AQA AS BIOLOGY EVALUATION EXAMS TEST 2025/2026
QUESTIONS AND ANSWERS GRADED A+
✔✔Permeability - ✔✔How permeable a substance is depends on the size, polarity and
charge of the molecule. If it is small, non-polar and fat soluble it is very permeable and
can pass through the cell membrane.
✔✔Phospholipid - ✔✔Triglyceride in which one of the three fatty acid molecules is
replaced by a phosphate molecule. Phospholipids are important in the structure an
functioning of plasma membranes.
✔✔Plasma Membrane - ✔✔Membranes consisting of a phospholipid bilayer found
around and within all cells. The cell-surface membrane is the plasma membrane that
surrounds cells.
✔✔Protein Channel - ✔✔A protein completely spanning the phospholipid bilayer which
form water-filled tubes to allow water-soluble ions to diffuse across the membrane.
✔✔Carrier Protein - ✔✔A protein completely spanning the phospholipid bilayer which
bind to ions or molecules then change shape in order to move these molecules across
the membrane.
✔✔Cell membrane - ✔✔A selectively permeable membrane surrounding the cell and
controlling the entry and exit of materials
✔✔Channel Protien - ✔✔A protein completely spanning the phospholipid bilayer which
form water-filled tubes to allow water-soluble ions to diffuse across the membrane.
✔✔Concentration - ✔✔The concentration of a solution tells us how much of a
substance is dissolved in water. The higher the concentration, the more particles of the
substance are present.
✔✔Co-transport - ✔✔The transport of one substance coupled with the transport of
another substance across a plasma membrane in the same direction through the same
protein carrier.
✔✔Diffusion - ✔✔The net movement of molecules (or ions) from a region of high
concentration to a region of low concentration. It is passive.
✔✔Facilitated diffusion - ✔✔Diffusion involving the presence of protein carrier
molecules to allow the passive movement of substances (normally large, polar or
charged molecules) across plasma membrane.
✔✔Net - ✔✔Overall.
,✔✔Partially permeable - ✔✔Also called semi-permeable. A partially permeable
membrane allows water and other small molecules to pass through, but not larger
molecules such as starch.
✔✔Passive transport - ✔✔Transport of molecules that occurs as a result of the random
movement of particles, so that there is a net movement from a higher to a lower
concentration. Passive transport does not require energy.
✔✔Cell sap - ✔✔The liquid found in the vacuole of plant cells, consisting of water with
dissolved sugars, salts and amino acids
✔✔Cell wall - ✔✔Outer structure which provides support and prevents the cell from
bursting from the uptake of water by osmosis. Plant, fungal and bacterial cell walls have
different structures and chemical compositions.
✔✔Cellulose - ✔✔A carbohydrate. It forms the cell wall in plant cells.
✔✔Concentration - ✔✔The concentration of a solution tells us how much of a
substance is dissolved in water. The higher the concentration, the more particles of the
substance are present.
✔✔Cytoplasm - ✔✔The living substance inside a cell (not including the nucleus).
✔✔Dilute - ✔✔A solution with low concentration.
✔✔Dissolve - ✔✔When a substance breaks up and mixes completely with a solvent to
produce a solution.
✔✔Flaccid - ✔✔Lacking turgor. Lacking in stiffness or strength. Soft and floppy.
✔✔Isotonic - ✔✔A solution which has the same water potential as the cell within it.
✔✔Osmosis - ✔✔The passage of water from a region where there is a higher water
potential to a region where there is a lower water potential through a partially permeable
membrane.
✔✔Plasmolysed - ✔✔Description of a plant cell in which the vacuole has shrunk and the
membrane has pulled away from the wall due to water loss by osmosis.
✔✔Solute - ✔✔The dissolved substance in a solution.
✔✔Solution - ✔✔Mixture formed by a solute and a solvent.
,✔✔Solvent - ✔✔The liquid in which the solute dissolves to form a solution.
✔✔Sucrose - ✔✔A disaccharide made from glucose and fructose. It is used as table
sugar.
✔✔Turgid - ✔✔Enlarged and swollen with water. Having turgor. Description of a plant
cell in which the vacuole has swollen due to water gain by osmosis.
✔✔Vacuole - ✔✔A space within the cytoplasm of plant cells that contains cell sap.
✔✔Volume - ✔✔Refers to the amount of space inside of the object, e.g. it is the space.
✔✔Water potential - ✔✔The pressure created by water molecules. It is the measure of
the extent to which a solution gives out water. The greater the number of water
molecules present, the higher (less negative) the water potential. Pure water has a
water potential of zero.
✔✔Calibration Curve - ✔✔A general method for determining the concentration of a
substance in an unknown sample by comparing the unknown to a set of standard
samples of known concentration
✔✔Concentration - ✔✔The concentration of a solution tells us how much of a
substance is dissolved in water. The higher the concentration, the more particles of the
substance are present.
