Term
| What are the 2 types of regulatory proteins involved in cell cycle control |
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Definition
cyclins
cyclin-dependent kinases (Cdks) |
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Term
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Definition
| protein that periodically rises and falls in concentration in step with the eucaryotic cell cycle. Cyclins activate specific protein kinases (Cdks) and thereby help control progression from one stage of the cell cycle to the next |
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Term
| cyclin-dependent kinases (Cdks) |
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Definition
| protein kinase that has to be complexed with a cyclin protein in order to act. Different Cdk-cylcin complexes trigger different steps in the cell-division cycle by phosphorylating specific target proteins |
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Term
| MPF (maturation-promoting factor) |
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Definition
a cyclin-Cdk complex that triggers cell's passage past the G2 checkpoint into M phase
it catalyses the phosphorylation of proteins that in turn bring about the events of mitosis, including condensation of chromosomes, formation of the mitotic spindle, and breakdown of the nuclear envelope. Levels of cyclins and MPF rise as the cell enters mitosis, reach a peak during mitosis, and then fall during anaphase. |
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Term
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Definition
| The kinetochore is the protein structure on chromosomes where the spindle fibers attach during cell division to pull the chromosomes apart. |
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Term
| platelet-derived growth factor (PDGF) |
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Definition
| stimulates the division of human fibroblast cells in culture |
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Term
[image]
what does this indicate? |
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Definition
| cdks need to be phosphorylated/dephosphorylated to be active |
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Term
| What causes levels of cyclin to fall ? |
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Definition
targeted proteolysis --- degradation
Proteolysis is the directed degradation (digestion) of proteins by cellular enzymes called proteases. The hydrolytic breakdown of proteins into simpler, soluble substances such as peptides and amino acids, as occurs during digestion.
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Term
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Definition
A process by which proteins are marked for proteasome degradation. Proteins called ubiquitins are transferred to the substrate protein, targeting it for destruction by the proteasome.
A proteasome is a large protein complex in the cytosol that is re
responsible for degrading cytosolic proteins that have beenmarked for destruction by ubiquitylation or by some other means |
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Term
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Definition
| protein complexes with a ring-like structure that help carry out chromosome condensation...coiling the chromatids into a more compact form |
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Term
| Why is important for condensins to do their work? |
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Definition
| condensed chromosomes are easier to move as discrete units |
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Term
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Definition
| hold the chromatids together, protein complex that forms a ring that holds sister chromatids together after DNA has been replicated in the cell cycle |
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Term
| What controls chromosome movement during mitosis? |
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Definition
| Microtubules - long stiff, cylindrical structure composed of protein tubulin. used by eucaryotic cells to regulate their shape and control their movements |
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Term
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Definition
it is a microtubule organizing center that is centrally located in animal cells, it separates to form the two spindle poles during mitosis.
during assembly of spindle microtubules at the centrosome |
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Term
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Definition
| star-shaped system of microtubules emanating from a centrosome or from a pole of a mitotic spindle |
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Term
| What do spindles include? |
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Definition
| centrosomes, the spindle microtubules, and the asters |
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Term
| during prometaphase what do spindle microtubules attach to? |
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Definition
| kinetchores of chromosomes which begin to move the chromosomes |
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Term
| What occurs to the chromosomes during metaphase? |
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Definition
| chromosomes line up at the metaphase plate (the midway point between the spindle's two poles) |
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Term
| In anaphase what occurs to the sister chromatids? |
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Definition
they separate, and move along the kinetochore microtubules toward opposite ends of the cell
microtubules shorten by depolymerizing at their kinetochore ends ---depolymerization is a process where polymers are broken down into their monomer components |
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Term
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Definition
| the destruction of cohesins |
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Term
| Separase (a protease) cleaves cohesins. What activates separase? |
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Definition
Anaphase-promoting complex (APC)
this complex also affects destruction of M cyclin |
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Term
| nonkinetpchore micortubules from opposite poles overlap and push against each other causing... |
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Definition
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Term
| What occurs in telophase? |
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Definition
genetically identical daughter nuclei form at opposite ends of the cell
nuclear membrane reforms |
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