Respiration of a cell and cell cycle

Question 1

What are the main phases of the cell cycle?

Answer 1

G1, S (DNA synthesis), G2 and M (Mitosis)

Question 2

What is apoptosis?

Answer 2

Programmed cell death which helps eliminate damaged or unneccesary cells

Question 3

What controls the cell cycle progression?

Answer 3

Cyclin-dependent kinases (CDKs) and their partner proteins, cyclins

Question 4

What is the role of p53 in the cell cycle?

Answer 4

p53 is a tumour suppressor that can stop the cell cucle or initiate aapoptosis if DNA damage is detected

Question 5

Flashcard 5: Q: What is the significance of the G1 checkpoint?

Answer 5

A: It ensures the cell is ready for DNA replication and can proceed with the cell cycle.

Question 6

How does a growth factor influence the cell cycle?

Answer 6

It binds to receptors on the cell surface and triggers intracellular signals that promote cell division.

Question 6

What are oncogenes?

Answer 6

Mutated forms of proto-oncogenes that cause uncontrolled cell growth and may lead to cancer

Question 7

What is the role of Rb (Retinoblastoma protein) in the cell cycle?

Answer 7

Rb inhibits transcription factors that promote cell cycle entry. When phosphorylated, Rb releases these factors to allow cell division.

Question 8

What happens during the M phase of the cell cycle?

Answer 8

The cell undergoes mitosis, where chromosomes are divided and two daughter cells are formed.

Question 9

What can cause DNA mutations that lead to cancer?

Answer 9

UV radiation, chemicals, and ionizing radiation can cause mutations that disrupt normal cell cycle regulation.

Question 10

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What is the function of cyclin-Cdk complexes?

Answer 10

They regulate different stages of the cell cycle by phosphorylating target proteins.

Question 11

What is the role of the electron transport chain in cell respiration?

Answer 11

It transfers electrons to generate ATP, the cell’s energy currency.

Question 12

What is the first enzyme involved in glycolysis, and what is its function?

Answer 12

Hexokinase – It phosphorylates glucose to glucose-6-phosphate using ATP, trapping glucose in the cell.

Question 13

What enzyme converts glucose-6-phosphate into fructose-6-phosphate?

Answer 13

Phosphoglucose isomerase – It catalyzes the isomerization of glucose-6-phosphate to fructose-6-phosphate.

Question 14

Which enzyme is responsible for the key regulatory step in glycolysis and how does it function

Answer 14

Phosphofructokinase-1 (PFK-1) – It converts fructose-6-phosphate to fructose-1,6-bisphosphate, using ATP, and is tightly regulated by energy levels in the cell.

Question 15

Which enzyme converts dihydroxyacetone phosphate (DHAP) into glyceraldehyde-3-phosphate (G3P)?

Answer 15

Triose phosphate isomerase – It ensures that DHAP is converted to G3P, so both molecules can proceed through glycolysis.

Question 15

What does the enzyme aldolase do during glycolysis?

Answer 15

Aldolase splits fructose-1,6-bisphosphate into glyceraldehyde-3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP).

Question 16

What is the role of glyceraldehyde-3-phosphate dehydrogenase in glycolysis?

Answer 16

Glyceraldehyde-3-phosphate dehydrogenase oxidizes glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate, producing NADH

Question 17

How is ATP produced in the step catalyzed by phosphoglycerate kinase?

Answer 17

Phosphoglycerate kinase transfers a phosphate group from 1,3-bisphosphoglycerate to ADP, producing ATP and 3-phosphoglycerate.

Question 18

What is the function of phosphoglycerate mutase?

Answer 18

Phosphoglycerate mutase shifts the phosphate group from the 3rd to the 2nd carbon, converting 3-phosphoglycerate to 2-phosphoglycerate.

Question 19

Which enzyme removes a water molecule from 2-phosphoglycerate, and what is the product?

Answer 19

Enolase – It converts 2-phosphoglycerate into phosphoenolpyruvate (PEP) by removing water.

Question 20

What is the final enzyme of glycolysis, and what reaction does it catalyze?

Answer 20

Pyruvate kinase – It transfers a phosphate from phosphoenolpyruvate (PEP) to ADP, forming ATP and pyruvate.