13. Photosynthesis
A section of Biology, 9700
Listing 10 of 183 questions
is a labelled diagram of a leaf palisade mesophyll cell, as seen with a high quality light microscope. cytoplasm mitochondrion nucleus golgi body chloroplast cell wall vacuole tonoplast plasmodesma An electron micrograph of the same leaf mesophyll cell at the same magnification would show more detail than is shown in . Explain why, at the same magnification, an electron micrograph is able to provide more detail than a light micrograph. Describe three additional features that could be seen on an electron micrograph of the leaf mesophyll cell that are not seen in . 1. 2. 3. The length of the labelled chloroplast in is 5.0 μm. Calculate the magnification of the cell shown in . Show your working. magnification × In , starch granules are visible within the chloroplasts. Starch is the most common storage compound of plants. It is composed of amylopectin and amylose. Describe the structural differences between amylopectin and amylose. State one role of magnesium ions within chloroplasts.
9700_w12_qp_22
THEORY
2012
Paper 2, Variant 2
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shows some of the reactions that take place inside a palisade mesophyll cell. CO2 rubisco glycerol amino acids hexose sugars sucrose cellulose starch ATP ATP GP TP NADP reduced NADP ADP + Pi A B ADP + Pi lipid protein C Identify substances A, B and C. A B C Name precisely the process that produces reduced NADP. Name the type of reaction that takes place to produce starch from hexose sugars and name the type of bonds formed. reaction bond Describe how carbon dioxide reaches the inside of a palisade mesophyll cell from the external atmosphere. The optimum pH for the activity of rubisco is pH8. Explain why the illumination of chloroplasts leads to optimum pH conditions for rubisco.
9700_w14_qp_41
THEORY
2014
Paper 4, Variant 1
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shows some of the reactions that take place inside a palisade mesophyll cell. CO2 rubisco glycerol amino acids hexose sugars sucrose cellulose starch ATP ATP GP TP NADP reduced NADP ADP + Pi A B ADP + Pi lipid protein C Identify substances A, B and C. A B C Name precisely the process that produces reduced NADP. Name the type of reaction that takes place to produce starch from hexose sugars and name the type of bonds formed. reaction bond Describe how carbon dioxide reaches the inside of a palisade mesophyll cell from the external atmosphere. The optimum pH for the activity of rubisco is pH8. Explain why the illumination of chloroplasts leads to optimum pH conditions for rubisco.
9700_w14_qp_42
THEORY
2014
Paper 4, Variant 2
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is a diagram of a palisade cell from a leaf. Using label lines and the letters X, Y and Z, identify a structure in that: • contains RuBP – X • is fully permeable – Y • is made mainly of phospholipids – Z An experiment was carried out to investigate the effect of light intensity on the rate of photosynthesis in an aquatic plant using the apparatus shown in . aquatic plant capillary tube test tube scale board plastic tube barrel of syringe plunger of syringe lamp d As photosynthesis took place, the oxygen produced formed a bubble of gas which moved along the scale in the capillary tube. The distance moved by the bubble in a fixed period of time was used to calculate the rate of photosynthesis. The light intensity was varied by altering the distance, d, between the lamp and the photosynthesising plant. The results are shown in Table 8.1. Table 8.1 light intensity / arbitrary units rate of photosynthesis / arbitrary units Using the data in Table 8.1, draw a graph to show the relationship between light intensity and the rate of photosynthesis. Explain the shape of the graph you have drawn, with reference to limiting factors. shows the absorption spectra of the photosynthetic pigments of a flowering plant. wavelength of light / nm absorbance chlorophyll a chlorophyll b carotenoids Name the accessory pigmentshown in . Outline the role of the accessory pigments in photosynthesis. Very little light of wavelength 550 nm is absorbed by the photosynthetic pigments. State what happens to most of this light. A graph can also be drawn to show the relationship between the wavelength of light and the rate of photosynthesis. State the name of this type of graph.
9700_w14_qp_43
THEORY
2014
Paper 4, Variant 3
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Questions Discovered
183