Cell Physiology Basics

Question 1

fundamental features of all cells

Answer 1

store genetic info, surrounded by plasma membrane

Question 2

central dogma of molecular biology

Answer 2

flow of genetic info from gene to protein. proteins are the functional unit of living organisms

Question 3

endomembrane system of eukaryotes

Answer 3

ER, Golgi, plasma membrane. constantly exchanging information and materials

Question 4

biosynthetic secretory pathway

Answer 4

proteins and antibodies the cell is making that are being exported out of the cell into the ECF

Question 5

endocytic pathway

Answer 5

taking stuff in from outside the cell

Question 6

cytoskeleton

Answer 6

not just structural. intermediate filaments, microfilaments, microtubules (long rod-like proteins)

Question 7

intermediate filaments

Answer 7

structural support to maintain shape of the cell

Question 8

microfilaments

Answer 8

enables cell mobility that involves changing shape of cells. mostly composed of actin. involved in all muscle contraction

Question 9

microtubules

Answer 9

components of cilia and flagella. form spindle during mitosis/meiosis. vesicular transport–how vesicles move within the cell. forms a network of tracks for the motor proteins Kinesin and Dynein

Question 10

motor proteins

Answer 10

attach vesicles to motor proteins to speed up movement. Kinesin and dynein

Question 11

Kinesin and Dynein

Answer 11

couple ATP hydrolysis to speed up axonal transport along microtubular highways

Question 12

Kinesin

Answer 12

goes from body to exterior of cell

Question 13

Dynein

Answer 13

goes from exterior to body of cell (retrograde transport)

Question 14

hydrophobic effect

Answer 14

refers to the spontaneous self-assembly of non-polar substances that are dispersed in water. maximizes entropy

Question 15

simple diffusion

Answer 15

anything hydrophobic can get across the lipid membrane. Gases are hydrophobic so, oxygen, can get through by simply diffusing

Question 16

facilitated diffusion

Answer 16

impermeable solutes aided y protein carriers or channels. movement of diffusion is down the concentration gradient

Question 17

active transport

Answer 17

pump impermeable solutes using energy. ATP or energy from another gradient is used.

Question 18

Diffusion

Answer 18

driven by entropy, things have a tendency to fill the entire area available to them`. Net movement from HIGH to LOW concentration. Molecules want to spread out

Question 19

Fick’s Law of Diffusion

Answer 19

Increase gradient, surface area, lipid solubility = more diffusion. The bigger something is and the thicker the membrane = slower diffusion

Question 20

Channel-mediated facilitated diffusion

Answer 20

channel, some sort of pore. Open on both sides of the membrane and works like a door. Can be open all the time or gated. Some type of trigger causes the door to open, like phosphorylation

Question 21

Carrier transport of facilitated diffusion

Answer 21

carriers have 2 distinct conformations. The undergo changes that reorient their “sidedness.” They have a binding site for the molecule being carried and when the molecule is bound, it will open on the other side to release the molecule. Net carrying of molecules from high->low conc. Uniporters–carry only a single solute

Question 22

Simple Diffusion vs Carrier Mediated (facilitated diffusion)

Answer 22

Simple diffusion is directly proportional to the transmembrane concentration gradient. The Carrier mediated transport can reach a maximum where all of the available carriers are saturated

Question 23

Primary Active transport

Answer 23

ATPase coupled ion pumps. Hydrolyzing ATP->ADP and couple that rxn to pumping up the concentration gradient (doing something thermodynamically unfavorable)

Question 24

Active transporters maintain

Answer 24

non-equilibrium ion distributions

Question 25

Sarco-endoplasmic reticulum calcium ATPase (SERCA)

Answer 25

Calcium ATPase present in muslce cells ER. Maintains low levels of Ca2+ by storing cytoplasmic Ca2+ into the endoplasmic reticulum

Question 26

Muscle endoplasmic reticulum stores

Answer 26

calcium, put into ER by sarco-endoplasmic reticulum calcium ATPase (SERCA)

Question 27

Plasma membrane calcium ATPase (PMCA)

Answer 27

on plasma membrane. pumps calcium from cytoplasm to the ECF. Want to maintain low levels of intracellular calcium

Question 28

pumped

Answer 28

actively moving substance against its concentration gradient

Question 29

Na+/K+

Answer 29

Uses phosphorylation as a switch. Has two conformations: E1 and E2. active transport

Question 30

E1 conformation of Na+/K+ pump

Answer 30

accessible from the ICF (cytoplasmic fluid). High affinity for Na+, low affinity for K+. Once all binding sites for Na+ are filled, transfer Phosphate from ATP to the carrier.

Question 31

E2 conformation of Na+/K+ pump

Answer 31

accessible from the ECF. Low affinity for Na+, high affinity for K+. Releases Na+ into ECF. Once K+ is bound, the carrier is dephosphorylated and flips back to E1 ICF open conformation

Question 32

5 steps of Na+/K+ pump

Answer 32

In E1 conformation (1) transporter binds Na+ in cytosol (2) phosphorylation by ATP favors conformational change to E2 (3) Na+ release, K+ binds from ECF (4) Dephosphorylated favors E1 conformation (5) K+ released into ICF and the cycle can repeat

Question 33

secondary active transport

Answer 33

still utilizing energy to pump a molecule against a gradient, but not directly using chemical energy from ATP. Using alternative gradient created by primary active transport (vast majority use sodium gradient as energy source)

Question 34

Symport

Answer 34

secondary active transport, moving two molecules in the same direction. Ex: sodium moved in the same direction as the molecule it’s powering against gradient

Question 35

Sodium Glucose transporter (SGLT)

Answer 35

secondary active symporter. Uses Na+ to moving down concentration gradient to pump glucose against its gradient. when sodium is bound, high affinity for gluc.

Question 36

SGLT conformational changes can happen

Answer 36

when both Na+ and glucose are bound, or if nothing is bound.

Question 37

Antiporter

Answer 37

molecules moving in opposite directions

Question 38

metabolism

Answer 38

sum of all chemical reactions in a biological entity: energy metabolism and oxidative metabolism

Question 39

energy metabolism

Answer 39

breaking down carbon fuels and making energy in the form of ATP. Transferring energy into a usable form–ATP

Question 40

Glycolysis

Answer 40

Uses substrate level phosphorylation to produce ATP. Involves redox rxn wherein oxidation of a metabolic intermediate is coupled to the reduction of NAD+–>NADH (put an electron on it)

Question 41

Glycolysis must reduce

Answer 41

NAD+–>NADH to continue. NAD+ is the limiting factor for glycolysis