Biology 0610 | Paper 2 Mock 01 | Multiple Choice (Extended)

Reading the table, the insect-resistant GM variety yields 9 t/ha with low insect damage while the normal variety yields only 6 t/ha with high damage. The data therefore show the GM crop gives a higher yield with less insect damage: fewer plants are eaten, so more survives to be harvested. The figures directly contradict any claim of a lower yield, no growth, or no difference between the two varieties.

Respiration A uses oxygen and releases a large amount of energy, giving carbon dioxide and water, which are the features of aerobic respiration. Respiration B, using no oxygen, releasing little energy and producing lactic acid, is anaerobic respiration. Combustion is burning (not respiration in cells) and photosynthesis makes food using light rather than releasing energy from it, so neither fits. The use of oxygen with products of carbon dioxide and water identifies aerobic respiration.

Roots and shoots respond to gravity in opposite ways. A root grows downwards, towards gravity, so it is positively gravitropic (this anchors the plant and reaches water). A shoot grows upwards, away from gravity, so it is negatively gravitropic (this lifts leaves towards light). So the root is positive and the shoot is negative gravitropic; saying both respond the same way misses this opposite behaviour.

Blood flows through the kidney so that waste can be filtered out and removed as urine. The kidney's job is to strip urea, the toxic nitrogen waste, out of the blood, so blood in the renal vein contains far less urea than blood arriving in the renal artery. Oxygen and glucose are not the kidney's target wastes, and carbon dioxide is removed by the lungs, not the kidney.

A shoot growing towards a light source coming from one side is showing positive phototropism: 'photo' for light, and 'positive' because the growth is towards the stimulus. This is an advantage because it moves the leaves into more light for photosynthesis. Negative phototropism would be growth away from light, hydrotropism is a response to water, and shoot gravitropism is a response to gravity, so growth towards the window is positive phototropism.

Dividing cells are common in a growing root tip because mitosis is producing new cells for growth. Growth means increasing the number of cells, and mitosis makes genetically identical cells to do this, which is why a rapidly growing region has many cells in division. The cells are not losing chromosomes, and meiosis (which makes gametes such as pollen) does not happen in a growing root tip. Link a region of rapid growth to mitosis making new cells.

A gene can exist in more than one version, and each different version is called an allele. Here the seed-colour gene has a green version and a yellow version, so each of these is an allele of that gene. An allele is not the same as a gamete (a sex cell), a chromosome (the whole DNA thread that carries many genes) or a phenotype (the observable feature the allele helps produce).

An egg cell is large because its cytoplasm contains food (energy) stores of fats and proteins that nourish the embryo during its first days before it can obtain nutrients from the mother. It is not larger because it carries more chromosomes (a gamete carries a half set), needs to swim, or has many mitochondria for movement; those describe the sperm's job, whereas the egg is a supply store.

In bright light the pupil narrows to protect the retina, so the correct stimulus-and-response pairing is bright light with the pupil becoming narrower, which is Row C. Rows that pair bright light with a wider pupil, or dim light with a narrower pupil, get the response the wrong way round, since dim light actually widens the pupil to let more light in.

Each mitotic division doubles the number of cells: 1 becomes 2, 2 becomes 4, and 4 becomes 8 after the third hour, following the doubling pattern in the table. This is repeated mitosis, where every cell divides into two, so the number follows \(1 \rightarrow 2 \rightarrow 4 \rightarrow 8\), a doubling each hour. After 3 hours there are 8 cells.

Each stoma is bordered by a pair of guard cells, and it is these cells that open and close the pore by changing shape as they gain or lose water. On a dry afternoon the guard cells lose water, become flaccid, and close the stoma to conserve water. Palisade cells carry out photosynthesis, root hair cells absorb water from soil, and xylem vessels transport water; none of these control the opening and closing of the stoma.

ADH makes the kidney reabsorb more water, giving a small volume of dark, concentrated urine. Person P drank little and produced a small, dark urine, which is the sign that the kidneys were acted on by the most ADH to conserve water. Person Q drank a lot and made pale, dilute urine, showing less ADH, so the kidneys were losing the excess water instead of saving it.

The table shows carbon dioxide in exhaled air rising from 4% to 6% after exercise. During exercise the muscles respire faster, and aerobic respiration releases carbon dioxide, so more carbon dioxide is produced and breathed out. Reduced respiration would lower carbon dioxide, photosynthesis does not occur in the lungs, and the oxygen level of the air is not what causes this rise, so increased respiration in the muscles is the cause.

Useful protein is only obtained when the bacteria multiply and switch the gene on. The correct row describes a bacterium that reproduces rapidly so the gene is expressed and protein is made in bulk: rapid division copies the recombinant plasmid into millions of cells, each reading the gene to build the protein. Rows describing slow or absent division give no protein, and a bacterium that loses the plasmid loses the gene entirely, so it cannot make protein in bulk.

