biochemsitry exam 3 Photosynthesis

Photosynthesis

In which of the following organelles does photosynthesis take place?

Ribosomes

Photoplasts

Membranes

Chloroplasts

Chloroplasts

Which of the following structures is formed in chloroplasts when the thylakoid membrane is organized into paired folds?

Lamellae

Calcium channel

Porin

Stroma

Lamellae

Which of the following explains how chloroplasts differ from mitochondria?

Only mitochondria have a double membrane.

Only the mitochondrion has DNA, RNA, and ribosomes.

In chloroplasts, the proton gradient is generated between the thylakoid lumen and the stroma.

Chloroplasts cannot generate ATP.

In chloroplasts, the proton gradient is generated between the thylakoid lumen and the stroma.

Which of the following are the primary roles of carotenoids in photosynthesis?

Resonance transfer pigments and Photo-oxidation

Resonance transfer and Photodiffusion protection

Accessory light harvesting and Photoprotection from reactive oxygen species

Accessory light harvesting and Photo-oxidation

Accessory light harvesting and Photoprotection from reactive oxygen species

When light energy is absorbed by chlorophyll, an electron is promoted to a higher orbital and then transferred to a suitable acceptor, resulting in light energy conversion to chemical energy. Which of the following terms describes this type of reaction?

Mutase

Oxidation–reduction

Ligase

Isomerise

Oxidation–reduction

Which of the following represents the molecules of A and B in the reaction sequence below?
Chl + hv → Chl*

Chl* + A → Chl^.+ + A^–

Chl^.+ + A^– → Chl^.+ + B⁺

Electron-transfer

CO₂

Proton-donor

Chlorophyll

Electron-transfer

Where do electrons from water ultimately flow to, via PSI and PSII?

NADP⁺

NADH

NAD⁺

NAPDH

NADP⁺

Which of the following is NOT a property of photosystem II (PSII)?

Similar photosystem in photosynthetic bacteria

Found in cyanobacteria, green algae, and higher plants

Uses quinines as terminal electron acceptors

Light-driven H₂O evolution

Light-driven H₂O evolution

Which of the following is a property of both the P700 and the P680 reaction centres?

Contain chlorophyll monomers

Activated by visible light

Electron acceptors

Involved in light-driven O₂ evolution

Activated by visible light

Which of the following is the product(s) of the R. viridis photosynthetic reaction centre?

NADPH

Protons

Reduced ferredoxin

Mobile reduced quinone

Mobile reduced quinone

Which of the following is the equivalent of product formed, as defined by the quantum yield of photosynthesis?

Coenzyme Q

Carbohydrate

Light input

Photons

Light input

Which of the following statements regarding light is correct?

The energy of 700 nm light is greater than that of 400 nm light.

The quantum yield of photosynthesis can be described as CO₂ fixed per photon absorbed, or O₂ evolved per photon absorbed.

Photosynthesis allows 2 electrons to flow for each pair of photons absorbed per centre.

The energy of a photon of light is calculated by E = hν .

The energy of 700 nm light is greater than that of 400 nm light.

Which of the following terms defines photophosphorylation?

Dephosphorylation of ATP, resulting in a photon of light being released

Production of hexose from CO₂

ATP synthesis driven by light energy

Activation of enzymes with light

atp synthesis driven by light energy

Which of the following two components constitute the proton-motive force?

A pH gradient and an ATP/H⁺ ratio

An ATP/H⁺ ratio and a membrane potential

A membrane potential and a pH gradient

An ATP/H⁺ ratio and an ion equilibrium

a membrane potential and a pH gradient

Which of the following describes when does cyclic photophosphorylation take place?

When NADPH is high and therefore energy is used to drive the citrate cycle

When the proton gradient is not high enough to go all the way through the system

When ferredoxin is used to reduce the Mn cluster

When the NADPH/ NADP⁺ ratio is high and energy is used in generating ATP

When the NADPH/ NADP⁺ ratio is high and energy is used in generating ATP

Which of the following components are produced in the light reactions of photosynthesis and are used to convert carbon dioxide to sugar?

Water and ATP

Light and ATP

ATP and NADP⁺

ATP and NADPH

ATP and NADPH

Which of the following does NOT contribute to the activation of rubisco?

Ribulose-1,5-bisphosphate released from E

Zn²⁺ binding

Rubisco activase

Carboxylation of E

Zn²⁺ binding

Which of the following statements regarding the enzyme rubisco is correct?

Ribulose-1,5-bisphosphate is the substrate and carbon dioxide is the product.

It is the least abundant enzyme in plants.

Its catalytic site has both carboxylase and oxygenase activity.

It releases 2 molecules of glyceraldehyde-3-phosphate as products.

Its catalytic site has both catboxylase and ocygenase activity

Which of the following describes how photorespiration avoided in C-4 plants?

Carbon dioxide carried toward an oxygen-rich area of the plant

Carbon dioxide transportation from the mesophyll cells to the bundle sheath cells

Increased concentration of ribulose-1,5-bisphosphate

Decreased concentration of phosphoglycolate

Carbon dioxide transportation from the mesophyll cells to the bundle sheath cells

Which of the following is NOT a characteristic of a C-4 plant?

Pyruvate-P_i dikinase

Carbon dioxide uptake in the daytime and fixation at night

Expenditure of 2 high-energy phosphate bonds for each transport of carbon dioxide

Transport of carbon dioxide and reducing power from the mesophyll cells to the bundle sheath cells

Carbon dioxide uptake in the daytime and fixation at night

Which of the following essential enzymes in C-4 plants is used to conserve CO₂ and avoid photophosphorylation?

PEP carboxylase

Ribulose-5-phosphate kinase

Aldolase

Rubisco

PEP carboxylase