These questions test your knowledge of lipid and carbohydrate structure and function

Reviewed by Jonathan Loomes-Vrdoljak on 25 July 2019

Metabolism 1

Congratulations - you have completed Metabolism 1 . You scored %%SCORE%% out of %%TOTAL%%. Your performance has been rated as %%RATING%%
Your answers are highlighted below.
Question 1

Which of the following macromolecules is incorrectly matched to its function?

A
Carbohydrates - quick energy source
B
Lipids - hormonal signalling
C
Proteins - enzymes
D
Nucleic acids - quick energy source
Question 1 Explanation: 
One of the main functions of nucleic acids are information storage and transmission
Question 2

If cellulose is a carbohydrate, why can it not be used for quick energy in humans?

A
It is used for quick energy, but it is normally present in dense polysaccharide chains, which make it hard to be broken down
B
Humans lack the enzyme to break down beta-glycosidic linkages present in cellulose
C
It is used for quick energy, but its breakdown product can also be used as fibre
D
It is actually a protein
Question 3

What is the generic molecular formula for carbohydrates?

A
[C(H2O)]n , with n≥3
B
[C(H2O)]n-2 , with n≥3
C
[C(H2O)]n-2 , with n≥4
D
[C(H2O)]n-2 , with n≥5
Question 4

Lactase is a brush border enzyme in the small intestine. It is absent in people with lactose intolerance. The enzyme hydrolyses lactose into which of the following 2 monomers?

A
Glucose and fructose
B
Glucose and mannose
C
Glucose and galactose
D
Fructose and galactose
Question 5

Which of the following disaccharide constituents are incorrect?

A
Lactulose (laxative) = galactose + fructose
B
Sucrose (table sugar) = glucose + galactose
C
Lactose (sugar found in cow’s milk) = glucose + galactose
D
Maltose (product of starch breakdown) = glucose + glucose
Question 5 Explanation: 
Sucrose is formed from glucose and fructose.
Question 6

You request for your patient to have a fasting blood test. What is the name of the extensively branched polysaccharide produced by the liver whose monomers are released during the fasting state to maintain energy levels?

A
Cellulose
B
Amylose
C
Amylopectin
D
Glycogen
Question 6 Explanation: 
Cellulose - unbranched repeating monomers of β-glucose (produced in plants cannot be broken down by humans) Amylose - unbranched repeating monomers of α-glucose (normally produced in plants) Amylopectin - branched repeating monomers of α-glucose (normally produced in plants) Glycogen - branched repeating monomers of α-glucose (produced by the liver in humans)
Question 7

What is the composition of triglycerides?

A
Glycerol and a carboxylic acid
B
Glycerol and 3 fatty acids
C
Glycerol and 3 polysaccharides
D
A polysaccharide and 3 fatty acids
Question 8

In what form is fat stored in adipose tissue?

A
Triglycerides
B
Glycogen
C
amino acids
D
Carboxylic acids
Question 8 Explanation: 
Triglycerides are esters formed by a glycerol and 3 fatty acids. When energy is needed, they are broken down into their constituents where glycerol is converted back to glucose by the liver and the free fatty acids undergo beta oxidation to become acetyl Co-A. Glycogen is a way of storing glucose to be released during a decrease in plasma glucose levels. Amino acids are protein subunits Carboxylic acids are functional groups on different molecules in the body. For example, they are attached to the α carbon on each amino acid
Question 9

What fat forms the main constituent of a cell's plasma membrane?

A
Phospholipid
B
Fatty acid
C
Glycerol
D
Triglyceride
Question 10

Your patient has dangerously low levels of cholesterol. How would you expect their cell membrane to behave?

A
It would be rigid as cholesterol adds extra fluidity to the membrane
B
It would be more fluid as cholesterol adds structural support to the membrane
C
Permeability would decrease because the other membrane molecules can pack closer together
D
Membrane surface receptors would be affected
Question 11

What is a ketone body?

A
An altered amino acid formed by the metabolism of proteins released from muscle in starvation mode
B
A protein formed from glycogen in the liver when the body is not receiving sufficient glucose
C
3-4 polar carbon chain formed by beta oxidation of fatty acids in the liver.
D
A product of the breakdown of glycogen
Question 11 Explanation: 
Ketone bodies can be formed from fatty acids released from adipose tissue in a starved state (i.e. when cells are not receiving enough glucose to undergo their normal metabolic processes)
Question 12

You are doing a history on a patient when you notice a sweet smell of pear drops on their breath. What compound can this be?

A
Fructose - they must have eaten a pear before the consultation
B
Glucose - salivary amylase can break down polysaccharide chains beginning in the mouth
C
Ketone body - a volatile compound produced by the liver through beta oxidation of fatty acids.
D
Lactose - they lack the enzyme normally present in the mouth to break down this compound
Question 12 Explanation: 
The aroma of pear drops or nail polish remover on a patient's breathe could indicate diabetic ketoacidosis, a medical emergency - due to a lack of insulin, cells cannot take up glucose so the liver metabolises fatty acids into ketone bodies as an alternative energy source.
Question 13

Which of the following energy sources does not match where it is consumed?

A
Glucose - most tissues, brain
B
Fatty acids - most tissues except the brain
C
Ketones - most tissues, including the brain, but not the liver
D
Amino acids - most tissues
Question 14

When can triglyceride storage be pathological?

A
When it spills into ectopic tissue
B
When it can be broken down into glycerol and free fatty acids
C
If it is stored for too long it can ferment
D
When storage balances utilisation
Question 14 Explanation: 
When excess adipose tissue spills over into ectopic tissue, it can impair the normal functioning of that tissue. For example, central obesity in a patient with sleep apnoea can press on the diaphragm and lungs reducing the patient's ability to breath at night.
Question 15

Which of the following glucose transporters are insulin sensitive?

A
GLUT1
B
GLUT2
C
GLUT3
D
GLUT4
Question 15 Explanation: 
Insulin attaches to it's respective receptor on insulin sensitive cells (ex. adipose tissue or striated muscle cells) and subsequently triggers the exocytosis of vesicles containing the GLUT4 transporter to the membrane so that cells can absorb glucose
Question 16

A mutation in the gene that codes for the GLUT3 protein will have the largest impact on which cells?

A
Hepatocytes
B
Beta cells of the pancreas
C
Alpha cells of the pancreas
D
Neurons
Question 16 Explanation: 
GLUT2 transporters are found on hepatocytes and beta cells
Question 17

Which of the following glucose transporters are found in the kidney?

A
GLUT1
B
SGLT2
C
SGLT1
D
GLUT2
Question 17 Explanation: 
SGLT1 is found in the gut, and SGLT2 is found in the kidneys. An easy way to remember the distribution of SGLT1 and SGLT2 is that you have two kidneys (so SGLT2) and only one gut (so SGLT1)
Question 18

Which glucose transporter uses secondary active transport to move glucose across the cell membrane?

A
GLUT 1
B
GLUT 3
C
SGLT1
D
GLUT 2
Once you are finished, click the button below. Any items you have not completed will be marked incorrect. Get Results
There are 18 questions to complete.

Spotted an error?

13 + 12 =