Bio exam #2

Amino acid

Building block of proteins.

Peptide bond

Covalent bond between amino acids.

Polypeptide

Chain of fewer than 50 amino acids.

Protein

Folded chain of more than 50 amino acids.

Primary structure

Amino acid sequence of a protein.

Secondary structure

Formation of α‑helix or β‑sheet.

Tertiary structure

Full three-dimensional folding of a protein.

Quaternary structure

Assembly of multiple polypeptides to form a functional protein.

Denaturation

Loss of protein shape and function.

Renaturation

Regaining of former protein shape and function.

Nucleotide

Building block of DNA and RNA.

DNA

Double-stranded genetic material.

RNA

Single-stranded molecule used for protein synthesis.

Transcription

Process of synthesizing mRNA from DNA.

Translation

Process of synthesizing protein from mRNA.

Phosphodiester bond

Covalent bond between sugar and phosphate in nucleic acids.

Glycosidic bond

Bond between sugar and base in nucleic acids.

Hydrogen bond

Bond that forms base pairs in nucleic acids.

Purine

Double ring nitrogenous bases (Adenine, Guanine).

Pyrimidine

Single ring nitrogenous bases (Cytosine, Thymine, Uracil).

Plasma membrane

Boundary that separates the inside of a cell from the outside.

Cytoplasm

Fluid interior of the cell.

Ribosome

Cell structure responsible for protein synthesis.

Nucleoid

Region in prokaryotes where DNA is located.

Organelle

Specialized structure within a cell that performs a specific function.

Prokaryote

Type of cell that lacks a nucleus.

Eukaryote

Type of cell that contains a nucleus and organelles.

Surface area-to-volume ratio

Ratio that limits cell size as it affects the efficiency of transport.

Phospholipid

Molecule that is amphipathic, having both hydrophobic and hydrophilic regions.

Integral protein

Protein that is embedded within the cell membrane.

Peripheral protein

Protein that is attached to the surface of the membrane.

Cholesterol

Lipid that regulates fluidity of the cell membrane.

Glycoprotein

Molecule consisting of a protein attached to a carbohydrate.

Glycolipid

Molecule consisting of a lipid attached to a carbohydrate.

Selective permeability

The ability of the cell membrane to control entry and exit of substances.

Diffusion

Movement of substances from high to low concentration.

Osmosis

Diffusion of water across a semipermeable membrane.

Passive transport

Transport of substances across a membrane without the use of energy.

Facilitated diffusion

Transport process that uses proteins to help substances cross the membrane.

Active transport

Transport process that requires ATP to move substances against their concentration gradient.

Endocytosis

Process by which a cell takes in material from the outside.

Isotonic

Solution in which the solute concentration is equal inside and outside the cell.

Hypotonic

Solution in which the solute concentration is lower outside the cell.

Hypertonic

Solution in which the solute concentration is higher outside the cell.