Illustrate and explain the difference between α-D-glucopyranose and  β-D-glucopyranose structures.

It is important to note that galactose is an important component of glyco- proteins. What is the effect on glycoprotein synthesis in case of galactosemic patients who are not given galactose in their diet? Explain this observation.

Draw the α-l-glucopyranose sugars using Haworth projections:

Explain the primary, secondary, tetriary and quaternary structure of glutathione reductase protein.

Identify the structure of O-a-D-sorbopyranosyl-(24)-B-D-glucopyranose below. The following structures will help: НО Н ОН х Н H H D-sorbose Н OH CH₂OH Н Н Н OH HO Н H HO H н HO ОН Н н Н О ОН O H Н CH₂OH OH OH н 0 CH2OH Н OH Н H OH Н CH₂OH H ОН Н OH Н Н Н РО OH Н HO OH н н -O CH2O Н O H H OH н Н OH CH₂OH о CHOH H H Н Ко OH H OH Н Н OH Н OH Н OH Н CH₂OH -OCHOH H OH O CH OH Н OH Н Н CH₂OH ОН он OH OH H OH H O OH CH₂OH OH ОН Н O OH OH D-glucose Н ОН Н ОН ОН

What is the secondary structure of glutelin? Are there many or few alpha helices, beta sheets?

An enzyme that catalyzes disulfide– sulfhydryl exchange reactions, called protein disulfide isomerase (PDI), has been isolated. PDI rapidly converts inactive scrambled ribonuclease into enzymatically active ribonuclease. In contrast, insulin is rapidly inactivated by PDI. What does this important observation imply about the relation between the amino acid sequence of insulin and its threedimensional structure?

Draw (using Haworth projections) the fragments of xylan and glucomannanstructures as shown.

Name the α-ketoacid that is formed by the transamination of each of the following amino acids: (a) Alanine (d) Leucine (b) Aspartate (e) Phenylalanine (c) Glutamate (f) Tyrosine

Briefly describe the structural differences for each pair listed: A) Glycogen and Cellulose   B) Lactose and Sucrose