cell cycle

binary fission

  • a form of asexual reproduction in unicellular organisms, in which the parent cell divides into two approximately equal parts

  • is an exponential process - a type of asexual reproduction where a single cell is spilt into two new cells

prokaryotic asexual reproduction

  1. chromosomes (DNA) uncoils

  2. DNA replicates

  3. DNA is pulled to opposite poles

  4. new cell wall begins

  5. new cell wall completes, dividing cytoplasm in half

  6. DNA re-loops into chromosomes

  7. new cell separates

exponential growth

  • the growth of a population in which rate of growth is a proportion to population size

  • after each round of replication the number of cells double

what is eukaryotic cell cycle

3 cell replications are: growth, repair and reproduction

  • reproduction: its purpose is to form a cell division in which a parent cell divides to produce two genetically identical daughter cells.

  • growth and development: multicellular organism grow in size by increasing the number of their cells through repeated cell replications + development in multicellular organisms involve a balance between cell replication and cell death

  • repair: helps maintain and repair damaged cells + repairing tissues require the production of new cells to replace those that die

3 main stages of cell cycle

  • interphase: the phase in the cell cycle when the cell is not undergoing mitosis

  • mitosis: the division of a nucleus that results in two cells that are genetically identical to the parent cells

  • cytokinesis: the division of a cell following mitosis, when the cytoplasm divides and the cell splits into two daughter cells

what are the checkpoints?

G1 checkpoint - occurs towards end of G1 in interphase

  • growth phase

  • cell increases in size and organelles multiply

  • chromosomes exist as chromatin

G2 checkpoint - occurs towards end of G2 in interphase

  • periods of rapid growth

  • material needed to form spindle

  • the cells chromatin condense into chromosomes

M checkpoint - occurs towards end of metaphase in mitosis

  • examines whether sister chromatids are correctly attached to the spindle microtubules

S phases - apart of interphases stages

  • DNA can produce an exact copy of itself

what are the 4 phases of mitosis?

  • prophase

  • metaphase

  • anaphase

  • telophase

What is a plasmid and how is it useful to the prokaryote

Its role is to carry genes for replicating DNA and transferring themselves from one host cell to another. By carrying out genes, it makes it beneficial for prokaryotes to survival.

Where does cytokinesis occur in relation to stages of the cell cycle?

Cytokinesis begins in anaphase and ends in telophase, reaching completion as the next interphase begins.

Explain how cytokinesis is different in animals and plants

Cytokinesis is different in animal and plant cells because animal cells occurs by the furrowing of the cytoplasm, whilst in plant cells, cytokinesis is initiated with the formation of a cell plate in the middle of the cell