The Cell Cycle & Mitosis

Question 1

The Cell Cycle

Answer 1

• every hour about 1 billion cells die and 1 billion are made in the body
• the cell cycle is a repeating cycle of events in the life of a cell
• it consist of 2 main stages:
  a) Interphase, the cell grows and prepares for cell division
  b) cell division - Mitosis, for repair or growth and Meiosis, to produce reproductive cells (sperm or ovum)

Question 2

Interphase

Answer 2

• a cell spends about 90% of it’s time in this phase
• the cell takes in nutrients, grows and replicates DNA
• 3 main phases:
  a) G1, first growth phase
  b S, Synthesis phase
  c) G2, second growth phase

Question 3

G1

Answer 3

• apart of interphase
• cell grows and produces new proteins and organelles

Question 4

S

Answer 4

• apart of interphase
• DNA is replicated

Question 5

G2

Answer 5

• cell produces the organelles and structures needed for the cell division

Question 6

Chromosomes

Answer 6

• a structure found inside the nucleus of a cell
• allows DNA to be accurately copied during cell division

Question 7

Mitosis

Answer 7

• M phase
• ensures when a cell divides, that both new resulting cells have 1 complete copy of the genetic material from the cell

Question 8

Prophase (1)

Answer 8

• apart of Mitosis
• Chromatin condenses to become Chromosomes (2 sister Chromatids)
• Nuclear Envelope disintegrates
• Spindle Fibres form
• Centrioles move to opposite poles it the cell

Question 9

Metaphase (2)

Answer 9

• apart of Mitosis
• Chromosomes move to the middle of the cell
• Spindle Fibres attach to the Centromeres of the Chromosome

Question 10

Anaphase (3)

Answer 10

• apart of Mitosis
• sister Chromatids separate at the Centromere
• pulled to opposite pole by the Centriole

Question 11

Telophase (4)

Answer 11

• apart of Mitosis
• Spindle Fibres breaks down
• 2 new Nuclei are formed
• cell splits into 2 new daughter cells by pinching inward
• Cytoplasm divides = Cytokinesis

Question 12

End Result

Answer 12

• 2 new genetically identical daughter cells
• Cytokinesis animal cell forms a Cleavage Furrow
• Cytokinesis plant cell forms a cell plate

Question 13

Cell Growth, Repair & Death

Answer 13

• different cells undergo cell growth and division at different rates
• cell division is necessary to replace injured or damaged cells
• regulated cell death (Apoptosis) is a natural part of the cell cycle

Question 14

Cancer

Answer 14

• a mutation in DNA that results in uncontrolled cell division
• can cause tumor formation, lump of cells that don’t have purpose
• belgian tumor = non cancerous
• malignant tumor = cancerous