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13+ · Biology

CE.S-B2 Biology: Cells, Body Systems and Reproduction

ISEB COMMON ENTRANCE ISEB Common Entrance Biology (13+) · Calculator allowed · about 60 minutes

Total Marks

Name: _______________________________ Date: ____ / ____ / ______

Answer ALL questions. Show all your working.

Which part of an animal cell controls the cell's activities and contains the genetic material?

A) Cytoplasm
B) Nucleus
C) Cell membrane
D) Vacuole

(Total for Question 1 is 1 mark)

State the function of each of the following animal cell structures.

(a)The cell membrane.(1)

(b)The mitochondria.(1)

(Total for Question 2 is 2 marks)

Give three structures found in a plant cell that are not found in an animal cell, and state one function of each.

(a)Structure 1 and its function.(1)

(b)Structure 2 and its function.(1)

(c)Structure 3 and its function.(1)

(Total for Question 3 is 3 marks)

A student draws a plant cell she has viewed under a light microscope.

(a)The actual width of the real cell is 0.05 mm. In her drawing, the width of the cell is 25 mm. Calculate the magnification of the drawing. Use: magnification = image size / actual size.(2)

(b)In the same drawing, the cell membrane is shown as a line 2 mm thick. Using your magnification from part (a), calculate the actual thickness of the cell membrane in micrometres (1 mm = 1000 micrometres).(2)

(Total for Question 4 is 4 marks)

For each specialised cell below, give one way it is adapted to its function.

(a)Root hair cell.(1)

(b)Sperm cell.(1)

(c)Red blood cell.(1)

(Total for Question 5 is 3 marks)

State the function of each organ in the human digestive system.

(a)The stomach.(2)

(b)The small intestine.(2)

(Total for Question 6 is 4 marks)

The table below is about digestive enzymes.

(a)Name the enzyme that breaks down starch into sugars.(1)

(b)Name the enzyme that breaks down protein into amino acids.(1)

(c)Name the enzyme that breaks down fats into fatty acids and glycerol.(1)

(d)Bile is not an enzyme. Explain what bile does to help digest fats.(2)

(Total for Question 7 is 5 marks)

Describe the path taken by blood as it flows from the right atrium of the heart, through the lungs, and back to the left ventricle.

(Total for Question 8 is 4 marks)

Compare the structure of arteries and veins.

(a)Give three structural differences between an artery and a vein.(3)

(b)Explain why arteries need thick, muscular walls.(2)

(Total for Question 9 is 5 marks)

Describe four ways in which the alveoli are adapted for efficient gas exchange.

(Total for Question 10 is 4 marks)

A student measures her breathing rate (breaths per minute) at rest and repeats the measurement three times, then measures it again immediately after two minutes of exercise. Resting results: 16, 18, 17. After exercise: 30, 32, 31.

(a)Calculate the mean resting breathing rate.(2)

(b)Describe the pattern shown by the data.(1)

(c)Explain, in terms of respiration, why breathing rate increases after exercise.(3)

(Total for Question 11 is 6 marks)

Answer the following questions about the skeletal system.

(a)Name the type of joint found at the knee.(1)

(b)Name the type of joint found at the hip.(1)

(c)State the difference between a tendon and a ligament.(2)

(d)Give one function of the human skeleton other than movement.(1)

(Total for Question 12 is 5 marks)

The biceps and triceps are an antagonistic muscle pair that move the arm at the elbow. Explain how this pair of muscles works together to bend and straighten the arm.

(Total for Question 13 is 6 marks)

State two physical changes that typically happen during puberty in males, and two that typically happen in females.

(a)One change in males.(1)

(b)A second change in males.(1)

(c)One change in females.(1)

(d)A second change in females.(1)

(Total for Question 14 is 4 marks)

The menstrual cycle in humans is typically 28 days long.

(a)State the day of the cycle on which menstruation (the period) typically begins.(1)

(b)State approximately when ovulation occurs in a 28-day cycle.(1)

(c)Describe what happens to the lining of the uterus if the released egg is not fertilised.(2)

(d)Name one hormone involved in controlling the menstrual cycle.(1)

(Total for Question 15 is 5 marks)

Answer the following questions about the human reproductive system.

(a)State the function of the testes.(1)

(b)State the function of the oviduct (fallopian tube).(1)

(c)State the function of the ovary.(1)

(d)State the function of the uterus.(1)

(e)The testes are held outside the main body cavity, in the scrotum. Explain why this is important for sperm production.(2)

(Total for Question 16 is 6 marks)

Human gestation (pregnancy) lasts approximately 40 weeks.

(a)Assuming 1 month is approximately 4 weeks, calculate the length of a typical human gestation in months.(2)

(b)Calculate the approximate number of days in a 40-week gestation.(2)

(c)Describe the role of the placenta during pregnancy.(2)

(Total for Question 17 is 6 marks)

State the function of each of these flower structures.

