Biological Basics and Biochemistry

Flashcards covering the fundamentals of biology, including chemical bonds, molecular structures of macromolecules, enzyme kinetics, cell theory, and microscopy techniques.

Atom

The fundamental building block of matter composed of protons, neutrons, and electrons.

Molecule

A group of 2 or more atoms held together by chemical bonds.

Electronegativity

The ability of an atom to attract electrons.

Ionic bond

A chemical bond involving the transfer of electrons from atom to atom where both atoms have different electronegativities.

Covalent bond

A chemical bond involving electrons shared between atoms of similar electronegativities.

Non-polar covalent bond

A covalent bond involving equal sharing of electrons between two atoms of identical electronegativity.

Polar covalent bond

A covalent bond involving unequal sharing of electrons between two atoms of different electronegativities, leading to the formation of a dipole.

Hydrogen bond

A weak bond between molecules with a hydrogen attached to a highly electronegative atom ($F$, $O$, or $N$) that is attracted to a negative charge on another molecule.

High heat capacity

The property of water describing its ability to absorb a large amount of energy before changing temperature, also explaining high heat of vaporization.

Cohesion

The property of water describing its attraction to like substances and itself via hydrogen bonds.

Adhesion

The property of water describing its attraction to unlike substances, such as in capillary action.

Organic molecules

Molecules composed of carbon atoms.

Monomer

The simplest unit of a macromolecule.

Polymer

A structure formed by the linking of monomers.

Hydroxyl group

A polar and hydrophilic functional group with the chemical formula $-OH$.

Carboxyl group

A polar, hydrophilic, and weak acid functional group with the chemical formula $-COOH$.

Amino group

A polar, hydrophilic, and weak base functional group with the chemical formula $-NH_2$.

Phosphate group

A polar, hydrophilic, and acidic functional group with the chemical formula $(PO_4)^{3-}$.

Methyl group

A functional group with the chemical formula $-CH_3$.

Monosaccharide

A single sugar molecule, such as glucose or fructose.

Disaccharide

A two-sugar molecule joined by a glycosidic linkage, such as sucrose, lactose, or maltose.

Polysaccharide

A series of connected monosaccharides.

Dehydration synthesis

The chemical mechanism by which polymer bonds are formed.

Hydrolysis

The chemical mechanism by which polymer bonds are broken.

Starch

A polymer of alpha-glucose molecules used to store energy in plant cells.

Glycogen

A polymer of alpha-glucose molecules used to store energy in animal cells, differing from starch in polymer branching.

Cellulose

A polymer of beta-glucose that serves as a structural molecule for the walls of plant cells and wood.

Chitin

A structural molecule in insect exoskeletons and fungal cell walls consisting of beta-glucose groups with a nitrogen-containing group ($n\text{-acetylglucosamine}$) attached.

Triglycerides

Lipids consisting of three fatty acid chains attached to a glycerol backbone used for insulation and energy storage.

Saturated fatty acid

A triglyceride containing no double bonds and straight chains that stack densely to form fat plaques.

Unsaturated fatty acid

A triglyceride containing double bonds that cause kinks in the chains, preventing dense stacking.

Amphipathic

An expression for a molecule, like a phospholipid, that exhibits both hydrophobic and hydrophilic properties.

Steroids

Lipid derivatives containing three 6-membered rings and one 5-membered ring, including sex hormones and cholesterol.

Carotenoids

Lipid derivatives comprising fatty acid carbon chains with conjugated double bonds and six-membered C-rings at each end, including carotenes and xanthophylls.

Porphyrins

Lipid derivatives containing a 4 joined pyrrole ring that often complexes with a metal.

Brown fat cell

A specialized adipocyte with considerable cytoplasm, lipid droplets scattered throughout, and a high concentration of mitochondria.

Apoenzyme

An enzyme that is not currently combined with its necessary cofactor.

Holoenzyme

An enzyme that is active and combined with its cofactor.

Primary structure

The protein structure defined by the sequence of amino acids connected by peptide bonds.

Secondary structure

The 3D shape resulting from hydrogen bonding between amino and carboxyl groups of adjacent amino acids, forming alpha helices and beta sheets.

Tertiary structure

The 3D structure that forms due to non-covalent interactions between amino acid R groups, including disulfide bonds and hydrophobic effects.

Quaternary structure

The 3D shape of a protein that arises from the grouping of two or more separate peptide chains.

Denaturation

A process where a protein is taken out of its ideal environment and reversed back to its primary structure.

Nucleoside

A molecular unit consisting of a five-carbon sugar and a nitrogenous base.

Purines

Nitrogenous bases consisting of 2 rings, specifically adenine and guanine.

Pyrimidines

Nitrogenous bases consisting of 1 ring, specifically cytosine, uracil, and thymine.

RNA World Hypothesis

The theory proposing that self-replicating RNA molecules, which can store genetic information and catalyze reactions, were precursors to current life.

Central Dogma of Genetics

The principle stating that biological information must travel from $DNA \rightarrow RNA \rightarrow \text{proteins}$.

Centrifugation

A technique that spins and separates cell homogenates into layers based on density.

Anabolic reaction

A chemical reaction where small molecules are assembled into larger molecules.

Catabolic reaction

A chemical reaction where large molecules are broken down into smaller units.

Competitive inhibitor

A substance that mimics a substrate and inhibits an enzyme by binding directly to the active site, increasing $K_m$ but leaving $V_{max}$ unchanged.

Noncompetitive inhibitor

A substance that inhibits an enzyme by binding to a location other than the active site, altering $V_{max}$ while $K_m$ remains unchanged.

Km (Michaelis constant)

The substrate concentration at which the rate of reaction is half of the maximum velocity ($V_{max}$) of the enzyme.

Cooperativity

A phenomenon where an enzyme becomes more receptive to additional substrate molecules after one substrate binds to an active site, as seen in hemoglobin.