NAS 2 CHALLENGE FINAL PAPER 2025/2026 ANSWERS
AND QUESTIONS GRADED A+
✔✔enzymes - ✔✔catalyze chemical reactions by lowering activation energy barriers
and converting substrate molecules to products
✔✔substrate - ✔✔reactant acted upon by an enzyme
enzymes active site binds to this
✔✔active site - ✔✔part of an enzyme to which substrates bind and where a reaction is
catalyzed
✔✔enzymes - ✔✔promote chemical reactions by bringing substrates together in an
optimal orientation, thus creating an ideal chemical environment for the reaction to
occur
always return to original state
✔✔decomposition - ✔✔single compound breaks down into two or more elements or
new compounds
These reactions often involve heat, light, electricity
✔✔synthesis - ✔✔multiple reactants combine to form a single product
Release energy in form of heat and light (exothermic)
Hydrogen and oxygen -> water
✔✔exchange - ✔✔any class of reactions between two substances that involves an
exchange of one or more ionic components (positive and negative charges)
✔✔solvent - ✔✔substance solute is dissolved in
✔✔polar molecule - ✔✔a molecule that has electrically charged areas
covalent bonds - polarity if its atoms differ in electronegativity
can form hydrogen bonds
✔✔nonpolar molecule - ✔✔cannot mix with water
✔✔dissociation - ✔✔leads to acidic and basic conditions
, the splitting of a molecule into smaller molecules, atoms, or ions, especially by a
reversible process
✔✔PH - ✔✔measure of acidity
measure of hydrogen ion concentration
✔✔basic/alkaline - ✔✔if pH is above 7 it is...
✔✔acidic - ✔✔if pH is below 7 its...
✔✔diffusion - ✔✔Movement of a substance from an area of high concentration to an
area of low concentration
✔✔dialysis - ✔✔small molecules can diffuse through semipermeable membranes
✔✔osmosis - ✔✔net movement of water through semipermeable membrane
✔✔organic compound - ✔✔any member of large class of gaseous, liquid, or solid
chemical compounds, must contain hydrogen
✔✔monomer - ✔✔small unit that can join together with other small units to form
polymers
✔✔polymer - ✔✔large compound formed from combinations of many monomers
✔✔carbohydrates - ✔✔glucose, glycogen, monosaccharides, polysaccharides
✔✔lipids - ✔✔fatty acids, alcohols, monoglycerides, diglycerides, steroids, terpenes,
carotenoids
✔✔proteins - ✔✔insulin, histone, hemoglobin
macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen
✔✔nucelic acid - ✔✔RNA, DNA
✔✔function - ✔✔_____ of a protein is dependent on its 3D structure determined by a
sequence of amino acids in the protein polymer
✔✔proteins - ✔✔embodiment of the transition from one-dimensional to three
✔✔cell theory - ✔✔All life is made up cells which are the basic units of life and come
from preexisting cells
AND QUESTIONS GRADED A+
✔✔enzymes - ✔✔catalyze chemical reactions by lowering activation energy barriers
and converting substrate molecules to products
✔✔substrate - ✔✔reactant acted upon by an enzyme
enzymes active site binds to this
✔✔active site - ✔✔part of an enzyme to which substrates bind and where a reaction is
catalyzed
✔✔enzymes - ✔✔promote chemical reactions by bringing substrates together in an
optimal orientation, thus creating an ideal chemical environment for the reaction to
occur
always return to original state
✔✔decomposition - ✔✔single compound breaks down into two or more elements or
new compounds
These reactions often involve heat, light, electricity
✔✔synthesis - ✔✔multiple reactants combine to form a single product
Release energy in form of heat and light (exothermic)
Hydrogen and oxygen -> water
✔✔exchange - ✔✔any class of reactions between two substances that involves an
exchange of one or more ionic components (positive and negative charges)
✔✔solvent - ✔✔substance solute is dissolved in
✔✔polar molecule - ✔✔a molecule that has electrically charged areas
covalent bonds - polarity if its atoms differ in electronegativity
can form hydrogen bonds
✔✔nonpolar molecule - ✔✔cannot mix with water
✔✔dissociation - ✔✔leads to acidic and basic conditions
, the splitting of a molecule into smaller molecules, atoms, or ions, especially by a
reversible process
✔✔PH - ✔✔measure of acidity
measure of hydrogen ion concentration
✔✔basic/alkaline - ✔✔if pH is above 7 it is...
✔✔acidic - ✔✔if pH is below 7 its...
✔✔diffusion - ✔✔Movement of a substance from an area of high concentration to an
area of low concentration
✔✔dialysis - ✔✔small molecules can diffuse through semipermeable membranes
✔✔osmosis - ✔✔net movement of water through semipermeable membrane
✔✔organic compound - ✔✔any member of large class of gaseous, liquid, or solid
chemical compounds, must contain hydrogen
✔✔monomer - ✔✔small unit that can join together with other small units to form
polymers
✔✔polymer - ✔✔large compound formed from combinations of many monomers
✔✔carbohydrates - ✔✔glucose, glycogen, monosaccharides, polysaccharides
✔✔lipids - ✔✔fatty acids, alcohols, monoglycerides, diglycerides, steroids, terpenes,
carotenoids
✔✔proteins - ✔✔insulin, histone, hemoglobin
macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen
✔✔nucelic acid - ✔✔RNA, DNA
✔✔function - ✔✔_____ of a protein is dependent on its 3D structure determined by a
sequence of amino acids in the protein polymer
✔✔proteins - ✔✔embodiment of the transition from one-dimensional to three
✔✔cell theory - ✔✔All life is made up cells which are the basic units of life and come
from preexisting cells
