A
The region on an enzyme where the substrate binds to undergo a chemical reaction.
Active Site
The green pigment located in thylakoid membranes that absorbs light energy for photosynthesis.
Chlorophyll
The metabolic process occurring in the cytoplasm that breaks down glucose into two pyruvate molecules without requiring oxygen.
Glycolysis
Passive movement of water molecules across a semi-permeable membrane from an area of high water concentration to low water concentration.
Osmosis
The stage of the cell cycle where DNA is replicated before mitosis occurs.
Interphase (The S- Phase)
The minimum amount of energy required for a chemical reaction to begin, which enzymes lower.
Activation Energy
The specific site inside the chloroplast where the light-independent phase (Calvin cycle) occurs.
Stroma
The folds of the inner mitochondrial membrane that increase the surface area for the electron transport chain.
Cristae
The movement of substances against a concentration gradient using transport proteins and cellular energy (ATP).
Active Transport
The enzyme responsible for unwinding and unzipping the DNA double helix during replication.
Helicase
What happens to an enzyme's active site when exposed to high temperatures or extreme pH, preventing it from functioning.
Denaturation
Stacks of thylakoids inside a chloroplast that increase internal surface area for light absorption.
Grana
The byproduct of anaerobic respiration in human or animal muscle cells that causes localised fatigue.
Lactic Acid
What happens to the Surface Area-to-Volume (SA:V) ratio of a cell as the cell grows larger.
SA:V ration decreases
Why DNA replication is described as "semi-conservative".
Each new DNA molecule consists of one original strand and one newly synthesised strand?
Model of enzyme action where the enzyme changes shape slightly to fit the substrate more tightly upon binding.
Induced Fit Model
What happens to water during the light-dependent phase, and what useful gas is released as a byproduct.
Water is split into hydrogen and oxygen gas (O2) is released
The ultimate biological purpose of cellular respiration in all living cells.
To produce ATP (the cells energy currency, for life processes).
What happens to a plant cell placed in a hypertonic (high solute) solution.
It becomes plasmolysed (loses water and the cell membrane pulls away from the cell wall)
The primary purpose of mitosis in multicellular organisms.
Growth, repair of damaged tissues, and cell replacement
Why increasing substrate concentration increases reaction rate only up to a point, after which the rate plateaus.
All active sites become saturated (occupied) with substrate, making enzyme concentration the limiting factor
Why leaves growing in deep shade are often darker green and thinner than leaves growing in full sunlight.
Shade leaves produce higher concentrations of chlorophyll (darker green) and have a higher surface area-to-volume ratio (thinner) to maximise light capture in low light
Why muscle cells maintain high numbers of mitochondria compared to skin epithelial cells.
Muscle cells have high metabolic energy demands for contraction, requiring large amounts of ATP produced via aerobic respiration
Why cells must divide via mitosis once they reach a maximum size limit, referring specifically to transport rates.
As a cell grows, its volume increases faster than its surface area; a low SA:V ratio means diffusion becomes too slow to supply nutrients and remove wastes fast enough to sustain the cell.
Why DNA replication occurs continuously on the leading strand but discontinuously (forming Okazaki fragments) on the lagging strand.
DNA polymerase can only synthesize DNA in the 5' to 3' direction, and since DNA strands are antiparallel, one strand must be built backwards in short fragments