Identification by Function

Help Questions

Biochemistry › Identification by Function

Questions 1 - 10
1

Atkins diet is a special diet that involves low intake of carbohydrates. Which of the following molecules might be elevated in a person following the Atkins diet?

Ketone bodies in blood

Glycogen stores in liver

Blood glucose

More than one of these

Explanation

Carbohydrates are first lines of energy source for tissues. If there is a decrease in the amount of carbohydrates, then other energy sources such as fatty acids and proteins are mobilized and undergo metabolism to produce energy. One of the byproducts of fatty acid metabolism are ketone bodies; therefore, a decrease in carbohydrates will lead to an increase in fatty acid metabolism and, subsequently, an increase in ketone bodies.

Glycogen stores will be depleted because liver will respond to the decreased glucose levels and break down glycogen to component glucose molecules. Low carbohydrate concentration will decrease blood glucose levels.

2

Which of the following is/are function(s) of nucleic acids?

I. Store genetic information

II. Form ribosomes

III. Store energy

I and II

III only

I and III

II and III

Explanation

The main function of nucleic acid is to form the genetic material. Recall that DNA is utilized to make RNA (also made up of nucleic acid) during transcription. There are three kinds of RNA molecules: mRNA, tRNA, and rRNA. mRNA is used to synthesize proteins, tRNA facilitates protein synthesis, and rRNA makes up ribosomes; therefore, nucleic acids are important for formation of ribosomes. Remember that nucleic acids are not used to synthesize ATP or store energy in any form. ATP itself is a nucleoside triphosphate, not a nucleic acid.

3

Atkins diet is a special diet that involves low intake of carbohydrates. Which of the following molecules might be elevated in a person following the Atkins diet?

Ketone bodies in blood

Glycogen stores in liver

Blood glucose

More than one of these

Explanation

Carbohydrates are first lines of energy source for tissues. If there is a decrease in the amount of carbohydrates, then other energy sources such as fatty acids and proteins are mobilized and undergo metabolism to produce energy. One of the byproducts of fatty acid metabolism are ketone bodies; therefore, a decrease in carbohydrates will lead to an increase in fatty acid metabolism and, subsequently, an increase in ketone bodies.

Glycogen stores will be depleted because liver will respond to the decreased glucose levels and break down glycogen to component glucose molecules. Low carbohydrate concentration will decrease blood glucose levels.

4

Which of the following is/are function(s) of nucleic acids?

I. Store genetic information

II. Form ribosomes

III. Store energy

I and II

III only

I and III

II and III

Explanation

The main function of nucleic acid is to form the genetic material. Recall that DNA is utilized to make RNA (also made up of nucleic acid) during transcription. There are three kinds of RNA molecules: mRNA, tRNA, and rRNA. mRNA is used to synthesize proteins, tRNA facilitates protein synthesis, and rRNA makes up ribosomes; therefore, nucleic acids are important for formation of ribosomes. Remember that nucleic acids are not used to synthesize ATP or store energy in any form. ATP itself is a nucleoside triphosphate, not a nucleic acid.

5

Upon examination, a patient is found to have low levels of glucose in his blood. Which of the following observation(s) might be found in this patient?

I. The patient is lethargic

II. Decreased levels of glycogen

III. Decreased levels of fatty acids

I, II, and III

II only

I and II

I and III

Explanation

Glucose is a monosaccharide that is utilized for energy production in cells. Decrease in glucose levels in blood and tissues will lead to decreased production of energy (ATP) and, subsequently, will cause the person to be lethargic. Recall that glucose undergoes glycolysis to create products that will eventually undergo Krebs cycle and/or oxidative phosphorylation to generate ATP.

Glycogen is a storage molecule found typically in liver. It is made up of numerous glucose molecules bonded together by glycosidic bonds. If there is a decrease in blood glucose levels, liver initiates the breakdown of glycogen to individual glucose molecules and deposits these molecules in the blood; therefore, this patient’s liver will break down glycogen and create individual glucose molecules.

Fatty acid is another type of macromolecule used to synthesize energy. If there is a decrease in levels of glucose, fatty acids from adipose tissue and muscle will be mobilized and released into the blood. These fatty acids will now travel to tissues and supply energy (by generating ATP).

6

Upon examination, a patient is found to have low levels of glucose in his blood. Which of the following observation(s) might be found in this patient?

I. The patient is lethargic

II. Decreased levels of glycogen

III. Decreased levels of fatty acids

I, II, and III

II only

I and II

I and III

Explanation

Glucose is a monosaccharide that is utilized for energy production in cells. Decrease in glucose levels in blood and tissues will lead to decreased production of energy (ATP) and, subsequently, will cause the person to be lethargic. Recall that glucose undergoes glycolysis to create products that will eventually undergo Krebs cycle and/or oxidative phosphorylation to generate ATP.

Glycogen is a storage molecule found typically in liver. It is made up of numerous glucose molecules bonded together by glycosidic bonds. If there is a decrease in blood glucose levels, liver initiates the breakdown of glycogen to individual glucose molecules and deposits these molecules in the blood; therefore, this patient’s liver will break down glycogen and create individual glucose molecules.

Fatty acid is another type of macromolecule used to synthesize energy. If there is a decrease in levels of glucose, fatty acids from adipose tissue and muscle will be mobilized and released into the blood. These fatty acids will now travel to tissues and supply energy (by generating ATP).

7

What type of lipid structure requires a phosphate group, and what is the most common use of this lipid structure in a cell?

Phospholipids, cell membranes

Steroids, cholesterol

Triacylglycerides, fats

Free floating fatty acids, acetyl-CoA

Phospholipids, ATP

Explanation

Phospholipids, as the name implies, require a phosphate head group attached to two fatty acid tails. Their polar phosphate head groups and non-polar fatty acid tails are perfect for a bi-layer membrane, where 2 layers of phospholipids are arranged such that their non-polar tails face each other and their polar phosphate head groups face outwards.

8

What type of lipid structure requires a phosphate group, and what is the most common use of this lipid structure in a cell?

Phospholipids, cell membranes

Steroids, cholesterol

Triacylglycerides, fats

Free floating fatty acids, acetyl-CoA

Phospholipids, ATP

Explanation

Phospholipids, as the name implies, require a phosphate head group attached to two fatty acid tails. Their polar phosphate head groups and non-polar fatty acid tails are perfect for a bi-layer membrane, where 2 layers of phospholipids are arranged such that their non-polar tails face each other and their polar phosphate head groups face outwards.

9

Which of these is not a valid classification of protein function?

All of these are functions of proteins

Enzymes

Receptors

Signaling molecules

Structural elements

Explanation

Proteins are the most diverse group of macromolecule. They can be fibrous (structural) or globular (receptors, enzymes, signaling molecules, and more).

10

Which of these is not a valid classification of protein function?

All of these are functions of proteins

Enzymes

Receptors

Signaling molecules

Structural elements

Explanation

Proteins are the most diverse group of macromolecule. They can be fibrous (structural) or globular (receptors, enzymes, signaling molecules, and more).

Page 1 of 6