Cell  Notes     Name:____________________________  

Daintrey’s Doings and Hayward’s Happenings J 1  

Cells

I. The Cell: Who discovered it? Cell Theory A. Intro:

• Cells are the BASIC BUILDING BLOCKS OF ALL LIVING THINGS, the smallest unit that can function on its own.

• In 1665, HOOKE observed tiny room-like structures while looking at a thin slice of cork through a compound microscope. He called these structures CELLS.

• The CELL THEORY is how we as biologists gauge whether or not an object is living.

B: The Cell Theory 1. The cell is the basic building block of all life on earth 2. All living things are made up of one or more cells 3. All cells have to come from pre-existing cells C. Characteristics of Living Things:

1. Living things respond to their environment. 2. Living things need energy. 3. Living things grow. 4. Living things need to get rid of wastes. 5. Living things reproduce.

D. What did this discovery mean? 1. Why was the development of the cell theory important for the progress of science? Scientists finally had a way to describe what life was

Cell  Notes     Name:____________________________  

Daintrey’s Doings and Hayward’s Happenings J 2  

2. What would have been the limitations of this “new science” when cells were discovered?

Microscopes back then were like first generation ipods now, not capable of doing as much as the new generation. This means they couldn’t see inside of the cell.

II: Organelles The inside of the CELL is made up of many structures that we now call ORGANELLES (like mini organs that keep the cell working the way it should) Organelles are what define a cell as eukaryotic (an animal or a plant cell), if they do not have organelles they are called prokaryotic (bacteria cell) A. Organelle Structure and Function The organelles inside the cell serve many functions together including: 1. PROVIDING PROTECTION AND SUPPORT

2. FORMING A BARRIER BETWEEN THE CELL AND THE ENVIRONMENT

3. BUILDING AND REPAIRING CELLS 4. TRANSPORTING MATERIALS 5. STORING AND RELEASING ENERGY 6. GETTING RID OF WASTE MATERIAL 7. INCREASING IN NUMBER

• Most cells share similar characteristics. It is these characteristics that we are going to learn about although there are some major differences between animal and plant cells.

• Take a look at the pictures of animal and plant cells below and see if

you can determine any major differences.

Cell  Notes     Name:____________________________  

Daintrey’s Doings and Hayward’s Happenings J 3  

Cell  Notes     Name:____________________________  

Daintrey’s Doings and Hayward’s Happenings J 4  

B. Definitions: Now that you have seen them, what do those organelles do anyway? Keep reading to find out J

1. Cell Wall: Supporter and Protector

- Provides a protective and supportive barrier in plant cells.

- Made of cellulose (Plant Fibre)

2. Cell Membrane: Doorway to the Cell - Controls nutrients and waste entering and leaving the cell. - Provides a protective outer barrier - Has two layers of fat molecules (Lipids) that include

proteins. - ***Cells with membranes around the organelles are called

Eukaryotic. Cells with NO membranes around the organelles are called Prokaryotic (Bacteria).

3. The Cytoplasm: Goo that everything floats in - Watery fluid that contains everything inside the cell

membrane and outside the nucleus. - It is where most of the chemical activities within the cell

take place. - Allows for the transport of materials between the

organelles of the cell.

Cell  Notes     Name:____________________________  

Daintrey’s Doings and Hayward’s Happenings J 5  

4. Nucleus: The BOSS! - Controls the activities of the cell (The

Brain of the cell) - Contains all the genetic information

a. Nuclear Membrane Double layered membrane that controls

molecules entering and leaving the nucleus. b. Nucleolus - Dark area inside the nucleus. - Plays a role in protein production.

c. Chromosomes - Genetic material of

the cell (Made up of DNA)

- DNA holds the construction plans for all pieces of the cell.

- DNA is duplicated during replication and passed on to other identical cells

5. Endoplasmic Reticulum (ER): Transportation

System - Transports and stores materials

(Protein) within the cell - Connects organelles together - “Rough” ER has ribosomes and

“smooth” ER does not - Runs through the cytoplasm like a

maze of freeways!

