Flashcards in Fiser Chapter 1. CELL BIOLOGY Deck (19)
cell membrane composition
lipid bilayer with protein channels, enzymes, and receptors
What increases membrane fluidity?
Cells are negative inside compared to outside due to Na/K ATPase (3 Na out, 2 K in)
Na gradient is used for co-transport of glucose, proteins, and molecules
Adhesion molecules (cell-cell and cell-extracellular matrix, respectively) which anchor cells
Tight junctions versus Gap junctions
Tight junctions: cell-cell occluding junctions; form an impermeable barrier (eg epithelium)
Gap junctions: allow communication between cells (connexin subunits)
Intramembrane proteins; transduce signal from receptor to response enzyme
Ligan-triggered protein kinase
Receptor and response enzyme are a single trans-membrane protene (insulin, epidermal growth factor). Binding actiates the kinase domain, which phosphorylates substrate proteins.
Examples of glycolipids and glycoproteins on cell membrane
ABO bloody-type antigens: glycolipids
HLA-type antigens: glycoproteins (Gp)
Water moves from area of low solute concentration to an area of high solute concentration and approach osmotic equilibrium
Cell cycle sequence
G1, S (proteine synthesis, chromosomal duplication), G2, M (mitosis, nucleus divides)
Can also go to G0 (quiescent) from G1
What detemines cell cycle length?
G1: growth factors affect cell here too
Prophase (centromere attachment, spinder formation, nucleus disappears)
Metaphase: chromosome alignment
Anaphase: chromosomes pulled apart
Telophase: separate nucleus reforms around each set of chromosomes
Steroid and tyroid hormones
Both transcription factors (bind DNA and help transcription of genes), but steroid binds receptor in CYTOPLASMand then enters nucleus, while thyroid hormone binds receptor in nucleus
Purines and pyrimidines
Purines: adenine and guanine
Pyrimidines: cytosine, uracil (RNA), thymidine (DNA), "pyramids cut"
AU or AT is with 2 hydrogen bonds; GC is with 3 hydrogen bonds
Glycolysis overall does what?
Turns a glucose molecule into 2 ATP and 2 pyruvate
Krebs cycle overall does what?
Located on inner matrix of mitochondria, it takes the 2 pyruvate molecules created in glycolysis, to create NADH and FADH2. These then enter the ETC to create ATP. Overall 1 glucose creates 36 ATP
How much ATP does each glucose molecule create during aerobic metabolism?
Glycolysis then krebs cycle then ETC:
Lactic acid (from cori cycle) and amino acids are converted to glucose
Fat and lipids NOT available for gluconeogenesis because acetyle CoA (breakdown of fat metabolism) cannot be converted back to pyruvate