✔✔Dilute - ✔✔A solution with low concentration.
✔✔Serial Dilution - ✔✔A set of solutions which increase/decrease in concentration by
the same factor each time e.g 2, 5 or 10
✔✔Solute - ✔✔The dissolved substance in a solution.
✔✔Solution - ✔✔Mixture formed by a solute and a solvent.
✔✔Solvent - ✔✔The liquid in which the solute dissolves to form a solution.
✔✔Volume - ✔✔Refers to the amount of space inside of the object, e.g. it is the space.
✔✔Active transport - ✔✔Movement of a substance from a region where it is in a low
concentration to a region where it is in a high concentration. The process requires the
expenditure of metabolic energy in the form of ATP.
, ✔✔Carrier Protein - ✔✔A protein completely spanning the phospholipid bilayer which
bind to ions or molecules then change shape in order to move these molecules across
the membrane.
✔✔Concentration - ✔✔The concentration of a solution tells us how much of a
substance is dissolved in water. The higher the concentration, the more particles of the
substance are present.
✔✔Co-transport - ✔✔The transport of one substance coupled with the transport of
another substance across a plasma membrane in the same direction through the same
protein carrier.
✔✔Cytoplasm - ✔✔The living substance inside a cell (not including the nucleus).
✔✔Endocytosis - ✔✔The taking in of substances by a living cell through invagination of
its membrane to form a vesicle.
✔✔Exocytosis - ✔✔The process by which a cell secretes substances using vesicles.
Uses energy.
✔✔Facilitated diffusion - ✔✔Diffusion involving the presence of protein carrier
molecules to allow the passive movement of substances (normally large, polar or
charged molecules) across plasma membrane.
✔✔Glucose - ✔✔A monosaccharide.
✔✔Sucrose - ✔✔A disaccharide made from glucose and fructose. It is used as table
sugar.
✔✔Electrons - ✔✔Negatively charged subatomic particle that orbits the positively
charged nucleus of all atoms
✔✔Magnification - ✔✔The process of enlarging the appearance, not the physical size,
of something.
✔✔Object - ✔✔The material placed under the microscope for observation
✔✔Image - ✔✔The appearance of the material when viewed through a microscope
✔✔Magnification = - ✔✔size of image/size of object
✔✔Size of real object = - ✔✔size of image/magnification
✔✔Size of image = - ✔✔size of object x magnification
QUESTIONS AND ANSWERS GRADED A+
✔✔Permeability - ✔✔How permeable a substance is depends on the size, polarity and
charge of the molecule. If it is small, non-polar and fat soluble it is very permeable and
can pass through the cell membrane.
✔✔Phospholipid - ✔✔Triglyceride in which one of the three fatty acid molecules is
replaced by a phosphate molecule. Phospholipids are important in the structure an
functioning of plasma membranes.
✔✔Plasma Membrane - ✔✔Membranes consisting of a phospholipid bilayer found
around and within all cells. The cell-surface membrane is the plasma membrane that
surrounds cells.
✔✔Protein Channel - ✔✔A protein completely spanning the phospholipid bilayer which
form water-filled tubes to allow water-soluble ions to diffuse across the membrane.
✔✔Carrier Protein - ✔✔A protein completely spanning the phospholipid bilayer which
bind to ions or molecules then change shape in order to move these molecules across
the membrane.
✔✔Cell membrane - ✔✔A selectively permeable membrane surrounding the cell and
controlling the entry and exit of materials
✔✔Channel Protien - ✔✔A protein completely spanning the phospholipid bilayer which
form water-filled tubes to allow water-soluble ions to diffuse across the membrane.
✔✔Concentration - ✔✔The concentration of a solution tells us how much of a
substance is dissolved in water. The higher the concentration, the more particles of the
substance are present.
✔✔Co-transport - ✔✔The transport of one substance coupled with the transport of
another substance across a plasma membrane in the same direction through the same
protein carrier.
✔✔Diffusion - ✔✔The net movement of molecules (or ions) from a region of high
concentration to a region of low concentration. It is passive.
✔✔Facilitated diffusion - ✔✔Diffusion involving the presence of protein carrier
molecules to allow the passive movement of substances (normally large, polar or
charged molecules) across plasma membrane.
✔✔Net - ✔✔Overall.
,✔✔Partially permeable - ✔✔Also called semi-permeable. A partially permeable
membrane allows water and other small molecules to pass through, but not larger
molecules such as starch.
✔✔Passive transport - ✔✔Transport of molecules that occurs as a result of the random
movement of particles, so that there is a net movement from a higher to a lower
concentration. Passive transport does not require energy.
