cells and control Flashcards
what do chromosomes contain
genetic information
where is genetic information stored
the nucleus of a cell
how is genetic information stored
chromosomes
what are chromosomes
coiled up lengths of DNA molecules
what is a diploid cell
2 copies of each chromosome (normal body cells)
where does each copy of the chromosomes come from
1 mother
1 father
what does mitosis make
two identical cells - nucleus contains same number of chromosomes as the original cells
what is mitosis for
growth and repair
what happens in mitosis
multicellular organisms divide to produce new cells in the cell cycle.
how do multi cellular organisms use mitosis
to grow and to replace cells which may have been damaged
what is asexual reproduction
uses mitosis to reproduce
what is the first stage of cell cycle
interphase
what happens during interphase
before it divided, the cell has to grow and increase the amount of sub cellular structures such as mitochondria and ribosomes.
it then duplicates the dna, copied and forms X-shaped chromosomes.
what happens after interphase
mitosis and cytokinesis
what are the four stages of mitosis in order
prophase
metaphase
anaphase
telophase
(PMAT)
what is prophase
the chromosomes condense, getting shorter and fatter.
the membrane around the nucleus breaks down and the chromosomes lie free in the cytoplasm
what is metaphase
the chromosomes line up at the centre of the cell
what is anaphase
cell fibres pull the chromosomes apart.
the two arms of each chromosome go to opposite ends of the cell
what is telophase
membranes form around each of the sets of chromosomes.
these become the nuclei of the two new cells - nucleus has divided
what is cytokinesis
the cytoplasm and cell membrane divided to form separate cells
when does cytokinesis happen
happens before telophase ends
what is produced by mitosis
2 new daughter cells
characteristics of the daughter cells
- same sets of chromosomes in its nucleus
- genetically identical diploid cells
- genetically identical to the parent cell
what is growth
increase in size or mass
what is cell differentiation
the process by which a cell changes to become specialised for its job
what do specialised cells allow
multicellular organisms to work more efficiently
what is cell elongation
where a plant cell expands, making the cell bigger and so making the plant grow
what is cancer
uncontrolled cell division which results in a mass of abnormal cells called a tumor which invades and destroys surrounding tissues
what are percentile charts used for
to monitor growth over time, so overall pattern in development can be seen and any problems highlighted
what 3 measurements are taken for percentile charts
length
mass
head circumference