Cell Cycle

Question 1

What are the stages of the cell cycle?

Answer 1

•interphase- cell growth + DNA replication
•nuclear division- when the nucleus divides e.g. mitosis or meiosis
•cytokinesis- when the cytoplasm divides

Question 2

What occurs in the G1 and G2 phases?

Answer 2

Cell growth, protein synthesis, new organelles formed

Question 3

What occurs in the S phase?

Answer 3

DNA replication

Question 4

What is the order of stages of mitosis?

Answer 4

Prophase, metaphase, anaphase, telophase

Question 5

What occurs in prophase?

Answer 5

•chromosomes become visible
•centrioles move to the poles of the cell
•spindle fibres develop from centrioles- forming the spindle apparatus
•the nuclear envelope breaks down, leaving the chromosomes in cytoplasm

Question 6

What occurs in metaphase?

Answer 6

•chromosomes (made of 2 chromatids joined at the centromere) line up in the centre of the cell
•the spindle attaches to the cebtromere

Question 7

What occurs in anaphase?

Answer 7

•The centromeres divide into 2 and the spindle fibres pull individual chromatids apart
•chromatids move to the opposite poles and are now known as chromosomes

Question 8

What occurs in telophase?

Answer 8

•chromatids uncoil and become long and thin
•a nuclear envelope forms, forming 2 nuclei

Question 9

How do prokaryotic cells divide?

Answer 9

Binary fission

Question 10

Describe the process of binary fission

Answer 10

•circular DNA and plasmids replicate- both copies of circular DNA attach to cell membrane
•cell gets bigger and DNA loops move to opposite sides
•cytoplasm divides and new cell walls begin to form
•2 daughter cells are produced.