Cell Parts

Cellular Respiration and Photosynthesis

Group 6: Lee Longley, Kathie Jiang, Cooper Schulz, Galia Shakked

Cellular Respiration

C6H12O6 + 6 O2 → 6 CO2  + 6 H2O + Energy

Cellular respiration is the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen.

     

Anaerobic Respiration

Does not require oxygen Occurs in cytoplasm Includes glycolysis and fermentation

Glycolysis

Process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid and a net gain of 2 ATP molecules.

Input: Glucose Output: 2 ATP, 2 pyruvates

Fermentation

Fermentation releases energy from food molecules by producing ATP in the absence of oxygen.

Input: pyruvates Output: ethyl alcohol/lactic acid,

CO2,NAD+ Alcoholic Fermentation:

pyruvic acid + NADH →  Alcohol + CO2 + NAD+

Lactic Acid Fermentation: pyruvic acid + NADH → lactic acid + NAD+

Aerobic Respiration

Requires oxygen Takes place in mitochondria Includes Krebs Cycle (citric acid cycle)

and Electron Transport Chain

Krebs Cycle (Citric Acid Cycle) During the Krebs cycle, pyruvic acid is

broken down into carbon dioxide in a series of energy-extracting reactions. It occurs in the matrix of mitochondria.

Input: 2 pyruvates Output: 4 CO2 , 2 ATP, some NADH,

FADH

Electron Transport System (Chain)

The electron transport system uses the high-energy electrons from the Krebs cycle to convert ADP to ATP. It occurs in the cristae of the mitochondria, and produces the most ATP.

Net gain: 32 ATP Input: 6O2

Output: 6H2O (including glycolysis [2 ATP] + Krebs cycle [2 ATP]: 36 ATP)

Photosynthesis

Photosynthesis is the process of using the energy of sunlight to convert water and carbon dioxide into high energy carbohydrates and oxygen.

Photosynthesis is only used by light dependent plants and other photosynthetic eukaryotes. It is their main source of energy.

Where Photosynthesis Occurs Photosynthesis occurs in the cells

chloroplasts. They contain saclike photosynthetic membranes called thylakoids. These are arranged in stacks called grana and absorb water and the energy from the sun to output oxygen, ATP, and NADPH. The oxygen is released from the cell, and the energy is then used for the Calvin Cycle.

Calvin Cycle

After energy from the chloroplasts is made, it is then used in the Calvin Cycle to produce high-energy sugars. The ATP and NADPH is used to build high-energy compounds that can store more energy for a longer period of time.

Input: 6CO2, 12 ATP, 12 NADPH Output: Two 3-Carbon molecules

Factors Affecting Photosynthesis

A shortage of water can slow or stop photosynthesis

Photosynthesis depends on enzymes that function best at temperatures between 0C and 35C

The intensity of light also affects the rate of photosynthesis. A higher intensity increases the rate, but eventually levels off at the plants maximum rate of photosynthesis

Comparing Photosynthesis and Cellular Respiration

  Photosynthesis Cellular Respiration

Where Chloroplasts Mitochondria

When Presence of light All the Time

Input CO2, H2O Glucose & O2

Output Glucose & O2 CO2, H2O

Energy Source Light Chemical Bonds

Energy Result Energy Stored Energy Released

Animal or Plant? Plants only Both

Energy Storage

Adenosine triphosphate (ATP) is the main chemical compound that stores and releases energy. It consists of adenine, ribose, and three phosphate groups

PhosphateRibose

Adenine

ATP and ADP Energy

To release energy, ATP breaks off one phosphate group. ADP is ATP with one less phosphate group, and has less energy than ATP. Cells only have enough ATP for a few seconds of activity, as it stores very little energy.

Question Time!

1. What is the principal pigment in plants?

A.ChlorophyllB.ChloroplastsC.ChloroformD.Biomass

2. Where do light-dependent reactions occur?

A.ChloroplastsB.Cell WallC.ChlorophyllD.Cytoplasm

3. What are the inputs of the Calvin Cycle?

A. ATP and NADPHB. SunlightC. OxygenD. Ozone

4. What is a calorie?

A. The amount of energy needed to raise the temperature of 100 grams of water 50 degrees Celsius.

B. Bad for your health.C. A chemical compound that stores and

releases energy. D. The amount of energy needed to raise

the temperature of 1 gram of water 1 degree Celsius.

5. What are the inputs of Glycolysis?

A. Pyruvic AcidB. ATPC. GlucoseD. Noodles

6. Which of the following is not a part of a mitochondrion?

A. MatrixB. CristaeC. Inner MembraneD. Granum

7. Which of these doesn’t perform cellular respiration?

A. Polar bearB. A shipC. TurtlesD. Panda

8. The Krebs Cycle takes place in the…

A. AtmosphereB. MatrixC. StoveD. Cristae

9. What makes the most ATP?

A. Cellular RespirationB. PhotosynthesisC. Electron Transport SystemD. Monsters, Inc.

10. Which of the following is not an example of fermentation?

A. KimchiB. AlcoholC. Bread YeastD. Tomatoes

Answers!

1. A.2. A.3. A.4. D.5. C.6. D.7. B.8. B.9. C.10. D.