B1 Form and function: Molecules Flashcards
How are macromolecules produced from monomers?
Through condensation reactions, which link monomers together by removing a water molecule each time a bond forms.
How are polymers broken down into monomers?
Through hydrolysis reactions, which add water to break the bonds between monomers.
What are the form and function of monosaccharides?
Monosaccharides are single sugar units (like glucose, fructose).
They’re quick energy sources, soluble in water, and used in respiration and building larger carbohydrates.
What are polysaccharides used for?
Polysaccharides like starch, glycogen, and cellulose are used for energy storage and structural support.
Long chains = slow digestion = energy reserves.
How does cellulose’s structure relate to its role in plants?
Cellulose is made of beta-glucose, forming straight, unbranched chains linked by hydrogen bonds → strong microfibrils → rigid cell walls.
What role do glycoproteins play in cells?
They’re proteins with attached carbohydrates, found on cell surfaces, used for cell–cell recognition, signaling, and immune response.
How are triglycerides and phospholipids formed?
Both are made by condensation reactions:
Triglycerides = glycerol + 3 fatty acids
Phospholipids = glycerol + 2 fatty acids + 1 phosphate group
Water is removed at each link.
What’s the difference between saturated, monounsaturated, and polyunsaturated fatty acids?
Saturated: no double bonds
Monounsaturated: 1 double bond
Polyunsaturated: 2+ double bonds
What do triglycerides do in adipose tissue?
They store long-term energy and provide thermal insulation.
How do phospholipids form bilayers?
They self-arrange into bilayers in water:
Hydrophilic heads face water
Hydrophobic tails hide inside
Why can steroids pass through membranes easily?
They are non-polar lipids, so they can slip through the hydrophobic interior of the phospholipid bilayer.
What’s the general structure of an amino acid?
Central carbon
Amino group (–NH₂)
Carboxyl group (–COOH)
Hydrogen atom
R-group (variable side chain)
How are dipeptides and proteins formed?
By condensation reactions between amino acids, forming peptide bonds.
2 amino acids = dipeptide
Many = polypeptide or protein
Why do we need amino acids in our diet?
Some amino acids are essential—the body can’t make them, so we must get them from food.
(Essential ≠ important; it means you can’t build them yourself.)
How do pH and temperature affect protein structure?
They can disrupt hydrogen and ionic bonds, leading to denaturation—loss of shape and function.
High temps = unfold
Wrong pH = bond breakage
What causes the diversity in protein shapes?
The R-groups of amino acids have different properties (polar, non-polar, charged, etc.), which influence folding and function.
R-group variety = form diversity = function diversity
How does the primary structure affect a protein?
The order of amino acids (primary structure) determines how the protein folds, and thus its final shape and function.
A single swap can ruin everything (e.g. sickle cell disease)
What are the forms of secondary structure in proteins?
Alpha helices (coils)
Beta-pleated sheets (zig-zags)
Formed by hydrogen bonding
What stabilizes a protein’s tertiary structure?
Hydrogen bonds
Ionic bonds
Disulfide bridges
Hydrophobic interactions
How do polar and non-polar amino acids affect tertiary structure?
Non-polar R-groups hide inside (away from water)
Polar R-groups face outside
This folding pattern stabilizes the protein’s shape in water-based environments.
What’s the difference between quaternary structure in conjugated and non-conjugated proteins?
Non-conjugated: 2+ polypeptide chains
Conjugated: includes prosthetic groups (e.g. heme in hemoglobin)
