Cell Theory

1. All organisms are made of one or more cells.
2. The cell is the basic unit of structure and function of living things.
3. All cells come from other living cells.
4. Cells contain genetic information that is passed on to the next generation.
5. Cells are chemically very similar.
6. The flow of energy in living things occurs in cells.

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.

Nucleolus

Region of nucleus where ribosomes are produced.

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.

Lysosome

A membrane-bound organelle that contains digestive enzymes to break down molecules in eukaryotic cells.

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.

Archeans

Prokaryotic unicellular organisms that generally live iin extreme habitats such as hot springs.

Bacteria

A prokaryotic unicellular organism.

Endosymbiotic Theory

How eukaryotes formed - organelles originated as independent prokaryotic cells and were engulfed by other prokaryotic cells.

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.

Cytoskeleton

Network of protein fibers inside of a cell to:
1. support cell shape
2. provide anchor points for organelles
3. help a cell move
4. play a role in directing the movement of materials during cell division.

Extracellular Matrix (ECM)

A structure that surrounds and supports cells made of proteins. In animal cells.

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.

Resting Potential

The electrical potential that exists in a nerve cell membrane when it is at rest (no signal). Maintained by the sodium potassium pump. Inside of cell is negatively charged while outside of the cell is positively charged.

Action Potential

Impulse from a nerve cell which causes resting potential to reverse - causes sodium (Na+) channels to open causing Na+ to rush into the cell. The inside of the cell becomes positively charged while the outside of the cell becomes negatively charged. Then returns to resting potential.

Neurotransmitters

A chemical that transmits a nerve signal across a synapse. Released when action potential reaches end of nerve cell to send messages to other cells.

Synapse

Space between axon of one neuron and dendrite of another neuron.

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.

Intracellular Transport

Movement of substances inside a cell.

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.

Cytosol

Liquidy part of the cytoplasm.

Centrioles

Composed of sets of microtubules that help move arrange microtubules for cell division. Only found in animal cells.

Cilia/Flagella

Projections of microtubules in certain cells used for movement. Cilia are short fibers. Flagella are long fibers.

Hydrophilic

water loving, polar heads on phospholipids

Hydrophobic

water hating, nonpolar fatty acid chains on phospholipids