BIOG 1440 - Prelim 1

Hydrogen bonding

Strong intermolecular interaction between H and O due to partial positive H and strong electronegativity on O

Hydrophobic effect

Nonpolar molecules seperate from polar molecules because they are not entropically favourable to interact

Homeoviscous adaptation

The ability for a membrane to become more or less viscous via negative feedback and adjusting the amount of lipids; e.g., DesK protein in B. subtilis

Fluid mosaic model

The concept that a membrane must be able to be fluid

Unsaturated fat

Has a kink due to the hydrogen being removed (“unsaturated”) and therefore creating a double bond in fatty acid tail

Phospholipid

Phosphate group (-), glycerol, fatty acid tail

Enzyme functions in cell membrane

Cell-cell recognition; transport; joining (plasmodesmata, gap junctions); signal transduction

Aquaporins

Water passively diffuses through this protein channels in membrane

Osmosis

Passive diffusion of water from low concentration of solute to high through semipermeable membrane

Hypotonic

Less solute in solution; animal cell lyses, plant cell turgid

Hypertonic

More solute in solution; animal cell shrivels, plant cell plasmolyzes

Isotonic

Consistent concentration of solute inside and outside of cell; plant cell flaccid

Aquaporin

Transmembrane protein for facilitating the diffusion of water; present in mammals and E. coli; crucial in human kidney

Active Transport

Moving materials against (up) the concentration gradient, requiring energy (ATP, proton gradient, or exo/endocytosis)

Primary active transport

Directly use ATP to move particles against concentration gradient

Secondary active transport

Utilizes a protein gradient, or proton-motive force, to transport molecules against concentration gradient; especially prevalent in plants, fungi, bacteria; protons move alongside particles in cotransport; alternating access model

Na-K pump

Example for alternating access model; creates an electrochemical gradient/membrane potential important for cell/nerve signaling

Exocytosis

Removing many particles via golgi, vacuoles, and out of cell

Phagocytosis

Type of endocytosis that immune cells use to absorb problematic bacteria

Pinocytosis

Type of endocytosis absorbing water/fluids

Receptor-mediated Endocytosis

Performing endocytosis only when certain antibodies are present/signalled.

Symporters

Particles (nutrients) that move with protons during proton-motive force transport

Antiporters

Particles that move against protons during proton-motive force

Carrier protein

Used to facilitate diffusion for alternating access model

Channel protein

Used to facilitate diffusion

Enzyme

A protein used to catalyze a reaction

Strategies of enzymes

Concentrate substrates, stabilize transition state, orientate substrates, facilitate active site

Induced fit

Shape of an enzyme changes only after substrates bind tightly

K_eq

Equilibrium constant [A][B]/[AB]

ΔG

Gibbs free energy; <0 is exergonic, >0 is endergonic

Catabolic reaction

Breaks down reactants, releases energy

Anabolic reaction

Combines reactants, uses energy

Allosteric enzyme site

Restrict enzyme activity by binding to site; common in feedback inhibition

Gycolysis

Glucose+O2+NAD=2 Pyruvate+NADH+2ATP in cytoplasm

Pyruvate oxidation

2 Pyruvate + 2CoA + 2NAD = 2 Acetyl CoA + 2 NADH + 2 CO₂ in mitochondrial matrix

Tricarboxylic Acid Cycle

2 Acetyl CoA + 6NAD⁺ + 2 FAD = 6 NADH + 2 FADH₂ + 4 CO2 in mitochondrial matrix

Oxidative phosphorylation

NADH+FADH₂+25ADP = 25 ATP + NAD⁺ + FAD + H₂O in inner mitochondrial membrane

Phototrophy

Obtain energy from light

Autotrophy

Generate their own energy

Heterotrophy

Cannot make its own food