BIO 114 Study Guide Flashcards

Saturated vs. Unsaturated Lipids

• Saturated lipids:
  • All carbon molecules with single bonds.
  • Animal origin.
• Unsaturated lipids:
  • Carbons bonded with double/triple bonds.
  • Plant origin (e.g., olive, sunflower).

Denaturation

• Breakdown of polypeptide/protein structure.
• Leads to loss of function.
• Causes: Heat, light, salt, acid, base (e.g., egg white).

Cell Structure (Eukaryotes)

• Golgi apparatus: Packaging/deployment, vesicle formation (secretory and transitory).
• Nucleus:
  • Double membrane with nuclear pores.
  • Contains genetic material.
• Rough Endoplasmic Reticulum (RER): Protein synthesis.
• Smooth Endoplasmic Reticulum (SER): Lipid synthesis.
• Ribosomes: Site of protein synthesis (70\% protein, 30\% rRNA).
• Mitochondrion:
  • Double membraned.
  • Produces energy.
• Lysosomes: Digestive enzymes/housekeepers.
• Peroxisomes: Break down peroxides.
• Chloroplasts:
  • Double membraned.
  • Photosynthesis occurs here.
  • Grana (thylakoid membranes).
  • Stroma and lamellae.
• Cytoskeleton:
  • Filaments: actin (microfilaments), intermediate filaments, microtubules.
• Centrioles: 9 triplets microtubule arrangement + 0.
• Flagellum: 9 doublets + 2; mobility.
• Cilia: 9 doublets + 2; mobility (e.g., paramecium), stereocilia.
• Basal body: (9 + 0).
• Cell wall: Present in plants.

Fluid Mosaic Model of Plasma Membrane

• Phospholipid bilayer with embedded proteins.
  • Fluid: phospholipid bilayer.
  • Mosaic: embedded protein.
• Hydrophilic: Water-loving portion of the plasma membrane.
• Hydrophobic: Water-fearing portion of the plasma membrane.
• Semi-permeable membrane/selectivity.
• Plasma membrane = cytomembrane = cytolemma.

Types of Embedded Proteins

• Channel: Facilitates transport.
• Cell recognition: Histocompatibility.
• Carrier: Facilitates transport.
• Receptor: Combines with molecules based on shape and size.
• Enzymes: ATP synthetase.
• Signal transduction.
• Sodium-potassium pump: Involved with active transport.

Solutions

• Solvent: Liquid that dissolves a solute (e.g., salt).
• Solute: Substance dissolved by the solvent (e.g., salt, sugar).
• Solution: Homogeneous mixture of solvent and solute.

Tonicity

• Isotonic Solution:
  • Rate of movement across the membrane (solvent or solute) is in equilibrium.
  • No overt change in cell volume.
• Hypotonic Solution:
  • Less solute outside the cell.
  • Cell swells (takes up water).
  • Volume changes, and cell may lyse.
• Hypertonic Solution:
  • More solute outside the cell.
  • Cell releases water.
  • Volume changes, cell may shrivel, break up, and die.
  • Apoptosis: programmed cell death.
• Dialysis membrane: size constraints determine what passes through.

Transport

• Active process: Requires energy (ATP); e.g., sodium-potassium pump.
• Passive process: Does not require energy.
  • Diffusion: High concentration to low concentration.
  • Facilitated transport across the membrane.
  • Osmosis: Diffusion of water.

Molecular transport

• Exocytosis: Large molecules secreted into the external environment via secretory vesicles.
• Endocytosis: Small ions, small molecular weight compounds along with liquid surrounded by membrane form a vesicle inside the cell.
  • Pinocytosis: Cell drinking.
  • Phagocytosis: Cell eating.

Diffusion and Osmosis

• Diffusion: Movement across a membrane from high to low concentrations (down a concentration gradient).
• Osmosis: Movement of water across a membrane from high water concentration to low water concentration.

Cell Junctions

• Gap junctions: Allow flow of ions.
• Anchor/Intermediate junctions: Involved in tissue formation.
• Tight junctions: Prevent leakage.
• Plasmodesmata: Channels in plant cells.

