Enzyme Regulation, Cell Transport, and Cell Structure: Biology Chapter 6-8

noncompetitive inhibitor

binds outside active site; changes shape

substrate

reactant molecule for enzyme

plasmolysis

plant cell shrinks from wall

receptor-mediated endocytosis

uptake via specific receptors

Sodium-potassium pump

active transport; pumps Na+ out, K+ in

selective permeability

only some molecules can pass

proton pump

active transport of H+ ions

tonicity

ability of solution to affect cell water balance

transport proteins

helps solute cross membrane

turgid

firm plant cell (hypotonic)

activation energy

energy needed to start a reaction

allosteric regulation

enzyme regulation at site other than active site

active site

enzyme region where substrate binds

anabolic pathway

builds molecules; requires energy

catabolic pathway

breaks down molecules; releases energy

catalyst

speeds up reactions without being consumed

chemical energy

energy stored in bonds

coenzyme

organic enzyme helper (vitamin)

cofactors

non-protein helper (metal ion)

competitive inhibitor

binds active site, blocks substrate

cooperativity

substrate binding increases activity at other sites

endergonic reaction

requires energy; ΔG > 0

enzyme

protein catalyst

enzyme-substrate complex

enzyme bound to substrate

exergonic reaction

releases energy; ΔG < 0

feedback inhibition

end product inhibits pathway

free energy (ΔG)

energy available to do work

induced fit

enzyme changes shape slightly to fit substrate

metabolic pathway

sequence of enzyme reactions

metabolism

total of all enzyme reactions

transport vesicle

carries molecules between organelles

vacuole

storage; central vacuole in plants (water, ions, waste)

vesicle

small transport/storage sac

active transport

requires energy; moves against gradient

amphipathic molecule

both hydrophobic and hydrophilic (phospholipid)

aquaporin

channel protein for water

concentration gradient

difference in solute concentration

cotransport

one solute's downhill movement drives another uphill

diffusion

passive spread of molecules

electrochemical gradient

gradient of ions (concentration + charge)

endocytosis

taking in molecules by vesicle

exocytosis

secretion by vesicles fusing with membrane

facilitated diffusion

passive transport via protein channels/carriers

flaccid

limp plant cell (isotonic)

fluid mosaic model

membrane structure of lipids, proteins, and carbs

gated channel

ion channel that opens/closes in response to stimuli

hypertonic

more solute; cell loses water

hypotonic

less solute; cell gains water

integral protein

penetrates bilayer

ion channel

protein allowing ions to cross

isotonic

equal solute; no net water movement

ligand

signaling molecule that binds receptor

membrane potential

voltage across membrane

osmoregulation

control of solute/water balance

osmosis

diffusion of water

passive transport

no energy needed

peripheral protein

loosely bound to membrane surface

phagocytosis

"cell eating"; engulfing particles

pinocytosis

"cell drinking"; fluids taken in

cell wall

rigid layer in plants, fungi, some prokaryotes; gives structure + protection

chloroplast

organelle for photosynthesis; has thylakoids, stroma, grana

chromatin

uncondensed DNA + protein in nucleus

chromosomes

condensed chromatin; has genetic info

cytoplasm

cytosol + organelles but nucleus

cytoskeleton

protein fibers (microtubules, microfilaments, intermediate filaments) that support, shape, + move cell

cytosol

semifluid in cytoplasm

electron microscopes

high-resolution microscope using electron beams

endomembrane system

has nuclear envelope, ER, golgi apparatus, lysosomes, vacuoles, plasma membrane

rough ER

protein synthesis

smooth ER

lipid synthesis, detox, carbohydrate storage

eukaryotic cell

has nucleus + membrane-bound organelles

extracellular matrix

glycoprotein-rich network in animal cells for signaling, support

gap junction

animal cell communication channel

glycoprotein

protein with carbohydrate chain; cell recognition/signaling

golgi apparatus

packages, sorts, ships proteins + lipids

light microscope

visible light; up to 1000x magnification

lysosome

digestive organelle with hydrolytic enzymes

mitochondria

site of cellular respiration + ATP production

nuclear envelope

double membrane around nucleus, with pores

nucleoid

DNA region in prokaryotes (no membrane)

nucleolus

dense region inside nucleus; makes rRNA + ribosome subunits

nucleus

stores DNA, directs cell activity

organelle

membrane-bound structure with specific function

plasma membrane

selective barrier; phospholipid bilayer

plasmodesmata

channels between plant cells

prokaryotic cells

lacks nucleus & organelles

ribosome

site of protein synthesis (free or bound)