glucose
  • This increases the rate of respiration
  • Increase the temperature
  • This increases enzyme activity
21
Q
A