1. Ch. 8 Cell Structure & Function Lesson 1: What Do Cells Do?

2. Cells
Main Idea: All living things are made of cells. To stay alive and healthy, cells need food and water. They also need a way to get rid of waste.
Plant Cells and Animal Cells
A single cell is the smallest structure that carries out activities necessary for life.
A cell is like a tiny factory: different parts of the factory produce or control different things.
1. gets food or water
2. keeps cell clean
3. in charge of reproduction

3. Like parts of a factory, all parts must work together to run smoothly.
An organism can’t survive without cells doing their work.
Animal and plant cells look different, but share
many similar features.
Common features:
1. cell membrane
2. nucleus
3. cytoplasm
Cell membrane
Outer covering of cell
Water and food enter through it
Wastes leave through it

4. Plant cells have extra structure called cell wall which adds more support to plant cell.
Nucleus
Control center of cell
Carries information for
reproduction
Directs all cell activities
Cytoplasm
Gel-like material that surrounds all parts of cell within membrane
Contains nucleus and cells’ organelles

5. Cell Transportation Organelle-small structure that has certain job
1. mitochondria
2. vacuoles
3. nucleus
4. cell membrane
5. golgi bodies and endoplasmic
reticulum
Chloroplast-special organelle that uses energy of sunlight combined with water and carbon dioxide to make food for cell
Cell Transportation
Cell membrane holds cell matter inside, but allows water, gasses, and wastes to pass through.

6. In passive transport, matter moves into or out of cell
without cell using any energy
Simplest kind of passive transport-diffusion
Diffusion:
Spreads substances through gas or liquid (can smell dinner across room b/c food molecules diffuse through air)
Transports many gases into and out of cells
Substances diffuse from areas of high concentration to areas of low concentration
Special form of diffusion-osmosis

7. Osmosis:
Diffusion of water across membrane
Membrane stops many substances that are
dissolved
Often keeps water inside cells
Sometimes a cell needs to move materials opposite to the way diffusion would move them.
In active transport, substances move from areas with less matter to areas with more matter
Cell must use energy to do this.
Large proteins in cell membrane help move materials in and out.
Protein acts as tunnels that allow certain materials to pass.

8. Using Energy Scientists study these proteins for clues to how cells
operate.
Using Energy
All living things need energy to survive.
Plants use chloroplasts to make food
by using energy of sunlight, water, and
carbon dioxide
Process takes place in chloroplasts and depends on
green pigment called chlorophyll.
Chlorophyll captures energy from sunlight.
Photosynthesis:
1. series of chemical reactions join water from
ground with carbon dioxide from air.

9. 2. By products are oxygen, which plant releases
into air, and a molecule called glucose.
Glucose
1. High energy material that is classified as sugar
2. Plants and animals use sugar for food.
3. Plant and animal cells have organelles called
mitochondria.
4. Mitochondria-break down sugars so cells can
use sugars as energy
Mitochondria
1. perform cell respiration
(reverse reaction to photosynthesis)
2. Break down sugars to make energy

10. Cell Division 3. process combines glucose with oxygen to
form water and carbon dioxide
4. lot of energy released in process
5. store energy in molecule called ATP which is
released during cell respiration
6. ATP acts like battery-cell can draw from
ATP whenever it needs to use
energy
Cell Division
Body is made of trillions of cells
Began as one single cell
Cells copy themselves in process known as cell
division
New organisms begin when cells from two parents
combine to form fertilized egg.
Soon the single cell divides into 2 cells.

11. Two cells divide into 4 cells
Four cells divide into 8 cells
Sometimes cells divide within hours
allowing organism to grow very quickly.
As cells divide, they differentiate
(become different from one another)
Early on, cells organize themselves into 3 groups called
germ layers:
1. form the skin and nerves
2. becomes the lining of the digestive tract
3. produces all other body parts
Bacteria and other single-celled organisms can copy
themselves which results in new individuals.
When conditions favor division, a bacteria colony can
double very quickly.

12. That’s all folks!