Cell Bio 1 Flashcards
Ubiquitin tags proteins for degradation to which organelles?
proteasomes & lysosomes
Organelle which is involved in:
- translation & folding of new proteins
- manufacturer of lysosomal enzymes
- site of N-linked glycosylation
ROUGH endoplasmic reticulum
extensive RER cells inc pancreatic, goblet, plasma cells
Organelle which is involved in:
1. steroid & lipid Synthesis
SMOOTH endoplasmic reticulum
extensive SER cells inc adrenal cortex, hepatocytes, testes, ovaries
Organelle which:
- modifies, sorts & packages molecules destined for cell secretion
- site of O-linked glycosylation
Golgi apparatus
Organelle involved in aerobic respiration - type of DNA?
Mitochondria - contains mitochondrial genome as Circular DNA
Organelle involved in DNA maintenance & RNA transcription
Nucleus
Organelle involved in breakdown of large molecules e.g. proteins, polysaccharides
Lysosome
Organelle involved in Ribosome production
Nucleolus
Organelle involved in translation of RNA into proteins
Ribosome
Organelle involved in catabolism of v long chain fatty acids & AAs? What forms at the end of this?
Peroxisome
- hydrogen peroxide
Organelle involved in degradation of protein molecules (that have been tagged with ubiquitin)
Proteasomes (& lysosomes)
What proteins regulate the cell cycle?
What enzymes do they control?
- Cyclin proteins
- CDK (cyclin-dependent kinase) enzymes
G0 phase of cell cycle?
Resting phase
- quiescent cells e.g. hepatocytes and more permanently resting cells e.g. neurons
G1 phase of cell cycle?
under influence of which gene?
regulatory proteins?
Gap 1: cells increase in size
- determines length of cell cycle
- under influence of p53
- cyclin D/CDK4, cyclin D/CDK6 & cyclin E/CDK2: regulates transition from G1 to S phase
S phase of cell cycle?
mechanism?
regulatory proteins?
Synthesis of DNA, RNA & histone
- centrosome duplication (to prepare itself for division)
- cyclin A/CDK2: active in S phase
G2 phase of cell cycle?
regulatory proteins?
Gap 2: cells continue to increase in size
- cyclin B/CDK1: regulates transition from G2 to M phase
M phase of cell cycle?
length?
Mitosis: cell division
- shortest phase of cell cycle
6 phases of mitosis?
- Prophase
- Prometaphase
- Metaphase
- Anaphase
- Telophase
- Cytokinesis
What occurs during prophase?
chromatin in nucleus condenses
What occurs during pro metaphase?
nuclear membrane breaks down -> allowing microtubules to attache to the chromosomes
What occurs during metaphase?
chromosomes aligned at middle of cell
What occurs during anaphase?
paired chromosomes separate at the kinetochores and move to opposite sides of the cell
What occurs during telophase?
chromatids arrive at opposite poles of cell
What occurs during cytokinesis?
actin-myosin complex in cell centre contacts -> ‘pinched’ into 2 genetically identical diploid daughter cells
