Biology Review: Macromolecules, Cell Biology, Microorganisms, and Metabolism (Video Notes)

Vocabulary flashcards covering core terms and definitions from the lecture notes on macromolecules, cell biology, metabolism, and microorganisms.

Carbohydrates

Macromolecule made of sugar monomers (C, H, O); simple (ring-shaped) or complex; examples include bread, pasta, and fruits.

Lipids

Macromolecule composed of glycerol and fatty acids; contains C, H, O with fewer oxygens than carbohydrates; includes fats (solid) and oils (liquid).

Proteins

Macromolecule made of amino acids linked by peptide bonds; 20 amino acids; functions include enzymes, structure, transport, and signaling.

Nucleic Acids

DNA and RNA; polymers of nucleotides; store/transmit genetic information; DNA is double-stranded; RNA is usually single-stranded.

Dehydration synthesis

Bond formation between monomers with removal of a water molecule, creating covalent bonds (glycosidic, peptide, phosphodiester, ester).

Hydrolysis

Chemical reaction that adds water to break polymers into monomers.

Monomer

A single molecular unit that can join with others to form polymers.

Polymer

A large molecule made of many monomer units bonded together.

Primary structure (protein)

Linear sequence of amino acids in a polypeptide chain, held together by covalent bonds.

Secondary structure

Local folding of the polypeptide backbone into alpha helices or beta-pleated sheets via hydrogen bonds.

Tertiary structure

Three-dimensional folding of a protein due to interactions among R groups (ionic, covalent, H-bonds, van der Waals, hydrophobic).

Quaternary structure

Association of two or more polypeptide chains into a functional protein (e.g., dimers, tetramers).

Glycosidic bond

Covalent bond linking monosaccharides in carbohydrates.

Ester bond

Bond linking fatty acids to glycerol in lipids (not a polymer in lipids).

Peptide bond

Covalent bond linking amino acids in proteins.

Phosphodiester bond

Bond connecting nucleotides in nucleic acids.

Monosaccharides

Simple sugars (e.g., glucose, fructose, galactose) with general formula CH2O.

Disaccharides

Two monosaccharides linked together (e.g., lactose, sucrose, maltose).

Polysaccharides

Long chains of monosaccharides (e.g., starch, glycogen, cellulose, chitin, dextrans).

Triglycerides

Fats composed of glycerol bound to three fatty acids; can be saturated, unsaturated, or trans.

Saturated fat

Fat with no double bonds in fatty acids; typically solid at room temperature (e.g., butter).

Unsaturated fat

Fat with one or more double bonds in fatty acids; usually liquid at room temperature (e.g., olive oil).

Trans fat

Hydrogenated unsaturated fats with trans double bonds; often solid at room temperature.

Phospholipids

Lipids with a glycerol backbone, two fatty acids, and a phosphate-containing head; major component of membranes.

Steroids

Lipids with four fused rings; include cholesterol and various hormones.

Waxes

Lipids that provide protective coatings and water resistance.

Pigments

Molecules that produce color in cells and can participate in light absorption.

Eicosanoids & Prostaglandins

Lipid signaling molecules involved in inflammation, signaling, and other physiological processes.

Cholesterol

Sterol that modulates membrane fluidity and serves as a precursor for steroid hormones.

Amino acids

20 building blocks of proteins; each has an amino group, carboxyl group, and side chain.

Nucleotides

Monomers of nucleic acids consisting of a sugar, phosphate group, and a nitrogenous base.

DNA

Deoxyribonucleic acid; stores genetic information; double helix; bases A, T, C, G.

RNA

Ribonucleic acid; transfers genetic information and helps synthesize proteins; bases A, U, C, G; usually single-stranded.

Dehydration synthesis (polymers)

Reaction that links monomers to polymers by removing water; forms covalent bonds.

Hydrolysis (polymers)

Reaction that breaks polymers into monomers by adding water.

Glycosidic linkages

Bonds linking monosaccharides in carbohydrates.

Ester bonds (lipids)

Bonds linking fatty acids to glycerol in triglycerides.

Peptide bonds

Bonds linking amino acids in proteins.

Phosphodiester bonds

Bonds linking nucleotides in nucleic acids.

Microscopic energy carriers (NAD+, NADH, FAD, FADH2)

Electron carriers that shuttle electrons during metabolism.

Oxidation

Loss of electrons in a chemical reaction.

Reduction

Gain of electrons in a chemical reaction.

OIL RIG

Oxidation is Loss of electrons; Reduction is Gain of electrons.

ATP

Adenosine triphosphate; main energy currency of the cell; produced by substrate-level phosphorylation and chemiosmosis.

Glycolysis

Glucose breakdown in the cytosol to pyruvate, yielding ATP and NADH.

Pyruvate oxidation

Pyruvate is converted to acetyl-CoA in the mitochondria, producing NADH and CO2.

Citric acid cycle (Krebs)

Metabolic cycle in mitochondria that oxidizes acetyl-CoA to CO2, producing NADH, FADH2, and ATP.

Electron transport chain (ETC)

Series of protein complexes in membranes that transfer electrons and pump protons to create a gradient for ATP synthesis.

ATP synthase

Enzyme that uses the proton gradient to convert ADP and Pi into ATP (chemiosmosis).

