Biology 0610 | Paper 6 Mock 01 | Alternative to Practical

This question tests using a scale bar, classifying an arthropod, growth calculations, and the characteristics of living organisms.

(a) Measured against the scale bar in Fig. 10.1, the drawn locust body is about 22 mm (accept the value your ruler gives against the bar) [1].

(b) From Table 10.1, the body length at instar 3 is 20 mm [1].

(c) The locust has six legs and three main body parts (head, thorax, abdomen) [1]; an animal with six legs and three body parts is an insect [1]. [2]

(d) The increase in body length shows the characteristic growth [1].

(e) Shedding the exoskeleton to grow is moulting (accept ecdysis) [1].

(f) Increase from instar 1 to instar 5: \[44 - 8 = 36\ \text{mm}\] Working [1], answer 36 mm [1]. [2]

(g) Percentage increase = increase over the starting value, times 100: \[\frac{36}{8}\times 100 = 450\%\] Working [1], answer 450% [1]. Note the denominator is the original instar-1 length. [2]

(h) The pattern is that body length increases at each instar [1], and the increase gets larger at the later instars (the jumps grow: 5, 7, 10, 14 mm) [1]. [2]

(i) An arthropod must shed its exoskeleton because the exoskeleton is hard and cannot stretch [1]; it must be shed so a new, larger one can form and the body can grow [1]. [2]

(j) To measure length accurately, place the locust against a ruler (or use calipers) [1] and measure from the head to the tip of the abdomen at eye level while it is still [1]. [2]

(k) Any two variables kept constant: temperature, food supply, humidity, using the same locust [2].

(l) Any three other characteristics, each with an observation [4]: movement - it walks / jumps; nutrition - it feeds on leaves; sensitivity - it jumps when touched; reproduction - it lays eggs. (Also acceptable: respiration, excretion.)

This is the food-energy (calorimetry) experiment: burning food heats water, and the temperature rise lets you calculate the energy released.

(a) Highest temperature [1] Reading the thermometer in Fig. 6.1 gives \(46\,^{\circ}\text{C}\). [1]

(b) Volume of water [1] Reading the measuring cylinder gives \(25\ \text{cm}^3\). [1]

(c) Temperature rise [1] \[46-21=25\,^{\circ}\text{C}\] [1]

(d) Apparatus holding the food [1] The mounted needle. [1]

(e) Energy released [2] \[E=\text{volume}\times 4.2\times \text{temp rise}=25\times 4.2\times 25=2625\ \text{J}\] working [1], answer \(2625\ \text{J}\) [1].

(f) Energy per gram [2] \[\frac{2625}{0.40}=6562.5\ \text{J g}^{-1}\] (accept about \(6560\ \text{J/g}\) or \(6.56\ \text{kJ/g}\)) working [1], answer [1].

(g) Why the value is much lower than the packet [3] Any three of: much heat is lost to the surrounding air, the tube and the clamp [1]; not all the heat from the flame passes into the water [1]; the food may not burn completely, so some energy stays in the unburnt food [1].

(h) Two variables for a fair comparison [2] Any two of: volume of water; distance from the food to the tube; starting temperature; the same thermometer. [2]

(i) Two changes to improve accuracy [2] Any two of: shield the apparatus from draughts or insulate the tube; stir the water before reading; hold the flame closer to the tube; use a lid to trap heat. [2]

(j) One safety precaution [1] Any one of: wear eye protection; tie back long hair; keep the flame away from flammable materials; take care with the hot tube. [1]

(k) Why repeat the test [2] Repeating lets you calculate a mean and reduces the effect of anomalies [1], making the result more reliable [1].

This question tests careful measurement from drawings, a ratio, a magnification calculation, and how artery and vein structure relate to their functions.

(a) Measuring the wall thickness of vessel A along the marked line gives a value in the region of 20 to 32 mm (accept your own careful reading) [1].

(b) Measuring the wall thickness of vessel B gives about 6 to 12 mm [1].

(c) Measuring the lumen diameter of vessel B gives about 55 to 65 mm [1].

(d) Record your three measurements in the table [1] and calculate the ratio of wall thickness to lumen diameter for vessel B as \( \dfrac{\text{wall thickness}}{\text{lumen diameter}} \) [1]; for example \( \dfrac{9}{60} = 0.15 \) [1]. A worked example table is:

(e) The artery is vessel A [1], because it has the thicker wall relative to its lumen, which is needed to withstand the high pressure of blood pumped from the heart [1].

(f) Real size = image size ÷ magnification, so the real wall thickness of A is \( \dfrac{\text{measured value}}{50} \); for example \( \dfrac{26}{50} = 0.52\ \text{mm} \) [1 working, 1 answer].

(g) Vessel A suits carrying high-pressure blood because its thick, muscular wall withstands the high pressure [1]; elastic tissue lets the wall stretch and recoil to smooth the flow [1]; and the relatively narrow lumen helps keep the pressure high [1].

(h) Vessel B returns blood to the heart because its wide lumen offers little resistance, so blood at low pressure flows back easily [1]; its valves stop the blood flowing backwards [1]; together these help return the blood to the heart, even against gravity [1].

(i) Both drawings were made at the same magnification so that the sizes of the two vessels can be compared fairly (directly) [1].

(j) Any two features used to tell the vessels apart: A has a thicker wall; A has a smaller lumen; A has a more muscular wall [2].

(k) The tissue in the wall of A that allows it to recoil after stretching is elastic tissue [1].