1. Cellular Respiration and Photosynthesis
PREAP REVIEW

2. Do you understand osmosis?
Cell (compared to beaker)  hypertonic or hypotonic
Beaker (compared to cell)  hypertonic or hypotonic
Which way does the water flow?  in or out of cell

3. The Cell Membrane

4. Phospholipids Phosphate Lipids Phosphate head
hydrophilic (water loving)
Lipid tails
hydrophobic (repels water)
Arranged as a bilayer
“attracted to water”
Lipids
“repelled by water”
Why is a bilayer
needed?

5. Arranged as a Phospholipid bilayer
Serves as a cellular barrier / border
sugar
H2O
salt
polar
hydrophilic
heads
nonpolar
hydrophobic
tails
impermeable to polar molecules
polar
hydrophilic
heads
waste
lipids

6. How do molecules pass through the cell membrane?
Membrane becomes semipermeable via protein channels
specific channels allow specific material across cell membrane
inside cell
H2O aa
sugar
salt
outside cell
NH3

7. Cell membrane defines cell
Cell membrane separates living cell from its watery environment
thin barrier = 8 nm thick
Controls traffic in and out of the cell; “gatekeeper”
allows some substances to cross more easily than others
hydrophobic (nonpolar) vs. hydrophilic (polar)

8. Comparison of Fermentation to Cellular Respiration
Lactic Acid
Cellular Respiration
Location
glucose
cytoplasm
glycolysis
(pyruvic acid)
lactic acid +
2 ATP
carbon dioxide
+ water
+ 36 ATP
mitochondria

9. Which process – lactic acid fermentation or cellular respiration – produces the greatest amount of energy?
Cellular respiration (36 ATP molecules)
Which process – lactic acid fermentation or cellular respiration – can take place under anaerobic conditions (i.e., without oxygen)?
Lactic acid fermentation
Under what conditions do humans need to use both processes?
During a time of intense exercise, humans revert from cellular respiration to lactic acid fermentation.

10. Comparison of Photosynthesis and Cellular Respiration
Food synthesized
Food broken down
Energy from the sun stored as glucose
Energy of glucose is
released
Carbon dioxide taken in
Carbon dioxide given off
Oxygen given off
Oxygen taken in
Produces sugars from PGAL
Produces CO2 and H2O
Requires light
Does not require light
Occurs only in the presence of chlorophyll
Occurs in ALL living
cells

11. Comparison of Photosynthesis and
Cellular Respiration
Photosynthesis
Function:
Energy capture
Energy release
Location:
Chloroplasts
Mitochondria
Reactants:
CO2 (carbon dioxide) and H2O
C6H12O6 (glucose) and O2
Products:
C6H12O6 and O2
CO2 and H2O
Photosynthesis Equation:
6CO H2O C6H12O O2
Cellular Respiration Equation:
C6H12O O CO H2O
energy
energy

12. Reviewing Content
In cells, the energy available in food is used to make an energy-rich compound called
a. water b. glucose c. ATP d. ADP.
The first step in releasing the energy of glucose in the cell is known as
a. alcoholic fermentation.
b. glycolysis.
c. the Krebs cycle.
d. electron transport.

13. Reviewing Content
The process that releases energy from food in the presence of oxygen is
a. lactic acid fermentation.
b. glycolysis.
c. cellular respiration.
d. photosynthesis.
Which organisms perform cellular respiration?
a. plants only c. animals only
b. fungi and bacteria d. all living organisms

14. Reviewing Content The net gain of energy from glycolysis is
a. 4 ATP b. 2 ATP c. 32 ATP d. 36 ATP.
Because fermentation takes place in the absence of oxygen, it is said to be
a. aerobic c. essential to O2 production.
b. anaerobic d. cyclic.
The Krebs cycle takes place within the
a. chloroplast c. mitochondrion.
b. nucleus d. cytoplasm.

15. Reviewing Content
The electron transport chain uses the high-energy electrons from the Krebs cycle to
a. produce glucose.
b. convert ADP to ATP.
c. produce chlorophyll.
d. change NAD+ to NADH.
A total of 36 molecules of ATP are produced from 1 molecule of glucose as a result of
a. alcoholic fermentation.
b. lactic acid fermentation.
c. glycolysis.
d. cellular respiration.

