1. Cellular Transport and energy

2. Cells get materials from the external environment.
The cell needs to move materials into and out of the cell
These include wastes, large molecules, nutrients, and other substances
Materials pass through the cell membrane
The membrane is selectively permeable
It “chooses” what will enter and exit
Certain materials are able to pass through the membrane all the time
Water and gases
Larger materials are not able to pass through unless the membrane allows

3. 2 Types of Transport Passive and Active
Passive transport does not require energy to move materials
Active transport does require energy

4. Diffusion A type of passive transport (no energy needed)
Materials move from areas of greater concentration to areas of less concentration
Will occur until there is an equal concentration on either side of the membrane
Diffusion of water is called osmosis
Water will move through the membrane until there is an equal concentration on either side

5. Facilitated Diffusion
Also passive transport (no energy needed)
Diffusion with help
Proteins within the cell membrane (carrier and channel proteins) bind to materials and bring them into the cell
Can also move materials out of the cell
Used for larger materials

6. Endocytosis and Exocytosis
2 types of active transport
Used for large materials
Endocytosis
Endo=into
Brings materials into the cell
The cell membrane forms a vesicle around the material and brings the materials into the cell
Exocytosis
Exo=exit
Releases materials from the cell
Vesicles bind to the cell membrane and open to the external environment, releasing the materials

7. Cell Size and Transport
The size of the cell has an impact on the efficiency of transport
As the cell grows, the inside of the cell grows faster than the membrane
The membrane is the only way to get materials in and out
Because the membrane cannot keep up, larger cells have a difficult time getting materials in and out
This limits the size that cells can be

9. Cells and Energy Cells need to do their jobs The energy is…ATP!
ATP is a nucleic acid that the cell uses for energy
The energy is made within the cell
2 processes
Cellular respiration
Photosynthesis
These processes are cycles
Not just that, there are cycles within cycles
And cycles in the cycles in the cycles

10. ATP Adenosine Triphosphate
An Adenosine molecule (a nucleic acid) bonded to 3 phosphates (tri=3)
The bonds are very high energy
Energy is released from ATP when bonds between 2 of the phosphates are broken
This forms ADP: adenosine diphosphate (di=2)
ATP  ADP + P + Energy
The ADP is now able to bond to another phosphate, repeating the cycle

11. Cellular Respiration Occurs in all living things
Uses oxygen and sugar to produce energy, carbon dioxide, and water
The first step occurs in the cytoplasm
Called glycolysis
Glucose (a sugar) is broken down into smaller molecules
The second step occurs in the mitochondria
This step requires oxygen to occur
Called aerobic respiration
The products from glycolysis enter a step called the Krebs Cycle
Carbon dioxide and water are released
A lot of ATP are produced

13. Equation for Cellular Respiration

14. If no oxygen is present, cells cannot enter aerobic respiration
Anaerobic respiration
The first step (glycolysis) is the same
However, without oxygen, the products cannot proceed to the Kreb’s Cycle
Enters Fermentation
Makes less ATP
Occurs in the cytoplasm

15. 2 Types of Fermentation Lactic Acid Fermentation
Produces lactic acid, which is what causes muscle cramps
Alcoholic Fermentation
Produces adult drinks, and also is responsible for bread rising in the presence of yeast (a fungi)

17. Photosynthesis Occurs only in organisms that contain chloroplasts
Uses sunlight, water and carbon dioxide to produce oxygen and sugar
Again, cycles in cycles
A pigment in chloroplasts, called chlorophyll, absorbs sunlight

18. Why are plants green?
Objects appear to be the color of the light that they are reflecting
Plants reflect green light
The other colors of light are absorbed
Plants, then, absorb the rest of the colors of light except for green
Black objects absorb all colors of light
White objects reflect all colors of light
What is hotter on a sunny day, a white shirt or a black shirt?

19. Reactions in Photosynthesis
Step 1: Light energy breaks water down and releases oxygen and other molecules
Step2: The molecules enter the Calvin Cycle, which uses the products from step 1 and carbon dioxide to form sugar
Plants can then use their own sugars to make ATP by advancing them to their mitochondria
Other organisms must breathe oxygen and eat foods to get the materials necessary for respiration

21. Comparison of Respiration and Photosynthesis
Cellular Respiration: C6H12O6 + 6O2 → 6CO2 + 6H2O + energy
Photosynthesis: CO2 + 6H2O + energy→ C6H12O6+ 6O2
One way to think about this: Ask yourself, what do plants need? What do they make?
Need Carbon Dioxide, water, sunlight
Make Oxygen and food (sugars)
Respiration is the exact opposite.
You can ask yourslef, what do you need to survive? What do you make?
You need food (sugar), and oxygen
You make carbon dioxide, water, and energy for your cells