Cell  Notes     Name:____________________________  

Daintrey’s Doings and Hayward’s Happenings J 6  

6. Mitochondria: Powerhouse of the Cell - Produce chemical energy for the

cell - Bean shaped with lots of folds on

the inside to increase surface area

- They have the ability to reproduce inside the cell if it needs more energy

- Found in plant and animal cells

7. Chloroplast: The lean green power machine! (get it, it’s for plants) - Produce chemical energy for the plant

cell - Contain chlorophyll which accounts for

their green colour - Oval shaped

8. Vacuoles: Storage Tanks - Used for storage of water and food - Transport

materials within the cell

- Vacuoles can fuse with lysosomes

- Very large in plant cells and help with structure

Cell  Notes     Name:____________________________  

Daintrey’s Doings and Hayward’s Happenings J 7  

9. Golgi Body (Complex): UPS Ships overnight! - Collects proteins from the cell,

packages it into different types of vesicles and then ships those off into the cell (or outside the cell) to where it is needed

- Looks like a stack of pancakes

10. Ribosome’s: Protein Producers - Made up of protein and RNA - Produce more protein to be used in the cell - Proteins are needed for cell growth and repair.

- Are found floating in the cytoplasm or attached to the ER

11. Lysosomes: Suicide Sacs - Little sacs of digestive enzymes that are used to help break

down unwanted parts of the cell. (Old Organelles that are not functioning properly)

- Can explode and kill the entire cell as well

12. Centriole - Centrioles are little organelles that have spindle fibres that aid

in cell division in Animal Cells. - The spindle fibres that come from the centriole attach to the

chromosomes inside of the nucleus. - Plant cells do not

have centrioles, so their cell division is less exact

Cell  Notes     Name:____________________________  

Daintrey’s Doings and Hayward’s Happenings J 8  

13. What are the major differences between a plant and an animal cell? Plant Cell Animal Cell

1. Cell Wall 2. Large Water Vacuole 3. Chloroplasts and

Mitochondria for Energy

1. Centrioles control cell division

III. Moving Materials in and out of Cells

- Cells and all of their organelles need NUTRIENTS and WATER to function and make energy so there must be a way of getting these into the cell. Cells also must be able to get rid of WASTES.

- The outer layer of plant cells is the CELL WALL and the outer layer of animal cells is the CELL MEMBRANE. All materials entering and leaving the cell must pass through this. The cell wall just has openings in it, which most materials can pass through.

- The CELL MEMBRANE is what actually acts as the “GATEKEEPER” of the cell and controls what enters and leaves the cell.

A. Cell Membranes are made up of proteins and fatty acids

- are selectively permeable (some materials are allowed to move through and some are not)

Example: The small molecules can pass through the membrane but the large molecules cannot and thus stay on one side.

Cell  Notes     Name:____________________________  

Daintrey’s Doings and Hayward’s Happenings J 9  

How do these molecules move? B. Diffusion: The movement of materials from an area of high concentration (lots of molecules) to an area of low concentration (less molecules) - When a cell needs certain nutrients there is less of the material

inside the cell than there is outside the cell. Therefore, the nutrients will move inside the cell automatically because of the concentration difference.

A real life example of diffusion: spraying air freshener in a corner

of a room… C. Osmosis: - Cells are made up of 99.9% WATER and this is very important in the

functioning of cells. - Osmosis is just a fancy word for the DIFFUSION OF WATER. It is

the process by which cells take in water or lose water and it helps them maintain proper balance.

D. Active Transport: - What happens when a molecule is too big to fit through the openings in

the cell membrane but needs to get into the cell?

- They would need to use a method called ACTIVE TRANSPORT. In this method special carrier proteins in the cell membrane shuttle these molecules across. Many vitamins and minerals must use this method of entering the cell, as they are very large molecules.