Cells Flashcards
Cholesterol
a steroid with an attached OH (hydroxyl) group
Glycolipid
lipids with attached carbohydrate groups.
T/T the head of the lipid bilayer is hydrophobic
False
3 Types of membrane proteins
integral, transmembrane, peripheral, glycoprotein
Glycocalyx
sugary coat formed by carbohydrate portions of glycolipids and glycoproteins in the PM; allows cells to recognize each other
6 Functions of membrane proteins
ion channels, carriers, receptor, linkers, enzymes, cell identity markers
What molecules is the PM highly permeable to? Moderately permeable?
oxygen, carbon dioxide, steroids
water, urea
the more hydrophobic or lipid-soluble a substance, the greater the membrane’s permeability to that substance
T/F The inner surface of the plasma membrane is more positively charged
False
T/F Na+ is more concentrated inside the cell
False
5 Factors that influence rate of diffusion
steepness of concentration gradient, temperature, mass of diffusing substance, surface area, diffusion distance
Important example of simple diffusion
oxygen and carbon dioxide between blood and body cells, and between blood and air within the lungs during breathing
Most abundant ion channel in the PM
K+ or Cl-
Transport maximum
Once all of the carriers are occupied, the transport maximum is reached, and a further increase in the concentration gradient does not increase the rate of facilitated diffusion
How does glucose enter the body cells?
Carrier mediated facilitated diffusion
Aquaporins
integral membrane proteins that function as water channels, play a critical role in controlling the water content of cells; responsible for the production of cerebrospinal fluid, aqueous humor, tears, sweat, saliva, and the concentration of urine
Osmotic pressure
amount of pressure needed to restore the starting condition; the higher the solute concentration, the higher the solution’s osmotic pressure
Hypotonic soultion
lower concentration of solutes than the cytosol; RBCs hemolysis (burst)
Hypertonic
higher concentration of solutes than the cytosol; RBCs crenate (shrink)
2 Sources of energy for active transport
(1) hydrolysis of adenosine triphosphate (ATP) is the source in primary active transport; (2) energy stored in an ionic concentration gradient is the source in secondary active transport
Most abundant primary active transport pump
Na+/K+ ATPase
Symporters
transporter in secondary active transport that move two substances in the same direction
Antiporters
transporters in secondary active transport that move two substances in opposite directions
6 Steps in receptor mediated endocytosis
(1) binding (2) vesicle formation (3) uncoating (4) fusion with endosome (5) recycling of receptors to PM (6) degradation in lysosomes
2 Types of phagocytes
macrophages and nuetrophils
Bulk-phase endocytosis
the plasma membrane folds inward and forms a vesicle containing a droplet of extracellular fluid
Transcytosis
vesicles undergo endocytosis on one side of a cell, move across the cell, and then undergo exocytosis on the opposite side
What % of the total cell volume is cytosol?
55%
Microfilaments
thinnest, generate movement and provide mechanical support
What does the centrosome consist of?
pair of centrioles and the pericentriolar matrix
Functions of centrosomes
microtubule organizer, pericentriolar matrix organizes mitotic spindles
Rough ER
synthesize glycoproteins and phospholipids
Smooth ER
synthesizes fatty acids and steroids; inactivates or detoxifies drugs; removes the phosphate group from glucose-6-phosphate; stores and releases calcium ions that trigger contraction in muscle cells
Functions of the golgi complex
Modifies, sorts, packages, and transports proteins received from the rough ER; makes transfer, secretory and membrane vesicles
Difference between autolysis and autophagy
autophagy is the digestion of worn-out organelles
and autolysis is the entire cell
Function of proteasome
destruction of faulty, damaged, or unneeded proteins
T/F Mitochondria play role in apoptosis
True
T/F the nuclear envelope has a lipid bilayer
True
Proteome
all of an organism’s proteins.
T/F Introns code for proteins
False. Exons do.
Interphase
DNA replicates and organelles produced; G1, S, and G2 phases
2 Events in the mitotic phase
nuclear division (mitosis) and a cytoplasmic division (cytokinesis)
Prophase
chromatin fibers condense and shorten into chromosomes
Metaphase
microtubules of the mitotic spindle align the centromeres of the chromatid pairs along the metaphase plate
Anaphase
centromeres split, separating the two members of each chromatid pair and move toward opposite ends of the cell
Telophase
chromosomes unravel into chromatin and a nuclear envelope forms around them
