Biology Exam 2 Review

phospholipid bilayer

double layer of phospholipids that make up the cell membrane

membrane interior

fatty acids (hydrophobic, nonpolar) facing inward & interacting via Van der Waal forces

membrane exterior

phosphate group heads (hydrophilic, polar) facing away from each other

liposomes

spherical lipid bilayers with an internal aqueous compartment and a hydrophobic layer in the middle

micelles

single-layer structures with a hydrophobic core and a hydrophilic exterior

bilayer sheet

basic structural arrangement of the cell membrane before curving into a closed shape

cell membrane structure

semipermeable; nonpolar region bigger than polar region (harder to get through)

small molecules = pass easily

polar molecules & ions: need protein help to cross

cholesterol

in the cell membrane; regulate membrane fluidity

low temperatures = increased fluidity, preventing crystalization

high temperatures = decreased fluidity, preventing membrane from letting everything through

channel proteins

proteins that form pores to let specific ions or molecules cross the membrane by facilitated diffusion

carrier proteins

proteins that bind a molecule, change shape, and release it on other side of the membrane

receptor proteins

proteins that detect signals and trigger a response inside the cell

enzymes

proteins that speed up chemical reactions at or near the membrane

anchor proteins

proteins that attach to the interior or exterior of the cell membrane for stability

protein pumps

proteins that actively move ions or molecules across the membrane using energy (ATP)

passive transport

uses energy found in a molecule’s electrochemical gradient to move itself; requires no external energy for transport

simple & facilitated diffusion

simple diffusion

moves down an electrochemical gradient; goes through the lipid bilayer alone; no protein help

facilitated diffusion

moves down an electrochemical gradient; requires a transport protein

active transport

requires an external addition of energy to facilitate transport ffor a molecule up/against its gradient

primary & secondary

primary active transport

involves use of ATP to provide energy for proteins to pump molecules or ions against their concentration gradient

secondary active transport

uses an existing concentration gradient to move another molecule

transported solute

moves with concentration gradient

coupled ion

moves against concentration gradient

endergonic

requires an input of energy; nonspontaneous

exergonic

releases energy; spontaneous

catabolic

breaks down molecules to release energy

anabolic

builds molecules and requires energy

nonspontaneous

requires energy input to occur

spontaneous

occurs without energy input

hydrolysis

breaks bonds by adding water

dehydration synthesis

forms bonds by removing water

exergonic, spontaneous, catabolic, hydrolysis

endergonic, nonspontaneous, anabolic, dehydration synthesis

ATP

cellular energy currency; can directly energize proteins in PAT; can energize cellular processes through energy coupling

ATP hydrolysis

spontaneous reaction that breaks off phosphate group from ATP; negative ΔG = reaction releases free energy

michales-menten model

graph used to show the rate of an enzyme reaction based on substrate concentration

Km

the substrate concentration at which we have reached half of the maximum velocity

Vmax

the maximum rate of the reaction that can be achieved with a given amount of enzymes

competitive inhibition

binds active site; ↑ Km, Vmax same; substrate increased to reach Vmax

noncompetitive inhibition

binds allosteric site; Vmax ↓, Km same; enzyme activity reduced

speeds up reaction

head, increasing substrate concentration, increasing enzyme concentration

slows/stops reaction

low temperatures (molecules not moving fast enough), denaturation, unsuitable pH, mutations, competitive & allosteric inhibitors

metabolism

a series of net catabolic reactions that transfer energy carrying electrons to NAD⁺ and FAD, driving ATP production

oxidation in metabolism

glucose losing electrons as its broken into smaller molecules

NADH and FADH₂ donating electrons in the electron transport chain and becoming NAD + and FAD

reduction in metabolism

NAD+ and FAD accepting electrons lost and becoming NADH and FADH₂

substrate level phosphorylation

enzymes transfer a phosphate group directly to ADP to make ATP

oxidative phosphorylation

uses ATP synthase and an electron transport chain to produce large amounts of ATP

6 carbons

glucose

3 carbons

pyruvate

acetyl-CoA

2 carbons

1 carbon

CO₂

electron carriers

NAD+ and FAD (oxidized); NADH and FADH₂ (reduced)

glycolysis

the oxidation of glucose into pyruvate, occurs in cytoplasm

pyruvate oxidation

the oxidation of pyruvate into acetyl CoA, occurs in mitochondrial matrix

oxidative phosphorylation

transfer of electrons from NADH and FADH2 through protein complexes in the inner mitochondrial membrane; releases energy to make large amounts of ATP

electron transport chain

set of proteins in the inner mitochondrial membrane where NADH and FADH2 are oxidized and electrons move through complexes

complex I

NADH is oxidized back to NAD+; transfers electrons and pumps protons

complex II

FADH₂ is oxidized back to FAD

complex III

transfers electrons and pumps proteins

complex IV

transfers electrons to oxygen (final electron acceptor), forms water, and pumps protons

mitochondrial matrix

innermost space of the mitochondria where pyruvate oxidation + citric acid cycle takes place

inner mitochondrial membrane

the folded membrane where the electron transport chain + ATP synthase are located, producing ATP

proton motive force (PMF)

a gradient of protons in the inner membrane space that want to go back into the matrix

final electron acceptor

oxygen, which receives electrons at complex IV and forms water

purpose of the ETC

to create the proton motive force

ATP synthase

enzyme that uses the proton gradient to produce ATP

function: spins like a turbine to power the conversion of ADP + phosphate into ATP