16. Reviewing Content
During heavy exercise, the buildup of lactic acid in muscle cells results in
a. alcoholic fermentation.
b. oxygen debt.
c. the Calvin cycle.
d. the Krebs cycle.
When oxygen is your cells is depleted, ______ kicks in.
a. lactic acid fermentation.
b. aerobic cellular respiration.

17. Understanding Concepts
How is glucose changed during glycolysis? What products are produced as a result of glycolysis?
During glycolysis, 1 molecule of glucose is broken down into 2 molecules of pyruvic acid. The other products are ATP and high-energy electrons.
Use a formula to write a chemical equation for cellular respiration. Label it with the names of the compounds.
(light energy)
6C6H12O O  CO H2O
glucose oxygen  carbon dioxide + water

18. Understanding Concepts
How are fermentation and cellular respiration similar? What is the main difference between their starting compounds?
Both are processes that break down glucose and release the energy stored in the molecule. Both start with the process of glycolysis, which produces pyruvic acid. Cellular respiration requires oxygen as a reactant. Fermentation is anaerobic.

19. Understanding Concepts
When runners race for about 30 minutes, how do their bodies obtain energy?
At the beginning of a race, runner’s energy comes from ATP that is present in their muscles and that is produced by lactic acid fermentation. When they continue to race, their bodies use cellular respiration to use stored carbohydrates to make ATP. If they are not in good shape and unused to running for 30 minutes, toward the end of their endurance, their bodies will switch back to lactic acid fermentation because their muscles will not be getting enough oxygen for cellular respiration to take place. If they continue running, they may “hit the wall” and collapse.

20. Understanding Concepts
Complete the following concept map.
Light Energy
Photosynthesis
CO2 and H2O 2
Glucose and O2
Cellular Respiration 1
ATP

21. Review Questions from the Orca Book

22. 8.1 Section Assessment
What factors affect the diffusion of water through a membrane by osmosis?
The concentration on either side of the membrane (i.e., whether it is hypotonic, hypertonic, or isotonic) and the permeability of the membrane.
How do animal cells and plant cells react differently in a hypotonic solution?
In an animal cell, the extra water may cause the plasma membrane to burst. In a plant cell, the plasma membrane pushes against the cell wall, providing added support.

23. 8.1 Section Assessment
Compare and contrast active transport and facilitated diffusion.
Both active transport and facilitated diffusion use carrier proteins. Facilitated diffusion does not require energy; active transport does.
How do carrier proteins facilitate passive transport of molecules across a membrane?
Carrier proteins move substances that cannot diffuse through the plasma membrane from an area of higher to lower concentration.

24. 8.1 Section Assessment
A paramecium expels water when it is in freshwater. What can you conclude about the concentration gradient in the paramecium’s environment?
The environment is hypotonic and the concentration gradient is from outside to inside (water moves into the one-celled paramecium, and must be expelled or the paramecium could explode).

25. 9.3 Section Assessment
Compare the ATP yields of glycolysis, the Krebs cycle, and the electron transport chain.
Glycolysis  2 ATP molecules, Krebs cycle  2 ATP molecules, electron transport chain  32 ATP molecules
How do alcoholic fermentation and lactic acid fermentation differ?
Both are anaerobic; but alcoholic fermentation produces alcohol, 2 ATP, and CO2, while lactic acid fermentation produces lactic acid and 2 ATP. Lactic acid fermentation occurs in animals, while alcoholic fermentation takes place in bacteria and in some yeast.

26. 9.3 Section Assessment
How is most of the ATP from aerobic respiration produced?
Most is produced by reactions in the electron transport chain (32 of 36 ATP).
Why is lactic acid fermentation important to the cell when oxygen is scarce?
It supplies energy when oxygen is unavailable.
How many ATP molecules are produced after the electrons go down the electron transport chain?
32 ATP

27. 9.3 Section Assessment
Compare the energy-producing processes in a jogger’s leg muscles with those of a sprinter’s leg muscles. Which is likely to build up more lactic acid? Explain.
Aerobic respiration occurs in the muscles of both runners. The sprinter may build up more lactic acid because of an oxygen debt associated with a quick burst of energy.