3.2.2 Mitosis and cell cycle

Question 1

Describe the cell cycle in Eukaryotic cells

Answer 1

. G1- growth: cell increases in size & new organelles made. Cell activity occurs
. S- DNA synthesis: DNA replication produces 2 identical copies of the DNA strand. Copies = chromatids, joined at the centromere to form chromosome.
. G2- growth: cell increases in size & new organelles made in prep for mitosis
. M- mitosis: cell divides = 2 daughter cells, each with identical copy of the chromosomes

Question 2

What phases of the cell cycle are described as Interphase

Answer 2

G1, S and G2

Question 3

Mitosis in prokaryotic cells:

Prophase

Answer 3

Chromosomes condense and become visible.
Spindle fibres start to form

Question 4

Metaphase

Answer 4

The chromosomes line up at the equator.
The centromeres attach to the spindle fibres.

Question 5

Anaphase

Answer 5

The chromosomes are pulled apart.
The sister chromatids are pulled by the contracting (shortening) spindle fibres
To opposite poles of the cell (daughter c will receive identical copies of Chr.)

Question 6

Telophase

Answer 6

The chromosomes uncoil and 2 nuclei reform

Question 7

Cytokinesis

Answer 7

Cytoplasm normally divides.
Forming 2 cells

Question 8

Prokaryotic cell division

Answer 8

Binary fission:
1. DNA replication: produces the circular chromosomes & plasmids are copied
2. Cell expands & the cytoplasm divides to form 2 daughter cells

Daughter cell: single copy of each chromosome & variable no.of copies of plasmids

Question 9

Virus replication process

Answer 9

. Injection of DNA/RNA into host cell
. Replication of the nucleic acid & viral proteins by the host cell
. Assembly of viruses
. Release of viruses by budding or cell lysis