OCR A Level Biology

Topic Questions

A LevelBiologyOCRTopic Questions3. Exchange & Transport3.1 Exchange Surfaces

3.1 Exchange Surfaces

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1
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Explain why a single-celled organism, like an amoeba, requires diffusion alone for enough oxygen to be supplied.

  • The metabolic activity of single-celled organisms is low while the surface area-to-volume (SA: V) ratio is large

  • Carbon dioxide production is low and oxygen demand is high

  • Single-celled organisms, like amoeba, produce high amounts of carbon dioxide and require less oxygen

  • The metabolic activity of single-celled organisms is high while the surface area-to-volume (SA: V) ratio is small

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2
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A person was running for 15 minutes on a jogging track.

They stopped and started panting to allow more oxygen to be inhaled

Which of the following options correctly describes the process of inhalation?

  External intercostal muscle Internal intercostal muscle Diaphragm position Volume of thorax
A contract relax relaxes and downwards increases
B contract relax contracts and downwards increases
C relax contract contracts and upwards increases
D relax contract Relaxes and upwards decreases

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3
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The diagram below shows the parts of the gas exchange system in an insect.3-1-exchange-surfaces-easy-q3

Identify which part of the gas exchange system closes to reduce water loss.

  • Tracheoles

  • Trachea

  • Muscle

  • Spiracle

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4
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Which statement correctly describes the advantage of the tracheal system in insects for gaseous exchange?

  • It allows for the direct exchange of gases with body tissues

  • It provides a large surface area for efficient gas exchange

  • It allows insects to breathe efficiently even if the spiracles are closed

  • It helps in the diffusion of oxygen into the blood pigment of insects

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5
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The intake of oxygen in fish is carried out through gills. Gills use a specific design to maximise the amount of oxygen that diffuses into their blood.

Which of the following statements, correctly describes the counter-current system in fish?

1 The extensive capillary system which covers the gills ensures the blood flows in the opposite direction to the flow of water
2 The extensive capillary system around the alveoli keeps the distance short for diffusion
3 A large network of capillaries helps to directly extract oxygen from water

  • 1,2, and 3

  • 1 and 2 only

  •  1 and 3 only

  • 3 only

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1
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The table shows the surface areas and volumes of four animals of different genus.

Animal Genus Surface area (m2) Volume (m3)
Lepus 0.51 2.2 x 10-2
Camelus 23.73 2.91
Ambystoma 1.6 x 10-3 6.8 x 10-5
Corvus 0.36 1.8 x 10-2

Which of the options, A to D is the correct order of surface area to volume ratios for the different animals, arranged from the smallest to the largest?

  • Camelus, Corvus, Lepus, Ambystoma

  • Camelus, Corvus, Ambystoma, Lepus

  • Ambystoma, Lepus, Corvus, Camelus

  • Lepus, Camelus, Corvus, Ambystoma

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2
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The inner surface of the alveoli is covered in a thin layer of surfactant. A small amount of artificial surfactant can be sprayed into the lungs of premature babies at birth to assist with breathing.

Which of the following options does not explain how this artificial surfactant can assist a premature baby with breathing?

  • The artificial surfactant prevents the alveoli surfaces from sticking together.

  • The artificial surfactant plays an important role in defence mechanisms in the lung.

  • The artificial surfactant prevents the alveoli from collapsing after the first breath.

  • The artificial surfactant increases the surface tension at the air-liquid interface.

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3
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The normal breathing rate of a female is 14 breaths per minute and her tidal volume is 450 cm3. During exercise, her ventilation rate increases to 12.6 dm3 per minute and her tidal volume increases to 700 cm3.

Which row in the table below shows the correct values for her ventilation rate, tidal volume and breathing rate before and during exercise?

  Ventilation rate before exercise (cm3 per minute) Ventilation rate after exercise (cm3 per minute) Tidal volume before exercise (cm3) Tidal volume after exercise  (cm3) Breathing rate before exercise (breaths per minute) Breathing rate after exercise (breaths per minute)
A 32 12600 450 700 14 18
B 6300 12.6 450 700 14 0.018
C 6300 12600 450 700 14 18
D 32 12.6 450 700 14 0.018

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4
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Peak flow meters are used to measure peak expiratory flow (PEF), a measurement of the rate at which air can be expelled from the lungs.

The graph below shows average PEF values for men of different heights and ages.

ocr-as-3-1e-q5-ventilation-mechanism-in-mammals

Which of the following is the percentage decrease from the PEF of a 40 year old man of 183 cm to the PEF of a 55 year old man of 175 cm.

  • 10.2%

  • 9.2%

  • 1.5%

  • 12.3%

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5
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The gaseous exchange systems of insects and fish are effective but very different from one another.

Which of the following statements correctly describe the gaseous exchange systems of insects and fish?