Denitrifying bacteria break down nitrate ions in the soil and release nitrogen gas back into the air. They thrive in waterlogged, low-oxygen conditions, which is why such soils lose nitrate and become less fertile. Nitrogen-fixing bacteria do the opposite (adding nitrogen compounds to the soil), nitrifying bacteria make nitrates rather than remove them, and photosynthetic bacteria are not involved in this loss. The bacteria responsible for losing nitrate as nitrogen gas are the denitrifying bacteria.

When the solution around a cell is more concentrated than the cell contents, it has a lower water potential, so water moves out of the cell by osmosis, down the water potential gradient. Osmosis is passive and happens without warming, and movement is a net flow in one direction (outwards here), not equal in both directions, because there is a water potential difference between the cell and its surroundings.

Definitions must match the real meaning of each term. The correct row defines genetic engineering as changing an organism's genes by inserting or removing them, which is exactly the note's definition of genetic modification. Breeding the tallest plants together is selective breeding, not genetic engineering. The other wrong rows swap the vocabulary: a plasmid is a loop of DNA (not an enzyme that cuts DNA), and ligase is the joining enzyme (not a loop of DNA).

Protein digestion begins in the stomach, where the enzyme protease works in the acidic conditions created by hydrochloric acid. Each enzyme has an optimum pH, and the stomach protease is shaped to work best in acid. Amylase and maltase act on carbohydrates, not protein, and lipase acts on fat; and protein is not digested in alkaline or neutral conditions in the stomach. So protein digestion in the stomach involves protease working in acidic conditions.

The pupil reflex adjusts the amount of light entering the eye to suit the brightness. Moving into a dim corridor means less light is available, so the iris widens the pupil to allow more light to enter and reach the retina, helping you see in the low light. Widening the pupil is not about focusing on near objects (that is the job of the lens) or protecting the lens; it is about controlling light reaching the light-sensitive retina, and in dim conditions the aim is to let more in, not less.

Reacting quickly to danger is the fight-or-flight response, produced by the adrenal gland and adrenaline, which raises heart rate to ready the body fast. The pancreas with insulin lowers glucose after a meal, the pancreas with glucagon raises glucose during fasting, and the ovary with oestrogen controls puberty, so those gland-hormone pairs handle slower, longer-term changes rather than a rapid emergency response.

A benefit to the farmer is something that helps their crop or harvest. The table's benefit entry is that weeds can be killed without harming the crop: a herbicide-resistant crop lets the field be sprayed so the weeds die while the crop survives. The entry that the gene may spread to nearby weeds is listed as a concern, not a benefit, and a poisoned soil or fewer crops would be harms, not advantages.

The bases of a gene are read in triplets, and each triplet codes for one amino acid. The section shown contains three triplets (CAT, GGA and TTC), so it codes for 3 amino acids. Counting the triplets, not the individual bases, gives the number of amino acids; the nine individual bases here make up exactly three triplets, so the answer is three amino acids.

Light causes the guard cells to open the stomata, so more vapour can diffuse out and transpiration speeds up. The table shows the bubble moving furthest in bright light (11 mm) compared with dim light (6 mm) and darkness (2 mm), confirming that transpiration is fastest in bright light. In darkness the stomata tend to close, which is why the rate there is lowest.

The task is to find the wrongly classified row. ABO blood group falls into distinct categories (A, B, AB, O) with no intermediates, so it is discontinuous variation, but the row labels it continuous, making that row incorrect. The other rows are right: seed mass and hand span vary smoothly (continuous), and tongue rolling is either/or (discontinuous). So the blood-group row is the mistaken classification.

Burning coal releases sulfur dioxide, which dissolves in rain water to form an acid, producing acid rain that damages trees and lakes far downwind. Carbon dioxide and methane are greenhouse gases rather than the main cause of acid rain, and carbon monoxide is a toxic gas that binds to haemoglobin; the gas responsible for acid rain here is sulfur dioxide.

Excretion is the removal of the waste products of metabolism, the substances made by the chemical reactions inside cells. Carbon dioxide from respiration and urea from breaking down proteins are both such wastes, so removing them through the lungs and kidneys is excretion. It is not egestion, which removes undigested food that never entered the cells, and it is not movement or nutrition. Remember that excretion deals with waste the body itself made, not with food passing through the gut.

An insect-pollinated flower usually has brightly coloured, scented petals (often with nectar) to attract the insects that carry its pollen. Small dull green petals, no petals, or large feathery stigmas hanging outside are wind-pollination features. Insects are attracted by colour and scent.

