Chapter 2“The Cell”

Reference:PCI Life Science

Section 1 – Parts of a Cell

Cells,Tissues & OrgansRemember the human body is made of trillions of cells.The cells in your body group together to do certain jobs.

Cells,Tissues & OrgansFor example, in animals, muscle tissues work together to make the body move.

A group of tissues that work together is called an organ. Your heart, lungs, and stomach are examples of organs.

Each organ does a specific job.

Cells, Tissues & OrgansJust like your body is made of organs that work together, the tiny cells of your body are made of smaller units that work together.These units are called organelles.You can think of them as a cell's tiny organs.

Cells, Tissues & Organs Each organelle has a specific purpose.

Cells, Tissues & OrgansAnimal cells and plant cells are slightly different, but they share some similarities.

Cells, Tissues & OrgansPlant Cell:Unlike an animal cell, a plant cell has an extra barrier called a cell wall.

The cell wall is a solid layer surrounding a plant cell that gives the cell :Structure, shape and protection.

Cells, Tissues & Organs

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Parts of a Cell

OrganellesCELL MEMBRANEThe cell membrane is a thin, flexible covering around the outside of each cell. The cell membrane has several important jobs:1. It holds the cell together2. It protects the cell3. It keeps harmful substances from entering the cell4. It membrane controls the movement of needed materials, such as food, oxygen, and water into the cell.

OrganellesCELL OR PLASMA MEMBRANEOTHER MOLECULES:• GLYCOPROTEINS with attached

carbohydrate tails to recognize self.

• Contain the steroid cholesterol to make membranes more flexible.

OrganellesCELL WALL

• Found OUTSIDE the cell membrane.• Provides structure and support.• Cellulose in the cell wall makes plant cells

sturdy.• Bacteria have cell walls made of sugar and

proteins instead of cellulose.• FOUND ONLY IN PLANT CELLS &

BACTERIA

Organelles

CHLOROPLASTS• The organelle in plant cells

that capture light energy.• Where photosynthesis

takes place

OrganellesENDOPLASMIC RETICULUM (ER)• An organelle that is made of a

network of tubes that processes and transports proteins from place to place inside a cell

OrganellesENDOPLASMIC RETICULUM (ER)

Rough ER: ribosomes attachedSmooth ER: no ribosomes

attached.

OrganellesGOLGI Body • an organelle that processes, packs,

and transports proteins to be sent outside a cell

OrganellesLYSOSOME• an organelle that breaks down waste

materials in an animal cell.• Think of the lysosome as the “garbage

disposal” of the cell.

OrganellesMITOCHONDRIA• organelles that convert food into energy that a cell can use• You can call the Mitochondria the powerhouse of the cell!

THE MIGHTY MITOCHONDRIA!

OrganellesNucleus and NucleolusNUCLEUS is:• the information center• controls the chemical reactions that

happen in cytoplasm• stores DNA

OrganellesNucleus and NucleolusNUCLEOLUS is:• a round structure that is inside the nucleus

of a cell• makes ribosomes

OrganellesRIBOSOMES• an organelle that makes proteins for

a cell – “The Protein Maker”• Can be found free in the cytoplasm

or bound to the surface of Rough ER.

OrganellesVACUOLE• Storage space for: waste products,

nutrients, and water.

• Huge in plant cells, small in animal cells.

The CellAnimal cells and plant cells

have some similar cell parts.

DO NOW

Organelles –Animal Cell

Nucleus

Ribosomes

Cytoplasm

Vacuole

Mitochondria

Endoplasmic Reticulum

Cell Membrane

Golgi Body

Lysosomes

1 2

34

5 6

7 8

9

Organelles - Plant Cells

Nucleus

Golgi Body

Endoplasmic Reticulum

Ribosomes

Cell Wall

Vacuole Mitochondria

Cytoplasm Cell MembraneChloroplasts

1 2

3 4

5 6

7 8 9 10

Section 2 – Chemicals in a Cell

Chemicals in a CellThe molecules in cells are made of combinations of the elements carbon, hydrogen, nitrogen, oxygen, phosphorous, and sulfur.

Chemicals in a CellThese elements combine to form chemicals that organisms need to function.

WaterOne of the chemicals that cells need is water.Cells are about 70 percent water.Water is a molecule made of Hydrogen and Oxygen.H2O is the chemical symbol for water.

Water

Water is a useful chemical because it dissolves other chemicals, or causes them to break up into small pieces.

WaterImagine putting a spoonful of sugar into a cup of coffee. When you stir the coffee, the grains of sugar break up into smaller pieces. Eventually, the pieces are so small that you cannot see them.

Water works the same way inside a cell.

WaterA cell is small, so the particles that pass through it must be even smaller.The water in a cell dissolves materials into smaller pieces so that they can move from cell to cell.

ProteinsProteins are large molecules in a cell that carry out the functions of life.Proteins contain chains of smaller molecules called amino acids.

ProteinsWhen an organism takes in food, the protein in the food is broken down to supply the organism's cells with amino acids.

The amino acids are then linked together to form new proteins that the cells can use.

Proteins

ProteinsProteins do different jobs depending on how their amino acids are arranged.Proteins protect cells, digest food, fight infections, and keep an organism working.

» Antibodies» Enzymes» Collagen» Hemoglobin» Insulin

                                                             Photo Credit Hemera Technologies/AbleStock.com/Getty Images

ProteinsYou have learned that DNA is a molecule found in cells that contains genetic information.DNA determines what cells will do. Located in a cell's nucleus, DNA has the code that is needed to make proteins.

ProteinsWhen a cell needs to make a certain protein, the cell gets the necessary information from DNA.

This tells the cell how to put the amino acids together in a specific order to make the new protein.

CarbohydratesCarbohydrates are molecules that are made out of sugar.

These molecules are used for energy and energy storage. When an organism needs energy, its cells break down carbohydrates.

CarbohydratesBreaking down carbohydrates releases the energy that is stored inside.

Lipids

Lipids are molecules in a cell that either store energy or make up the cell membrane.Lipids are different from proteins and carbohydrates because they do not dissolve in water.There are two types of lipids:1.Fats and oils2.Phospholipids

LipidsFats and oils store energy. When an organism uses up all of its carbohydrates for energy, it can use fats or oils to get energy.Most of an animal's lipids are fats.Most of a plant's lipids are oils.

Lipids

Phospholipids are another type of lipid. These lipids make up the cell membrane.

**Remember, the cell membrane separates and protects the inside of a cell from the things around the cell.

Lipids

Cells are 70 percent water. Since phospholipids do not dissolve in water, they keep the inside of the cell stable.

ATP

Adenosine triphosphate (ATP) is a molecule that is very important to cells because it is the main fuel that is used for cell activities.

ATP

When a cell needs energy, the energy that isstored in carbohydrates and lipids must be turned into

The cell can only use the energy after it has been turned into ATP.