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

1

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

3

Nucleotide triphosphate

A-T base pair

G-C base pair

4 hydrogen bond -----

Purves 3.25 RNA is usually single-stranded

5

Figure 3.26 Hydrogen Bonding

in RNA

Purves 3.26 Hydrogen bonding in RNA

6

Purves 3.25: DNA is a polymer of nucleotides:

two strands are arrayed antiparallel

7

Purves 11.6: DNA double helix

8

Double helical staircase: Chateau Blois, France

PROTEINS

Table 3.2 The Twenty Amino Acids Found in Proteins (Part 1)

9

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

12

The primary structure

of insulin

see Purves 3.6

13

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

15

!-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

16

Insulin receptor/inhibitor- backbone model

17

Insulin receptor/inhibitor- space fill model

18