Chemistry and Biochemistry for the Human Body (Video)

Flashcards cover core vocabulary from the lecture notes on matter, atoms, chemical bonds, vital biomolecules, and basic biochemistry concepts relevant to human physiology.

Matter

Anything that occupies space and has mass.

Mass

The amount of matter in an object; remains the same regardless of location.

Weight

Mass affected by gravity; varies with gravity.

Element

A pure substance that cannot be created or broken down by ordinary chemical means; defined by its number of protons.

Atom

The smallest unit of an element that retains the element’s properties.

Proton

Positively charged subatomic particle in the nucleus.

Neutron

Electrically neutral subatomic particle in the nucleus.

Electron

Negatively charged subatomic particle orbiting the nucleus; very small mass.

Atomic Number

Number of protons in an atom; identifies the element.

Mass Number

Sum of protons and neutrons in the nucleus.

Isotope

Atoms of the same element with different numbers of neutrons.

Radioisotope

Isotope that is radioactive and can decay, emitting energy.

Electron Shell

Regions around the nucleus where electrons reside at certain energy levels.

Valence Electron

Electrons in the outermost energy level involved in bonding.

Octet Rule

Most atoms are most stable with eight electrons in their valence shell (except H and He).

Ion

An atom or molecule with a net electric charge due to gain or loss of electrons.

Cation

Positively charged ion (has lost electrons).

Anion

Negatively charged ion (has gained electrons).

Ionic Bond

Bond formed by attraction between oppositely charged ions after electron transfer.

Covalent Bond

Bond formed by sharing electrons between atoms.

Hydrogen Bond

Weak bond between a hydrogen in one molecule and an electronegative atom in another.

Molecule

Two or more atoms held together by chemical bonds.

Salt

Compound formed by ionic bonding that dissociates into ions in water.

Electrolyte

Ions in solution that conduct electricity.

Acid

Substance that releases hydrogen ions (H+) in solution.

Base

Substance that releases hydroxide ions (OH−) or accepts H+ in solution.

pH

Negative base-10 logarithm of the hydrogen ion concentration; measures acidity/basicity.

Buffer

A solution of a weak acid and its conjugate base that minimizes pH changes.

Water

Universal solvent; polar molecule that dissolves many substances and participates in heat absorption and lubrication.

Hydrophilic

Water-loving; substances that readily dissolve in water.

Hydrophobic

Water-fearing; substances that do not dissolve well in water.

Solution

Homogeneous mixture where solute is uniformly distributed in solvent.

Colloid

Mixture with medium-sized particles that scatter light and are not fully dissolved.

Suspension

Mixture with larger particles that settle out over time.

Dehydration Synthesis

Monomers join to form polymers with the release of a water molecule.

Hydrolysis

Polymers are broken down by adding water; bonds are cleaved.

Monomer

Smallest unit that can join to form polymers.

Polymer

Long chain of monomers bonded together.

Carbohydrate

Organic compound: carbon, hydrogen, and oxygen in a roughly 2:1:1 ratio; includes sugars and starches.

Monosaccharide

Simple sugar; e.g., glucose, fructose, galactose (hexoses) and ribose, deoxyribose (pentoses).

Disaccharide

Two monosaccharides linked by a glycosidic bond; e.g., sucrose, lactose, maltose.

Polysaccharide

Polymers of monosaccharides; starch, glycogen, cellulose.

Glucose

A hexose sugar; primary energy source for many cells.

Lipid

Group of hydrophobic biomolecules mainly composed of hydrocarbons; includes fats, oils, phospholipids, steroids.

Triglyceride

Glycerol backbone + three fatty acids; major storage form of fat.

Phospholipid

Glycerol with two fatty acids and a phosphate-containing head; amphipathic (hydrophobic tails, hydrophilic head).

Sterol/Cholesterol

Sterol lipid with four-ring structure; important for membranes and hormone synthesis.

Prostaglandin

Signaling lipid derived from unsaturated fatty acids; regulates inflammation and other processes.

Protein

Large biomolecule composed of amino acids; performs structure, enzymes, signaling, and transport functions.

Amino Acid

Building blocks of proteins; have amino and carboxyl groups and a variable R-group; essential vs nonessential.

Peptide Bond

Covalent bond linking amino acids via dehydration synthesis.

Polypeptide

Chain of amino acids; shorter than a full protein.

Nucleic Acid

Biomolecule (DNA or RNA) that stores and transmits genetic information.

Nucleotide

Subunit of nucleic acids: one or more phosphate groups, a pentose sugar, and a nitrogenous base.

DNA

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

RNA

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

Adenine

Purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA.

Cytosine

Pyrimidine base found in DNA and RNA; pairs with guanine.

Guanine

Purine base found in DNA and RNA; pairs with cytosine.

Thymine

Pyrimidine base found in DNA; pairs with adenine (RNA uses uracil instead of thymine).

Uracil

Pyrimidine base found in RNA; pairs with adenine.

Double Helix

Two DNA strands wound around each other; stabilized by hydrogen bonds between bases.

ATP

Adenosine triphosphate; main energy currency of the cell; energy released by hydrolysis of high-energy phosphate bonds.

ADP

Adenosine diphosphate; product of ATP hydrolysis; can be re-phosphorylated to ATP.

AMP

Adenosine monophosphate; product of further ATP hydrolysis; participates in energy metabolism.

Amino Acid Pool

Reservoir of free amino acids available for protein synthesis.

Denaturation

Unfolding of a protein’s structure, often causing loss of function due to heat, pH change, or chemicals.

Enzyme

Biological catalyst (often a protein) that speeds up chemical reactions by lowering activation energy.

Substrate

Substance that binds to an enzyme’s active site during a reaction.

Active Site

Region of an enzyme where the substrate binds.

Induced Fit

Model where the enzyme changes shape slightly to fit the substrate better during binding.

DNA vs RNA Roles

DNA stores genetic information; RNA transcribes/helps translate genetic information into proteins.