3.2.2 Mitosis and cell cycle Flashcards
What is the first stage of the cell cycle?
G1 - Growth: cell increases in size & new organelles are made. Cell activity occurs.
What occurs during the S phase of the cell cycle?
DNA synthesis: DNA replication occurs to produce two identical copies of the DNA strand.
What is the purpose of the G2 phase in the cell cycle?
Cell increases in size & new organelles are made in preparation for mitosis.
What does the M phase of the cell cycle represent?
Mitosis: cell divides to produce 2 daughter cells, each with an identical copy of the chromosomes.
What are the three phases of Interphase?
- G1
- S
- G2
What happens during prophase in mitosis?
The chromosomes condense and become visible. The spindle fibre starts to form.
What occurs during metaphase of mitosis?
The chromosomes line up at the equator of the cell and the centromeres attach to the spindle fibres.
What is the key event during anaphase?
The chromosomes are pulled apart. The chromatids move to the poles of the cell.
What happens during telophase?
The chromosomes uncoil and two nuclei reform.
What is cytokinesis?
The division of the cytoplasm forming two cells after telophase.
What are the checks in the cell cycle intended to ensure?
That DNA has been copied correctly.
True or False: Uncontrolled cell division can lead to the formation of tumors and cancers.
True
What is the method of cell division in prokaryotic cells?
Binary fission
What are the two stages of binary fission?
- DNA replication
- Cell expansion and cytoplasm division
What does each daughter cell receive after binary fission of prokaryotic cells?
A single copy of the circular chromosome and a variable number of copies of the plasmids.
How do viruses replicate?
They inject DNA/RNA into host cells and utilize the host’s machinery.
List the stages of viral replication.
- Injection of DNA / RNA into host cell
- Replication of nucleic acid and viral proteins
- Assembly of viruses
- Release of viruses by budding or cell lysis
