cell structure and function

prokaryotic cells

simple, lack a nucleus, and membrane-bound

eukaryotic cells

complex, have a nucleus, specialized organelles.

organelle structure and function

Organelles perform different functions within a cell, and this is called the Division of Labour.

What is the fluid mosaic model?

A model that describes the structure of the cell membrane.

What is the structure of the cell membrane?

A fluid, dynamic phospholipid bilayer.

What do the hydrophilic heads of the phospholipid bilayer face?

Outward, towards the water.

What do the hydrophobic tails of the phospholipid bilayer face?

Inward, away from the water.

simple diffusion

the passive movement of small molecules from high to low concentration area.

facilitated diffusion

the passive transport of molecules or ions across a cell membrane with the help of transport proteins.

osmosis (simple diffusion of water)

the natural movement of water from low to high concentration through the membrane

chemical modification transport (Group translocation)-energy requiring process

membrane transport where a substance is chemically altered during or immediately after its passage across a cell structure.

endosymbiotic theory

theory that eukaryotic cells formed from a symbiosis among several different prokaryotic organisms

organelle

A tiny cell structure that carries out a specific function within the cell

nucleus

Control center of the cell

mitochondria

Powerhouse of the cell, organelle that is the site of ATP (energy) production

ribosome

Makes proteins

endoplasmic reticulum

forms a maze of passageways where proteins and other materials are carried from one part of the cell to another.

golgi apparatus

A system of membranes that modifies and packages proteins for export by the cell

phospholipid bilayer

two layered structure (phosphate head + 2 lipid tails arranged tail to tail) of cell membranes that control what enters and leaves the cell.

integral protein

a type of membrane protein that is permanently attached to the biological membrane.

peripheral protein

A protein loosely bound to the surface of a membrane or to part of an integral protein and not embedded in the lipid bilayer.

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

passive transport

the movement of substances across a cell membrane without the use of energy by the cell

isotonic

a solution with the same solute concentration (like salt or sugar) as another solution, usually the inside of a cell

hypertonic

a higher solute (like salt or sugar) concentration than another solution, usually the inside of a cell. CELL SHRINKS.

hypotonic

a solution with a lower solute concentration (more water) compared to another solution. CELL SWELLS