Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Cell Biology
| Question | Answer |
|---|---|
| Single-celled organisms | grow and divide when essential nutrients are present and stop growing and dividing when nutrients are absent |
| Multicellular organisms | generally isolated from environmental fluctuations |
| Differentiated cells stops dividing because | the organs and tissues they form would not be properly organized |
| Hematopoietic stem cells | continue producing new red and white blood cells and thus continue dividing |
| Epithelial cells lining organs | continuously renewed |
| Non-dividing cells can be made to divide by specific signals | example: lymphocytes are induced to proliferate by interaction with an appropriate foreign substance (antigen) |
| Cell cycle | all of the events that occur from one mitotic division to the next, during which all of a cell's DNA is doubled and partitioned equally between two daughter cells |
| M phase | includes the process of mitosis and cytokinesis |
| Mitosis | partitions duplicated chromosomes into two nuclei; easily observed in a light microscope where the highly condensed chromosomes can be seen as well as cells undergoing division |
| Cytokinesis | entire cell divides |
| Interphase | period between divisions when cell grows and replicates its chromosomes; DNA replication occurs only during synthesis portion of interphase |
| Gap phases | important functions in preparing cells for the synthesis and mitosis phases and providing checkpoints to halt the cell cycle if something goes wrong during synthesis and mitosis |
| G0 | most cells in a fully developed animal stop proliferation, non-dividing state, remain here for weeks or lifetime; can re-enter cell cycle |
| Cdk | cyclin-dependent protein kinases regulate entry of cells into S or M phase |
| Protein kinase | enzyme that transfers a phosphate group from ATP to the hydroxyl group of specific serine, threonine, and tyrosine residues in proteins |
| Phosphorylation | mechanism to control a protein's enzymatic activity, cell lifetime, binding to partners, and subcellular location |
| Cdks control | initiation of DNA synthesis, mitosis, and cytokinesis; by themselves are inactive, must bind to a partner protein (cyclin) in order to become enzymatically active kinases |
| Cyclins | 4 classes, each defined by specific stage of the cell cycle in which they bind their corresponding Cdk |
| G1-Cdk complex | cyclin D (3 of this type in mammals) with Cdk4 and Cdk6 |
| G1/S - Cdk complex | cyclin E and Cdk2 |
| S/Cdk complex | cyclin A and Cdk2 |
| M/Cdk complex | cyclin B and Cdk1 |
| Rb substrate for Cdks | associates with transcription factor E2F preventing E2F from functioning; phosphorylation of Rb by Cdk releases it from E2F allowing E2F to stimulate expression of genes required for transition from G1 to S, including DNA replication genes |
| Cyclin production | controlled transcription brings about synthesis of cyclins and controlled protein degradation brings about degradation of cyclins |
| Ubiquitin-proteasome | cyclin degradation mediated by this; 76 amino acid protein joined by way of its C-terminus to the epsilon amino group of specific lysine residues in proteins |
| Origin of cancer | genetic disease because requires alterations within specific genes; usually not inherited since alterations that cause it arise in somatic cells of an individual during its lifetime |
| Cancer cell properties | display uncontrolled growth (cancer cells do not respond to signals that cause normal cells to stop growing and dividing), anchorage-independent; do not require growth factors |
| Normal cells | anchorage dependent; secrete proteins that interact with surface receptors that signal a proper environment, immortal; numerous chromosomal aberrations |
| Cancer cells do not need growth factors | the cell cycle can not respond to interaction of GFs with cell surface receptors that send regulatory signals into the cell |
| Aneuploidy | cancer cells may lack large segments or even entire chromosomes and segments of different chromosomes may be joined together |
| Causes of cancer | environmental effects that damage DNA |
| benzopyrene | soot, tobacco, and cigarette smoke, converts metabolically to a derivative that covalently modifies Guanine residues in DNA |
| Tumor-suppressor genes | normal genes that encode proteins which prevent proliferation; mutations that inactivate them cause LOF on proliferation and promote cancer |
| Oncogenes | mutant versions of normal, proto-oncogenes encoding proteins that promote proliferation; mutations cause expression of proto-oncogenes at wrong time creating inappropriate signals to proliferate and promote cancer; GOF; cause genetic instability |
Created by:
ilk0710
Popular Biochemistry sets