BIOLOGY I EXAM 1 2026
LATEST UPDATE QUESTIONS
AND CORRECT VERIFIED
ANSWERS ALREADY GRADED
A+
polypeptide - ans-polymer of amino acids connected by peptide
bonds
amino end - ans-the end that has a free amino group
carboxyl end - ans-the end that has a free carboxyl group
R group - ans-chemical group attached to the central carbon atom
of an amino acid, whose structure & composition determine the
identity of the amino acid
- also known as a side chain
hydrophobic amino acid - ans-do not readily interact with water or
form H bonds
- identifying: look at R group (carbons/hydrogens)
FACE INWARDS
hydrophilic amino acid - ans-polar - tend to form H bonds
basic - R groups gain proton (+ charge)
acidic - R groups lose proton (- charge)
- identifying: look at R group (electronegative atoms like oxygen,
+ (basic), - (acidic)
FACE OUTWARDS
,ACIDIC/BASIC = FACE EACH OTHER & BECOME NEUTRAL
how many amino acids are there? - ans-20
3 special amino acids - ans-glycine, proline, cysteine
glycine - ans-R group is H, symmetric, nonpolar, small, increases
rotation of C-N bond & flexibility of polypeptide backbone
proline - ans-R group linked, restricts rotation, folding constraints
cysteine - ans-R group can form S-S disulfide bonds, cross-bridges that
connect same or diff proteins
FACE AWAY FROM EACH OTHER
4 levels of structure for protein folding - ans-1. primary structure
2. secondary structure
3. tertiary structure
4. quaternary structure
primary structure - ans-sequence of amino acids
secondary structure - ans-either an alpha helix or beta pleated sheet
- stabilized by hydrogen folding
alpha helix - ans-right-handed coil
- hydrogen bonds in b/n carbonyl & amino groups
- R groups project outwards
beta sheet - ans-pleated sheet
, - hydrogen bonds across chains run antiparallel
- R groups alternate above & below
tertiary structure - ans-3-D conformation
- several secondary structures
- distribution & interaction of R groups = important
- ionic & hydrogen bonds
- Van der Waals forces
- hydrophobic interactions
- disulfide S-S bridges
quaternary structure - ans-interaction of individual polypeptides
- complex of protein subunits w/ tertiary structure
- function depends on structure
denatured - ans-unfolding of proteins by chemical treatment or high
temperature
- results in loss of function
chaperones - ans-proteins that help protect slow-folding or denatured
proteins until they can attain their proper 3D structure
lipids - ans-makes up cell wall, stores energy, signals molecules
what kinds of molecules are lipids? - ans-hydrophobic
- chemically diverse (not defined by chemical structure)
(ex. fatty acids, oils, waxes, steroids)
3 types of lipids - ans-1. triacylglycerol
2. steroids
LATEST UPDATE QUESTIONS
AND CORRECT VERIFIED
ANSWERS ALREADY GRADED
A+
polypeptide - ans-polymer of amino acids connected by peptide
bonds
amino end - ans-the end that has a free amino group
carboxyl end - ans-the end that has a free carboxyl group
R group - ans-chemical group attached to the central carbon atom
of an amino acid, whose structure & composition determine the
identity of the amino acid
- also known as a side chain
hydrophobic amino acid - ans-do not readily interact with water or
form H bonds
- identifying: look at R group (carbons/hydrogens)
FACE INWARDS
hydrophilic amino acid - ans-polar - tend to form H bonds
basic - R groups gain proton (+ charge)
acidic - R groups lose proton (- charge)
- identifying: look at R group (electronegative atoms like oxygen,
+ (basic), - (acidic)
FACE OUTWARDS
,ACIDIC/BASIC = FACE EACH OTHER & BECOME NEUTRAL
how many amino acids are there? - ans-20
3 special amino acids - ans-glycine, proline, cysteine
glycine - ans-R group is H, symmetric, nonpolar, small, increases
rotation of C-N bond & flexibility of polypeptide backbone
proline - ans-R group linked, restricts rotation, folding constraints
cysteine - ans-R group can form S-S disulfide bonds, cross-bridges that
connect same or diff proteins
FACE AWAY FROM EACH OTHER
4 levels of structure for protein folding - ans-1. primary structure
2. secondary structure
3. tertiary structure
4. quaternary structure
primary structure - ans-sequence of amino acids
secondary structure - ans-either an alpha helix or beta pleated sheet
- stabilized by hydrogen folding
alpha helix - ans-right-handed coil
- hydrogen bonds in b/n carbonyl & amino groups
- R groups project outwards
beta sheet - ans-pleated sheet
, - hydrogen bonds across chains run antiparallel
- R groups alternate above & below
tertiary structure - ans-3-D conformation
- several secondary structures
- distribution & interaction of R groups = important
- ionic & hydrogen bonds
- Van der Waals forces
- hydrophobic interactions
- disulfide S-S bridges
quaternary structure - ans-interaction of individual polypeptides
- complex of protein subunits w/ tertiary structure
- function depends on structure
denatured - ans-unfolding of proteins by chemical treatment or high
temperature
- results in loss of function
chaperones - ans-proteins that help protect slow-folding or denatured
proteins until they can attain their proper 3D structure
lipids - ans-makes up cell wall, stores energy, signals molecules
what kinds of molecules are lipids? - ans-hydrophobic
- chemically diverse (not defined by chemical structure)
(ex. fatty acids, oils, waxes, steroids)
3 types of lipids - ans-1. triacylglycerol
2. steroids
