Cells – The Basic Units of Cells – The Basic Units of LifeLife

Basic Regions of the Cell

Cytoplasm -the cell substance between the cell membrane and the nucleus, containing the organelles, cytoskeleton, and various particles.

Nucleus - a part of the cell containing DNA and RNA and responsible for growth and reproduction

The control center of the cell.

Cell Membrane - The semipermeable membrane that encloses the cytoplasm of a cell. Also called the plasma membrane.

Cell Organelle

s

Organelles found in Both Animal and Plant Cells

The Plasma Membrane

(or Cell Membrane)The semipermeable membrane that encloses the cytoplasm of a cell.

Made up of fatty molecules arranged in a double layer

It is selectively permeable – meaning it lets only SOME substances in or out. It controls what enters and leaves the cell.

It has receptor proteins which detect signals from outside the cell

The Nucleus

Contains all genetic information for the cell in the form of DNA

Inside nucleus -instructions contained in the DNA are copied into RNA.

Then the RNA leaves the nucleus and brings instructions to the rest of cell for producing proteins

The Nuclear Membrane

Surrounds the nucleus

Composed of two layers

Has openings (pores) for “traffic” in and out of the nucleus.It is attached to the endoplasmic

reticulum.

Mitochondria (singular

“mitochondrion”)Called the “Power PlantsPower Plants” of the cell

They convert organic materials into energyenergy (they make a substance called ATP).

Carry out cellular respiration.cellular respiration.Sugar + oxygen carbon dioxide + water + energy(ATP)

They control the level of water and other materials in the cell.

A cell can have hundreds or thousands of mitochondria, which can occupy up to 25% of the cell's cytoplasm.

Cellular Respiration

Sugar + Oxygen Carbon Dioxide +Water + Energy(ATP)

Takes place in the mitochondriamitochondria of cells of both animals and plants.

Mitochondrion

Ribosomes

Their function is to assemble proteinsassemble proteins (from amino acids)

Look like little “dots”. Some on the surface of endoplasmic reticulum and some “free” in the cytoplasm

Each cell contains thousands.

Endoplasmic ReticulumConnected to the nuclear membrane.

A network of tubes.

The cell’s transport systemtransport system

The “rough type” has ribosomes on its surface.

The “smooth type” lacks ribosomes.

Help transport proteins to different parts of the cell.

Golgi Apparatus

Protein Protein packaging packaging plantplant. Packages molecules into small sacs called vesiclesvesicles.These are sent to other parts of the cell.

Vacuole

SacsSacs with a membrane. Used for storagestorage, digestiondigestion and waste removalwaste removal. Contain water solutions. Usually oneone large centrallarge central vacuole in plant cells and more than one more than one smallersmaller vacuole in animal cells.

Lysosomes

Digestive “plant” for proteins, fats and carbohydrates. They fuse with a food vacuole, digest it and carry the wastes to the cell membrane for disposal. Help keep the cell “clean” by destroying used up organelles.

lysosome animation

Organelles found in Animal Cells

Only

Centrioles

There is one pair in each cell. Each centriolecentriole is made up of a ring of nine microtubulesmicrotubules.During cell division, or mitosismitosis, the centriolescentrioles produce spindle fibersspindle fibers which help to pull chromosomes apart.

Centrioles are found only in animal cells.

                              

Organelles found in Plant Cells Only

ChloroplastsFound in all higher plant cells.

They contain chlorophyllchlorophyll, which makes them greengreen.

They capture light energy from the sun to carry out photosynthesisphotosynthesis in the cell.carbon dioxide + water + energy sugar + oxygen

CO2 + H2O + energy C6H12O6 + O2

chlorophyll

chlorophyll

The Cell Wall

Protects the cellMakes the cell rigid (found only in plants)Lets water and nutrients pass through (porous)Thicker than cell membranesMade up of cellulose and other materials

The Differences Between Animal and Plant Cells

Animal Cells Plant Cells

Contain centriolescentrioles Don’t contain centrioles

Don’t contain chlorplasts

Contain chloroplastschloroplasts

Do not have a Cell Wall

Have a Cell WallCell Wall

Have more than one more than one smallsmall vacuolevacuole

Usually have one one largelarge central

vacuolevacuole

Usually smaller than plant cells

Usually larger than animal cells

Organelle FunctionMitochondria Energy center or "powerhouse" of the cell. Turns food into

useable energy (ATP)

Ribosomes Make protein

Golgi Apparatus Processes, packages and secretes proteins

Lysosome Contains digestive enzymes, breaks things down

Endoplasmic Reticulum

Transport, "intracellular highway"

Vacuole Stores water or other substances

Chloroplast Uses sunlight to create food, photosynthesis (only found in plant cells)

Cell Wall Provides additional support (plant and bacteria cells)

Cell membrane Gives form to cell and controls materials going into and out of cell

Nucleus Direct cell activity and forms ribosomes

Centrioles Organize spindle fibers and assist mitosis

Plastids (like chloroplasts)

Pigment-forming structures providing color.

Summary of Cell Organelles

Some other structures

found in Cells

Cilia (singular cilium)

cilia

Thin, tail-like projectionstail-like projections coming from the outer surface of the cell.One type is used for propulsionpropulsion. Another type used for sensingsensing.

Found in protozoa (propulsion)Found in cells lining our trachea (sweep mucus) and ovum (move ovum from

ovary to uterus)

cilia animations

Flagella (singular flagellum)

A “whip-like” organelle used to move about. Used by many unicellular organisms mainly. (eg. bacteria) flagella animations