SBI4U Exam Questions Answered Correctly Latest Update 2025-2026
isotopes - Answers two atoms of the same element with different atomic weights due to varying
neutron numbers. some isotopes are radioisotopes and emit alpha and beta particles.
radioisotopes have many medicinal uses, including cancer treatment and medical imaging.
isomers - Answers compounds with the same chemical formula but different structures (ex.
leucine and isoleucine, glucose and fructose). different shapes = different properties.
intermolecular forces - Answers Hydrogen Bonding - strongest
Dipole-dipole - holds polar molecules together (S- end attracted to S+ end)
London Dispersion - weakest, holds non-polar bonds together
water's 7 properties - Answers cohesion, adhesion, density, high specific heat capacity, high
specific heat of vaporization, ionization, polarity.
acid - Answers proton donor
base - Answers proton accepter
buffer - Answers weak acid or weak base that maintains optimum pH level (ex. bicarbonate
buffer system in the blood). release or take up H+ ions.
acidosis vs alkalosis - Answers acidosis - pH 7.1-7.3. disorientation and fatigue. common
causes are hypoventilation and drug overdose.
alkalosis - pH 7.5+. dizziness. common causes include antacids (ex. Tums), hyperventilation,
high altitude.
hydroxyl - Answers -OH. polar.
found in alcohol (ex ethanol) and sugars (ex glucose)
carboxyl - Answers -COOH. acidic.
found in organic acids (ex lactic acid, amino acid, fatty acids)
amino - Answers -NH2. basic.
found in nitrogenous bases and amino acids.
sulfhydryl - Answers -SH. smells disgusting.
found in protein (ex hair)
phosphate - Answers -PO4 (may have a 2- charge).
,found in ATP and DNA
carbonyl (aldehyde) - Answers -COH. tastes/smells good.
found in sugars, cinnamon, vanilla.
carbonyl (ketone) - Answers -CO-. solvent.
found in acetone.
-ane, -ene, -yne - Answers single, double, and triple carbon bonds
ester - Answers COCO
ex. phosphodiester bonds, fat (triglycerides).
hydrolysis - Answers water is used, energy is released, breaks apart larger molecules (hydro-
lysis). catabolic reaction.
ex. digestion.
dehydration synthesis - Answers water is made, energy is released, energy is stored in the bond.
builds larger molecules - anabolic
neutralization - Answers acid+base = H2O+salt (ionic)
redox - Answers common in cellular respiration (NADH/NAD+ and FADH2/FAD)
transfer of electrons between two molecules, ions, or atoms.
reduction - gains e-
oxidation - loses e-
reducing agent - supplies e-
oxidizing agent - takes e-
carbohydrates - Answers either quick energy (ex. glucose), stored energy (ex. glycogen, starch),
or structure (ex. cellulose, chitin)
simple sugars - Answers single chain of carbon atoms with attached OH groups.
starch - Answers enzymes hydrolyze alpha linkages in amylose (straight chains) and
amylopectin (branched chain) into glucose.
cellulose - Answers cell wall in plants. humans cannot digest the 1-4 beta linkages that make up
cellulose. herbivores can. cellulose stays undigested and ensures movement of food through
the digestive system (fibre).
, steps to drawing hexose ring structures - Answers 1. draw a hexagon with an oxygen between
the 1 prime and 5 prime carbon.
2. hydroxyl on carbon 1 can be placed above (beta linkage) or below (alpha linkage) the plane of
symmetry
3. (carbons 2-4) OH on the right are drawn below the plane of symmetry and on the left are
drawn above the plane of symmetry.
lipids - Answers concentrated energy molecules, hormones, cell membranes.
cushion organs and insulate the body.
triglyceride - Answers glycerol and 3 fatty acids.
unsaturated fats - Answers plant, vegetable, and fish fats. liquid at room temp. don't stack
tightly together and are a better dietary choice.
saturated fats - Answers most animal fats. solid at room temp. deposit in arteries and
contribute to heart disease.
hydrogenated/trans fats - Answers hydrogenation adds H atoms to double bonds. typically are
semi solid.
cholesterol - Answers often found in cell membranes. hormones (ex. estrogen and testosterone)
can be made from cholesterol. excess cholesterol can have negative health effects.
phospholipids - Answers the phospholipid bilayer makes makes up the cell membrane. "heads"
of the phospholipid are hydrophilic and polar and touch water. tales are hydrophobic and are
found on the inside of the bilayer. forms a semi permeable bilayer.
types of proteins - Answers transport (hemoglobin, sodium potassium pump), enzymes
(amylase, rubisco), antibodies, contractile (motor proteins like actin and myosin), hormones
(insulin), storage (ovalbumin), receptor (insulin receptor), structural (keratin, collagen)
protein - Answers multipurpose molecules. chains of 20 different amino acids. may be
hydrophilic or hydrophobic. polypeptide chains fold into their protein structure.
denaturing proteins - Answers unfolding proteins and altering their shape causes them to not
function properly. proteins can be denatured if they are out of their optimal pH range or are
heated up. cooling proteins causes them to slow down, not denature.
protein folding - Answers primary - order of amino acids held by polypeptide bonds, made in
ribosomes.
