cell & molecular

fluid mosaic model

describes the cell membrane as a flexible, constantly moving "sea" of lipids (mainly phospholipids) with a "mosaic" of various proteins and carbohydrates embedded or attached

simple diffusion

The process where molecules move from an area of higher concentration to an area of lower concentration without the need for energy input.

Facilitated diffusion

is a process of passive transport in which substances move across a cell membrane with the assistance of carrier proteins, without the use of energy.

active transport

The process by which cells move substances across the plasma membrane against their concentration gradient, using energy from ATP.

secondary active transport

A form of active transport that uses the energy from the movement of one molecule down its concentration gradient to drive the transport of another molecule against its gradient.

Primary protein structure

is the linear sequence of amino acids linked by peptide bonds, forming a polypeptide chain

Secondary protein structure

is the regular repeating patterns, generally stabilized by hydrogen bonds between of the peptide backbone

Tertiary protein structure

is the final, unique 3D shape a single polypeptide chain folds into

Quaternary protein structure

Arrangement of multiple polypeptide chains into a single functional unit

Competitive inhibition

The inhibitor and substrate compete for the same binding spot on the enzyme

Noncompetitive inhibition

is a type of enzyme inhibition where the inhibitor binds to a site separate from the active site

Allosteric regulation

a biological mechanism where a molecule binds to an enzyme at a site other than its active site, causing a conformational change

Allosteric activator

is a molecule that boost the enzyme's activity and speeding up the reaction

Allosteric inhibitor

is a molecule that reduces the enzyme's activity or blocks substrate binding

α-Helix

A right-handed spiral or coil where hydrogen bonds form between amino acids

β-Sheet

A pleated, zigzag arrangement of polypeptide strands that lie side-by-side, connected by hydrogen bonds