Chapter 2 - Biological Molecules
Section 1 - Carbohydrates
LECTURE VIDEO
DESCRIPTION
They’re not just pasta—they’re your body’s primary fuel source and a structural marvel. Unwrap the sweet science of carbohydrates for A-Level Biology. This video breaks down the sugars, from the simplest monosaccharides to the complex polymers. We’ll make it crystal clear:
How a glucose molecule is structured (and why its isomerism matters).
The difference between glycogen, starch, and cellulose (and why you can digest one but not the other).
The Benedict’s Test: A step-by-step guide to mastering this core practical.
Why cellulose is the ultimate plant superhero.
Stop cramming and start understanding the energy of life.
TIMESTAMPS
STUDY RESOURCES
00:00:00 – Intro
00:00:13 – Overview Of This Video
00:00:50 – Levels Of An Organism
00:04:57 – Monomers V.S Polymers
00:07:04 – What Are Carbohydrates?
00:11:10 – Monosaccharide Structure
00:21:35 – Monosaccharide Functions
00:28:38 – Condensation V.S Hydrolysis
00:31:44 – Disaccharides
00:39:56 – Polysaccharides – Glycogen
00:45:35 – Polysaccharides – Starch
00:48:01 – Why does glucose NEED to be stored as a polysaccharide?
00:54:32 – Polysaccharides – Cellulose
00:59:54 – Putting The Pieces Of The Puzzle Together…
01:03:18 – Iodine Test
01:05:28 – Benedicts Test For Reducing Sugars
01:12:42 – Testing For NON-Reducing Sugars
01:15:14 – Questions & Answers
01:33:42 – Outro
NOTES – All you need to know in one place!
QUESTIONS – Test your Big Brain!
Section 2 - Lipids
LECTURE VIDEO
DESCRIPTION
They’re not just fats (that give you a triple chin)—they’re insulation, protection, and a powerhouse of energy storage. Dive into the hydrophobic world of lipids for A-Level Biology. This video cuts through the grease to explain:
The structure of a triglyceride and why it’s so efficient for storage.
The undeniable difference between saturated & unsaturated fats (no confusion!).
The Emulsion Test: How to prove the presence of lipids in a sample.
The amazing dual-nature of the phospholipid and why it’s the foundation of every cell membrane.
Understand the molecules that shape your cells and store your energy.
TIMESTAMPS
STUDY RESOURCES
00:00:00 – Intro
00:00:13 – Overview Of This Video
00:00:40 – Levels Of An Organism
00:02:41 – Types Of Lipids
00:05:45 – Triglycerides [FUNCTION]
00:15:06 – Periodic Table Of Elements
00:17:55 – Fatty Acids & Glycerol Structure
00:21:58 – Saturated V.S Unsaturated Fatty Acids
00:26:58 – One Glycerol + Three Fatty Acids = Triglyceride
00:35:10 – Lipids DO NOT Have Monomers Or Polymers
00:36:25 – Fats V.S Oils
00:43:33 – Solubility Of Lipids
00:47:40 – Phospholipids Structure & Function
00:54:24 – One Glycerol + Two FA + One Phosphate = Phospholipid
00:56:45 – Summary Page
00:59:57 – Lipid Emulsion Test
01:05:02 – Questions & Answers
01:08:52 – Outro
NOTES – All you need to know in one place!
QUESTIONS – Test your Big Brain!
Section 3 - Proteins
LECTURE VIDEO
DESCRIPTION
They’re the most diverse molecule in your body. From enzymes to antibodies, proteins do it all. Decode the complexity of proteins for A-Level Biology. This video is your guide to the building blocks of life. We’ll make sure you understand:
The 4 levels of protein structure (primary to quaternary) and the bonds that hold them together.
How a single amino acid change can cause a disease like sickle cell anemia.
The Biuret Test: How to confidently test for proteins.
Why shape is everything for enzyme function.
Learn the language of life, one amino acid at a time.
TIMESTAMPS
STUDY RESOURCES
00:00:00 – Intro
00:00:13 – Overview Of This Video
00:01:01 – Levels Of An Organism
00:02:51 – What Are Proteins?
00:12:04 – Amino Acids
00:21:38 – Peptide Bond
00:26:17 – Polypeptide
00:29:34 – Primary Structure Of A Protein
00:32:33 – Secondary Structure Of A Protein
00:37:53 – Tertiary Structure Of A Protein
00:50:51 – Quaternary Structure Of A Protein
00:52:21 – Denaturation
00:55:10 – Globular V.S Fibrous Proteins
01:01:00 – Hemoglobin (+ Sickle Cell Anemia)
01:09:25 – Collagen
01:21:30 – Pieces Of The Puzzle
01:23:25 – Biuret Test
01:25:54 – Questions & Answers
01:32:59 – Outro
NOTES – All you need to know in one place!
QUESTIONS – Test your Big Brain!
Section 4 - Water
LECTURE VIDEO
DESCRIPTION
It’s not ‘just’ water—it’s the unique solvent that makes life possible on Earth. Plunge into the surprising properties of water for A-Level Biology. This video reveals why H₂O is the ultimate biological molecule. We’ll cover:
The power of hydrogen bonding and why it gives water its “superpowers.”
How cohesion & surface tension allow insects to walk on water.
Why water is the perfect metabolite & solvent for all life processes.
Its role as a temperature buffer in organisms and ecosystems.
See why life is impossible without this incredible molecule.
TIMESTAMPS
STUDY RESOURCES
00:00:00 – Intro
00:00:13 – Overview Of This Video
00:01:31 – Structure Of Water
00:08:44 – Cohesion
00:11:12 – Adhesion
00:13:59 – Universal Solvent
00:23:05 – High Specific Heat Capacity
00:27:29 – High Latent Heat Of Vaporization
00:33:22 – Chapter 2 Summary
00:35:57 – Questions & Answers
00:39:19 – Outro
NOTES – All you need to know in one place!
QUESTIONS – Test your Big Brain!