Cell Biology Flashcards
composition of a cell membrane
- lipid bilayer - contains protein channels, enzymes, and receptors
- cholesterol- membrane fluidity
Electrical gradient of a cell memebrane
Negative inside compared to outside. 3 Na out 2 Kin based on Na/K ATP ase.
Na gradient used for cotransport of glucose, proteins and other molecules
desmosomes/hemidesmosomes
adhesion molecules (cell - cell/ cell - extracellular matrix)
tight junctions
cell-cell occluding junctions, form an impermeable barrier (epithelium)
Gap junctions
connexin subunits, allow communication between cells
G proteins
intramembrane protein, transduce signal from receptor to response enzyme
Ligand- triggered protein kinase
receptor and response enzyme are a single transmembrane protein ( insulin, epidermal growth factor)
ABO blood type antigens
glycolipids on cell membrane
HLA - type antigens
glycoproteins (Gp) on cell membrane
G1 cell cycle
- determines cell cycle length
- growth factors affect cell during G1
- cells can move to Go (quiesecent) from here
Mitosis
nuclear division
- prophase: centromere attachment, spindle formation, nucleus disappears
- Metaphase: chromosome alignment
- Anaphase: chromosomes pulled apart
- Telophase: separate nucleus reforms around each set of chromosomes
- Cytokinesis: contractile ring and cleavage furrow, separation of cells
nucleus
contains a double membrane, outer membrane continuous with rough endoplasmic reticulum
nucleolus
inside the nucleus, no membrane, ribosomes are made here
Transcription
DNA strand is used as a template by RNA polymerase for synthesis of an mRNA strand
Transcription factors
- steroid hormones- binds receptor in CYTOPLASM, then acts as a transcription factor
- thyroid hormone- binds receptor in NUCLEUS
- others: AP-1, NF-kB, STAT, NFAT