Biological Membranes (OCR A Level Biology)

Exam Questions

3 hours35 questions
1
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Active transport is used to reabsorb useful molecules and ions into the blood from the proximal convoluted tubule in the kidney nephron.

Which of the following is not necessary for active transport?

  • Specific carrier proteins

  • ATP

  • Specific channel proteins

  •  Partially permeable membrane

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Which of the following processes does not require ATP?

  • Facilitated diffusion

  • Pinocytosis

  • Phagocytosis

  • Exocytosis

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An animal cell is placed in pure water.

Which of the following correctly describes the changes occurring in the cell?

  • Water will move into the cell by osmosis and it will become turgid

  • Solutes will move out of the cell by diffusion

  • Water will move into the cell by osmosis and it will burst

  • Water will move out of the cell and it will become crenated

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If a plant cell is put into a hypertonic solution, the plant cell does not shrink but it becomes plasmolysed.

Which of the following plant cell structures prevents the cell from shrinking?

  • The protoplast

  • The nucleus

  •  The permanent vacuole

  •  The cell wall

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Which of the following does not occur in osmosis?

  • Water molecules move in both directions across a partially permeable membrane

  • Water molecules diffuse across a partially permeable membrane

  • Water molecules only move down a water potential gradient across a partially permeable membrane

  • The net movement of water molecules is from an area of higher water potential to an area of lower water potential

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Which of the following, A to D, is not an example of cell signalling?

  • The hormone insulin being removed from the blood by the glomerulus.

  • The neurotransmitter acetylcholine causing depolarisation.

  • The hormone prolactin binding to a cell receptor in breast tissue.

  • Epithelial cells releasing cytokines in response to histamine.

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Different sized mammals have different surface area to volume ratios.

The table shows the surface areas and volumes of four different groups of mammals.

Mammal genus Surface area
(m2)
Volume
(m3)
Oryctolagus 0.48 2.0 ×10-2
Equus 18.26 2.24
Mus 1.9 ×10-3 7.2 ×10-5
Rattus 0.32 1.6 ×10-2

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

  • Oryctolagus, Rattus, Equus, Mus

  • Mus, Rattus, Oryctolagus, Equus

  • Mus, Oryctolagus, Rattus, Equus

  • Equus, Mus, Oryctolagus, Rattus

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Membranes are found within and surrounding cells.

Which of the statements, A to D, is not a role of membranes in cells?

  • acts as a barrier between areas

  • cell signalling

  • provides support for cell

  • site of chemical reactions

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Cut pieces of agar jelly can be used to investigate the factors affecting diffusion rates in cells.

Four pieces of agar jelly containing universal indicator were soaked in the same concentration of hydrochloric acid for one minute.

The cubes were then removed and blotted dry.

Which of the following pieces of agar jelly would be the first to turn entirely red?

  • a cube with edges 4cm each

  • a cuboid with edges 2cm, 4cm and 6cm

  • a cuboid with edges 3cm, 3cm and 5cm

  • a sphere with diameter 4cm

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The diagram below shows part of a plasma membrane.q11-paper-2-june-2017-ocr-a-level-biology

Which of the label lines points to a structure that could contain a sulfur atom?

  • 1, 2 and 3

  • Only 1 and 2

  • Only 2 and 3

  • Only 1

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Cells require vitamins and minerals in order to function correctly. These vitamins and minerals need to cross the plasma membrane.

Vitamins are either fat soluble or water soluble. Vitamins A, D, E and K are fat soluble.

Which of the following combinations enter a cell by facilitated diffusion?

  • vitamin A and calcium ions

  • vitamin C and calcium atoms

  • vitamin C and calcium ions

  • vitamin A and calcium atoms

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The graph shows how the concentration of a substance affects its rate of absorption into a cell.1-3-h-q5-paper-1

Substance X enters by simple diffusion, substance Y by facilitated diffusion. 

Why does the curve for substance Y plateau above a certain concentration?

  • ATP levels are used up and the cell has to prioritise

  • The concentration of Y being the same inside and outside of the cell

  • Carrier proteins are saturated

  • Above a certain concentration, the membrane is impermeable to Y

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8
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An experiment to calculate the water potential of potato was performed using the following protocol:

  1. Dice potato into 1cm3 cubes.
  2. Add potato cubes to 6 test tubes, each containing solution with a different sucrose concentration.
  3. Wait 12 hours.
  4. Weigh the cubes from each test tube and plot a graph. 