1 The mass of an insect increases when environmental carbon dioxide levels increase.
2 Bony fish have countercurrent systems which maintain a concentration gradient.
3 Little gaseous exchange occurs in the trachea of insects as cartilage is impermeable to gases.
4 In fish, when the floor of the buccal cavity is lowered, the opercular valve closes.

  • Statements 1 and 2.

  • Statements 2 and 4.

  • Statements 3 and 4.

  • Statements 1 and 4.

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1
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The graphs, A to D, represent gas exchange in bony fish.

The graphs show the oxygen saturation in blood in the lamellae and water flowing over the lamellae.q8-paper-1-nov-2020-ocr-a-level-biology

Which graph, A to D, shows the relationship between blood oxygen saturation and distance along the lamellae?

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2
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Which of the following statements, A to D, correctly explains a feature of an efficient gaseous exchange surface?

  • The layers are thin for a short diffusion distance.

  • There is a good blood supply, so the system reaches equilibrium quickly.

  • There is an increased surface area to reduce surface area to volume ratio.

  • Ventilation takes place to reduce concentration gradient of dissolved gases.

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3
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Peak expiratory flow (PEF) is a measure of the maximum rate at which a person can exhale.

The graph below shows the typical PEF values for men of different ages and heights.

q9-paper-1-june-2018-ocr-a-level-biology

Which of the following is the percentage increase from the PEF of a 20 year old man of 175cm to the PEF of a 45 year old man of 183cm?

  • 19.4%

  • 10.9%

  • 12.3%

  • 5.2 %

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4
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Bony fish absorb dissolved oxygen from the water using gills. Water is passed through the buccal cavity and over the gill lamellae. The oxygen saturation of the blood and water changes as the water passes over the gills.

Which of the statements, A to D, correctly describes the way oxygen is transferred into the blood at the gills?

  • Blood and water flow in a concurrent system with a constant concentration gradient between them.

  • Blood and water flow in a countercurrent system with a constant concentration gradient between them.

  • Blood and water flow in a concurrent system with a greater concentration gradient between them at the start of the gill lamella.

  • Blood and water flow in a countercurrent system with a greater concentration gradient between them at the start of the gill lamella.

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5
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Which graph represents the counter-current exchange system in fish gills?

q2-paper-1-specimen-ocr-a-level-biology

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6
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Which row of the table contains five correct statements about forced expiration?

  Ribs Diaphragm Pressure in thorax External intercostal muscles Internal intercostal muscles
A. Move down and inwards Contracts Increases Relax Relax
B. Move down and inwards Relaxes Increases Relax Contract
C. Move down and inwards Relaxes Decreases Recoil Contract
D. Move up and outwards Contracts Decreases Contract Contract 

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7
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During a gas exchange investigation, measurements were recorded from four animals that were observed as they breathed normally over a period of 5 minutes. Note that the efficiency of gas exchange was the same in all four animals and that tidal volume refers to the volume of air that moves into the lungs with each normal breath.

Which animal had the highest oxygen intake during five minutes of normal breathing?

Animal Tidal volume / dm3 Breathing rate / breaths per minute
A. 0.2 10
B. 0.6 20
C. 0.5 18
D. 0.33 24

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8
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An alveolus has several features to allow efficient gas exchange. gase-exchange-mcq

Which row of the table below matches each structural adaptation to the correct feature of gas exchange?

  I II III
A High concentration of oxygen to maintain a steep concentration gradient One cell thick for short diffusion distance Allows stretch and recoil for passive expiration
B High concentration of carbon dioxide to maintain a steep concentration gradient Allows gases to dissolve to aid diffusion One cell thick for short diffusion distance
C One cell thick for short diffusion distance High concentration of oxygen to maintain a steep concentration gradient Allows gases to dissolve to aid diffusion
D One cell thick for short diffusion distance Allows gases to dissolve to aid diffusion High concentration of oxygen to maintain a steep concentration gradient

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9
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The diagram shows a trace recorded from a spirometer.

Which label represents the tidal volume?spirometer-trace-mcq

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10
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The image shows a section from the gas exchange system of an insect.-V0FO6_N_insect-gas-exchange-mcq

Which option gives the correct names for the structures labelled?

  I II III IV V VI
A Muscle tissue Spiracle Trachea Tracheoles Air sac Exoskeleton
B Spiracle Exoskeleton Trachea Tracheoles Muscle tissue Air sac
C Air sac Spiracle Exoskeleton Trachea Tracheoles  Muscle tissue
D Spiracle Air sac Tracheoles Trachea Muscle tissue Exoskeleton

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11
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Which of the follow statements best explains the effect of abdominal pumping in active insects?

  • To create mass flow of air in through the spiracles

  • To lower the pressure in the thorax to allow more air to be drawn in

  • To clear the tracheoles of fluid to allow gases to diffuse more easily

  • To create a pumping action which increases pressure in the body for ventilation

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