Unit 1 - Protein Control of Cell Division Flashcards
What is the cytoskeleton?
A microscopic network of proteins and tubules in cytoplasm, that supports the shape and function of cells
What are microtubules?
Microscopic hollow tubes made of tubulin that are part of cell’s cytoskeleton
What is tubulin?
The protein that polymerises into long chains or filaments that form microtubules
What is the microtubule organising centre?
The structure found in eukaryotic cells from which microtubules are produced for the formation of spindle fibres
What are spindle fibres?
Microtubules to which the chromosomes are attached by kinetochores during cell division
What is the cell cycle?
A 4 stage process in which the cell increases in size, copies its DNA, prepares to divide and divides by mitosis
What is mitosis?
The division of the nucleus to form two nuclei, each with a full complement of chromosomes
What is cytokinesis?
The division of cytoplasm to form two daughter cells
What are kinetochores?
A complex of proteins associated with the centromere of a chromosome during cell division, to which the microtubules of the spindle attach
What is the centromere?
The specialised DNA sequence of a chromosome that links a pair of sister chromatids
What are cyclin proteins?
Proteins that control the progression of cells through the cell cycle by activating cyclin-dependent kinase enzymes
What do cyclin-dependent kinases cause?
The phosphorylation of proteins, which stimulates the cell cycle
What is p53?
A tumour-suppressor protein that is dysfunctional in several major cancers
What is p53?
A tumour-suppressor protein that can stimulate DNA repair, arrest the cell cycle or cause cell death by activation of caspases
What is proto-oncogene?
A normal gene, usually involved in the control of the cell growth or division, which can mutate to form a tumour-promoting oncogene
What is tumour-promoting oncogene?
A mutated proto-oncogene that has the potential to cause cancer
What is apoptosis?
Programmed cell death triggered by cell death signals that can be external or internal
What are death signal molecules?
External or internal signals that result in the activation of protease enzymes called caspases, which cause apoptosis
What are caspase cascades?
Protease enzymes involved in a series of reactions that destroy a cell
What is metamorphosis?
The process that involves a significant change in an organism’s physical form during development
What are growth factors?
A naturally occurring substance, usually a protein or steroid hormone, capable of stimulating cell growth
What does the cytoskeleton consist of?
Different protein strctures including microtubules
What are microtubules?
Hollow cylinders composed of tubulin.
Where do microtubules radiate from?
MTOC ( Microtubule organising centre)
What does the formation and breakdown of microtubule involve?
-Polymerisation of tubulin (growth of microtubule)
-Depolymerisation of tubulin (shrinkage of microtubule)
What are the functions of the cytoskeleton?
- Gives mechanical support and shape to cells
- Microtubules control membrane-bound organelles and chromosomes
- Microtubules form spindle fibres that are active during cell division
What is cell division required for?
Growth and repair
What are the 2 parts of the cell cycle?
- Interphase
- Mitotic phase
What phase lasts longer, Interphase or mitotic phase?
Interphase
What are the 3 sub-phases of interphase?
- G1
- S phase
- G2
What happens during G1 sub-phase?
Growth period where proteins and organelles are synthesised
What happens during S phase?
Cell continues to grow, DNA is replicated in prep for mitosis
What happens during G2 sub-phase?
Another growth period where proteins and organelles are synthesised?
What are the 2 sub-phases of the mitotic phase?
- Mitosis
- Cytokinesis
What happens during mitosis?
Chromosomal material is separated by spindle microtubules
What happens during cytokinesis?
The cytoplasm separates into two daughter cells
What are the 4 stages of mitosis?
- Propase
- Metaphase
- Anaphase
- Telophase
( Pass Me Another Tequila )
What happens during prophase?
- DNA condenses into chromosomes, both have two sister chromatids.
- Nuclear membrane breaks down
- Spindle microtubules extend from MTOC by polymerisation and attach to chromosomes via kinetochores in centromeme
What happens during metaphase?
- Chromosomes are aligned at the metaphase plate (equator of spindle)
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