MCAT Biology Practice Exam Questions
and Answers (Latest Update 2025)
the chemical reaction that breaks down all the major macro-
molecules - Correct Answers ✅Hydrolysis
What is the strongest type of INTER-molecular bonds? -
Correct Answers ✅Hydrogen bonds are the strongest
intermolecular bonds....
diople-dipole bonds are weaker. . . Vander wall bonds are the
weakest.
Why is water a liquid at high temperatures? - Correct
Answers ✅Hydrogen bonding bonds the water molocules
closer together.
What is an ampipathic molecule? give an Example. - Correct
Answers ✅A molecule with both hydrophobic and
hydrophilic regions.
Example: PhoshpoLipid (Phospho=philic,lipid= phobic)
What is a lipid? - Correct Answers ✅A lipid is a biological
molecule with low solubility in water.
Lipid means fat. Liposuction is fat removal.
Peptides are NOT lipids.
What are the 6 major groups of lipids? - Correct Answers
✅1) fatty acids...
,MCAT Biology Practice Exam Questions
and Answers (Latest Update 2025)
the next 3 have a 3 carbon back bone:
2) Tri-glyceride
3) Phospholipids
4) Glycolipids
5) Steroids
6) Terpenes - A large class of organic compounds. examples:
smelly pine oils, beer hops aroma and vitamin A.
What is the structure of a Tri-glyceride? - Correct Answers
✅triglicerides are esters. Composed from 3 carbon glycerol
backbone and 3 fatty acid chains dangling. Each carbon chain
is attached by an ester bond.
What happens if you add water to an ester group in a Tri-
glyceride? How is this reaction rate increased? - Correct
Answers ✅Water cleaves the ester bond into an alcohol and
a carboxylic/ fatty acid. LIPASES speed are the enzyme that
speed this reaction.
in terms of water solubility, What is important to know about
the longer the carbon chain in a Tri-glyceride when broken
down? - Correct Answers ✅longer carbon chains are less
water soluble.
In longer chains the polar carboxylic acid are less significant.
,MCAT Biology Practice Exam Questions
and Answers (Latest Update 2025)
How soluble is a Shorter chain fatty acids? - Correct
Answers ✅Shorter chain fatty acids are slightly water
soluble.
explain what is so special about Saturated Fatty
Acids........Also, explain the melting point. - Correct Answers
✅saturated fatty acids have only single, alkane bonds along
the carbon chain. They have a straighter chain and have
more van der wall forces, and therefor a higher melting point.
explain what is so special about Unsaturated Fatty Acid....
Also, explain the melting point. - Correct Answers
✅Unsaturated fatty acids have at least one double bond.
They are not saturated with Hydrogen. they have a LOWER
melting point.
At room temperatures unsaturated fatty acids may be oily,
like Healthy peanut butter.
explain the phospho-lipids structure. Where are phoshpo
lipids common? - Correct Answers ✅Phospholipids are also
built on a 3 Carbon backbone.
One of the carbon has a Phosphate PO4 group. the other 2
carbons have carbon chains attached by a ester bond.
This is the lollypop of the cell membrane. Esters have 2
oxygens.
, MCAT Biology Practice Exam Questions
and Answers (Latest Update 2025)
What regions are poplar nonpolar in a membrane? - Correct
Answers ✅1)the phosphates are Polar, water lovin, hydro
philic regions that face the outside.
2) Nonpolar, hydro phobic carbon chain regions face the
inside.
Explain glycolipids structure. - Correct Answers
✅glycolipids have 3 carbon backbone with
2 Carbon chains attached by an ester group.
THe third carbon has a carbohydrate
What do steroids look like? - Correct Answers ✅Slightly
amphipathic 4 ring structures
lipids are insoluble. So how do they move through the blood?
- Correct Answers ✅They are usually carried by
lipoproteins, like HDL or LDL.
What are the major classes of lipoproteins? - Correct
Answers ✅1) Chylomicrons which are the largest
2) VLDLs these are low denstiy, but large.
