Cell division

Question 1

Characteristics of process of mitosis

Answer 1

• Produces genetically identical daughter cells
• produces 2 cells
• involves 1 division
• produces diploid cells in humans-23 pairs of chromosomes
• keeps same chromosome number

Question 2

Roles of mitosis

Answer 2

• Generates all cells in adult body EXCEPT gametes
• occurs throughout human body and plants
  -used for growth, repair and asexual reproduction

Question 3

Describe process of mitosis

Answer 3

1- Cell grows
2- DNA replicates to form 2 copies of each chromosome (chromatids). These get joined together at a single point
3- Nuclear membrane breaks down, and chromosomes line up across centre of cell, attached to spindle fibres
4- Chromatids are pulled apart and move to opposite ends of the cell
5- Cytoplasm and cell membrane divides to form 2 identical cells

Question 4

Characteristics of process of Meiosis

Answer 4

• Produces non-identical daughter cells
• produces 4 cells
• 2 cell divisions
• produces haploid cells in humans- 23 unpaired chromosomes
• halves number of chromosomes

Question 5

Role of meiosis

Answer 5

• only to produce gametes
  -only occurs in ovary and testis (animal) or ovary and anther (plant)
  -used for sexual reproduction

Question 6

Describe process of meiosis

Answer 6

1- Same as mitosis
2- Same as mitosis
3- Nuclear membrane breaks down and homologous pairs of chromosomes join together
4- homologous pairs exchange sections of DNA before attaching to spindle fibres in pairs, at centre of cell
5- Homologous pairs are pulled apart and moved to opposite ends of the cell, and the cell divides
6- Chromosomes line up along centre of cell attached to spindle fibres, before the chromatids separate and each cell divides again