(a)Petals.(1)

(b)Sepals.(1)

(c)Anther.(1)

(d)Stigma.(1)

(e)Ovary.(1)

(Total for Question 18 is 5 marks)

Compare insect-pollinated flowers with wind-pollinated flowers.

(Total for Question 19 is 6 marks)

A student wants to investigate the effect of temperature on the percentage of cress seeds that germinate.

(Total for Question 20 is 6 marks)

Cells are usually very small. This question looks at why, by comparing two cube-shaped cells.

(a)A cube-shaped cell has sides of length 2 mm. Calculate its surface area to volume ratio.(2)

(b)A second cube-shaped cell has sides of length 4 mm. Calculate its surface area to volume ratio.(2)

(c)State which cell would be more efficient at obtaining substances by diffusion, and explain why, using your answers to (a) and (b).(2)

(Total for Question 21 is 6 marks)

A tissue sample starts with 5 cells. The cells divide by mitosis, doubling in number every 20 minutes.

(a)Calculate how many cells will be present after 2 hours.(3)

(b)Name the type of cell division responsible for this increase in cell number.(1)

(Total for Question 22 is 4 marks)

Mark scheme · CE.S-B2 Biology: Cells, Body Systems and Reproduction

Question 1

B1 B (nucleus)
Answer: B - Nucleus

Question 2

(a) B1 controls what substances enter and leave the cell
(a) Answer: Controls the movement of substances into and out of the cell.
(b) B1 site of (aerobic) respiration, releasing energy for the cell
(b) Answer: They are the site of aerobic respiration, releasing energy the cell needs.

Question 3

(a) B1 cell wall - made of cellulose, gives the cell strength/support/shape (any one function)
(a) Answer: Cell wall - supports and strengthens the cell.
(b) B1 chloroplast - contains chlorophyll and is the site of photosynthesis
(b) Answer: Chloroplast - site of photosynthesis.
(c) B1 permanent vacuole - contains cell sap, helps keep the cell rigid/turgid
(c) Answer: Permanent (large) vacuole - keeps the cell turgid/rigid by storing cell sap.

Question 4

(a) M1 correct substitution: 25 / 0.05
(a) A1 500 (allow x500, magnification has no units) cao
(a) Answer: x500
(b) M1 real size = image size / magnification = 2 / 500 (= 0.004 mm), or correct unit conversion shown
(b) A1 4 micrometres (or 4 um) cao ft from (a)
(b) Answer: 4 micrometres

Question 5

(a) B1 long extension/large surface area for absorbing water and mineral ions
(a) Answer: Has a long extension giving a large surface area to absorb water and minerals.
(b) B1 tail/flagellum for swimming, or many mitochondria for energy to swim to the egg
(b) Answer: Has a tail (flagellum) and many mitochondria to provide energy for swimming to the egg.
(c) B1 no nucleus (more room for haemoglobin) or biconcave shape (large surface area) for carrying oxygen
(c) Answer: Has no nucleus, leaving more space for haemoglobin, and a biconcave shape that increases surface area for carrying oxygen.

Question 6

(a) B1 produces (hydrochloric) acid which kills bacteria
(a) B1 produces protease/pepsin which begins digestion of protein
(a) Answer: Produces hydrochloric acid (kills bacteria in food) and produces protease (pepsin), which begins digesting protein.
(b) B1 site of further digestion (enzymes from pancreas, bile from liver)
(b) B1 absorption of digested food (nutrients) into the blood, aided by villi increasing surface area
(b) Answer: Completes digestion using enzymes and bile, and absorbs digested food into the blood - its villi give a large surface area for absorption.

Question 7

(a) B1 amylase
(a) Answer: Amylase.
(b) B1 protease (accept pepsin)
(b) Answer: Protease (pepsin).
(c) B1 lipase
(c) Answer: Lipase.
(d) B1 emulsifies fat, breaking it into small droplets
(d) B1 this increases the surface area of fat for lipase to act on
(d) Answer: Bile emulsifies fat into small droplets, increasing the surface area for lipase to break it down more quickly.

Question 8

B1 right atrium to right ventricle
B1 right ventricle pumps blood through the pulmonary artery to the lungs
B1 blood picks up oxygen (and releases carbon dioxide) at the lungs and returns via the pulmonary vein
B1 blood enters the left atrium, then passes to the left ventricle
Answer: Right atrium - right ventricle - pulmonary artery - lungs (gas exchange) - pulmonary vein - left atrium - left ventricle.