secondary - alpha or beta helix created by H bonds
isotopes - Answers two atoms of the same element with different atomic weights due to varying
neutron numbers. some isotopes are radioisotopes and emit alpha and beta particles.
radioisotopes have many medicinal uses, including cancer treatment and medical imaging.
isomers - Answers compounds with the same chemical formula but different structures (ex.
leucine and isoleucine, glucose and fructose). different shapes = different properties.
intermolecular forces - Answers Hydrogen Bonding - strongest
Dipole-dipole - holds polar molecules together (S- end attracted to S+ end)
London Dispersion - weakest, holds non-polar bonds together
water's 7 properties - Answers cohesion, adhesion, density, high specific heat capacity, high
specific heat of vaporization, ionization, polarity.
acid - Answers proton donor
base - Answers proton accepter
buffer - Answers weak acid or weak base that maintains optimum pH level (ex. bicarbonate
buffer system in the blood). release or take up H+ ions.
acidosis vs alkalosis - Answers acidosis - pH 7.1-7.3. disorientation and fatigue. common
causes are hypoventilation and drug overdose.
alkalosis - pH 7.5+. dizziness. common causes include antacids (ex. Tums), hyperventilation,
high altitude.
hydroxyl - Answers -OH. polar.
found in alcohol (ex ethanol) and sugars (ex glucose)
carboxyl - Answers -COOH. acidic.
found in organic acids (ex lactic acid, amino acid, fatty acids)
amino - Answers -NH2. basic.
found in nitrogenous bases and amino acids.
sulfhydryl - Answers -SH. smells disgusting.
found in protein (ex hair)
phosphate - Answers -PO4 (may have a 2- charge).
,found in ATP and DNA
carbonyl (aldehyde) - Answers -COH. tastes/smells good.
found in sugars, cinnamon, vanilla.
carbonyl (ketone) - Answers -CO-. solvent.
found in acetone.
-ane, -ene, -yne - Answers single, double, and triple carbon bonds
ester - Answers COCO
ex. phosphodiester bonds, fat (triglycerides).
hydrolysis - Answers water is used, energy is released, breaks apart larger molecules (hydro-
lysis). catabolic reaction.
ex. digestion.
dehydration synthesis - Answers water is made, energy is released, energy is stored in the bond.
builds larger molecules - anabolic
neutralization - Answers acid+base = H2O+salt (ionic)
redox - Answers common in cellular respiration (NADH/NAD+ and FADH2/FAD)
transfer of electrons between two molecules, ions, or atoms.
reduction - gains e-
oxidation - loses e-
reducing agent - supplies e-
oxidizing agent - takes e-
carbohydrates - Answers either quick energy (ex. glucose), stored energy (ex. glycogen, starch),
or structure (ex. cellulose, chitin)
simple sugars - Answers single chain of carbon atoms with attached OH groups.
starch - Answers enzymes hydrolyze alpha linkages in amylose (straight chains) and
amylopectin (branched chain) into glucose.
cellulose - Answers cell wall in plants. humans cannot digest the 1-4 beta linkages that make up
cellulose. herbivores can. cellulose stays undigested and ensures movement of food through
the digestive system (fibre).
, steps to drawing hexose ring structures - Answers 1. draw a hexagon with an oxygen between
the 1 prime and 5 prime carbon.
2. hydroxyl on carbon 1 can be placed above (beta linkage) or below (alpha linkage) the plane of
symmetry
3. (carbons 2-4) OH on the right are drawn below the plane of symmetry and on the left are
drawn above the plane of symmetry.
lipids - Answers concentrated energy molecules, hormones, cell membranes.
cushion organs and insulate the body.
triglyceride - Answers glycerol and 3 fatty acids.
unsaturated fats - Answers plant, vegetable, and fish fats. liquid at room temp. don't stack
tightly together and are a better dietary choice.
saturated fats - Answers most animal fats. solid at room temp. deposit in arteries and
contribute to heart disease.
hydrogenated/trans fats - Answers hydrogenation adds H atoms to double bonds. typically are
semi solid.
cholesterol - Answers often found in cell membranes. hormones (ex. estrogen and testosterone)
can be made from cholesterol. excess cholesterol can have negative health effects.
phospholipids - Answers the phospholipid bilayer makes makes up the cell membrane. "heads"
of the phospholipid are hydrophilic and polar and touch water. tales are hydrophobic and are
found on the inside of the bilayer. forms a semi permeable bilayer.
types of proteins - Answers transport (hemoglobin, sodium potassium pump), enzymes
(amylase, rubisco), antibodies, contractile (motor proteins like actin and myosin), hormones
(insulin), storage (ovalbumin), receptor (insulin receptor), structural (keratin, collagen)
protein - Answers multipurpose molecules. chains of 20 different amino acids. may be
hydrophilic or hydrophobic. polypeptide chains fold into their protein structure.
denaturing proteins - Answers unfolding proteins and altering their shape causes them to not
function properly. proteins can be denatured if they are out of their optimal pH range or are
heated up. cooling proteins causes them to slow down, not denature.
protein folding - Answers primary - order of amino acids held by polypeptide bonds, made in
ribosomes.
secondary - alpha or beta helix created by H bonds
