Biology1 review

A comprehensive set of vocabulary flashcards covering basic terminology, biological macromolecules, enzymes, lipids, nucleic acids, and scientific theories based on the lecture notes.}.

Dehydration (condensation) reaction

A polymerization reaction that results in the release of water ($H_2O$).

Hydrolysis

A depolymerization reaction which utilizes water ($H_2O$) to break bonds.

Disaccharides

Composed of two monosaccharides joined together by a glycosidic bond. Formation requires a dehydration (condensation) reaction. Ex. Sucrose

Cellulose

Structural support polysaccharides made of many glucose monomers, important in plant cell walls.

Polypeptides

Strands of many amino acids held together by peptide bonds.

Peptide bonds

Bonds formed by dehydration reactions between the carboxyl group of one amino acid and the amino group of another.

Primary structure

The simple linear amino acid sequence resulting from mRNA translation.

Secondary structure

Folding patterns of the primary sequence, including $\alpha$-helices and $\beta$-pleated sheets, determined by intermolecular forces between polypeptide backbones.

Tertiary structure

Interactions between R groups, such as hydrophobic interactions, disulfide bonds, hydrogen bonding, and ionic bonding.

Disulfide bonds

Covalent bonding between two sulfur atoms in the tertiary structure of a protein.

Quaternary structure

Multiple polypeptide chains (tertiary subunits) come together to form one functional protein.

Conjugated proteins

Proteins composed of amino acids and non-protein components. Ex. Metalloproteins and glycoproteins (proteins that contain various carbohydrates).

Catalysts

Increase reaction rates by decreasing activation energy without shifting the equilibrium point or altering spontaneity.

Ribozymes

RNA molecules that are capable of acting as enzymes.

Cofactor

A non-protein molecule that helps enzymes function.

Coenzyme

An organic cofactor, such as a vitamin.

Phosphatase

An enzyme that cleaves a phosphate group off of a substrate molecule.

Phosphorylase

An enzyme that directly adds a phosphate group to a substrate by breaking substrate bonds.

Kinase

An enzyme that indirectly adds a phosphate group to a substrate by transferring it from an ATP molecule without breaking substrate bonds.

Competitive inhibition

Directly competes for the active site. Can be overcome by increasing the substrate concentration. Kinetics: Km increased, Vmax does not change.

Noncompetitive inhibition

Binds to the allosteric site. Cannot be overcome by increasing substrate concentration. Kinetics: Vmax is decreased, Km does not change

$$V_{max}$$

The maximum reaction velocity reached when all enzyme active sites are occupied (saturation).

Michaelis constant ($K_M$)

The substrate concentration required to reach half of the maximum velocity ($\frac{1}{2}\,V_{max}$).

Phospholipids

Amphipathic lipids composed of a glycerol backbone, one phosphate group (polar head), and two fatty acid tails (nonpolar).

Cholesterol

An amphipathic lipid component of cell membranes that serves as a precursor to steroid hormones, vitamin D, and bile acid.

Lipoproteins

Complexes of lipids and proteins that carry lipophilic (hydrophobic) molecules through the blood.

Sphingolipids

Lipids with a backbone containing aliphatic amino alcohols, such as sphingosine.

Nucleoside

A molecule made of one ribose or deoxyribose sugar and one nitrogenous base.

Nucleotide

A molecule made of one ribose or deoxyribose sugar, one nitrogenous base, and one or more phosphate groups.

DNA (deoxyribonucleic acid)

An antiparallel double helix molecule containing deoxyribose sugars with a hydroxyl group only on the $3'$ carbon.

Phosphodiester bonds

Bonds formed between the $5'$ phosphate group of one nucleotide and the $3'$ hydroxyl group of another to create the sugar-phosphate backbone.

mRNA (messenger RNA)

Single-stranded molecule resulting from DNA transcription containing information to create proteins.

tRNA (transfer RNA)

RNA that participates in protein synthesis by carrying amino acids to ribosome enzymes.

rRNA (ribosomal RNA)

RNA that complexes with proteins to form the ribosome enzyme.

miRNA (microRNA)

RNA capable of silencing gene expression by base pairing to mRNA molecules.

dsRNA (double stranded RNA)

A genetic information reservoir used by some viruses that contains equal amounts of A/U and G/C.

Protobionts

Abiotic, lipid capsules that emerged as a precursor to cells in primordial Earth.

RNA World Hypothesis

The theory that early life relied on self-replicating RNA to store genetic information and catalyze reactions before DNA and proteins evolved.