7 013 BioII 2 14 07 Sive - MIT
Transcript of 7 013 BioII 2 14 07 Sive - MIT
Student questions of the dayStudent questions of the day……..
Q1: Why are trans fats useful to the food industry?
A: These are derived from liquid (unsaturated) oils A: These are derived from liquid (unsaturated) oils
which have a short shelf life. which have a short shelf life.
Partial hydrogenation leading to partial saturation Partial hydrogenation leading to partial saturation
solidifies the fat and greatly increases shelf life.solidifies the fat and greatly increases shelf life.
Q2: Do “ring” or “cyclic” carbohydrates refer to the
monomer or polymer?
A: Both. However, ring monomers are very common,A: Both. However, ring monomers are very common,
while ring polymers are not. while ring polymers are not.
7.013
2.14.07
Biochemistry II
Quiz:
Identify the class of macromolecules
to which each of the following belong
glucose
carbohydrate
sphingomyelin
lipid
aldosterone
ecdysteronelipid
NUCLEIC ACIDS
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See Purves 3.14:
Sugars used in nucleic acids
Used in DNA
Used in RNA
Figure 3.24 Nucleotides Have
Three Components
Purves 3.24 Nucleotides have three components
Sugar structure wrong!2
3’ OH
! PO4
attacks
Nucleic acid polymerization
(A = base)
phosphodiester bond
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Nucleotide triphosphate
A-T base pair
G-C base pair
4 hydrogen bond -----
Purves 3.25 RNA is usually single-stranded
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Figure 3.26 Hydrogen Bonding
in RNA
Purves 3.26 Hydrogen bonding in RNA
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Purves 3.25: DNA is a polymer of nucleotides:
two strands are arrayed antiparallel
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Purves 11.6: DNA double helix
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Double helical staircase: Chateau Blois, France
PROTEINS
Table 3.2 The Twenty Amino Acids Found in Proteins (Part 1)
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10Table 3.2 The Twenty Amino Acids Found in Proteins (Part 3)11
Figure 3.5 Formation of Peptide Linkages
Purves 3.5 Peptide bond formation
energy
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The primary structure
of insulin
see Purves 3.6
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A single amino acid change causes sickle-cell anemia
(Prof. Vernon Ingram)
14 The secondary structure of a protein
H bonds between N-H and
C=O
of peptide bond
See also Purves 3.6
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!-helix "-pleated sheet
Spider silk: "- pleated sheets that can be unfolded
Via H-bond breakage of !-helices
Purves 3.6 Tertiary
and quaternary protein structure
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Insulin receptor/inhibitor- backbone model
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Insulin receptor/inhibitor- space fill model
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