Kaarten: Cell Biology - Chapter 2: Cell Chemistry and Bioenergetics | Quizlet

noncovalent attractions

- hydrogen bonds

- electrostatic attractions (ionic bonds)

- van der Waals attractions

- hydrophobic force

effect of water on noncovalent bonds

presence of water REDUCES strength of ion and hydrogen bonds

acids

substances that release hydrogen ions when dissolved in water

bases

proton acceptors

buffers

mixtures that can react with acids or bases to keep the pH within a particular range

four major families of small organic molecules

sugars, fatty acids, amino acids, nucleotides

sugars form

polysaccharides

fatty acids form

lipids

amino acids form

proteins

nucleotides form

nucleic acids (DNA and RNA)

condensation reaction

a reaction in which two molecules become covalently bonded to each other through the loss of a small molecule, usually water; also called dehydration reaction

hydrolysis

breaking down complex molecules by the chemical addition of water

covalent bond gives

flexibility to the molecule (many conformations)

noncovalent bond gives

one preferred conformations (thus specifies binding to other molecules)

catalysts

substances that speed up chemical reactions

enzymes

proteins that act as biological catalysts

ribozymes

RNA molecules that function as enzymes

catabolic pathways

release energy by breaking down complex molecules into simpler compounds (oxidation)

anabolic (biosynthetic) pathways

consume energy to build complex molecules from simpler ones

metabolism

catabolic and anabolic reactions in a cell

aerobic respiration

cell obtains energy from sugars

complementary process to aerobic respiration

photosynthesis

substrates

the specific reactants that an enzyme acts on

diffusion

movement of molecules from an area of higher concentration to an area of lower concentration

change in free energy equation

ΔG = ΔG° + RTln([X]/[Y])

ΔG less than 0

favorable reaction

ΔG bigger than 0

unfavorable reaction

overall free energy change of the reaction must be

negative

carrier molecules (coenzymes)

store energy in energy-rich covalent bonds

ATP (adenosine triphosphate)

high-energy phosphoanhydride bond

ADP to ATP (energetically unfavorable)

phosphorylation - binding of an inorganic P

ATP to ADP (energetically favorable - no repulsion between adjacent negative charges)

hydrolysis - loss of an inorganic P

condensation reaction with ATP makes

a high-energy intermediate compound

high energy electron carriers

NADH, NADPH

NAD+

nicotinamide adenine dinucleotide

NADP+

nicotinamide adenine dinucleotide phosphate

NADH

the reduced form of NAD+; an electron-carrying molecule that binds to enzymes that catalyze catabolic reactions

NADPH

the reduced form of NADP+; an electron-carrying molecule that binds to enzymes that catalyze anabolic reactions

other activated carrier molecules

coenzyme A, FADH2, carboxylate biotin, S-Adenosylmethionine, uridine diphosphate glucose

alternative pathway of ATP hydrolysis

ATP ---> AMP + pyrophosphate ---> AMP + 2 Pi

head polymerization

proteins and fatty acids; each monomer carries a high energy bond that will be used for the addition of the NEXT monomer

tail polymerization

DNA, RNA, polysaccharides; each monomer carries a high-energy bond for its OWN addition

glycolysis

oxidation of sugars; net products are 2 ATP and 2 NADH

aerobic cells transport pyruvate to

mitochondria (oxidation to CO2 and H2O)

glycolysis reaction

glucose + 2 NAD+ 2 ADP + 2 Pi ---> 2 pyruvate (3C) + 2 NADH + 2 H+ + 2 net ATP

fermentation (anaerobic respiration)

pyruvate and NADH stay in the cytosol ---> ethanol + CO2 (yeasts) or lactate (muscle)

triacylglycerols

storage form of fatty acids

adipocytes

fat cells storing fatty acids in the form of triacylglycerols in their cytosol

glycogen

storage form of glucose in animals (short term storage)

starch

storage form of glucose in plants

Fat and starch are both stored in _______ in plants.

chloroplasts

degradation of pyruvate (by dehydrogenase complex)

CO2 + NADH + acetyl CoA

oxidation of fatty acids (takes place in mitochondria)

acetyl CoA + FADH2 + NADH

Krebs Cycle (Citric Acid Cycle)

complete oxidation of acetyl groups' carbon atoms in acetyl CoA into CO2

oxaloacetate and alpha-ketoglutarate

vital intermediates produced in the citric acid cycle and glycolysis

Electron Transport Chain (ETC)

series of electron carrier proteins that shuttle high-energy electrons during ATP-generating reactions

nitrogen cycle

the transfer of nitrogen from the atmosphere to the soil, to living organisms, and back to the atmosphere

animals acquire sulfur through

diet

plants, bacteria, fungi can _________ sulfate

reduce