BIOLOGY 189 EXAMS EVALUATION 2025/2026 QUESTIONS
AND SOLUTIONS GRADED A+ TIP
✔✔What are the three main differences between DNA and RNA? - ✔✔DNA = 2 stands
of double helix, sugar, thymine
RNA = single stranded, sugar, uracil
✔✔what is complementary base pairing and how does it work? - ✔✔bases only bind to
specific bases
C - G, A - T, RNA = A - U
✔✔copy DNA strand 5' GAATGCCGTTAC 3' - ✔✔C - T AND G-A
3' AGGCATTACCGT 5'
5' GTAACGGCATTC 3'
✔✔What is transcription? - ✔✔the process by which info of DNA is copied to a new
molecule of mRNA. DNA stories it for reference
✔✔What is translation? - ✔✔the process in which cellular ribosomes create proteins
mRNA produced by transcription from DNA is decoded by a ribosome to produce
specific amino acid chain/polypeptide
✔✔What is the molecule and process (1-3)L Gene Expression - ✔✔1: transcription DNA
- synthesis of mRNA
2: mRNA: movement of mRNA into cytoplasm - translation
3: synthesis of protein through ribosomes and a polypeptide or amino acid is produced
✔✔Define: Purine - ✔✔larger 6 membered fused to a 5 membered ring A & G
✔✔Define: Pyrimidine - ✔✔has 1 six membered ring C&T
✔✔Define: Phosphodiester linkage - ✔✔links sugar together in the backbone of
DNA/RNA - bond between nucleotide
✔✔What are the biological roles of proteins? there are 7 - ✔✔Enzymes: speed up
reaction
Defensive: antibodies recognize foreign substances
Hormonal Regulation: ex: insulin
Storage: amino acids
Structural: collagen movement
Transport: ex: hemoglobin
Motor proteins and contraction
, ✔✔What are the building blocks of proteins? what parts of these building blocks are the
same? what part is different? - ✔✔1. Amino Acids are the monomers (building blocks)
2. Same are the number (20) backbone, first carbon
3. Different = order they are in, side group - R group
✔✔Describe a polypeptide - ✔✔more than 20 amino acids - A POLYMER/MANY
AMINO ACIDS LINKED TOGETHER BY PEPTIDE BONDS
✔✔Describe protein primary structure. Part? Bond? Shape? - ✔✔Linkage of amino
acids in a chain to form peptides (nitrogen and carbon bonds).
Amino Acids = bond
Linear in shape
✔✔Describe protein secondary structure. Part? Bond? Shape? - ✔✔Part: amino and
carboxyl groups
bond: hydrogen bonds - amongst backbone
Shape: alpha helix or beta pleated sheet
✔✔Describe protein tertiary structure. Part? Bond? Shape? - ✔✔Amino acids R-groups
reacting with each other.
Bond: hydrogen/ionic bonds - hydrophobic/hydrophilic, disulfide bridges
Shape: 3-D, R group
✔✔Describe protein quaternary structure. Part? Bond? Shape? - ✔✔interactions of R
groups of 2 or more different polypeptides bound together using all interaction/bonds
giving a fibrous or globular shape. last stage of a protein being built. ex: hemoglobin
✔✔What conditions can affect protein structure? - ✔✔Temperature, pH, contractions
✔✔Define R group - ✔✔in proteins the side chains are attached to the alpha carbon
atoms of the amino backbone. different with each amino acid
✔✔Define disulfide bridge - ✔✔covalent bond, further reinforces the shape of a protein.
