302 TERM 1 ULTIMATE SHOWDOWN

Which one of the side chains below is not hydrophilic?

• 1

• 2

• 3

• 4

Which of the following is true?

1.Glucose molecules are bonded together by hydrogen bonds

2.The alpha-glucose in starch has an alpha-helical structure

3.Glycogen is branched and (thus) has lesser hydrogen bonds than cellulose.

4.In cellulose, two glucose molecules are linked by an a-1,4 glycosidic linkage

• 1, 2 & 3

• 3

• 2 & 3

• 3 & 4

Which of the following statements about lipids are false?

1.Lipids have a high solubility in non-polar solvents

2.The hydrophilic head of phospholipids contains glycerol, phosphate group and hydroxyl group

3.Only one H2O molecule is removed in the formation of triglyceride due to condensation reaction

4.Steroids has a 4 fused ring structure

• 1 and 3

• 2 and 4

• 2 and 3

• All of the above

Which of the options are the most correct?

1.Radiation and organic solvents affects the foldings and shape of proteins

2.A denatured protein might still be biologically active, but it’s activity decreases significantly

3.Hydrogen bonds in secondary structure are formed between the N-H groups and C=O groups

• 3

• 1 & 2

• 1, 2 & 3

• 1 & 3

In the secondary structure of proteins, which of the following may polypeptide chains form?

• Alpha helices or Beta pleated sheets

• Alpha pleated sheets or beta helices

• A helically coiled structure

• A linear structure

Which of the following statements about lipids are correct

1.Lipids can be hydrophilic, hydrophobic or amphipathic in nature

2.All steroids have a common structure — 4 interconnecting rings

3.Saturated fat is usually liquid at room temperature while unsaturated fat is usually solid.

4.The structure of phospholipid consists of two hydrophobic fatty acid "tails" and a hydrophilic "head" consisting of a phosphate group.

• 1 & 3

• 2 & 3

• 2 & 4

• 1 & 4

Which of the following statements regarding the denaturation of a protein or regarding the denatured protein is correct?

• During the denaturation of a protein, the covalent trisulfide bridges formed between the R groups of the amino acids in the proteins are disrupted

• The denatured protein may be returned to its original shape

• The tertiary, secondary and primary structures of the protein are affected in the denaturation of the protein

• The denatured protein will be biologically active

Some raw meats in the world can be cooked with just lemon or lime juice, how is that possible?

• The acids in the juice will decrease the activation energy of the enzyme used to break the proteins and allow the meat to be cooked more easily.

• The acids in the juice will break the peptide bonds between amino acids to form ion dipole interactions with the amino acids, causing the protein to be broken down and thus it will change texture and colour of the meat.

• The acidic juices will remove the enzyme inhibitors and will allow the proteins to be broken down and thus the proteins will change and the meat will be cooked.

• The acid in the juice can denature the proteins in the meat, causing the protein to be reduced to its primary structure, which changes the texture and the colour of the meat.

Which of the following statements are false?

1.B-glucose molecules flip 180 degrees with respect to its neighbour to form an a-helix.

2.A single a-glucose molecule consists of 5 OH groups, 12 Hydrogen atoms and 6 Carbon atoms.

3.Maltose gets broken down into glucose by amylase.

4.A single beta-glucose consists of 5 OH groups, 13 Hydrogen atoms and 6 Carbon atoms.

• 1 & 4

• 2 & 3

• 1 & 3

• All of the above

How many of the following statements is/are correct?

A: The secondary structure is necessary in the tertiary structure

B: The hydrogen bond that holds beta pleated sheet together is intramolecular in nature

C: All the amino acids with NH₂ are basic

D: Hydrogen bonds can help stabilise both secondary and tertiary structure

• 1

• 2

• 3

• 4