Photosynthesis Review Worksheet

Photosynthesis Review Worksheet

Part A

Match the terms below with the correct description

Chlorophyll

Chloroplast

Electromagnetic spectrum

Electron transport chain

Grana

Light-dependant reactions

Calvin Cycle

Photon

Photosynthesis

Photosystem

Stroma

Thylakoid

a. ____ Photon _______packet of solar energy

b. Light-dependant reactions energy-capturing portion of photosynthesis that takes place in thylakoid membranes of chloroplasts and cannot proceed without solar energy, it produces ATP and NADPH

c. Chlorophyll green pigment that absorbs solar energy and is important in photosynthesis

d. Stroma large, central compartment in a chloroplast that is fluid filled and contains enzymes used in photosynthesis

e. Chloroplast membrane-bounded organelle with chlorophyll – containing membranous thylakoids; where photosynthesis takes place

f. Photosystem Photosynthetic unit where solar energy is absorbed and high-energy electrons are generated; contains a pigment complex and an electron acceptor

g. ETC Passage of electrons along a series of carrier molecules form a higher to a lower energy level; the energy released is used for the synthesis of ATP.

h. Photosynthesis Process usually occurring within chloroplasts whereby chlorophyll traps solar energy and carbon dioxide is reduced to a carbohydrate.

i. Photosystem Series of reactions in which light is captured to provide the energy to fix carbon dioxide into glucose in the chloroplast.

j. Calvin cycle Synthesis portion of photosynthesis that takes place in the stroma of chloroplasts and does not directly require solar energy; it uses the products of the light dependant reactions to reduce carbon dioxide to a carbohydrate

Part B

Answer the following questions

1. Explain the difference between autotrophs and heterotrophs. Give two examples of each.

Auto – make their own food: plants, cyanobacteria

Hetero – get food from others: people, fish

2. Explain why chloroplasts are green. (use the correct information from the electromagnetic spectrum)

Red and blue wavelengths are absorbed by pigments allowing green wavelengths to be reflected which we then see.

3. What is NADPH? What is the difference between NADP+ and NADPH? How does NADP+ turn into NADPH?

NADPH = electron carrier

NADP+ is empty and oxidized

NADPH is carrying electrons and is reduced

4. Write the chemical equation for the process of photosynthesis.

CO2 + H20 + PHOTON à (CH2O)n + O2 + H2O

5. What are the reactants and products of Light Dependant Reactions? Where in the chloroplast do they occur?

Reactants: Photon, H2O, Pheophytin,

Products: ATP, NADPH, O2

Location: Thylakoid membrane

6. What are the reactants and products of Light-Independent Reactions? Where in the chloroplast do they occur?

Reactants: CO2, RuBP

Products: G3P, more RuBP

Location: Stroma

Part C

The Light Dependent Reactions of photosynthesis occur on the thylakoid membranes of the chloroplast. Below is a diagram that describes the path of the electrons throughout the L-D reactions. Use it to answer the next set of questions.

1. Describe the first set of Light-Dependant reactions.

Photon splits H2O releasing O & H. Electrons are stripped from H+ and energized. The energized electrons travel down the ETC and are passed to the second photosystem.

2. Every time a photon is absorbed in the chlorophyll a 2 electrons are excited. They are not recycled. Where does the supply of electrons come from and where do they end up at the end of L-D set of reactions?

From - H20

End up - NADPH

3. What products result specifically from Photosystem I and Photosystem II?

O2, ATP, NADPH

4. When a water molecule is split, what is it split into? Where do all the resulting components end up?

H+ - stroma O2 - atmosphere

5. At what steps of L-D reactions is ATP made. What is it specifically used for? (this will be different depending when and where is it produced)

ETC of Photosystem II

Used to fuel Calvin cycle

6. Describe the action of protein carrier: ATP synthase? Explain why is it important to build up a Hydrogen ion concentration gradient in order to have it properly function?

H+ flowing back into the stroma pass through ATP-synthase. The energy of H+ moving down its concentration gradient provides the power for ATP-synthase.

Part D

1. What are Light-Independent Reaction often called? Calvin Cycle

2. Why is there a need to go on with Light – Independent reactions? Why not stop with the Light –Dependant Reactions since ATP and NADPH are energy carrying molecules?

Energy may need to be stored as carbs rather than used immediately

3. Where does the Carbon Dioxide come from? What will happen to it and what will it eventually become?

CO2 from atmosphere

Fixed into G3P (eventually complex carbohydrates)