Genes and cell divison Flashcards
In relation to genes, what does each cell contain?
The same amount of DNA and instructions to build every protein used in the body.
What do ‘switched on’ genes produce?
Protein. During the cell’s life, many genes are switched off. Only genes switched on produce protein.
What are genes?
Sections of DNA located on specific chromosomes.
- position of gene on chromosome is called its locus.
- genes that occur on the same chromosome are linked.
Why do cells divide?
So organisms can grow, repair damaged tissue or prepare for asexual reproduction.
What are the two types of cell divison?
Mitosis and Meiosis
What is the main purpose of mitosis?
Growth and repair of cells
What is the main purpose of meiosis?
production of gametes.
What is the final stage of mitosis?
cytokinesis, the division of the cytoplasm.
What happens during the interphase of mitosis?
- DNA replication
- Synthesis of new organelles
- Accumulation of stored energy.
What cells does mitosis occur in?
Somatic cells
Where does meiosis occur?
Testes and ova
What happens during the prophase of mitosis?
- DNA becomes visible as long, thin threads
- Shorten and thicken to become chromosomes
- each consist of two strands attached at the centromere
- nucleus breaks down
What happens during the metaphase of mitosis?
- chromosomes move to equator
- spindle microtubules attach to centrometres
What does PMAT stand for?
Preparation, move to the middle, action, the end.
(Prophase, metaphase, anaphase, telophase)
What happens during prophase?
Preparation, visible chromosomes, nucleus breaks down.