The mean mass of the potato cubes was 2.50g before being added to the solution and the graph shows the masses of potato cubes after the experiment. 1-3-h-q4-paper-1

What concentration of sucrose has the same water potential as the potato?

  • 0.00 mol dm-3

  • 0.12 mol dm-3

  • 0.30 mol dm-3

  • 0.66 mol dm-3

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9
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Membranes in cells include the following components:

  1. Cholesterol
  2. Glycoproteins
  3. Phospholipids
  4. Proteins

Which row of the table shows the correct function of each component? 

 

Stabilising the hydrophobic layer

Recognising self / non-self

Being not fully permeable to water

Transporting ions through membranes

A

1

2

3

4

B

3

1

2

4

C

1

3

1

2

D

4

3

4

2

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    10
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    Proteins in the cell surface membranes of mouse cells and human cells were labelled with coloured dyes, with a different colour for human and mouse proteins.

    When a cell from each species is fused together, the different-coloured labels are first found in different regions of the hybrid cell’s cell surface membrane. After 40 minutes, the labels are evenly distributed around the entire cell surface membrane. This is shown in the diagram below; the viewpoint is looking down onto the surface of the membrane.

    1-3-h-q2-paper-1 Which of the following statements explains this observation?

    • Groups of protein and phospholipid molecules in the cell surface membrane are attached to each other and move together.

    • Only protein molecules in the outer layer of the cell surface membrane can move freely between phospholipid molecules.

    • All protein molecules in the cell surface membrane are fixed to structures within the cell, but phospholipid molecules move freely between them.

    • Protein molecules in the outer layer of the cell surface membrane and those which span the bilayer can move freely between phospholipid molecules.

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    Some essential molecules such as vitamins A, D, E and K are able to easily cross cell surface membranes. Which of the following statements explain why this is possible?

    1 The vitamins are hydrophobic molecules.
    2 The vitamins are non-polar.
    3 The vitamins diffuse through the phospholipid bilayer.
    4 The vitamins are not repelled by the fatty acid tails.
    • Statements 1, 2 and 3.

    • Statements 2, 3 and 4.

    • Statements 1, 3 and 4.

    • All four statements.

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    Pacinian corpuscles are pressure receptors found at the ends of sensory neurone axons. They are made of many layers of plasma membrane separated by a gel. 

    Deformation of these membranes due to changes in pressure cause them to become more permeable to Na+. Which of the following statements explain why this occurs?

    1 Voltage gated ion channels open in the plasma membrane.
    2 The increased pressure causes sodium ion channels to open.
    3 The pressure applied pushes the sodium ions across the membrane.
    4 Temporary spaces appear between phospholipids in the bilayer.
    • Statements 2 and 4

    • Statements 1 and 3

    • Statements 1, 2 and 3.

    • Statement 2 only.

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    Visking tubing is often used as a model for a cell surface membrane. Glucose passes through cell membranes by facilitated diffusion but is able to freely pass through visking tubing.

    Which of the statements below does not explain a reason for this?

    • Cell membranes have a hydrophobic core.

    • A concentration gradient is not formed across a cell membrane to allow ions to move via diffusion.

    • The permeability of visking tubing is dependent on the size of its pores.

    • Ions diffuse through channel proteins in cell membranes.

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    4
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    Which of the following is not an example of a process that would be directly impacted by a reduction in oxygen availability for the organism?

    • The loading of potassium ions from the soil into root hair cells.

    • Pinocytosis of lipid droplets into the intestinal epithelium.

    • The movement of sodium ions from endodermal cells into xylem.

    • The movement of sodium ions into the descending limb of the nephron.

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    An investigation was completed into the effect of ethanol concentration on the permeability of beetroot cell membranes using a colorimeter.

    The results of the investigation are shown below:

    Ethanol concentration (%) Mean absorbance (arbitrary units) Standard deviation
    0 0.03 0.03
    20 0.03 0.03
    40 0.06 0.02
    60 0.42 0.03
    80 0.90 0.05
    100 0.95 0.16

    Which of the following answers states the correct percentage increase in absorbance when ethanol concentration was increased from 80% to 100%?

    • 18.00%

    • 5.00%

    • 5.56%

    • 5.26%

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