forms where 2 cysteine monomers which have sulfhydryl groups are brought closer
together by the folding of the protein
✔✔Define: Peptide linkage - ✔✔when 2 amino acids are positioned so that the carboxyl
group of one is adjacent to the amino group of the other they become joined by a
dehydration reaction with the removal of another molecule
* the process yields a polypeptide, a polymer of many amino acids linked by peptide
bonds
✔✔Define: alpha helix - ✔✔a delicate coil held together by hydrogen bonding between
every 4th AMINO ACID
AND SOLUTIONS GRADED A+ TIP
✔✔What are the three main differences between DNA and RNA? - ✔✔DNA = 2 stands
of double helix, sugar, thymine
RNA = single stranded, sugar, uracil
✔✔what is complementary base pairing and how does it work? - ✔✔bases only bind to
specific bases
C - G, A - T, RNA = A - U
✔✔copy DNA strand 5' GAATGCCGTTAC 3' - ✔✔C - T AND G-A
3' AGGCATTACCGT 5'
5' GTAACGGCATTC 3'
✔✔What is transcription? - ✔✔the process by which info of DNA is copied to a new
molecule of mRNA. DNA stories it for reference
✔✔What is translation? - ✔✔the process in which cellular ribosomes create proteins
mRNA produced by transcription from DNA is decoded by a ribosome to produce
specific amino acid chain/polypeptide
✔✔What is the molecule and process (1-3)L Gene Expression - ✔✔1: transcription DNA
- synthesis of mRNA
2: mRNA: movement of mRNA into cytoplasm - translation
3: synthesis of protein through ribosomes and a polypeptide or amino acid is produced
✔✔Define: Purine - ✔✔larger 6 membered fused to a 5 membered ring A & G
✔✔Define: Pyrimidine - ✔✔has 1 six membered ring C&T
✔✔Define: Phosphodiester linkage - ✔✔links sugar together in the backbone of
DNA/RNA - bond between nucleotide
✔✔What are the biological roles of proteins? there are 7 - ✔✔Enzymes: speed up
reaction
Defensive: antibodies recognize foreign substances
Hormonal Regulation: ex: insulin
Storage: amino acids
Structural: collagen movement
Transport: ex: hemoglobin
Motor proteins and contraction
, ✔✔What are the building blocks of proteins? what parts of these building blocks are the
same? what part is different? - ✔✔1. Amino Acids are the monomers (building blocks)
2. Same are the number (20) backbone, first carbon
3. Different = order they are in, side group - R group
✔✔Describe a polypeptide - ✔✔more than 20 amino acids - A POLYMER/MANY
AMINO ACIDS LINKED TOGETHER BY PEPTIDE BONDS
✔✔Describe protein primary structure. Part? Bond? Shape? - ✔✔Linkage of amino
acids in a chain to form peptides (nitrogen and carbon bonds).
Amino Acids = bond
Linear in shape
✔✔Describe protein secondary structure. Part? Bond? Shape? - ✔✔Part: amino and
carboxyl groups
bond: hydrogen bonds - amongst backbone
Shape: alpha helix or beta pleated sheet
✔✔Describe protein tertiary structure. Part? Bond? Shape? - ✔✔Amino acids R-groups
reacting with each other.
Bond: hydrogen/ionic bonds - hydrophobic/hydrophilic, disulfide bridges
Shape: 3-D, R group
✔✔Describe protein quaternary structure. Part? Bond? Shape? - ✔✔interactions of R
groups of 2 or more different polypeptides bound together using all interaction/bonds
giving a fibrous or globular shape. last stage of a protein being built. ex: hemoglobin
✔✔What conditions can affect protein structure? - ✔✔Temperature, pH, contractions
✔✔Define R group - ✔✔in proteins the side chains are attached to the alpha carbon
atoms of the amino backbone. different with each amino acid
✔✔Define disulfide bridge - ✔✔covalent bond, further reinforces the shape of a protein.
forms where 2 cysteine monomers which have sulfhydryl groups are brought closer
together by the folding of the protein
✔✔Define: Peptide linkage - ✔✔when 2 amino acids are positioned so that the carboxyl
group of one is adjacent to the amino group of the other they become joined by a
dehydration reaction with the removal of another molecule
* the process yields a polypeptide, a polymer of many amino acids linked by peptide
bonds
✔✔Define: alpha helix - ✔✔a delicate coil held together by hydrogen bonding between
every 4th AMINO ACID
