BIO 225 STANDARD EXAM SHEET 2025/2026
QUESTIONS AND SOLUTIONS GRADED A+ TIP
✔✔Which bases are purines? - ✔✔guanine and adenine
✔✔Which bases are pyrimidines - ✔✔cytosine and thymine (uracil in RNA)
✔✔What is the difference between a nucleotide and a nucleoside - ✔✔Nucleotides
have a phosphate group
✔✔Does translation occur in the nucleus? - ✔✔NO! cytosol (and a little bit in the
mitochondria)
✔✔What is the absolute configuration of all amino acids? - ✔✔L-isomers
Co-R-N goes to the left
(different that the RS system)
✔✔Can peptide bonds rotate? - ✔✔no. pi bond cannot rotate.
✔✔Is chaperone folding an active process - ✔✔yes, requires ATP to sequester to
protein and prevent interactions with other proteins or molecules in the cytosol or the
ER
✔✔What is a proteasome - ✔✔barrel-shaped protein complex that degrades damaged
or unnecessary proteins tagged for destruction with ubiquitin
✔✔where does ubiquitilation occur - ✔✔Lysine (k)
✔✔what does 4 k48 ubiquitin labelling result in - ✔✔the destruction of the tagged
protein by a proteasome
✔✔phosphoanydride vs phosphoester bonds - ✔✔phosphoanhydride are high energy,
between the 1st and 2nd and 2nd and 3rd phosphate groups on a nucleotide
(phosphoester bond is the one that attaches the phosphates to the pentose sugar).
✔✔What is the rule of canonical base pairing called - ✔✔Chargaff's rule
✔✔How are the nitrogenous bases in DNA exposed - ✔✔structure has major and minor
grooves
✔✔what is the +1 site in DNA - ✔✔the transcriptional start site
✔✔what is upstream of the +1 site - ✔✔the promoter region
, ✔✔How does cAMP act as an enhancer of gene expression - ✔✔activate PKA which
phosphorylates CREB (bound to CRE on the gene) allowing CBP to bind to CREB and
recruits polymerase to activate transcription.
✔✔aldose vs ketose - ✔✔aldose - aldehyde
ketose - ketone
✔✔amylopectin vs. glycogen - ✔✔glycogen is more branched
✔✔what does branching of a carb allow - ✔✔very quick metabolism (fight or flight or to
regulate blood sugar)
✔✔how is glycogen metabolized in fight or flight (or to increase blood sugar). -
✔✔epinephrine or glucagon bind to a GPCR in the muscles or liver respectively -
causing a conformational change in the heteromeric G-protein (Gs) that results in the
activation of its alpha subunit via the bonding of GTP - the activated alpha subunit binds
to cyclase which, in turn, converts ATP to cAMP, activating PKA and phosphorylating
the protein responsible for glycogen synthesis making glucose more available in the
system.
✔✔what is amylose - ✔✔A long unbranched chain of alpha glucose.
✔✔Who is Rosalind Franklin - ✔✔The scientist who first discovered the helical nature of
DNA - although Watson and Crick are credited (Rosalind solved the x ray
crystallography diffraction pattern).
✔✔What does amphipathic mean - ✔✔a molecule that has both hydrophobic and
hydrophilic regions (like a phospholipid).
✔✔omega vs delta system - ✔✔omega starts from the tail - delta starts from the
carboxyl group
✔✔describe the fatty acid 17:2 cis∆5, trans∆9 - ✔✔polyunsaturated lipid with 17
carbons and a cis and trans double bond at carbon 5 and 9 starting from the carbon in
the carboxyl group
✔✔what are the two types of phospholipids - ✔✔phosphoglycerides and
phsophosphingolipids
✔✔What is the function of cholesterol - ✔✔it regulates the fluidity of the membrane,
preventing it from becoming too fluid or too stiff
QUESTIONS AND SOLUTIONS GRADED A+ TIP
✔✔Which bases are purines? - ✔✔guanine and adenine
✔✔Which bases are pyrimidines - ✔✔cytosine and thymine (uracil in RNA)
✔✔What is the difference between a nucleotide and a nucleoside - ✔✔Nucleotides
have a phosphate group
✔✔Does translation occur in the nucleus? - ✔✔NO! cytosol (and a little bit in the
mitochondria)
✔✔What is the absolute configuration of all amino acids? - ✔✔L-isomers
Co-R-N goes to the left
(different that the RS system)
✔✔Can peptide bonds rotate? - ✔✔no. pi bond cannot rotate.
✔✔Is chaperone folding an active process - ✔✔yes, requires ATP to sequester to
protein and prevent interactions with other proteins or molecules in the cytosol or the
ER
✔✔What is a proteasome - ✔✔barrel-shaped protein complex that degrades damaged
or unnecessary proteins tagged for destruction with ubiquitin
✔✔where does ubiquitilation occur - ✔✔Lysine (k)
✔✔what does 4 k48 ubiquitin labelling result in - ✔✔the destruction of the tagged
protein by a proteasome
✔✔phosphoanydride vs phosphoester bonds - ✔✔phosphoanhydride are high energy,
between the 1st and 2nd and 2nd and 3rd phosphate groups on a nucleotide
(phosphoester bond is the one that attaches the phosphates to the pentose sugar).
✔✔What is the rule of canonical base pairing called - ✔✔Chargaff's rule
✔✔How are the nitrogenous bases in DNA exposed - ✔✔structure has major and minor
grooves
✔✔what is the +1 site in DNA - ✔✔the transcriptional start site
✔✔what is upstream of the +1 site - ✔✔the promoter region
, ✔✔How does cAMP act as an enhancer of gene expression - ✔✔activate PKA which
phosphorylates CREB (bound to CRE on the gene) allowing CBP to bind to CREB and
recruits polymerase to activate transcription.
✔✔aldose vs ketose - ✔✔aldose - aldehyde
ketose - ketone
✔✔amylopectin vs. glycogen - ✔✔glycogen is more branched
✔✔what does branching of a carb allow - ✔✔very quick metabolism (fight or flight or to
regulate blood sugar)
✔✔how is glycogen metabolized in fight or flight (or to increase blood sugar). -
✔✔epinephrine or glucagon bind to a GPCR in the muscles or liver respectively -
causing a conformational change in the heteromeric G-protein (Gs) that results in the
activation of its alpha subunit via the bonding of GTP - the activated alpha subunit binds
to cyclase which, in turn, converts ATP to cAMP, activating PKA and phosphorylating
the protein responsible for glycogen synthesis making glucose more available in the
system.
✔✔what is amylose - ✔✔A long unbranched chain of alpha glucose.
✔✔Who is Rosalind Franklin - ✔✔The scientist who first discovered the helical nature of
DNA - although Watson and Crick are credited (Rosalind solved the x ray
crystallography diffraction pattern).
✔✔What does amphipathic mean - ✔✔a molecule that has both hydrophobic and
hydrophilic regions (like a phospholipid).
✔✔omega vs delta system - ✔✔omega starts from the tail - delta starts from the
carboxyl group
✔✔describe the fatty acid 17:2 cis∆5, trans∆9 - ✔✔polyunsaturated lipid with 17
carbons and a cis and trans double bond at carbon 5 and 9 starting from the carbon in
the carboxyl group
✔✔what are the two types of phospholipids - ✔✔phosphoglycerides and
phsophosphingolipids
✔✔What is the function of cholesterol - ✔✔it regulates the fluidity of the membrane,
preventing it from becoming too fluid or too stiff
