Unit 1 - AOS 1 - Mitosis and cell cycle Flashcards

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1
Q

The functions of cell division

A
  1. Asexual reproduction for unicellular organisms
  2. Asexual reproduction for multicellular organisms
  3. Sexual reproduction in multicellular organisms
  4. Growth and development of a multicellular organisms
  5. Repair and maintenance of a multicellular organism
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2
Q

Define Binary fission

A

Is cell division completed asexually by prokaryotes, that results in two genetically identical organisms.

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3
Q

3 types of asexual reproduction for multicellular organisms

A
  1. Budding: they produce growths from their bodies which eventually fall off and become cloned offspring (hydra)
  2. Autonomy: when an organism performs self amputation of one of its body parts (starfish)
  3. Vegetative reproduction: one way is through cell division to produce runners. Which are extensions from the parent plant that contain attached cloned offspring. (Spider and strawberry)
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4
Q

In sexual reproduction (multicellular) , cell division is required for two reasons …

A
  1. To make gametes like speed and ova
  2. To allow the multiple divisions needed to create a multicellular organism
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5
Q

Definition of cell cycle

A

This represents the processes that occur between one cell division and the next cell division in a cells life

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6
Q

3 main stages of the cell cycle

A
  • interphase
  • mitosis
  • cytokinesis
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7
Q

Interphase definition

A

The cell spends most of its life Performing it’s specialised sunrooms and then prepares for cell division when the time comes

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8
Q

Parts of the interphase are …

A
  1. G1
  2. Synthesis
  3. G2
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9
Q

What happens in the G1 phase of the Interphase ?

A
  • the cell grows after cell division to reach to full size (can double)
  • the cell performs it’s specialised function depending on what type of cell it is.
  • this is the longest part of the cell cycle for most cells
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10
Q

Explain what happens to cells that stop dividing

A
  • these cells stop progressing through the cell cycle and go into the G0 (gap zero)
  • they simply continue there specialised function until they die
  • e.g muscle cell, heart muscle cell, Brain cell
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11
Q

What happens in the synthesis phase of the interphase

A
  • the DNA is replicated creating two identical copies of each chromosome
  • the centriole pair also duplicates to create two pairs
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12
Q

Function of centriole

A

They are involved in the development of spindle fibres used during cell division

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13
Q

What happens in the G2 phase of the Interphase

A
  • prepares for mitosis through rapid growth of cytoplasm
  • the cell increases the synthesis of the proteins needed to make the spindle fibers used in mitosis
  • DNA is checked for replication errors that may have occurred during DNA replication in S phase.
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14
Q

Definition of mitosis

A

The process that sorts and divides the duplicated chromosomes into two identical sets of DNA so that each daughter cell get’s one set.

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15
Q

how many chromosomes do humans somatic cells have before replication and after replication?

A

46 –> 92

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16
Q

what are somatic cells?

A

Are body cells (excluding sex cells)

17
Q

Definition of cytoinesis

A

Process that divides the cytoplasm in half to create two separate daughter cells.

18
Q

Cytokinesis –> Animal cells

A
  • A cleavage furrow is formed
  • to constrict the cell membrane in the middle of the cell and divide it
19
Q

Cytokinesis in plant cells

A
  • Cell wall make cytokinesis challenging
  • Cell plate is created in middle of cell which is made from vesicles, containing material needed to build the cell wall.
  • Vesicles join to create new cell wall in the midline of the cell separating the 2 daughter cells.
20
Q

Chromatin defiition

A
  • Is the duplicated chromosomes before they are condensed
  • long and thin
21
Q

Sister chromatids

A
  • The 2 identical sides of each duplicated chromosome
22
Q

Centromere definition

A

Is what connects the 2 chromotids

23
Q

Kinetochores definition

A

is a protein structure that assemble on either side of the centromere.
- they are the sites of attachement for the microtubules/spindle fibres, which pull the sister chromotids apart.

24
Q

Centrosome

A

The centriole pair along with the surrounding proteins form the organelle centrosome.
- responsible for organizing microtubules

  • Only found in animal cells
25
Q

Prophase (mitosis)

A
  • Centrosomes migrate to opposite ends of the cell
  • Spindle fibers begin to form
  • nucleur envelope begins to dissolve
  • Chromatins begin to condense
  • Nucleolus begins to disappear
26
Q

Pro-Metaphase (mitosis)

A
  • Nuclear membrane is almost completely dissolved –> spindle fibers access to duplicated chromosomes
  • Nucleolus has disappeared
  • Kinetochore spindle fibers attach to kinetochore of chromosomes and begin to line them up on equatorial plate
  • Polar spindle fibers extend from opposite ends and push against each other –> elongating the cell
  • Astral spindle fibers help anchor the centrosomes at opposite poles
27
Q

Metaphase (mitosis)

A
  • Centrosomes fully migrated
  • Spindle fibres completely formed
  • Nuclear membrane completely dissolved
  • Chromosomes are lined up on equatorial plate
28
Q

Anaphase (mitosis)

A
  • Kinetochore spindle fibers shorten –> pulling sister chromatids apart
  • Polar spindle fibers push against each other even more elongating the cell
  • Each chromatid becomes its own chromosome
29
Q

Telophase (mitosis)

A

(reverse of prophase)

  • Spindle apparatus disassemble
  • Chromosomes de-condense and become chromatins
  • Nuclear membrane begins to reformulate
  • Nucleolus appears
  • Cleavage furrow (animals) or Cell Plate (Plants) begins to form signaling the beginning of cytokinesis
30
Q

Cells that undergo Binary fission and mitosis?

A

Binary fission = Prokaryotic cells

Mitosis = Eukaryotic cells

31
Q

When are the 3 checkpoints in the cell cycle?

A

G1, G2, Spindle checkpoint (metaphase)

32
Q

G1 checkpoint

A
  • Cell checks it has grown large enough to divide
  • Cell checks to see if DNA is undamaged and enough nutrients are present
33
Q

G2 checkpoint

A
  • Checks to see if DNA replication is finished and no mistakes