Block 2 Flashcards
what is the transcription rate, in nucleotides per second, in eukaryotes?
40 nucleotides per second
what does the cell theory state
all organisms are made of cells and all cells come from pre-existing cells
what is the primary aim of the cell cycle
produce two daughter cells that are genetically and functionally identical to the parent cell
what is interphase made up of
G1 Growth, S Synthesis, G2 Growth
what happens during G1 growth phase
cell replicates all organelles except DNA and nucleus, replication of centrosomes begin.
what happens during synthesis S
DNA strands separated and replicated (DNA replication)
what happens during G2
checks for completion of DNA synthesis, finishes up replication of centrosomes
describe mitosis
continuous process where nuclear membrane dissolves, two copies of DNA are separated and reform as two nuclei. Four phases in total
what are the four (five) phases in mitosis
prophase, (pro metaphase), metaphase, anaphase, telophase
what are centrosomes
two centrioles
when do centrosomes replicate
interphase
what occurs during prophase
chromatin forms chromosomes, mitotic spindle begins to form
what happens during prometaphase
nuclear envelope dissolves, spindle fibres looking for chromosomes kinetochore
what happens during metaphase
chromosomes complete migration to the middle of the cll, known as the metaphase plate
wha tahppens during anaphase
kinetochore disassembles, microtubules drag chomorosomes to the two poles of the cells
what happens during telophase
nuclear envelope re-forms, spindle disintegrates, two new nuclei form
what occurs during cytokinesis
cell division begins, actin-myosin ring causes plasma membrane to state pinching in. Cytoplasm divides
when does cytokinesis occur
immediately after mitosis
what is the G0 state
the state of non-dividing cells
what are some checkpoints of the cell cycle
G1 to S, G2 to M, M (SAC, between m,metaphase and anaphase)
where does cell cycle regulation occur
at the checkpoints
what is an MPF
mitosis promoting factor, composed of two distinct polypeptide subunits
what does a mitosis promoting factor do
induces mitosis
what ar the two polypeptide subunits in a MPF
CDK protein kinase, cyclin
what happens without effective cell cycle checkups
tumours form
what are two aspects of DNA mutation that result in cancer
proto oncogenes become oncogenes which promote uncontrollable cell replication, tumour suppressor genes become inactive
what is normal control of cell cyle
a balance of proto-oncogenes (RAS) and tumour suppressing genes
what are the names for small benign and larger benign tumours
polyp and adenoma
what is the name for a large malignant tumour
carcinoma
how does cancer spread to other parts of the body
through body fluids such as blood and lymph