Higher yields, reduced pesticide use, and insect resistance are all benefits of GM crops, so the odd one out is the drawback. The disadvantage is that genes may pass to wild plants, the environmental risk that a modified gene could escape into wild relatives. The other three statements are all advantages, so they cannot be the disadvantage being asked for.

Egestion and excretion are separated by where the material came from. Faeces is made of undigested food that passed through the gut but was never absorbed into the body's cells, so removing it is egestion. Excretion, by contrast, removes wastes made by the cells' own chemical reactions, such as urea or carbon dioxide. The faeces is not a product of respiration and is not simply water, so the correct reason is that it was never absorbed into the body's cells.

Typical mammal features include a body covered in hair, feeding the young on milk, and a constant (warm) body temperature. Only Organism 1 shows all three. The others fail at least one: feathers point to a bird, and scales or moist skin with a varying body temperature point to a reptile or amphibian. Check that every listed mammal feature is present, not just one.

Two life processes are shown together here. Sensitivity is detecting and responding to a stimulus, and the earthworm detects the bright light; movement is an action causing a change of position, and the worm pulls itself away. So the correct pairing is movement and sensitivity. It is not growth or reproduction, which concern increasing in mass and making new organisms, nor excretion, nutrition, respiration or egestion, none of which is happening in this quick escape.

Something is classified as living when it carries out the life processes, so yeast counts as a living organism because it can respire, grow and reproduce. Conducting electricity, dissolving in water or reflecting light are ordinary physical behaviours that many non-living substances also show and prove nothing about life. It is the presence of the biological processes, especially respiration, growth and reproduction, that confirms yeast is alive.

A long body made of many similar segments with legs on nearly every segment describes a myriapod, the group that includes centipedes and millipedes. Insects have just three body parts and three pairs of legs, arachnids have two body parts and four pairs of legs, and crustaceans have two pairs of antennae and are mostly aquatic, so none of these matches a many-segmented, many-legged body. The repeating leg-bearing segments are the giveaway for a myriapod.

Two processes are described. Nutrition is the taking in of food materials, which the organism does first; respiration is the chemical breakdown of those nutrient molecules in cells to release energy, which is then used to keep warm. So the pair is nutrition and respiration. It is not movement or excretion (removing waste), nor sensitivity or reproduction, and note that using the released energy for warmth is a use of respiration, not a separate life process here.

The skin defends the body by acting as a barrier that physically stops pathogens entering, which is its role in the body's first line of defence. It does not digest pathogens in the blood (that is closer to phagocytosis by white blood cells) and it does not make antibodies (that is the job of lymphocytes). Insulin is a hormone controlling blood glucose and has nothing to do with fighting pathogens. Keep the skin's role simple: it is a barrier that keeps pathogens out.

This asks for a pairing where both the stated advantage and the stated risk are genuine. The correct row gives higher yields and added vitamins as a real benefit alongside the real concern that modified genes may spread to wild plants, matching the note's point that inserted genes can escape to wild relatives. The other rows fail because their 'advantages' are biological nonsense: GM crops do not stop respiring or become non-living, and a modified crop does not have less vitamin content as a benefit.

Use \( \text{magnification} = \frac{\text{image size}}{\text{actual size}} \). Both sizes are in millimetres, so divide directly: \[ \frac{30\ \text{mm}}{0.15\ \text{mm}} = 200 \] The magnification is x200 (no unit). The value x2000 comes from dividing by 0.015 instead of 0.15, a decimal-point slip; check by reversing the sum: \( 200 \times 0.15 = 30\ \text{mm} \), which matches the image size.

Carbon dioxide is a raw material for photosynthesis and is often the factor limiting the rate, because it makes up only a small fraction of the air. Adding more carbon dioxide removes that limit, so the plants photosynthesise faster, make more food and grow better; this is the grower's aim. It is not done to reduce water loss, kill pests or warm the soil. The point of enriching the air with carbon dioxide is to increase the rate of photosynthesis.

The baby received these antibodies ready-made from its mother before birth, so they provide passive immunity. The baby's own body did not make them and does not produce replacements, so as the borrowed antibodies are gradually broken down their level falls and eventually reaches zero. The fall is not because the baby is being vaccinated, because the antibodies turn into pathogens, or because the baby keeps making more; it is simply that the baby does not replace these antibodies itself.

The stages must be ordered from what physically comes first to what comes last. The correct row runs cut the gene from human DNA, then seal it into the plasmid with ligase, then the bacterium expresses the gene. Expression, the making of the protein, is the final outcome, so any row that has the bacterium expressing the gene first, or that seals the gene into a plasmid before the gene has been cut out, breaks the required cause-and-effect order.