Question 1

Which of the structures below corresponds to the dipeptide serylalanine? Note the following structures:

Accepted Answer

C

Question 2

Phosphorus is an essential mineral element.It is an important atom in which one of the following?

Accepted Answer

Phosphorus is a key component of DNA, and is involved in the structure of nucleic acids. It is not a significant part of amino acids, proteins, polyethylene, or nylon.

Question 3

Which of the following describes a lipid?

Accepted Answer

Lipids are a group of small organic molecules that are insoluble in water. They include fats, oils, waxes, and steroids. They are characterized by their hydrophobic nature and their role in energy storage, structural components of cells, and signaling.

Question 4

Which of the following describes a fat?

Accepted Answer

A fat is a tri-ester of glycerol where each of the hydroxyl-group hydrogen atoms in glycerol has been replaced by the alkyl group of a relatively long hydrocarbon chain carboxylic acid. Option A describes an amino acid, option B describes a simple carbohydrate, option C describes hydrophobic molecules in general, and option D describes a phospholipid.

Question 5

Which of the following is not a protein?

Accepted Answer

Saturated triglycerides, such as triolein, are lipids, not proteins. Hormones, structural substances, antibodies, and transport facilitators are all proteins.

Question 6

Which of the following describes a triglyceride?

Accepted Answer

A triglyceride is a molecule composed of glycerol that is esterified with three fatty acids. In other words, it is a triester of glycerol where each of the hydroxyl-group hydrogen atoms in glycerol has been replaced by the alkyl group of a relatively long hydrocarbon chain carboxylic acid. This makes the molecule insoluble in water. A is describing a polysaccharide, B is describing a ketone or aldehyde, C is describing hydrophobic organic molecules in general, and D is describing a phospholipid.

Question 7

Which of these elements is not found in proteins?

Accepted Answer

Phosphorus (P) is found in nucleic acids such as DNA and RNA, but is not present in proteins.

Question 8

Which of the following is not a carbohydrate?

Accepted Answer

Carbohydrates generally follow the formula C_n(H₂O)_n. D) C₆H₁₄O₆ does not fit this pattern, as the hydrogen to oxygen ratio is not 2:1.

Question 9

Which of the following describes a steroid?

Accepted Answer

Steroids are a group of molecules that have a special grouping of 5- and 6-member rings in common. Examples of steroids include cholesterol, sex hormones, and cortisol.

Question 10

The breaking apart of a dissacharide into its monosaccharide components involves the addition of a water molecule and is called _______.

Accepted Answer

Hydrolysis is the process of breaking down a larger molecule into smaller components by the addition of water. In the case of a disaccharide, hydrolysis involves the breaking of the covalent bond between the two monosaccharides with the addition of a water molecule, resulting in two separate monosaccharides.

Question 11

Which of the following describes a phospholipid?

Accepted Answer

A phospholipid is a diglyceride with an organic phosphate group in place of one of the fatty acids. This structure gives phospholipids both hydrophobic and hydrophilic properties which make them important components of cell membranes. The other choices do not accurately describe a phospholipid.

Question 12

Which of the following is a fatty acid?

Accepted Answer

The answer of Which of the following is a fatty...

Question 13

Which of the structures below corresponds to the dipeptide alanylserine?

Accepted Answer

Alanylserine is a dipeptide consisting of alanine and serine residues. Alanine has a methyl group at the alpha carbon and a carboxyl group, while serine has a hydroxyl group at the beta carbon and a carboxyl group. The dipeptide is formed by a peptide bond between the carboxyl group of alanine and the amino group of serine.

Out of the given structures, only option B shows an alanine residue and a serine residue connected by a peptide bond. Thus, B corresponds to alanylserine.

Question 14

Which of the following refers to a primary structure?

Accepted Answer

Primary structure of a protein refers to the linear sequence of amino acids that make up the protein chain.

Question 15

Which of the following describes a protein?

Accepted Answer

A protein is a large biological polymer composed of amino acids.

Question 16

A peptide bond (also called an amide bond) joins two amino acids together.What atoms are linked by this bond?

Accepted Answer

The peptide bond links the carboxyl group (-COOH) of one amino acid with the amino group (-NH2) of the other amino acid, resulting in a C-N bond. The other options are not involved in peptide bond formation.

Question 17

Which of the following is a steroid?

Accepted Answer

The answer of Which of the following is a steroid?
...

Question 18

An amino acid is a compound that contains at least

Accepted Answer

Amino acids are composed of an amino group (-NH2) and a carboxylic acid group (-COOH), which are typically bonded to a central carbon atom, called the alpha carbon. This distinguishes amino acids from other organic compounds that contain an amino or a carboxylic acid group, but not both. Therefore, choice D is the best answer.

Question 19

Which of the following refers to a secondary structure?

Accepted Answer

A secondary structure refers to the shape a protein chain adopts as the result of hydrogen bonding between the amino acid backbones. This can take the form of either an alpha helix or a beta sheet.

Question 20

The backbone of a strand of nucleic acid consists of

Accepted Answer

The backbone of a strand of nucleic acid, such as DNA or RNA, consists of alternating phosphate and sugar units. The sugar is deoxyribose in DNA and ribose in RNA.

Quiz 15: Biochemistry