Cells

The basic unit of life which all living things are made of.
Unicellular

Organism composed of a single cell.
Multicellular

Organism composed of more than 1 cell.
Organization of a multicellular organism

Organelle

A differentiated structure within a cell that performs a specific function.
Eukaryotic Cell

A cell that has a nucleus and membrane-bound organelles.
Larger and more complex than prokaryotic cells.
Contains
linear DNA.
Can be unicellular or multicellular.
Prokaryotic Cell

A cell that lacks a nucleus and membrane-bound organelles.
Smaller and simpler than eukaryotic cells.
Unicellular.
Tissue

A group of cells working together to perform a function
Nucleus

The 'brain' of the cell. Organelle that contains DNA and controls the functions of the cell.
Mitochondria

Organelles that are the site of cellular respiration (process that
converts energy in glucose into useable energy, ATP)
'Powerhouse' of the cell
Ribosomes

Small organelles found in all cells, made of RNA and protein; sites
of protein synthesis.
'Workbenches of the cell'
Endoplasmic Reticulum

A network of membranes in an eukaryotic cell that is interconnected
with the outer nuclear membrane that allow for transport of material.
Two types:
Rough ER - has ribosomes attached for
protein synthesis.
Smooth ER - detoxifies and
lipid/carbohydrate synthesis
Golgi Body or Golgi Apparatus

A membranous organelle in an eukaryotic cell that modifies, packages,
sorts and transports molecules of the cell.
The 'post
office' of the cell.
Chloroplast

The organelle where photosynthesis occurs (process that converts solar energy into glucose); contains chlorophyll. NOT in animal cells.
Central Vacuole

A membrane-bound compartment that stores water, waste, and ions. NOT in animal cells.
Cell Wall

A rigid structure surrounding a cell, outside the cell membrane, that
gives the cell support and shape; made of cellulose.
NOT in
animals cells.
Bacteria

A prokaryotic unicellular organism.
Components of Cell Membrane
Fluid Mosaic Model

Membrane is fluid/flexible with components floating throughout.
1. Made primarily of phospholipids.
2. Proteins - help
transport material across membrane.
3. Glycolipid - carbohydrate
attached to phospholipid - recognition of the cell
4.
Glycoprotein - carbohydrate attached to proteins.
Semipermeable
Cell membrane allows some molecules to enter and leave the cell, but not all materials.
Organ

A collection of tissues joined in a structural unit to serve a common function, such as stomach, small intestine.
Passive Transport

Movement of materials across a membrane that does NOT require energy from the cell. Movement of material with the concentration gradient (from HIGH concentration to LOW concentration).
Diffusion

Type of passive transport (does NOT require energy) in which atoms and molecules move from an area where they are more concentrated to an area where they are less concentrated.
Osmosis

Diffusion of water into or out of the cell. Form of passive transport (does NOT require energy. Moves from high water concentration to low water concentration.
Facilitated Diffusion

Type of passive transport (does NOT require energy) that uses a
protein as a channel.
Movement of material from high
concentration to low concentration.
Active Transport

Movement of materials across a membrane that REQUIRES an input of energy from a cell. Movement of material against the concentration gradient (from LOW concentration to HIGH concentration).
Endocytosis

A type of active transport (REQUIRES energy) used to bring materials into the cell using a vacuole.
Exocytosis

A type of active transport (REQUIRES energy) used to move material out of the cell using a vacuole.
Sodium-Potassium Pump

Maintains, by active transport, the resting potential of a nerve cell by pumping sodium ions (Na+) into a cell and potassium ions (K+) out of a cell to keep the interior of the cell negative in relation to the cell's external environment, which is positive. Reverses charges - interior becomes positive and exterior become negative when an action potential is activated sending a message down the nerve cell.
Organ system

A group of organs that work together to perform a certain task, such as digestive system, nervous system etc.
Organism

An individual form of life, such as a plant, animal, bacterium,
protist, or fungus.
In an multicelled organism, it consists of a
body made up of organ systems that work together to carry on the
various processes of life.
Cell Membrane/Plasma Membrane

Membrane that surrounds all cells and controls what enters and leaves the cell. Composed of 2 layers of phospholipids.
Phospholipid Bilayer

The construction of the cell membrane - 2 layers of phospholipids arranged where the polar heads point outwards and nonpolar tails point inwards.
Carrier or Transport Proteins

Proteins that are embedded in the cell membrane involved with facilitated diffusion and active transport.
Concentration Gradient

The difference in concentration of molecules across a membrane.
Material will naturally move from high concentration (where
there are a lot of molecules) to low concentration (where there are a
low amount of molecules).
Equilibrium
A stable or balanced system. The number of solutes on each side are balanced.
Vesicles

A small organelle within a cell, consisting of fluid enclosed by a lipid bilayer membrane.
Cytoplasm
Consists of the cytosol (liquid part of cell) and organelles in the cell, which includes everything between the cell membrane and the nucleus. Where metabolic processes occur in the cell.
Hydrophilic

water loving, polar heads on phospholipids
Hydrophobic

water hating, nonpolar fatty acid chains on phospholipids