bruh is failing- Fundamentals of Chemistry and Cell Biology

Isotopes

Atoms with the same number of protons but a different number of neutrons.

Radioisotopes

Unstable isotopes that decay over time, releasing radiation, which can be used in medical imaging or as tracers in biological systems.

Electron Arrangements

Electrons are arranged in energy levels around the nucleus, and the chemical behavior of an atom is determined by the number of valence electrons in the outermost shell.

Ionic Bonds

Formed by the transfer of electrons from one atom to another, resulting in oppositely charged ions (e.g., NaCl).

Covalent Bonds

Formed by the sharing of electrons between atoms; if the sharing is unequal, the bond is polar; if equal, it is nonpolar.

Molecular Polarity

Determined by the polarity of bonds and molecular geometry; molecules with polar bonds arranged asymmetrically are polar.

London Dispersion Forces

Weak attractions between all molecules, significant in nonpolar substances.

Dipole-Dipole Interactions

Occur between polar molecules.

Hydrogen Bonds

Strong dipole attractions involving hydrogen and electronegative atoms (N, O, F).

Dehydration Synthesis

Removal of water to bond monomers into polymers.

Hydrolysis

Addition of water to break bonds in polymers.

Neutralization

Reaction between an acid and a base to produce salt and water.

Redox Reactions

Involve the transfer of electrons; oxidation = loss, reduction = gain.

Cohesion

Attraction between water molecules (surface tension).

Adhesion

Attraction between water and other substances (capillary action).

High Specific Heat

Water resists changes in temperature, helping organisms regulate heat.

Solvent Properties

Water dissolves polar and ionic substances, making it the universal solvent.

Density

Ice is less dense than liquid water, which insulates aquatic ecosystems.

Aqueous Solutions

Hydrophilic substances dissolve in water; hydrophobic do not.

Ionization & pH

Water can self-ionize into H+ and OH-. pH measures hydrogen ion concentration on a logarithmic scale.

Acids/Bases

Acids donate H+; bases accept H+. Strong acids/bases ionize completely. Buffers minimize pH changes.

Macromolecule Structure

Carbohydrates are polymers made of monosaccharide monomers.

Carbon Backbone

Organic molecules are based on carbon skeletons that can form rings or chains.

Functional Groups

Common in carbohydrates include hydroxyl (-OH) and carbonyl (C=O).

Monosaccharides

Simple sugars like glucose and fructose.

Disaccharides

Two monosaccharides joined (e.g., sucrose, lactose).

Polysaccharides

Long chains (e.g., starch, glycogen, cellulose).

Glycosidic bonds

Form through dehydration synthesis.

Alpha linkages

Digestible linkages.

Beta linkages

Indigestible by humans.

Function of carbohydrates

Provide short-term energy and structural support in plants (cellulose) and animals (glycogen).

Characteristics of lipids

Insoluble in water, high energy storage molecules.

Triglycerides

Formed by glycerol bonded to three fatty acids.

Saturated Fats

No double bonds; solid at room temperature.

Unsaturated Fats

One or more double bonds; liquid at room temperature.

Trans Fats

Artificially hydrogenated unsaturated fats; unhealthy.

Phospholipids

Form cell membranes; hydrophilic head and hydrophobic tails.

Steroids

Lipids with four carbon rings; include hormones and cholesterol.

Proteins

Built from 20 amino acids linked by peptide bonds.

Structural levels of proteins

Primary (sequence), Secondary (helix/sheet), Tertiary (folded shape), Quaternary (multiple subunits).

Function of proteins

Enzymes, transport, structure, signaling.

Denaturation

Disrupts shape and function of proteins.

Nucleic Acids

Monomers: Nucleotides (phosphate, sugar, nitrogen base).

DNA

Double-stranded, stores genetic information.

RNA

Single-stranded, involved in protein synthesis.

Complementary base pairing

A-T (U in RNA), G-C.

Enzymes

Catalysts that speed up chemical reactions by lowering activation energy.

Active Site

Where the substrate binds; specificity via lock-and-key or induced fit.

Cofactors/Coenzymes

Non-protein helpers (e.g., vitamins, metal ions).

Enzyme Activity

Affected by temperature, pH, substrate concentration.

Competitive Inhibitors

Block active site.

Non-competitive Inhibitors

Bind elsewhere, changing shape of enzyme.

Allosteric Regulation

Enzyme activity controlled by molecules binding to sites other than the active site.

Feedback Inhibition

End product inhibits an earlier enzyme.

Mitochondria

Site of cellular respiration and ATP production.

Chloroplasts

Site of photosynthesis in plant cells.

Cell Membrane

Semi-permeable phospholipid bilayer with embedded proteins.

Integral Membrane Proteins

Span the membrane.

Peripheral Membrane Proteins

Attached to surface.

Transport Mechanisms

Passive: Simple diffusion, osmosis, facilitated diffusion; Active: Requires ATP; against concentration gradient; Bulk: Endocytosis (into cell), exocytosis (out of cell).

Tonicity

Isotonic: No net water movement; Hypertonic: Water leaves cell; Hypotonic: Water enters cell.