Photosynthesis review

How many molecules of ATP and NADPH are used in a single turn of Calvin cycle?

3 molecules of ATP and 2 molecules of NADPH

Define: Calvin Cycle

A biochemical pathway that produces a three-carbon sugar from carbon dioxide during photosynthesis.

Define: C4 pathway

A carbon fixation pathway in which CO2 is incorporated into four-carbon compounds.

Define: CAM pathway

A carbon fixation pathway in which CO2 is incorporated into organic compounds at night and released to enter the Calvin cycle during the day.

Define: stoma

A small pore on the surface of a plant through which water, O2, CO2, and other gases enter or leave the plant.

The Calvin Cycle begins when CO2 combines with a five-carbon carbohydrate called... A. RuBP B. PGA C. 3-G3P D. NADPH

A. RuBP

Chlorophyll-a... A. absorbs mostly orange-red and blue-violet light. B. absorbs mostly green light. C. is an accessory pigment D. is responsible for the red color of many autumn leaves.

A. absorbs mostly orange-red and blue-violet light

C3 and C4 plants differ in terms of the number of... A. steps in the Calvin cycle B. carbon atoms in the compound that CO2 is initially incorporated into. C. carbon atoms in the end product of the Calvin cycle D. ATP molecules used in the Calvin cycle.

B. carbon atoms in the compound that CO2 is initially incorporated into.

Water participates directly in the light reactions of photosynthesis by... A. donating electrons to NADPH B. donating electrons to photosystem II C. accepting electrons form the electron transport chains. D. accepting electrons from ADP.

B. donating electrons to photosystem II

What is the relationship between chemiosmosis and ATP synthase?

Both are a part of making ATP. Chemiosmosis is the process that the ATP is created by photosynthesis and the ATP made is catalyzed by the enzyme ATP synthase.

What is the relationship between granum and stroma?

Both are found in chloroplasts. Light Reaction is in the granum (they are also stacks of thylakoids in the chloroplasts) and the Calvin Cycle is in the stroma (the stroma also surrounds the thylakoids)

What is the relationship between chlorophyll-a and carotenoids?

Both are pigments but they absorb different wavelengths. Chlorophyll-a is really important because it sends out electrons. Carotenoids are accessory pigments that help chlorophyll-a capture light energy during photosynthesis.

The photosystems and electron transport changes are located in the... A. outer chloroplast membrane. B. inner chloroplast membrane. C. thylakoid membrane. D. stroma

C. thylakoid membrane

How do CAM plants differ from both C3 and C4 plants?

CAM plants open their stomata at night, while C4 and C3 plants open their stomata during the day.

Using (CH2O) as the general formula for a carbohydrate, write the simplest overall equation for photosynthesis.

CO2 + H2O ⎯⎯⎯→ CH2O + O2

The definition of C4 pathway is?

CO2 fixed into four-carbon compounds

How does the structure of a chloroplast enable it to build up a concentration gradient of protons?

Chloroplasts contain thylakoids that have an inner space (thylakoid space). When protons are pumped into the thylakoid space across the thylakoid membrane, the protons become more concentrated. The protons stay inside the membrane unless they're needed.

Organic compounds that can be made from the products of the Calvin cycle include... A. only carbohydrates B. only amino acids C. only lipids D. carbohydrates, amino acids, and lipids

D. carbohydrates, amino acids, and lipids

Both photosystem I and photosystem II... A. Receive electrons from other photosystems B. Donate electrons to a transport chain that generates NADPH C. donate protons to each other D. contain chlorophyll-a molcules

D. contain chlorophyll-a molecules

As light intensity increases, the rate of photosynthesis... A. continues to decrease. B. continues to increase. C. initially decreases and then levels off. D. initially increases and then levels off.

D. initially increases and then levels off.

The energy that is used to establish the proton gradient across the thylakoid membrane comes from the... A. synthesis of ATP B. synthesis of NADPH C. passage of electrons along the electron transport chain of photosystem II. D. splitting of water

D. splitting of water

Does increasing temperature always increase the rate of photosynthesis? (short answer on test)

No, the rate of photosynthesis will increase with the temperature until a certain point. After that point, the temperature is too high for the enzymes to function correctly and the rate of photosynthesis will start to decrease after that point.

Which photosystem--I or II-- most likely evolved first? Explain your reasoning.

Photosystem II because when the photosystem II loses electrons, they are quickly replaced by electrons from water. Photosystem I relies on photosystem II to feed it electrons, so photosystem I most likely evolved AFTER photosystem II.

Explain the function of the accessory pigments.

The accessory pigments help chlorophyll-a by capturing the light wavelengths that chlorophyll-a cannot take in. This allows the cell to take in more energy from the light.

Where does the energy used in the Calvin cycle come from? (short answers)

The energy used in the Calvin cycle comes from the ATP and NADPH that are made in the Light Reactions stage of photosynthesis.

Define: carbon fixation

The incorporation of carbon dioxide into organic compounds.

Why does the rate of photosynthesis increase, peak, and then decrease as temperature increases?

The stomata starts to close, which causes the rate of photosynthesis to peak and then decrease.

Stomata can open and close in response to changes in the CO2 concentration inside the leak. Would you expect stomata to open or close if the CO2 concentration decreased?

The stomata would open because it would allow for more CO2 to enter the leaf from surrounding air, causing photosynthesis.

What are the energy-carrying end products of the light harvesting reactions?

They are ATP and NADPH

Why is photosynthesis referred to as a biochemical pathway?

This is because the product of one chemical reaction is then used to help a different chemical reaction. All the products are linked to each other.

The definition of Calvin cycle is?

a series of enzyme-assisted chemical reactions that produces a three-carbon sugar molecule.

The definition of light reactions is?

a series of reactions that involve pigments

The definition of pigment is?

a substance that absorbs light

The definition of carotenoids is?

absorb wavelengths of light different from those absorbed by chlorophyll

The definition of thylakoids is?

disk-shaped structures inside chloroplasts

The definition of carbon fixation is?

incorporation of carbon dioxide into organic compounds

The definition of heterotrophs is?

organisms that get energy by consuming food.

The definition of autotrophs is?

organisms that use energy from sunlight or inorganic substances to make organic compounds

The definition of stomata is?

small pores in leaves

The definition of granum is?

stack of thylakoids

The definition of chlorophyll is?

the primary pigment involved in photosynthesis.

The definition of photosynthesis is?

the process by which light energy is converted to chemical energy.

The definition of chemiosmosis is?

the process that relies on a concentration of gradient of protons

The definition of electron transport chain is?

the series of molecules down which excited electrons are passed in a thylakoid membrane

The definition of CAM pathway is?

water-conserving process of carbon fixation