Biology  by Bradford
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4.6 Regulation of Cell Cycle: revision map

The subtopic in the middle and four tasks round it: label a diagram, complete a table, put a process in order and fill 8 gaps. Every box rests on a learning objective of the topic in the AP Biology course and exam description. Type into the blanks and check them, or print it on A4, Letter or A3 with an answer key.

Unit 4 practice questionsThe whole Unit 4 map

Topic 4.6

Regulation of Cell Cycle

AP Biology ยท Unit 4 Cell Communication and Cell CycleName

4.6.A, 4.6.BCheckpoints

1234
  1. 1
  2. 2
  3. 3
  4. 4

4.6.BDamage found at a checkpoint

Number the steps in order.

  1. The damage is repaired, and the cell cycle continues.
  2. If the damage cannot be repaired, the cell goes through apoptosis.
  3. p53 switches on a gene that blocks the cell cycle, so the cell cannot enter S phase.
  4. DNA damage is detected during G1.
  5. p53 builds up and is activated.
Topic 4.6Regulation of Cell Cycle

4.6.AThe regulators

RegulatorRole
protein whose concentration rises and falls through the cycle
kinase that is active only when bound to its partner protein and phosphorylates target proteins
p53tumor suppressor: stops the cycle if DNA is damaged and can trigger apoptosis
Rbtumor suppressor: holds back the cell cycle until phosphorylated

4.6.BWhen control fails

Checkpoints let a cell check that conditions are right before it moves on. If the regulators are lost or altered by , a cell can divide without limit and ignore signals telling it to stop or to die, and the cells form a . Cancer cells commonly have a mutated p53 gene, so damaged DNA is passed on and changes build up. Some cells, such as mature neurons, leave the cycle and enter G0.

Word bank CDKCyclinG0 phaseG1 checkpointG2 checkpointmutationsspindle checkpointtumor

Answer key

Every box on the sheet with its gaps filled in, as the subtopic reads in full.

  1. LabelCheckpoints

    1. G1 checkpoint
    2. G2 checkpoint
    3. spindle checkpoint
    4. G0 phase

  2. TableThe regulators

    RegulatorRole
    Cyclinprotein whose concentration rises and falls through the cycle
    CDKkinase that is active only when bound to its partner protein and phosphorylates target proteins
    p53tumor suppressor: stops the cycle if DNA is damaged and can trigger apoptosis
    Rbtumor suppressor: holds back the cell cycle until phosphorylated

  3. OrderDamage found at a checkpoint

    1. DNA damage is detected during G1.
    2. p53 builds up and is activated.
    3. p53 switches on a gene that blocks the cell cycle, so the cell cannot enter S phase.
    4. The damage is repaired, and the cell cycle continues.
    5. If the damage cannot be repaired, the cell goes through apoptosis.

  4. GapsWhen control fails

    Checkpoints let a cell check that conditions are right before it moves on. If the regulators are lost or altered by mutations, a cell can divide without limit and ignore signals telling it to stop or to die, and the cells form a tumor. Cancer cells commonly have a mutated p53 gene, so damaged DNA is passed on and changes build up. Some cells, such as mature neurons, leave the cycle and enter G0.