3) LDLs
4) HDLs. these high density lipids are the smallest, and called
good proteins.
and Answers (Latest Update 2025)
the chemical reaction that breaks down all the major macro-
molecules - Correct Answers ✅Hydrolysis
What is the strongest type of INTER-molecular bonds? -
Correct Answers ✅Hydrogen bonds are the strongest
intermolecular bonds....
diople-dipole bonds are weaker. . . Vander wall bonds are the
weakest.
Why is water a liquid at high temperatures? - Correct
Answers ✅Hydrogen bonding bonds the water molocules
closer together.
What is an ampipathic molecule? give an Example. - Correct
Answers ✅A molecule with both hydrophobic and
hydrophilic regions.
Example: PhoshpoLipid (Phospho=philic,lipid= phobic)
What is a lipid? - Correct Answers ✅A lipid is a biological
molecule with low solubility in water.
Lipid means fat. Liposuction is fat removal.
Peptides are NOT lipids.
What are the 6 major groups of lipids? - Correct Answers
✅1) fatty acids...
,MCAT Biology Practice Exam Questions
and Answers (Latest Update 2025)
the next 3 have a 3 carbon back bone:
2) Tri-glyceride
3) Phospholipids
4) Glycolipids
5) Steroids
6) Terpenes - A large class of organic compounds. examples:
smelly pine oils, beer hops aroma and vitamin A.
What is the structure of a Tri-glyceride? - Correct Answers
✅triglicerides are esters. Composed from 3 carbon glycerol
backbone and 3 fatty acid chains dangling. Each carbon chain
is attached by an ester bond.
What happens if you add water to an ester group in a Tri-
glyceride? How is this reaction rate increased? - Correct
Answers ✅Water cleaves the ester bond into an alcohol and
a carboxylic/ fatty acid. LIPASES speed are the enzyme that
speed this reaction.
in terms of water solubility, What is important to know about
the longer the carbon chain in a Tri-glyceride when broken
down? - Correct Answers ✅longer carbon chains are less
water soluble.
In longer chains the polar carboxylic acid are less significant.
,MCAT Biology Practice Exam Questions
and Answers (Latest Update 2025)
How soluble is a Shorter chain fatty acids? - Correct
Answers ✅Shorter chain fatty acids are slightly water
soluble.
explain what is so special about Saturated Fatty
Acids........Also, explain the melting point. - Correct Answers
✅saturated fatty acids have only single, alkane bonds along
the carbon chain. They have a straighter chain and have
more van der wall forces, and therefor a higher melting point.
explain what is so special about Unsaturated Fatty Acid....
Also, explain the melting point. - Correct Answers
✅Unsaturated fatty acids have at least one double bond.
They are not saturated with Hydrogen. they have a LOWER
melting point.
At room temperatures unsaturated fatty acids may be oily,
like Healthy peanut butter.
explain the phospho-lipids structure. Where are phoshpo
lipids common? - Correct Answers ✅Phospholipids are also
built on a 3 Carbon backbone.
One of the carbon has a Phosphate PO4 group. the other 2
carbons have carbon chains attached by a ester bond.
This is the lollypop of the cell membrane. Esters have 2
oxygens.
, MCAT Biology Practice Exam Questions
and Answers (Latest Update 2025)
What regions are poplar nonpolar in a membrane? - Correct
Answers ✅1)the phosphates are Polar, water lovin, hydro
philic regions that face the outside.
2) Nonpolar, hydro phobic carbon chain regions face the
inside.
Explain glycolipids structure. - Correct Answers
✅glycolipids have 3 carbon backbone with
2 Carbon chains attached by an ester group.
THe third carbon has a carbohydrate
What do steroids look like? - Correct Answers ✅Slightly
amphipathic 4 ring structures
lipids are insoluble. So how do they move through the blood?
- Correct Answers ✅They are usually carried by
lipoproteins, like HDL or LDL.
What are the major classes of lipoproteins? - Correct
Answers ✅1) Chylomicrons which are the largest
2) VLDLs these are low denstiy, but large.
3) LDLs
4) HDLs. these high density lipids are the smallest, and called
good proteins.
