Question 1

A structural lipid found in the cell membrane is a:

Accepted Answer

Phospholipids are a major component of all cell membranes as they can form lipid bilayers. Steroids, such as cholesterol, are also present in cell membranes and play a role in membrane fluidity and stability. Triglycerides are not structural components of cell membranes; they are used mainly for energy storage.

Question 2

Peptide bonds join together molecules of:

Accepted Answer

Peptide bonds are formed between amino acids to create polypeptide chains, which serve as the building blocks of proteins. Glycerol and glucose are not involved in the formation of peptides, and water is not a molecule that can be joined through a peptide bond.

Question 3

An example of a catabolic process is

Accepted Answer

A catabolic process is a type of metabolic reaction that involves breaking down complex molecules into simpler ones, usually releasing energy in the process. Hydrolysis is a common example of a catabolic process, as it involves breaking bonds between molecules using water molecules, which releases energy in the form of heat. Dehydration synthesis and formation of a peptide bond are examples of anabolic processes, which involve building up complex molecules from simpler ones, and require energy input. Therefore, option A is the best choice as it is the only example of a catabolic process.

Question 4

Which lipid is part of vitamin D?

Accepted Answer

Vitamin D is a steroid hormone and therefore contains steroids as a lipid component. Glyercol, prostaglandins, and fatty acids are not typically found in vitamin D.

Question 5

The element that is present in all proteins but not in carbohydrates is:

Accepted Answer

Nitrogen is present in all proteins in the form of amino acids, but carbohydrates do not contain nitrogen. Carbohydrates are composed of carbon, hydrogen, and oxygen.

Question 6

Which of the following is not one of the major groups of organic substances in the human body?

Accepted Answer

The major groups of organic substances in the human body include proteins, lipids, and nucleic acids. Salts are considered inorganic substances.

Question 7

Which of the following represent(s)properties of water?

Accepted Answer

All of the given options represent properties of water. Water has a high specific heat, meaning it can absorb a lot of heat energy before its temperature rises significantly. It also has a high heat of vaporization, meaning it requires a lot of energy to evaporate. Finally, water has strong polarity due to its unequal distribution of electrons between its hydrogen and oxygen atoms, which makes it a versatile solvent and contributes to many of its unique properties.

Question 8

All of the following substances are organic except:

Accepted Answer

Organic compounds are based on carbon and typically found in living organisms. Lipids, carbohydrates, and proteins are all organic compounds, while electrolytes, such as sodium and potassium ions, are inorganic compounds.

Question 9

The basic building blocks of fats are:

Accepted Answer

Fats are composed of molecules known as triglycerides, which consist of three fatty acids attached to a glycerol molecule. Fatty acids are the basic building blocks of fats. Therefore, the best choice is D, fatty acids and glycerol. Monosaccharides and disaccharides are building blocks of carbohydrates, not fats. Amino acids are building blocks of proteins, not fats.

Question 10

The study of metabolism includes examination of:

Accepted Answer

The study of metabolism includes examination of both catabolism and anabolism, as well as the ATP requirements for these processes. Therefore, the correct answer is D - all of the above.

Question 11

Approximately what percentage of body weight is water?

Accepted Answer

Water makes up about 70% of the human body.

Question 12

The simple sugars that are the building blocks for other carbohydrates are:

Accepted Answer

Monosaccharides are single sugar molecules that cannot be broken down further into smaller carbohydrates. They are the simplest form of carbohydrate and are the building blocks for other types of carbohydrates. Examples of monosaccharides include glucose, fructose, and galactose.

Question 13

DNA:

Accepted Answer

DNA is a double helix structure made up of nucleotides that contain a sugar-phosphate backbone and nitrogenous bases (adenine, thymine, cytosine, and guanine). The two strands are held together by hydrogen bonds between complementary base pairs (A-T, C-G).

Question 14

The amino group in an amino acid is:

Accepted Answer

The amino group in an amino acid is a functional group consisting of a nitrogen atom bonded to two hydrogen atoms and one carbon atom, represented as NH3+.

Question 15

Humans can synthesize 13 of 21 basic amino acids; the remaining 8,which must be included in the diet,are called:

Accepted Answer

The remaining 8 amino acids that must be included in the diet are called essential amino acids, as they cannot be synthesized by the human body and must be obtained from food sources. Choices A and C are incorrect, as enzymes and structural proteins are not the same as essential amino acids. Choice D is also incorrect, as peptide bonds refer to the chemical bonds that link amino acids together to form proteins.

Question 16

AB + C→ AD + CB is an example of a(n)_____ reaction.

Accepted Answer

This is an example of an exchange reaction, where two reactants exchange atoms or ions to form two new products.

Question 17

The type of lipid found in sex hormones is:

Accepted Answer

Steroids are the type of lipid found in sex hormones. Sex hormones such as testosterone, estrogen, and progesterone are steroid hormones synthesized from cholesterol.

Question 18

The formation of sucrose involves the removal of a molecule of water.This is called:

Accepted Answer

Dehydration synthesis is the process of joining two molecules, such as glucose and fructose, to form a larger molecule, such as sucrose, by the removal of a water molecule. This process is also known as condensation.

Question 19

The approximate pH of gastric fluid is:

Accepted Answer

The approximate pH of gastric fluid is 2, making it extremely acidic. This acidity helps to break down food and kills harmful bacteria.

Question 20

The type of lipoprotein associated with "bad" cholesterol and the production of atherosclerotic changes in blood vessels is:

Accepted Answer

LDL (low-density lipoprotein) is known as "bad" cholesterol because it can contribute to the buildup of plaques in blood vessels, leading to atherosclerosis. HDL (high-density lipoprotein) is known as "good" cholesterol because it helps remove excess cholesterol from the blood and may protect against heart disease. VHDL is not a recognized type of lipoprotein.

Quiz 2: B: The Chemical Basis of Life