Module: Cell Division
Q: Describe the structure of a chromosome:
Chromosomes are made up of DNA and a protein called histone.
The DNA molecule is a double helix, running the length of the chromosome, with
sections along its length called genes.
Chromosomes only become visible when chromatin condenses prior to cell division,
after each DNA molecule has replicated and made an exact copy of itself.
The two copies of a chromosome are called sister chromatids and they lie parallel
along their length, joined at a specialised region, called the centromere.
Q: What does haploid mean?
Having one complete set of chromosomes.
Q: What does diploid mean?
Having two complete sets of chromosomes, normally a maternal and paternal one.
Q: What are the three main stages of the cell cycle?
1. Interphase
2. Mitosis
3. Cytokinesis
Q: What happens in interphase?
Newly formed cell grows, and its organelles replicate, replacing those lost in the
previous division.
The DNA replicates so its quantity doubles. Proteins, such as histones and enzymes,
are synthesised during interphase, requiring energy from ATP.
Q: State the 4 stages of mitosis:
PMAT
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
Q: What happens during cytokinesis?
The division of the cytoplasm to make two cells.
Q: What is meiosis?
A two-stage cell division in sexually reproducing organisms that produces 4
genetically distinct daughter cells each with half the number of chromosomes of the
parent cell.
Q: Describe the structure of a chromosome:
Chromosomes are made up of DNA and a protein called histone.
The DNA molecule is a double helix, running the length of the chromosome, with
sections along its length called genes.
Chromosomes only become visible when chromatin condenses prior to cell division,
after each DNA molecule has replicated and made an exact copy of itself.
The two copies of a chromosome are called sister chromatids and they lie parallel
along their length, joined at a specialised region, called the centromere.
Q: What does haploid mean?
Having one complete set of chromosomes.
Q: What does diploid mean?
Having two complete sets of chromosomes, normally a maternal and paternal one.
Q: What are the three main stages of the cell cycle?
1. Interphase
2. Mitosis
3. Cytokinesis
Q: What happens in interphase?
Newly formed cell grows, and its organelles replicate, replacing those lost in the
previous division.
The DNA replicates so its quantity doubles. Proteins, such as histones and enzymes,
are synthesised during interphase, requiring energy from ATP.
Q: State the 4 stages of mitosis:
PMAT
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
Q: What happens during cytokinesis?
The division of the cytoplasm to make two cells.
Q: What is meiosis?
A two-stage cell division in sexually reproducing organisms that produces 4
genetically distinct daughter cells each with half the number of chromosomes of the
parent cell.
