cell cycle

what is a cell?

the most basic unit of life

in which organisms does cell division occur?

multicellular organisms

not all cells retain the ability to…

divide

what types of cells undergo mitosis?

• unspecialised body cells

• cells that have the ability to divide

what are the two types of cell division in eukaryotic cells?

mitosis and meiosis

what is mitosis?

a type of cell division that produces 2 genetically identical diploid daughter cells

what is the purpose of mitosis?

• growth of tissues

• repairing damaged tissue

• replacement of lost cells

• produce new cells

• clonal expansion of B cells

what form of reproduction is mitosis?

asexual

how many divisions occur in mitosis?

1

how many chromosomes do the daughter cells produced by mitosis have?

46 - same as parent cell

where in the body does mitosis occur?

in somatic cells

• any cell in the body that is not a gamete

what is meiosis?

a type of cell division that produces 4 genetically non-identical haploid daughter cells

what is the purpose of meiosis?

to produce haploid sex cells (gametes) for sexual reproduction

how many divisions occur in meiosis?

2

how many chromosomes do the daughter cells produced by meiosis have?

23 - half the number of parent cell

what are the 3 steps of the cell cycle?

• interphase

• mitosis / nuclear division

• cytokinesis

what is the role of interphase?

cell growth and replication

how much % of the cell cycle is interphase?

around 90%

what are the 3 stages of interphase?

• G1 - growth one

• S - synthesis phase

• G2 - growth two

what occurs during the G1 phase?

• cell volume increases

• new proteins synthesised

• new organelles formed

what occurs during the S phase?

DNA replication - causes amount of DNA to double

what occurs during the G2 phase?

• cell volume increases

• new proteins synthesised

• new organelles formed ready for mitosis

what occurs during nuclear division?

nucleus divides into two (mitosis) or four (meiosis)

what occurs during cytokenesis?

cytoplasm divides and forms either 2 genetically identical daughter cells (mitosis) or 4 non-genetically daughter cells (meiosis)

what factors affect the growth rate of a cell?

• increasing temperature

• increasing oxygen

• increasing glucose

why does increasing temp increase the rate of cell growth?

it increases enzyme activity

why does increasing oxygen increase the rate of cell growth?

it increases respiration

why does increasing glucose increase the rate of cell growth?

increases respiration