Question 9

(a) B1 artery has a thick, muscular wall; vein has a thin wall
(a) B1 artery has a narrow lumen; vein has a wide lumen
(a) B1 vein contains valves; artery does not
(a) Answer: Arteries have thick muscular walls, a narrow lumen and no valves; veins have thin walls, a wide lumen and valves.
(b) B1 blood in arteries is at high pressure (pumped directly from the heart)
(b) B1 thick wall withstands this pressure and prevents the artery bursting
(b) Answer: Arteries carry blood at high pressure straight from the heart; the thick muscular wall withstands this pressure and stops the vessel bursting.

Question 10

B1 large (total) surface area
B1 wall is one cell thick, giving a short diffusion distance
B1 good (capillary) blood supply, maintaining a steep concentration gradient
B1 moist lining, allowing gases to dissolve
Answer: Alveoli have a large surface area, walls one cell thick, a rich capillary blood supply and a moist lining.

Question 11

(a) M1 (16 + 18 + 17) / 3
(a) A1 17 (breaths per minute) cao
(a) Answer: 17 breaths per minute
(b) B1 breathing rate increases (roughly doubles/nearly doubles) after exercise compared with rest
(b) Answer: Breathing rate is much higher after exercise than at rest (roughly doubles, from a mean of 17 to a mean of about 31).
(c) B1 exercising muscles respire (aerobically) faster to release more energy for contraction
(c) B1 this needs more oxygen (and glucose) to be delivered to the muscles
(c) B1 more carbon dioxide is produced and must be removed, so breathing rate/depth increases to supply more oxygen and remove more carbon dioxide
(c) Answer: Muscles respire faster during exercise, needing more oxygen and producing more carbon dioxide; breathing rate rises to supply the extra oxygen and remove the extra carbon dioxide.

Question 12

(a) B1 hinge joint
(a) Answer: Hinge joint.
(b) B1 ball and socket joint
(b) Answer: Ball and socket joint.
(c) B1 a tendon joins muscle to bone
(c) B1 a ligament joins bone to bone (holds joints together)
(c) Answer: Tendons connect muscle to bone; ligaments connect bone to bone, holding joints together.
(d) B1 support, or protection (of organs), or production of blood cells (red bone marrow), or storage of minerals (any one)
(d) Answer: Any one of: support, protection of organs, production of blood cells in bone marrow, or storage of minerals such as calcium.

Question 13

Level 1 (1-2): Basic statement that muscles work in pairs, or that one muscle contracts and one relaxes, with little further detail.
Level 2 (3-4): Describes that the biceps contracts to bend the arm and the triceps contracts to straighten it, with some reference to relaxation of the opposing muscle.
Level 3 (5-6): Full explanation using the term antagonistic pair, correctly stating both muscles are attached to bone by tendons across the joint, explains muscles can only pull (contract) not push, so one contracts while its partner relaxes for each movement, in both directions.
Indicative content:
- biceps and triceps are attached to bones by tendons, on either side of the elbow joint
- muscles can only pull/contract, they cannot push, which is why they must work in antagonistic pairs
- to bend (flex) the arm, the biceps contracts and shortens while the triceps relaxes
- to straighten (extend) the arm, the triceps contracts and shortens while the biceps relaxes
- the contracting muscle pulls on the bone across the joint, producing movement, while the relaxed partner is stretched

Question 14

(a) B1 testes enlarge and begin producing sperm, or voice breaks/deepens, or facial/body hair grows, or shoulders broaden (any one)
(a) Answer: Any one of: testes enlarge and begin producing sperm; voice deepens; facial/body hair grows; shoulders broaden.
(b) B1 a second, different change from the list above
(b) Answer: A second change different from part (a), e.g. voice deepens if part (a) named sperm production.
(c) B1 breasts develop, or hips widen, or menstruation/periods begin, or ovulation begins (any one)
(c) Answer: Any one of: breasts develop; hips widen; menstruation begins; ovulation begins.
(d) B1 a second, different change from the list above
(d) Answer: A second change different from part (c).

Question 15

(a) B1 day 1
(a) Answer: Day 1.
(b) B1 around day 14 (accept day 13-15)
(b) Answer: Approximately day 14.
(c) B1 the (thickened) uterus lining breaks down
(c) B1 it is shed/lost through the vagina as the menstrual bleed, and the cycle then repeats
(c) Answer: The thickened uterus lining breaks down and is shed through the vagina as the menstrual bleed, and the cycle then starts again.
(d) B1 oestrogen, or progesterone, or FSH, or LH (any one)
(d) Answer: Any one of: oestrogen, progesterone, FSH, LH.

