Photosynthesis (HL IB Biology)

During photosynthesis, the following reaction occurs.

            2H₂O → 4e^- + 4H⁺ + O₂

Which of the following statements relating to this reaction is not correct?

The graph shows the absorption spectra for chlorophyll a.

Which of the following statements, relating to the absorption spectra for chlorophyll and the action spectrum of photosynthesis for green plants, are correct?

I. The absorption spectra of chlorophyll pigments are obtained by measuring their absorption of indigo, violet, blue, green, yellow, orange and red light, whereas the action spectrum of chlorophyll is the wavelengths of light that bring about photosynthesis.

II. The absorption spectra for chlorophyll and the action spectrum of photosynthesis are both plotted using % absorbance on the Y-axis.

III. The absorption spectra for chlorophyll and the action spectrum of photosynthesis both display two main peaks, including a larger peak in the red region (~450 nm) and a smaller peak in the blue region (~670 nm).

IV. The absorption spectrum of chlorophyll displays a trough in the green/yellow portion of the visible spectra (~550 nm), whereas the action spectrum of photosynthesis does not.

A student investigated the effect of light intensity on the rate of photosynthesis by counting the number of bubbles released from the pondweed Elodea canadensis. The results are shown below.

Which of the following statements relating to the utilisation of carbon dioxide at differing light intensities are correct?

I. The rate of carbon dioxide uptake always increases proportionately as light intensity increases.

II. The rate of carbon dioxide uptake will decrease as the plant is moved away from the lamp.

III. The rate of carbon dioxide uptake will be greater at increased light intensities.

IV. The rate of carbon dioxide uptake becomes constant at increased light intensities as carbon dioxide becomes a limiting factor.

The graph below shows how varying light intensity affects the rate of carbon dioxide absorption by leaves, at different, fixed temperatures and carbon dioxide concentrations.

Which of the following rows correctly identifies the possible limiting factor for photosynthesis at I, II, III and IV?

The diagram below shows the Calvin cycle of the light-independent reactions.

Which of the following correctly identifies compound M to P?

The following steps describe non-cyclic photophosphorylation involving the electron transport chain.

1. Electrons from the photolysis of water replace lost electrons from photosystem II
2. Light passes to primary pigments in photosystem I and II
3. Electrons are passed from photosystem II to photosystem I via electron transport chain
4. Energy is released to synthesise ATP
5. Electrons are excited to a higher energy level

Which of the following represents the correct sequence of the steps?

The following molecules are all involved with the process of photosynthesis.

1. Glucose
2. ATP
3. Water
4. Reduced NADP
5. Carbon dioxide

Which of these molecules are involved with both the light dependent and light independent reactions?

Which of the following provides the best explanation of the process illustrated in the diagram?

Which of the following statements is not correct with regards to chemiosmosis in photosynthesis?

1. Protons move down their concentration gradient through ATP synthase located in the chloroplast membrane
2. The photolysis of water provides protons needed for chemiosmosis to occur
3. ADP is phosphorylated to ATP due to the energy released by the movement of electrons down the electron transport chain
4. A high concentration of protons build up outside the intermembrane space, creating a concentration gradient

Paper chromatography can be used to separate photosynthetic pigments obtained from chloroplasts. The chromatography strip shows distinct coloured pigment bands. Which pigments are represented by bands 3 and 4?

Which is the most correct statement about chlorophyll?

The graph shows how the rate of photosynthesis is affected by temperature. Which statements correctly explain why the rate decreases at higher temperatures?

1. Photosynthesis is an enzyme-catalysed metabolic pathway.
2. Enzymes denature at high temperatures.
3. Less carbon dioxide is available in the atmosphere.
4. Rate of respiration increases

A plant is grown in standard atmospheric air with a carbon dioxide concentration of approximately 400 ppm. The level of carbon dioxide is then reduced to below 100 ppm. Which of the following statements about the plant are correct? 

1. The rate of photosynthesis increases.
2. Respiration and growth continue until stored sugars are used up.
3. The rate of photosynthesis decreases.
4. Metabolism is reduced to save energy.

The following graphs show the absorption spectrum for chlorophyll a and the action spectrum showing the relative rate of photosynthesis at different wavelengths of light.

Why do the graphs look different?

A student designed the following experimental set-up to measure the effect of light intensity on the rate of photosynthesis. The experiment was repeated three times.

The results were inconsistent, how could the experimental set-up be improved?

The effect of different colours of light on the growth of Arabidopsis thaliana (thale cress) seedlings was studied. Three different colours of light were tested and measurements of seedling height, shoot length, and biomass were taken.

What conclusions can be drawn from the data?

In photosynthesis, the following reaction occurs: 

2H₂O → 4e^- + 4H⁺ + O₂ 

What happens to the oxygen generated through this reaction?

The image below shows a chloroplast.

Identify the location of the light independent and light dependent reactions.

Which events occur during the light dependent stage of photosynthesis?

1. ATP is produced
2. NADP is reduced to NADPH
3. Water splits into photons, electrons and oxygen
4. NADPH is oxidised to NADP

What are the functions of excited electrons in photosynthesis?

1. To generate a proton gradient
2. To reform RuBP
3. To reduce G3P
4. To reduce NADP

Which event occurs during non-cyclic photophosphorylation?

Which process is not part of the light-independent reaction of photosynthesis?

What allows the cyclic nature of the Calvin cycle?

Where is ATP synthase located in the chloroplast below?

The thylakoid intermembrane space has a small volume.

What advantage does this have for photosynthesis?