Cell Cycle 3.2.2

Question 1

In which type of organism does binary fission occur? (1)

Answer 1

Prokaryotic (1)

Question 2

What happens in binary fission? (2)

Answer 2

Cell replicates its genetic material (1)

and splits into 2 daughter cells (1)

Question 3

Explain the process of binary fission? (8)

Answer 3

1. Circular DNA + plasmids replicate (1)
2. Main DNA loop replicates once but plasmids replicate variable amount of times (1)
3. Cell gets bigger (1)
4. DNA loops move to opposite ‘poles’ (ends) of cell (1)
5. Cytoplasm begins to divide (1)
6. New cell walls form (1)
7. Cytoplasm divides + 2 daughter cells produced (1)
8. Each daughter has 1 copy of circular DNA but can have variable no. of plasmids (1)

Question 4

How do viruses invade host cells? (5)

Answer 4

1. Use attachment proteins to bind to complimentary receptor proteins on surface of host cells (1)
2. Different viruses have different attachment proteins therefore require different receptor proteins on host cells (1)
3. non-living therefore don’t undergo cell division (1)
4. Inject their DNA/RNA into host cell (1)
5. Hijack cell + use cells ‘machinery’ to replicate viral particles (1)

Question 5

Why are some viruses only able to infect one cell type? (2)

Answer 5

Different viruses have different attachment proteins (1)

therefore) require different receptor proteins on host cells (1

Question 6

What is mitosis? (2)

Answer 6

cell division (1)

that) produces 2 genetically identical daughter cells (1

Question 7

What is the purpose of mitosis? (2)

Answer 7

growth (1)

repair of damaged tissue (1)

Question 8

What are the different components of the cell cycle? (4)

Answer 8

Interphase (which consists off):

               - Gap phase 1 (1)
               - Synthesis (1)
               - Gap phase 2 (1)

Mitosis (1)

Question 9

What are the 5 main stages of the cell cycle? (IPMAT) (5)

Answer 9

1. INTERPHASE (1)
2. PROPHASE (1)
3. METAPHASE (1)
4. ANAPHASE (1)
5. TELOPHASE (1)

Question 10

Explain what happens in interphase? (4)

Answer 10

Normal functioning cell (1)

prepares to divide (1)

cell DNA unravels + replicates (1)

organelles replicated + ATP content’s increased (1)

Question 11

What happens in prophase? (4)

Answer 11

Chromosomes condense - shorter + fatter (1)

Centrioles start moving to opposite ends of cell forming spindles (network of protein fibres) (1)

nuclear envelope breaks down (1)

chromosomes lie free in cytoplasm (1)

Question 12

What happens in metaphase? (2)

Answer 12

chromosomes line up along middle of cell (1)

and) attach to spindle by their centromere (1

Question 13

What happens in anaphase? (4)

Answer 13

Centromeres divide (1)

separate each pair of sister chromatids (1)

spindles contract + pull chromatids to opposite poles of spindle (1)

(makes chromatids appear v-shaped) (1)

Question 14

What happens in telophase? (5)

Answer 14

chromatids reach opposite poles (on spindle) (1)

uncoil + become long + thin (now chromosomes again) (1)

nuclear envelopes form around each group of chromosomes (2 nuclei) (1)

Cytokenesis (cytoplasm divides) (1)

2 genetically identical daughter cells (produced) (1)

Question 15

What is a tumor? (1)

Answer 15

Uncontrolled cell division (1)

Question 16

What is cancer? (1)

Answer 16

tumor that invades surrounding tissue (1)

Question 17

Some cancer treatments disrupt the ____ _____. (1)

This controls the ____ __ ____ ________. (1)

Treatments don’t distinguish tumor cells from ______ cells. (1)

Answer 17

cell cycle (1)

rate of cell division (1)

normal cells (1)

Question 18

Whys is the treatment more likely to kill tumor cells than normal cells? (1)

Answer 18

they divide more frequently (1)