Photosynthesis

Name Skyler Fortescue Class Blue Date January 6, 2014

8.1 Energy and Life
Chemical Energy and ATP
For Questions 1–6, complete each statement by writing the correct word or words.

1. energy is the ability to do work.

2. The main chemical compound cells use for energy is Adenosine triphosphate (ATP)

3. Ribose is a 5-carbon sugar molecule that is part of an ATP molecule.

4. The phosphate groups of ATP are the key to its ability to store and supply energy.
5. ATP releases energy when it breaks bonds between its phosphate groups.
6. Most cells only store enough ATP for short amounts of activity.

7. Label each part of the diagram of an ATP molecule below.

Adenine Ribose three phosphates

8. Energy is needed to add a third phosphate group to ADP to make ATP. What is a cell’s source of this energy? They get this energy from food.

Heterotrophs and Autotrophs
For Questions 9-13, write True if the statement is true. If the statement is false, change the underlined word or words to make the statement true.

True 9. All heterotrophs must eat food to get energy.

True 10. Autotrophs do not need to eat food because they make food.

False sunlight 11. The energy in food originally came from ATP.

False pulling together 12. The term photosynthesis means “pulling apart with light” in Greek.

True__ 13. The energy of sunlight is stored in the chemical bonds of carbohydrates.

14. Complete the table comparing two types of organisms.

Autotrophs and Heterotrophs
Type
Description
Examples
Autotrophs
An organism that is able to create its own food through photosynthesis (simple organic substances)
Plants
Heterotrophs
An organism that “feeds” by absorbing complex organic substances.
Animals/humans

8.2 Photosynthesis: An Overview
Chlorophyll and Chloroplasts
For Questions 1–6, complete each statement by writing the correct word or words.

1. The chlorophyll of light determines its color.

2. Chemicals that absorb light are called pigments.

3. Chlorophyll makes plants look green because it reflects green light.

4. Chloroplasts contain an abundance of saclike photosynthetic membranes called Thylakoid.

5. The Stroma is the fluid portion of the chloroplast located outside the thylakoids.

6. The visible light absorbed by chlorophyll raises the energy level of the chlorophyll’s electrons.

7. Label the internal parts of the chloroplast below.

Stroma
Lumen Thylakoid

High-Energy Electrons
8. Where do the high-energy electrons carried by NADPH come from?
Photosystem I

An Overview of Photosynthesis
For Questions 9–11, write the letter of the correct answer on the line at the left.

B 9. What are the reactants of the photosynthesis reaction?
A. chlorophyll and light C. carbohydrates and oxygen
B. carbon dioxide and water D. high-energy electrons and air
C 10. What are the products of the light-dependent reactions?
A. chloroplasts and light C. oxygen and ATP
B. proteins and lipids D. water and sugars
A 11. Where do the light-independent reactions occur?
A. stroma C. chlorophyll
B. thylakoids D. mitochondria

14. Complete the illustration by writing the reactants and products of the light-dependent and light-independent reactions. Also, fill in the energy source that excites the electrons.

8.3 The Process of Photosynthesis
The Light-Dependent Reactions: Generating ATP and NADPH
For Questions 1–5, write True if the statement is true. If the statement is false, change the underlined word or words to make the statement true.

True 1. Photosystems are clusters of chlorophyll and proteins.

Photosystem II 2. The light-dependent reactions begin when photosystem I absorbs light.

True 3. Electrons from water molecules replace the ones lost by photosystem II.

NADPH 4. ATP is the product of photosystem I.

Energy 5. ATP and NADPH are two types of protein carriers.

6. How does ATP synthase produce ATP? Positive hydrogen ions pass through the ATP synthase which then causes it to go into the stoma and the ATP synthase spins which releases energy.
7. When sunlight excites electrons in chlorophyll, how do the electrons change?
The electron energy increases.
8. Where do the light-dependent reactions take place? In the thylakoid membrane

The Light-Independent Reactions: Producing Sugars
10. What does the Calvin cycle use to produce high-energy sugars?
The ATP and the NADPH produce sugars. 11. Why are the reactions of the Calvin cycle called light-independent reactions?
Because they get energy from ATP and NADPH and they do not require light. 12. What makes the Calvin cycle a cycle?
It repeats over and over. 13. Complete the diagram of the Calvin cycle by filling in the missing labels.
1ST blank: 12ccc
2nd: 12 ADP
3rd: 12 ccc
4th: 10 ccc
5th: 6 ADP
6th: 6cccccc

Factors Affecting Photosynthesis
14. What are three factors that affect the rate at which photosynthesis occurs?
Light, temperature and water.