✔✔Cell sap - ✔✔The liquid found in the vacuole of plant cells, consisting of water with
dissolved sugars, salts and amino acids
✔✔Cell wall - ✔✔Outer structure which provides support and prevents the cell from
bursting from the uptake of water by osmosis. Plant, fungal and bacterial cell walls have
different structures and chemical compositions.
✔✔Cellulose - ✔✔A carbohydrate. It forms the cell wall in plant cells.
✔✔Concentration - ✔✔The concentration of a solution tells us how much of a
substance is dissolved in water. The higher the concentration, the more particles of the
substance are present.
✔✔Cytoplasm - ✔✔The living substance inside a cell (not including the nucleus).
✔✔Dilute - ✔✔A solution with low concentration.
✔✔Dissolve - ✔✔When a substance breaks up and mixes completely with a solvent to
produce a solution.
✔✔Flaccid - ✔✔Lacking turgor. Lacking in stiffness or strength. Soft and floppy.
✔✔Isotonic - ✔✔A solution which has the same water potential as the cell within it.
✔✔Osmosis - ✔✔The passage of water from a region where there is a higher water
potential to a region where there is a lower water potential through a partially permeable
membrane.
✔✔Plasmolysed - ✔✔Description of a plant cell in which the vacuole has shrunk and the
membrane has pulled away from the wall due to water loss by osmosis.
✔✔Solute - ✔✔The dissolved substance in a solution.
✔✔Solution - ✔✔Mixture formed by a solute and a solvent.
,✔✔Solvent - ✔✔The liquid in which the solute dissolves to form a solution.
✔✔Sucrose - ✔✔A disaccharide made from glucose and fructose. It is used as table
sugar.
✔✔Turgid - ✔✔Enlarged and swollen with water. Having turgor. Description of a plant
cell in which the vacuole has swollen due to water gain by osmosis.
✔✔Vacuole - ✔✔A space within the cytoplasm of plant cells that contains cell sap.
✔✔Volume - ✔✔Refers to the amount of space inside of the object, e.g. it is the space.
✔✔Water potential - ✔✔The pressure created by water molecules. It is the measure of
the extent to which a solution gives out water. The greater the number of water
molecules present, the higher (less negative) the water potential. Pure water has a
water potential of zero.
✔✔Calibration Curve - ✔✔A general method for determining the concentration of a
substance in an unknown sample by comparing the unknown to a set of standard
samples of known concentration
✔✔Concentration - ✔✔The concentration of a solution tells us how much of a
substance is dissolved in water. The higher the concentration, the more particles of the
substance are present.
✔✔Dilute - ✔✔A solution with low concentration.
✔✔Serial Dilution - ✔✔A set of solutions which increase/decrease in concentration by
the same factor each time e.g 2, 5 or 10
✔✔Solute - ✔✔The dissolved substance in a solution.
✔✔Solution - ✔✔Mixture formed by a solute and a solvent.
✔✔Solvent - ✔✔The liquid in which the solute dissolves to form a solution.
✔✔Volume - ✔✔Refers to the amount of space inside of the object, e.g. it is the space.
✔✔Active transport - ✔✔Movement of a substance from a region where it is in a low
concentration to a region where it is in a high concentration. The process requires the
expenditure of metabolic energy in the form of ATP.
, ✔✔Carrier Protein - ✔✔A protein completely spanning the phospholipid bilayer which
bind to ions or molecules then change shape in order to move these molecules across
the membrane.
✔✔Concentration - ✔✔The concentration of a solution tells us how much of a
substance is dissolved in water. The higher the concentration, the more particles of the
substance are present.
✔✔Co-transport - ✔✔The transport of one substance coupled with the transport of
another substance across a plasma membrane in the same direction through the same
protein carrier.
✔✔Cytoplasm - ✔✔The living substance inside a cell (not including the nucleus).
✔✔Endocytosis - ✔✔The taking in of substances by a living cell through invagination of
its membrane to form a vesicle.
✔✔Exocytosis - ✔✔The process by which a cell secretes substances using vesicles.
Uses energy.
✔✔Facilitated diffusion - ✔✔Diffusion involving the presence of protein carrier
molecules to allow the passive movement of substances (normally large, polar or
charged molecules) across plasma membrane.
✔✔Glucose - ✔✔A monosaccharide.
✔✔Sucrose - ✔✔A disaccharide made from glucose and fructose. It is used as table
sugar.
✔✔Electrons - ✔✔Negatively charged subatomic particle that orbits the positively
charged nucleus of all atoms
✔✔Magnification - ✔✔The process of enlarging the appearance, not the physical size,
of something.
✔✔Object - ✔✔The material placed under the microscope for observation
✔✔Image - ✔✔The appearance of the material when viewed through a microscope
✔✔Magnification = - ✔✔size of image/size of object
✔✔Size of real object = - ✔✔size of image/magnification
✔✔Size of image = - ✔✔size of object x magnification
