QCAA BIOLOGY UNIT (1,2,3 $ 4)
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2025-2026 update
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TABLE OF CONTENT
UNIT 1…………………………19
UNIT 2…………......................36
UNIT 3………………………….46
UNIT 4………………………….66
QCAA BIOLOGY UNIT 01
cell membrane - ANS>>the insoluble boundary of all living cells that maintains the contents of the ce
and regulates movement of substances into and out of the cell
differentially permeable - ANS>>a quality of a membrane that means only certain kinds of molecule
can pass through it
,external environment - ANS>>the environment surrounding a cell
fluid mosaic phospholipid bilayer model - ANS>>the generally accepted model of membranes wher
proteins are embedded in a phospholipid layer
bilayer - ANS>>a double layer
internal environment - ANS>>all material contained within the cell membrane
phospholipid - ANS>>a type of lipid in which the phosphate head is hydrophilic and the two fat tails ar
hydrophobic
hydrophilic - ANS>>tending to interact with and dissolve in water
hydrophobic - ANS>>avoiding association with water
cytoplasm - ANS>>all the fluid, dissolved materials and organelles between the cell and nuclea
membrane
phytosterol - ANS>>a type of plant-derived lipid compound that is similar to cholesterol in structur
and function
cholesterol - ANS>>a type of lipid that maintains membrane fluidity
vesicle - ANS>>a small, membrane-bound sac in cytoplasm that transports, stores or digests structure
channel protein - ANS>>a protein that forms channels within membranes to allow the passage o
substances across the membrane
protein channel - ANS>>a passageway formed across the membrane for the movement of specifi
substances
,passive transport - ANS>>the movement of molecules that does not require input of energy
diffusion - ANS>>the passive movement of molecules from a region of high concentration to a regio
of low concentration
concentration gradient - ANS>>the difference in concentration of a substance between two differen
regions
equilibrium - ANS>>the point at which particles are distributed evenly throughout a system; they mov
at equal rates in all directions
facilitated diffusion - ANS>>a form of diffusion that requires a substance to be attached to a specifi
carrier molecule to move across a membrane
carrier protein - ANS>>a protein within membranes that assists other molecules to cross the membran
in facilitated and active transport
osmosis - ANS>>the movement of water across a selectively permeable membrane from a region of low
solute concentration to a region of high solute concentration
solvent - ANS>>a substance in which another substance can be dissolved to create a solution
solute - ANS>>a substance that can be dissolved in another substance
solution - ANS>>a mixture of solute and solvent
isotonic - ANS>>fluid with an equal solute concentration to another fluid
hypotonic - ANS>>solution with a lower solute concentration than another solution
hypertonic - ANS>>solution with a lower solute concentration than another solution
, permeable - ANS>>able to be passed through
turgid - ANS>>describes a cell that is tight and rigid from absorbing water
plasmolysis - ANS>>the point at which the cell membrane pulls away from the cell wall because of wate
loss
contractile vacuole - ANS>>a vacuole found in some freshwater unicellular organisms that maintain
osmotic balance by collecting water and emptying it from the cell
active transport - ANS>>the process of using energy to move molecules or ions across a membran
from a region of low concentration to a region of higher concentration
adenosine triphosphate - ANS>>the short-term energy storage molecule of cells
sodium-potassium pump - ANS>>a membrane protein that uses energy to transport sodium ions ou
of, and potassium ions into, cells against their concentration gradients
polar - ANS>>a molecule with an uneven distribution of charge, giving it distinct charged ends
endocytosis - ANS>>the movement of solids or liquids from the environment into a cell via vesicl
formation
phagocytosis - ANS>>the bulk transport of nutritious solids into a cell inside a vesicle
exocytosis - ANS>>the movement of solids or liquids from a cell to the environment via vesicl
formation
SA to V ratio - ANS>>Mathematical ratio of the cell membrane size to its cytoplasm
cytoplasmic streaming - ANS>>the mixing and movement of the cytoplasm
