Unit 2: Cell Structure and Function This document contains all the Essential Knowledge and Terminology student’s are expected to learn. It can be use

Ribosomes

Comprise ribosomal RNA (rRNA) and protein, synthesize protein according to mRNA sequence.

Endomembrane system

A group of membrane-bound organelles that work together to modify, package, and transport polysaccharides, lipids, and proteins intracellularly.

Rough ER

Associated with membrane bound ribosomes, allows for the compartmentalization of cells, and helps carry out protein synthesis.

Smooth ER

Functions include the detoxification of cells and lipid synthesis.

Golgi complex

A membrane-bound structure consisting of a series of flattened membrane sacs that modify, package, and transport proteins.

Mitochondria

Double membrane organelles involved in aerobic cellular respiration, with an outer smooth membrane and an inner highly convoluted membrane.

Lysosomes

Membrane-enclosed sacs containing hydrolytic enzymes that digest materials and play a role in apoptosis.

Vacuole

A membrane-bound sac that plays various roles; in plants, it maintains turgor pressure through nutrient and water storage.

Chloroplasts

Specialized organelles found in plants and photosynthetic algae that serve as the site for photosynthesis.

Surface area-to-volume ratio

Affects a biological system's ability to obtain resources, eliminate waste, and exchange chemicals and energy with the environment.

Passive transport

The net movement of molecules from high concentration to low concentration without the direct input of metabolic energy.

Active transport

Requires direct input of energy to move molecules from regions of low concentration to regions of high concentration.

Aquaporins

Membrane proteins that facilitate the transport of large quantities of water across membranes.

Facilitated diffusion

The process that enables the movement of large polar molecules through membranes with no energy input.

Tonicity

The relative concentration of solutes in a solution, affecting water movement across membranes.

Endocytosis

The process in which a cell takes in large molecules or particulate matter by folding the plasma membrane inward.

Exocytosis

The process in which internal vesicles release material to the external environment.

Osmoregulation

The process that maintains water balance and controls internal solute composition.

Solute potential

The potential of a solution to draw water in, calculated as Ψs = −iCRT.

Compartmentalization

The use of membranes and membrane-bound organelles to separate and localize metabolic processes within the cell.

Fluid mosaic model

A model for the structure of cell membranes, depicting a flexible arrangement of various molecules.

Selectively permeable

Describes cell membranes that allow certain substances to pass through while blocking others.

Cytosol

The aqueous component of the cytoplasm in which organelles, proteins, and other cell structures are suspended.

Eukaryotic cell

A cell characterized by the presence of membrane-bound organelles, including a nucleus.

Prokaryotic cell

A simpler cell type lacking internal membrane-bound organelles.

Metabolic energy

Energy required for the active transport of molecules and ions across the membrane.

Osmosis

The movement of water across a selectively permeable membrane from an area of low solute concentration to high solute concentration.

Plasma membrane

The lipid bilayer that forms the outer boundary of a cell, controlling the movement of substances in and out.

Concentration gradient

A difference in the concentration of a substance across a space, which influences diffusion.

Transport proteins

Membrane proteins that assist in the movement of substances across cell membranes.