Question 16

(a) B1 produce sperm (and the hormone testosterone)
(a) Answer: Produce sperm and the hormone testosterone.
(b) B1 carries the egg from the ovary to the uterus; usual site of fertilisation
(b) Answer: Carries the egg towards the uterus and is where fertilisation usually occurs.
(c) B1 produces eggs (and hormones oestrogen/progesterone)
(c) Answer: Produces eggs and hormones such as oestrogen.
(d) B1 where the fetus develops/grows during pregnancy
(d) Answer: Where the fetus develops during pregnancy.
(e) B1 sperm production needs a temperature slightly below normal (core) body temperature
(e) B1 the scrotum keeps the testes cooler, allowing sperm to be produced normally/efficiently
(e) Answer: Sperm production works best at a temperature slightly below normal body temperature; keeping the testes outside the body, in the scrotum, keeps them cooler so sperm are produced properly.

Question 17

(a) M1 40 / 4
(a) A1 10 (months) cao
(a) Answer: 10 months
(b) M1 40 x 7
(b) A1 280 (days) cao
(b) Answer: 280 days
(c) B1 allows exchange of oxygen and nutrients from mother's blood to fetus's blood, and waste (e.g. carbon dioxide) from fetus to mother
(c) B1 the mother's and fetus's blood do not mix; substances diffuse across the placenta
(c) Answer: The placenta allows oxygen and nutrients to pass from the mother's blood to the fetus's blood, and waste products such as carbon dioxide to pass the other way, by diffusion, without the two blood supplies mixing.

Question 18

(a) B1 attract pollinators (often by colour and/or scent)
(a) Answer: Attract pollinators, often using bright colour and/or scent.
(b) B1 protect the flower bud before it opens
(b) Answer: Protect the flower bud before it opens.
(c) B1 produces pollen (male gametes)
(c) Answer: Produces pollen, which contains the male gametes.
(d) B1 receives pollen during pollination
(d) Answer: Receives pollen grains during pollination.
(e) B1 contains the ovule(s)/female gamete(s); develops into the fruit after fertilisation
(e) Answer: Contains the ovule(s), the female gametes, and develops into the fruit after fertilisation.

Question 19

B1 insect-pollinated: large, brightly coloured petals
B1 wind-pollinated: small, dull or absent petals
B1 insect-pollinated: produces scent and nectar to attract insects
B1 wind-pollinated: no scent or nectar produced
B1 insect-pollinated: fewer, larger, sticky/spiky pollen grains, and the stigma is inside the flower
B1 wind-pollinated: large amounts of small, light, smooth pollen, and a large feathery stigma hanging outside the flower
Answer: Insect-pollinated flowers have large, bright, scented petals with nectar, and fewer, larger sticky pollen grains with the stigma inside the flower; wind-pollinated flowers have small, dull petals with no scent or nectar, and produce large amounts of small, smooth, light pollen, with a large feathery stigma hanging outside the flower to catch pollen from the air.

Question 20

B1 identifies the independent variable: temperature (e.g. testing at several different temperatures such as 5C, 15C, 25C, 35C)
B1 identifies the dependent variable: number/percentage of seeds that germinate (in a set time)
B1 states a control variable, e.g. same type/number of seeds, same amount of water, same light conditions
B1 gives a reason for controlling a variable, e.g. so that temperature is the only factor affecting the result (fair test)
B1 states that each temperature should be repeated (e.g. 3 times) and a mean calculated, to improve reliability
B1 describes how results are recorded, e.g. counting the number of seeds that have germinated after a set number of days at each temperature
Answer: Set up equal numbers of cress seeds on damp paper at several different temperatures (independent variable), keeping the number/type of seeds, amount of water and light conditions the same (control variables) to keep the test fair. Repeat each temperature (e.g. 3 times) and calculate a mean to improve reliability, then count the number/percentage of seeds that have germinated (dependent variable) after a fixed number of days at each temperature.

Question 21

(a) M1 surface area = 6 x 2² = 24 mm² and volume = 2³ = 8 mm³
(a) A1 ratio = 3 : 1 (or 3) cao
(a) Answer: 3 : 1
(b) M1 surface area = 6 x 4² = 96 mm² and volume = 4³ = 64 mm³
(b) A1 ratio = 1.5 : 1 (or 96:64 simplified) cao
(b) Answer: 1.5 : 1
(c) B1 the smaller (2 mm) cell, because it has the larger surface area to volume ratio (3 : 1, compared with 1.5 : 1)
(c) B1 a larger ratio means relatively more surface area is available, per unit of volume needing supply, for substances to diffuse across
(c) Answer: The 2 mm cell is more efficient, because its surface area to volume ratio (3:1) is larger than that of the 4 mm cell (1.5:1), so relatively more surface is available for diffusion for each unit of volume that needs supplying.

Question 22

(a) M1 number of doublings = 120 minutes / 20 minutes = 6
(a) M1 2⁶ (= 64), then multiplied by the starting number of cells: 5 x 64
(a) A1 320 (cells) cao
(a) Answer: 320 cells
(b) B1 mitosis
(b) Answer: Mitosis.

Biology: Cells, Body Systems and Reproduction - Worksheets, Questions and Revision