DHN 311 TEST PAPER 2025/2026 QUESTIONS WITH
SOLUTIONS RATED A+
✔✔intramolecular hydrogen bonds - ✔✔two peptide bonds bond to each other through
a hydrogen bond (on same molecule)
✔✔intermolecular hydrogen bonds - ✔✔bond takes place between atoms of two or
more separate molecules
✔✔what makes a hydrogen bond a hydrogen bond - ✔✔X-H--Y and X=O,N,F and
Y=O,N,F
✔✔significance of side chains on amino acids - ✔✔dictates role of an amino acid, also
dictates properties of the proteins resulting from the combination of certain amino acids
✔✔side chains begin to interact in the _______ structure - ✔✔tertiary
✔✔_________ interactions involve nonpolar side chains located in the interior of the
polypeptide molecule - ✔✔hydrophobic
✔✔_________ interactions form ionic bonds between charged side chain groups -
✔✔ionic
✔✔___________ is directly related to a protein's structure - ✔✔protein function
ex: we eat protein and body builds non-essential amino acids
✔✔how do proteins help the body structurally? - ✔✔skin and bone collagen (fibrous
protein)
✔✔how do proteins help the body with catalysis? - ✔✔enzyme proteins allow reactions
to occur in an organism under mild conditions with great specificity
✔✔how do proteins help the body with movement? - ✔✔they make up a large
percentage of muscle fiber and help in the movement of various parts of the body
✔✔how do proteins help the body with transport? - ✔✔transport small molecules
through an organism.
ex: hemoglobin transports oxygen to the cells
✔✔how do proteins help as hormones? - ✔✔help regulate cell growth
✔✔how to proteins help protect the body? - ✔✔proteins called antibodies help rid the
body of foreign harmful substances
, ✔✔how do proteins help the body with storage? - ✔✔help store other substances in an
organism
ex: iron is stored in the liver in a complex with the protein ferritin
✔✔how do proteins help the body with regulation? - ✔✔help mediate cell responses
ex: rhodopsin found in the eye is involved in the vision process
✔✔Primary protein structure - ✔✔peptide and covalent bonds
✔✔Secondary protein structure - ✔✔hydrogen bonds
side chains NOT interacting
✔✔Tertiary Structure - ✔✔hydrogen, non polar, ionic, and covalent bonds
(same as quaternary)
✔✔holoenzymes - ✔✔active enzyme
✔✔apoenzyme - ✔✔enzyme without its non-protein moiety
✔✔coenzyme - ✔✔indicates the non-protein moiety is a small organic molecule
✔✔co-substrate - ✔✔coenzyme that only transiently associates (loosely binds) with the
enzyme (NAD+)
✔✔activation energy - ✔✔energy barrier separating the reactants and the products
can be lowered by adding a catalysts/enzyme
✔✔G<0 means reaction proceeds forward (exothermic) and is _____ - ✔✔favorable
✔✔G>0 means reaction runs in reverse (endothermic) and is _______ - ✔✔unfavorable
✔✔endothermic reaction - ✔✔activation energy for forward reaction is greater than for
reverse
using ATP
✔✔exothermic reaction - ✔✔activation energy for forward reaction is less than for
reverse reaction
releasing energy
✔✔increase in temperature causes an __________ in enzyme activity to a certain point
- ✔✔increase
✔✔optimum pH _______ for different enzyme - ✔✔varies
SOLUTIONS RATED A+
✔✔intramolecular hydrogen bonds - ✔✔two peptide bonds bond to each other through
a hydrogen bond (on same molecule)
✔✔intermolecular hydrogen bonds - ✔✔bond takes place between atoms of two or
more separate molecules
✔✔what makes a hydrogen bond a hydrogen bond - ✔✔X-H--Y and X=O,N,F and
Y=O,N,F
✔✔significance of side chains on amino acids - ✔✔dictates role of an amino acid, also
dictates properties of the proteins resulting from the combination of certain amino acids
✔✔side chains begin to interact in the _______ structure - ✔✔tertiary
✔✔_________ interactions involve nonpolar side chains located in the interior of the
polypeptide molecule - ✔✔hydrophobic
✔✔_________ interactions form ionic bonds between charged side chain groups -
✔✔ionic
✔✔___________ is directly related to a protein's structure - ✔✔protein function
ex: we eat protein and body builds non-essential amino acids
✔✔how do proteins help the body structurally? - ✔✔skin and bone collagen (fibrous
protein)
✔✔how do proteins help the body with catalysis? - ✔✔enzyme proteins allow reactions
to occur in an organism under mild conditions with great specificity
✔✔how do proteins help the body with movement? - ✔✔they make up a large
percentage of muscle fiber and help in the movement of various parts of the body
✔✔how do proteins help the body with transport? - ✔✔transport small molecules
through an organism.
ex: hemoglobin transports oxygen to the cells
✔✔how do proteins help as hormones? - ✔✔help regulate cell growth
✔✔how to proteins help protect the body? - ✔✔proteins called antibodies help rid the
body of foreign harmful substances
, ✔✔how do proteins help the body with storage? - ✔✔help store other substances in an
organism
ex: iron is stored in the liver in a complex with the protein ferritin
✔✔how do proteins help the body with regulation? - ✔✔help mediate cell responses
ex: rhodopsin found in the eye is involved in the vision process
✔✔Primary protein structure - ✔✔peptide and covalent bonds
✔✔Secondary protein structure - ✔✔hydrogen bonds
side chains NOT interacting
✔✔Tertiary Structure - ✔✔hydrogen, non polar, ionic, and covalent bonds
(same as quaternary)
✔✔holoenzymes - ✔✔active enzyme
✔✔apoenzyme - ✔✔enzyme without its non-protein moiety
✔✔coenzyme - ✔✔indicates the non-protein moiety is a small organic molecule
✔✔co-substrate - ✔✔coenzyme that only transiently associates (loosely binds) with the
enzyme (NAD+)
✔✔activation energy - ✔✔energy barrier separating the reactants and the products
can be lowered by adding a catalysts/enzyme
✔✔G<0 means reaction proceeds forward (exothermic) and is _____ - ✔✔favorable
✔✔G>0 means reaction runs in reverse (endothermic) and is _______ - ✔✔unfavorable
✔✔endothermic reaction - ✔✔activation energy for forward reaction is greater than for
reverse
using ATP
✔✔exothermic reaction - ✔✔activation energy for forward reaction is less than for
reverse reaction
releasing energy
✔✔increase in temperature causes an __________ in enzyme activity to a certain point
- ✔✔increase
✔✔optimum pH _______ for different enzyme - ✔✔varies
