Question 113 marks
Question
Fig. 1.1 shows a spongy mesophyll cell from the leaf of a plant. The arrows show the net direction of movement of carbon dioxide molecules during daylight. A G B F E 0.01 mm D C Fig. 1.1 (a) The scale bar in Fig. 1.1 represents 0.01 mm. Convert 0.01 mm to micrometres. …… μm [1] (b) Table 1.1 shows: • the functions of some of the structures in plant cells • some of the names of the structures where these functions occur • some of the letters that label these structures in Fig. 1.1. Complete Table 1.1. Table 1.1 function structure letter in Fig. 1.1 nucleus chloroplast aerobic respiration contains cell sap and stores water A [5] (c) Carbon dioxide is a raw material for photosynthesis. (i) State the process by which carbon dioxide travels into the leaf from the air. …… [1] (ii) Describe the pathway taken by a molecule of carbon dioxide, from the air outside a leaf to a spongy mesophyll cell. …… [2] (d) Low concentrations of carbon dioxide in the air may restrict the rate of photosynthesis in plants. (i) State the term given to something present in the environment in such short supply that it restricts life processes. …… [1] (ii) State one other feature of the environment that may also restrict the rate of photosynthesis. …… [1] (e) Researchers have devised a process of artificial photosynthesis. They use gold nanoparticles as a catalyst to utilise green light to convert carbon dioxide to fuels, such as propane. Suggest the advantages to the environment of using artificial photosynthesis on a large scale. …… [2] [Total: 13]
Mark scheme
1(a) 10 (μm) ; 1 1(b) 5 one mark per correct row letter in function structure Fig. 1.1 storage of DNA / controls (named) activity of cell nucleus C ; / produces RNA / makes ribosomes photosynthesis chloroplast E ; / absorb light / AW mitochondrion aerobic respiration D ; / mitochondria contains cell sap and vacuole B ; stores water supports (the cell) / resists turgor pressure cell wall A ; / prevents bursting / AW 1(c)(i) diffusion ; 1 1(c)(ii) (enters through) stoma(ta) / between guard cells ; 2 (moves through) interconnecting / intercellular / air, spaces ; 1(d)(i) limiting factor ; 1 1(d)(ii) (low / no) light intensity / (extreme air) temperature / (low / no) water 1 (availability) / (incorrect) (wavelength of light / (short) day length ; 1(e) any two from: 2 1 reduces, extraction / conserves, (named) fossil / non-renewable, fuels ; 2 (temporarily) removes, carbon dioxide / greenhouse gases (from atmosphere) / does not add more, carbon dioxide / greenhouse gas (to the atmosphere) / idea that the process is carbon neutral ; 3 does not cause / prevents a further increase in, enhanced greenhouse effect ; 4 does not cause / prevents further increase in global warming / prevents further climate change ; 5 it is a sustainable process / uses renewable fuel source / described ; 6 AVP ; e.g. described example of less environmental impact caused by use of non-renewable (fossil) fuels ;