Metabolism

• Catabolism: Break down (digestive processes).
• Anabolism: Synthesis.

Enzymes

• Substrate: Reactant/metabolite that becomes a product: S + E \rightarrow E-S complex \rightarrow P + E
• Enzyme: Protein catalyst.
• Active Site: Where substrate binds to enzyme and is converted to product.
  • Lock and key theory
• Inhibition:
  • Competitive inhibition: Chemical looks like the natural substrate and can bind to the active site.
  • Non-competitive inhibition: Chemical binds at another site (allo) and changes the 3D structure of the enzyme; seen with feedback inhibition (A -> B -> C -> D -> E).
• Coenzyme: Organic molecules.
• Cofactors: Ions and coenzymes.

Thermodynamics

• First law of thermodynamics:
  • Energy cannot be created or destroyed.
  • Total energy of the universe is constant.
  • Law of conservation of energy.
• Second law of thermodynamics:
  • Energy can transform from one form to another (e.g., light to chemical).
  • Transformation isn't 100% efficient.

Redox

• Oxidation: Lose electrons (lose H ion): NADH \rightarrow NAD + 2e + H^+
• Reduction: Gain electrons (gain H ion).

Gibbs Free Energy

• Exergonic: Release of energy (\Delta G < 0, spontaneous).
• Endergonic: Need energy (\Delta G > 0, non-spontaneous).

Enthalpy

• Exothermic: Release heat (\Delta H < 0).
• Endothermic: Require heat (\Delta H > 0).

Factors Affecting Enzyme Activity

• Temperature (T), pH, substrate concentration ([S]), heavy metals (inhibit).
• Optimal T, pH, substrate concentration.
• Bell-shaped curve.

ATP

• Structure: Adenine, sugar, 3 phosphates.
• Function: Provides energy.

Cycles

• Coupled reactions: think cycles; think exchange of electrons; think exchange of energy.

Photosynthesis

• Fixing carbon: light reactions (PSI: make NADPH, ATP; PSII: make ATP) and dark reactions (Calvin Cycle): fix carbon dioxide ---> make sugar!!!
• Water, electrons, sunlight, chlorophyll, NADP+, hydrogen.

Chemical Bonds

• Covalent bonding:
  • Sharing valence (outer-shell) electrons.
  • Octet rule.
• Ionic bonding: Attraction between positive and negative ions.
• Non-bonding associations:
  • Hydrogen bonding: between H and an electronegative element (e.g., water).
  • Dipole-dipole interaction: molecule has a positive and negative end.
  • Van der Waals: weaker.

Functional Groups

• -CH, -OH, O=C-, -NH_2, -POH, -COOH

Dehydration vs Hydrolysis

• Dehydration: Removing water to MAKE a bond (anabolic/synthesize larger molecules).
• Hydrolysis: Breaking a bond with water (polymer + H_2O \rightarrow monomers; catabolic ->break down larger molecules).

Biomolecules

• Carbohydrates: Glucose = monomer/monosaccharide; glycogen (in animals), starch (in plants): polysaccharides (storing energy, structure: think cellulose, chitin).
• Lipids: Material that does not dissolve in water; fatty acids and glycerol; stored form of energy, also contributes to phospholipids (membrane), cholesterol, steroids (hormones).
  • Hydrocarbon tail (non-polar) -> Hydrophobic
  • Polar head (contains O, N, P) -> Hydrophilic
• Proteins: Monomers: 20 amino acids; polymers.
  • Four levels of structure:
    • Primary: Specific amino acid sequence
    • Secondary: Alpha helix, beta-pleated sheet
    • Tertiary: 3-D shape/folding into a functional polypeptide
    • Quaternary: 2 or more polypeptides in association (collagen, hemoglobin)
  • Function: enzyme, support, actin and myosin, antibody
• Nucleic Acids:
  • DNA (double stranded, deoxyribose sugar, ATCG) - contain the blueprints to make polypeptides
  • RNA (single stranded, ribose sugar, AUCG) – mRNA, tRNA (carries an amino acid), rRNA (made in the nucleolus)