Biochemistry Quiz & Flashcards

A peptide bond is a covalent bond that links amino acids, forming proteins.

Ribonuclease degrades RNA by catalyzing the hydrolysis of phosphodiester bonds.

ATP is the main energy currency, providing energy for cellular processes.

Amylase catalyzes the breakdown of starch into simple sugars like maltose.

The alpha helix is a common secondary structure formed by hydrogen bonds in proteins.

Disulfide bridges are covalent bonds that stabilize the tertiary structure by linking cysteine residues.

NAD+ acts as an electron carrier, accepting and transferring electrons during metabolic reactions.

Enzymes exhibit specificity, meaning they selectively bind to their substrates.

Competitive inhibitors bind to the active site, blocking substrate access and reducing enzyme activity.

Nucleotides consist of a sugar, phosphate group, and nitrogenous base, but not an amino acid.

Enzymes lower the activation energy, making it easier for reactions to occur.

tRNA transfers specific amino acids to the ribosome during protein synthesis.

Phospholipids form the lipid bilayer of cell membranes, providing structural integrity.

A misconception is that enzymes are consumed in reactions, while they actually remain unchanged.

Non-competitive inhibitors bind to allosteric sites, affecting enzyme activity without blocking the active site.

DNA contains deoxyribose sugar, while RNA contains ribose sugar and is usually single-stranded.

Feedback inhibition occurs when the end product of a pathway inhibits an early enzyme in the pathway.

Chaperone proteins help other proteins fold properly, preventing misfolding and aggregation.

NADH acts as an electron carrier, transferring electrons in metabolic processes like the Krebs cycle.

Ligases catalyze the joining of two molecules, often requiring ATP, such as in DNA ligation.

Saturated fatty acids have no double bonds between carbon atoms, making them solid at room temperature.

RNA polymerase transcribes DNA into RNA, an essential step in gene expression.

Proteins, specifically enzymes, are responsible for catalyzing biochemical reactions in cells.

Glycosidic bonds link monosaccharide units to form disaccharides and polysaccharides.

Anabolic reactions involve the synthesis of complex molecules from simpler ones, requiring energy input.

Nucleic acids are composed of a sugar, phosphate group, and nitrogenous bases, but not glycerol.

Temperature changes can increase or decrease enzyme activity by affecting reaction rates and enzyme stability.

Hemoglobin is responsible for transporting oxygen from the lungs to tissues and carbon dioxide back to the lungs.

Enzyme specificity is determined by the shape and chemical properties of its active site, which matches the substrate.

Hydrolysis reactions involve breaking bonds in molecules using water, typically splitting polymers into monomers.

Phospholipids are crucial components of cell membranes, forming the lipid bilayer that separates cell compartments.

Disulfide bridges are covalent bonds that stabilize the three-dimensional structure of proteins by linking cysteine residues.

Glycolysis is the metabolic process that breaks down glucose into pyruvate, generating ATP and NADH.

The tertiary structure of proteins is determined by interactions between side chains, creating a three-dimensional shape.

Denaturation involves the loss of a protein's functional shape due to the disruption of bonds and interactions.

Allosteric sites are regulatory sites where molecules can bind to modulate enzyme activity, often changing its shape.

Coenzyme A (CoA) is a common coenzyme that assists in metabolic reactions, particularly in the Krebs cycle and fatty acid metabolism.

Hydrogen bonds stabilize the base pairing between nucleotides in DNA and RNA, maintaining the double helix structure.

Oxidative phosphorylation is the process by which ATP is generated using the energy from electron transport chains and proton gradients.

Enzymes are proteins that act as biological catalysts, facilitating chemical reactions in living organisms.

Phosphodiester bonds link nucleotides together in a chain, forming the backbone of DNA and RNA molecules.

The active site of an enzyme is where substrates bind and the chemical reaction occurs, determining enzyme specificity.

Transcription is the process by which RNA is synthesized from a DNA template, producing messenger RNA (mRNA).

Coenzymes assist enzymes by transferring chemical groups between molecules, facilitating enzymatic reactions.

The lock and key model suggests that enzymes and substrates have specific complementary shapes that fit perfectly.

Carbohydrates provide energy through the breakdown of glucose and other sugars in cellular respiration.

NADP+ serves as the primary electron acceptor in photosynthesis, accepting electrons to form NADPH.

Hydrogen bonds between complementary base pairs hold the two strands of DNA together in a double helix.

Unsaturated fatty acids contain one or more double bonds between carbon atoms, unlike saturated fatty acids.

Dehydration synthesis involves the removal of water molecules to form covalent bonds between monomers, creating polymers.

Pyruvate is the end product of glycolysis, representing a key intermediate in cellular respiration.

Cholesterol helps stabilize the fluidity of cell membranes, preventing them from becoming too rigid or too fluid.

The central dogma describes the flow of genetic information from DNA to RNA to protein synthesis.