Aerobic respiration

Metabolic pathway using O2 as the final electron acceptor; yields ~30–38 ATP per glucose.

Anaerobic respiration

Respiration using non-oxygen final electron acceptors; yields less ATP than aerobic respiration.

Fermentation

ATP production via glycolysis only; regenerates NAD+; yields 2 ATP per glucose; lactate or ethanol byproducts.

Plasma membrane

Phospholipid bilayer that encloses cells; regulates transport and communicates with the environment.

Phospholipid bilayer

Two layers with hydrophilic heads outward and hydrophobic tails inward.

Membrane proteins

Proteins embedded in or associated with the membrane; include integral, peripheral, and lipid-anchored proteins.

Cholesterol (membrane)

Lipids that regulate membrane fluidity.

Glycoproteins & Glycolipids

Proteins and lipids with carbohydrate chains; involved in cell recognition.

Diffusion

Passive movement of molecules from high to low concentration across the membrane without ATP.

Osmosis

Diffusion of water across a semipermeable membrane along water concentration gradients.

Facilitated transport

Passive transport via carrier proteins or channels; requires no ATP.

Uniporter

Carrier protein that transports a single type of molecule in one direction.

Symporter

Carrier protein that transports two or more molecules in the same direction.

Antiporter

Carrier protein that transports two or more molecules in opposite directions.

Primary active transport

Active transport that uses ATP directly to move solutes against their gradient.

Secondary active transport

Active transport powered by an existing gradient, not direct ATP hydrolysis.

Na+/K+ pump

Pumps Na+ out and K+ in to maintain ion gradients essential for nerve and muscle function.

Endocytosis

Bulk intake of material by infolding of the cell membrane to form a vesicle.

Exocytosis

Export of material from the cell via vesicle fusion with the plasma membrane.

Endomembrane system

Interconnected membranes (nucleus, ER, Golgi, lysosomes, vesicles) that synthesize and transport cellular products.

Rough ER (RER)

ER with ribosomes; synthesizes and sorts glycoproteins.

Smooth ER (SER)

ER without ribosomes; lipid synthesis and detoxification processes.

Golgi apparatus

Organelle that sorts, tags, modifies, and packages proteins for secretion or delivery to organelles.

Lysosomes

Membrane-bound organelles containing hydrolytic enzymes for macromolecule digestion.

Peroxisomes

Organelles that break down fatty acids and detoxify harmful substances; contain catalase.

Ribosomes

Ribosomal RNA-protein complexes; site of protein synthesis; 70S in bacteria, 80S in eukaryotes.

Nucleus

Double-membrane-bound organelle containing the cell’s genetic material; contains chromatin and nucleolus.

Nucleolus

Nuclear region where ribosomal RNA (rRNA) synthesis and ribosome assembly occur.

Mitochondria

Organelles with double membrane; inner membrane folding into cristae; site of ATP production via respiration.

Cristae

Folded inner mitochondrial membranes that increase surface area for the electron transport chain.

Matrix

Space inside the mitochondrial inner membrane where Krebs cycle enzymes reside.

Cytoskeleton

Network of protein filaments (microtubules, intermediate filaments, microfilaments) that provide shape and movement.

Cilia & Flagella (9+2)

Hair-like organelles used for movement; arranged as nine doublets around a central pair in most eukaryotes.

Extracellular matrix (ECM)

Network outside the cell composed of collagen, elastin, fibronectin; provides support and signaling.

Tight junctions

Cell–cell junctions that seal gaps between cells to prevent leakage.

Desmosomes (adhesion junctions)

Spot welds that anchor cells together, providing mechanical strength.

Gap junctions

Channels that allow direct passage of ions and small molecules between neighboring cells.

Basal membrane components and integrins

Proteins and glycoproteins that connect cells to the ECM and participate in signaling.

Bacteria vs Archaea (key distinctions from notes)

Archaea are extremophiles with unique membrane lipids and cell-wall components; more closely related to eukaryotes in some aspects; distinct rRNA sequences.

Gram-positive cell wall

Thick peptidoglycan layer; teichoic acids; stains purple with Gram stain.

Gram-negative cell wall

Thin peptidoglycan layer plus an outer membrane containing lipopolysaccharides (LPS); stains pink/red after Gram stain.

Capsule / Glycocalyx

Protective extracellular layer; capsule is dense and sticky; slime layer is looser; aids in attachment and immune evasion.

Fimbriae & Pili

Filamentous structures on bacteria used for attachment (fimbriae) and genetic exchange (pili).

Endospores

Dormant, highly resistant bacterial cells formed under nutrient limitation; examples include Bacillus and Clostridium species.

Bacterial shapes

Cocci (spherical), bacilli (rod-shaped), vibrio (curved), spirillum (spiral), spirochete (flexible spiral).

Bacterial arrangements

Single, diplococci, streptococci (chains), staphylococci (clusters), tetrads, sarcina (packet).

Bacterial motility structures

Flagella drive movement; pili and nanotubes can also contribute to movement and distant interactions.

Virion

Fully formed, infectious viral particle capable of initiating infection.

Capsid

Protein shell encasing the viral genome.

Enveloped vs Naked viruses

Enveloped viruses have a host-derived lipid envelope; naked viruses lack an envelope.

Viral spikes

Proteins on the virus surface that mediate attachment to host cells.