Cell Cycle Flashcards
cell continuity
cells arise from pre-existing cells
chromosomes
threads made up of DNA and protein found in the nucleus that carry genetic information in the form of genes
gene
a section of DNA that codes for the production of a protein
haploid
one set of chromosomes in the nucleus
diploid
two sets of chromosomes in the nucleus
homologous pair
two chromosomes of equal length with the same sequence of genes
interphase
when a cell is not dividing
mitosis
a form of nuclear division in which one nucleus divides to form two nuclei, each containing identical sets of chromosomes
cancer
a group of disorders in which certain cells lose their ability to control both the rate of mitosis and the number of time mitosis occurs
meiosis
a form of nuclear division in which the daughter nuclei contain half the chromosome number of the parent nucleus
describe interphase
cellular processes occur: respiration, protein synthesis
chromosomes are elongated and thin- known as chromatin during this phase
cells spend 90% of its cycle in this phase
mitosis includes
prophase metaphase anaphase telophase 10% of the cycle
prophase
chromosomes duplicate and are double stranded chromatid pairs
nuclear membrane breaks down
spindle forms
nucleolus disappears
metaphase
chromatid pairs line up along the equator of the cell
spindle fibres attach the the centromeres
anaphase
spindle fibres contract and pull the centromeres until they split
sister chromatids separate and move to opposite poles of the cell
identical genes are now at opposite poles
telophase
spindle fibres break down
chromosomes at each end elongate and become chromatin threads
nuclear membrane forms around chromatin at both poles
nucleolus reappears
two identical nuclei have been formed
cell wall prevents
furrow formation
cell division in plant cells
vesicles containing cellulose gather along the centre of the cell; forms the cell plate
two cell walls form
cell division in animal cells
cleavage furrow (shallow groove) forms along cell equator gets deeper until it splits into two cells
mitosis functions in unicellular organisms
asexual reproduction
mitosis functions in multicellular organisms
produces new cells, not new individuals
responsible for growth, renewal and repair of cells
meiosis functions
sexual reproduction (produces sex cells) variation as a result of different gene combinations
cancer types
benign tumours - non life threatening and do not invade other tissues eg warts
malignant tumours - uncontrolled multiplication of abnormal cells
invades other cells and move around the body (metastasis)
cancer cells divide indefinitely
causes of cancer
carcinogens
- exposure to UV radiation
- exposure to asbestos fibres
- cigarette smoke from inhaling/second hand smoke
cancer treatment
surgery chemotherapy (slows down the rate of mitosis)
meiosis vs mitosis
meiosis:
4 daughter cells
daughter cells not identical to each other/parent
sexual reproduction: allows variation
mitosis:
2 daughter cells
daughter cells identical to each other/parent
asexual reproduction: growth + repair of cells