Chromosomes
State the components that make up a chromosome
DNA, histone protein, sister chromatids, centromere, telomeres
Name the stages of mitosis in order
Prophase, Metaphase, Anaphase, Telophase
Name the stages of cell cycle
Interphase, mitosis, cytokinesis
What are telomeres? Refer to their structure
Multiple repeat units of short sequence DNA that cap chromosome tips
What is the purpose of mitosis?
Produces 2 genetically identical daughter for growth, cell replacement/tissue repair, asexual reproduction
What are stem cells? What are the different types?
Cells that are unspecialised and retain the ability to differentiate into a range of cell types
Totipotent, Pluripotent, Multipotent
Outline what happens during metaphase
Sister chromatids line up at the cell equator attached to the mitotic spindle by their centromeres
What happens during cytokinesis? Is it different for plant and animal cells? Explain
Cytokinesis is the process of cell division where the cytoplasm is divided and two whole daughter cells are produced, it only occurs in animal cells. in plant cells a new cell wall is constructed
What are the functions of centromeres?
Site of attachment for spindle microtubules, holds the sister chromatids together, helps the cell move to opposite poles of the cell during anaphase
Outline what happens during prophase
chromosomes condense, sister chromatids are visible, nuclear envelope and nucleolus break down, centrosomes move to opposite poles of cell
Explain what happens during interphase
G1- cell synthesises proteins for replication, cell size doubles , S- DNA replicates, chromosomes consist of two sister chromatids, G2- Replication of DNA is checked and errors are repaired
What is the function of telomeres? Explain
Prevent the loss of DNA during replication, the enzyme responsible for replication cannot replicate the full length of the chain so telomeres provide protection against loss of DNA
Outline what happens in anaphase
Spindle fibres contract, centromeres divide, sister chromatids separate and are pulled apart to opposite poles of the cell, spindle fibres break down
Why is the regulation of cell cycles important?
Irregular growth of cells where growth or repair is not required can result in the formation of tumors which can lead to cancer