Questions and answers
2025-2026 update
100% verified questions and answers passing guaranteed
TABLE OF CONTENT
UNIT 1…………………………19
UNIT 2…………......................36
UNIT 3………………………….46
UNIT 4………………………….66
QCAA BIOLOGY UNIT 01
cell membrane - ANS>>the insoluble boundary of all living cells that maintains the contents of the ce
and regulates movement of substances into and out of the cell
differentially permeable - ANS>>a quality of a membrane that means only certain kinds of molecule
can pass through it
,external environment - ANS>>the environment surrounding a cell
fluid mosaic phospholipid bilayer model - ANS>>the generally accepted model of membranes wher
proteins are embedded in a phospholipid layer
bilayer - ANS>>a double layer
internal environment - ANS>>all material contained within the cell membrane
phospholipid - ANS>>a type of lipid in which the phosphate head is hydrophilic and the two fat tails ar
hydrophobic
hydrophilic - ANS>>tending to interact with and dissolve in water
hydrophobic - ANS>>avoiding association with water
cytoplasm - ANS>>all the fluid, dissolved materials and organelles between the cell and nuclea
membrane
phytosterol - ANS>>a type of plant-derived lipid compound that is similar to cholesterol in structur
and function
cholesterol - ANS>>a type of lipid that maintains membrane fluidity
vesicle - ANS>>a small, membrane-bound sac in cytoplasm that transports, stores or digests structure
channel protein - ANS>>a protein that forms channels within membranes to allow the passage o
substances across the membrane
protein channel - ANS>>a passageway formed across the membrane for the movement of specifi
substances
,passive transport - ANS>>the movement of molecules that does not require input of energy
diffusion - ANS>>the passive movement of molecules from a region of high concentration to a regio
of low concentration
concentration gradient - ANS>>the difference in concentration of a substance between two differen
regions
equilibrium - ANS>>the point at which particles are distributed evenly throughout a system; they mov
at equal rates in all directions
facilitated diffusion - ANS>>a form of diffusion that requires a substance to be attached to a specifi
carrier molecule to move across a membrane
carrier protein - ANS>>a protein within membranes that assists other molecules to cross the membran
in facilitated and active transport
osmosis - ANS>>the movement of water across a selectively permeable membrane from a region of low
solute concentration to a region of high solute concentration
solvent - ANS>>a substance in which another substance can be dissolved to create a solution
solute - ANS>>a substance that can be dissolved in another substance
solution - ANS>>a mixture of solute and solvent
isotonic - ANS>>fluid with an equal solute concentration to another fluid
hypotonic - ANS>>solution with a lower solute concentration than another solution
hypertonic - ANS>>solution with a lower solute concentration than another solution
, permeable - ANS>>able to be passed through
turgid - ANS>>describes a cell that is tight and rigid from absorbing water
plasmolysis - ANS>>the point at which the cell membrane pulls away from the cell wall because of wate
loss
contractile vacuole - ANS>>a vacuole found in some freshwater unicellular organisms that maintain
osmotic balance by collecting water and emptying it from the cell
active transport - ANS>>the process of using energy to move molecules or ions across a membran
from a region of low concentration to a region of higher concentration
adenosine triphosphate - ANS>>the short-term energy storage molecule of cells
sodium-potassium pump - ANS>>a membrane protein that uses energy to transport sodium ions ou
of, and potassium ions into, cells against their concentration gradients
polar - ANS>>a molecule with an uneven distribution of charge, giving it distinct charged ends
endocytosis - ANS>>the movement of solids or liquids from the environment into a cell via vesicl
formation
phagocytosis - ANS>>the bulk transport of nutritious solids into a cell inside a vesicle
exocytosis - ANS>>the movement of solids or liquids from a cell to the environment via vesicl
formation
SA to V ratio - ANS>>Mathematical ratio of the cell membrane size to its cytoplasm
cytoplasmic streaming - ANS>>the mixing and movement of the cytoplasm
