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\%$$$70\%$$ protein, $30\%$$$30\%$$ 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$$$9$$ triplets microtubule arrangement $+ 0$$$+ 0$$.

• Flagellum: $9$$$9$$ doublets $+ 2$$$+ 2$$; mobility.

• Cilia: $9$$$9$$ doublets $+ 2$$$+ 2$$; mobility (e.g., paramecium), stereocilia.

• Basal body: $(9 + 0)$$$(9 + 0)$$.

• 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$$$S + E \rightarrow E-S complex \rightarrow P + E$$

• 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^+$$$NADH \rightarrow NAD + 2e + H^+$$

• Reduction: Gain electrons (gain H ion).

Gibbs Free Energy

• Exergonic: Release of energy ($\Delta G < 0$$$\Delta G < 0$$, spontaneous).

• Endergonic: Need energy ($\Delta G > 0$$$\Delta G > 0$$, non-spontaneous).

Enthalpy

• Exothermic: Release heat ($\Delta H < 0$$$\Delta H < 0$$).

• Endothermic: Require heat ($\Delta H > 0$$$\Delta H > 0$$).

Factors Affecting Enzyme Activity

• Temperature (T), pH, substrate concentration $([S])$$$([S])$$, heavy metals (inhibit).

• Optimal T, pH, substrate concentration.

• Bell-shaped curve.

ATP

• Structure: Adenine, sugar, $3$$$3$$ 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$$$-CH$$, $-OH$$$-OH$$, $O=C-$$$O=C-$$, $-NH_2$$$-NH_2$$, $-POH$$$-POH$$, $-COOH$$$-COOH$$

Dehydration vs Hydrolysis

• Dehydration: Removing water to MAKE a bond (anabolic/synthesize larger molecules).

• Hydrolysis: Breaking a bond with water (polymer $+ H_2O \rightarrow$$$+ H_2O \rightarrow$$ 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$$$20$$ amino acids; polymers.

  • Four levels of structure:

    • Primary: Specific amino acid sequence

    • Secondary: Alpha helix, beta-pleated sheet

    • Tertiary: $3$$$3$$-D shape/folding into a functional polypeptide

    • Quaternary: $2$$$2$$ 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)