Topic 1: Biological Molecules Flashcards
What is maltose formed from?
Glucose + glucose
What is lactose formed from?
Glucose + galactose
What does glucose and fructose form?
Sucrose
What is the bond between two monosaccharides?
Glycosidic
What is a reducing sugar? And some examples.
A sugar that can donate electrons to reduce another substance easily, all monosaccharides are and some disaccharides are.
Test for reducing sugar?
Heated with Benedict’s reagent forming an insoluble red ppt if reducing sugar present.
Test for Starch?
Add Iodine solution to substance. Blue-black if present.
What monomer is Starch made up of?
alpha-glucose
How is starch suited to it’s role of energy storage?
- insoluble
- doesn’t readily diffuse out of cells and affect osmotic potential
- compact so a lot can be stored in a small space
- when broken down in hydrolysis it forms alpha-glucose which can be used in respiration.
How is glycogen different compared to starch?
Glycogen has shorter chains and is more branched than starch.
How is glycogen adapted for its function of short term storage?
- Insoluble
- Doesn’t readily diffuse and affect osmotic potential
- Compact so alot can be stored in a small space
- More branched so many enzymes can work on breaking it down simultaneously.
What are the monomers that form cellulose?
beta-glucose
How is cellulose adapted for its function?
- Each monomer is rotated 180o forming glycosidic bonds
- resulting in long straight, unbranched chains
- Chains run parallel to eachother and are linked by Hydrogen bonds giving strength
Why are lipids not polymers?
Not made up of repeating sub-units.
How are triglycerides and phospholipids different?
Triglycerides are made up of glycerol and 3 fatty acid tails, whereas in phospholipids one of the fatty acids is replaced by a phosphate molecule.
Emulsion test for lipids?
- Crush sample
- add ethanol shake, then add water
- further shake, if contents are cloudy-white a lipid is present
Protein test
- Add Biuret reagent to sample
- if solution turns purple peptide bonds are present.
What is the primary structure of a protein?
The sequence of amino acids in a polypeptide chain.
What is the secondary structure in a protein?
Polypeptide chain folds and hydrogen bonds form between carboxyl groups forming either alpha helixes or beta-pleated sheets.
What is the tertiary structure in a protein?
bonding between R groups form a complex 3D shape either ionic bonds or disulfide bonds, creating unique active site.
What is quarternary structure in a protein?
Proteins that have more than one polypeptide chain held together. Some may have a prosthetic group like haem-oglobin
Differences between 2 models of enzyme action?
- Active site moulds to substrate in Induced fit.
- Isn’t rigid fit like in lock and key
What is a competitive inhibitor in enzymes?
Directly takes place of substrate in active site, reducing activity of enzymes and overall rate of reaction.
What is a non-competitive inhibitor?
Inhibitor that binds to position other than active site, changing its structure reducing rate or reaction or preventing substrate binding at all.
3 differences between structure of DNA and RNA
- RNA is a singular helix, whereas DNA is a double helix
- RNA has AUCG, while DNA has ATCG
- RNA has only a ribose sugar, while DNA has a deoxyribose sugar
What are ribosomes made up of?
Proteins and rRNA
How does the structure of DNA relate to its function?
- Strands are joined by weak hydrogen bonds which can easily be broken for protein synthesis and replication
- Complementary base pairing leads to accurate replication and information transfer in mRNA
- Extremely large molecule, can store a large amount of info
- Helix so it is compact and can store a large amount of info in a small space
- Phosphodiester bonds protect the molecule and keep it stable
Roles of ATP?
- Smaller energy quantities prevent thermal damage
- Single step reaction immediately releases energy
- Can be rapidly resynthesised
- Phosphorylate other molecules making them more reactive
Energy usage from ATP hydrolysation
- Metabolic processes synthesis of macromolecules
- Movement of muscle filaments
- Active transport change shape of active site
- Secretion needed to form lysosomes
Properties of water?
- Reactive takes place in hydrolysis and condensation reactions
- Polar molecule so can be used as a solvent
- Relatively high specific heat capacity lose and gain a lot of energy without changing temp used as a buffer
- Large latent heat of vaporisation providing cooling effect with little water loss
- Strong cohesive properties can be used in xylem due to H bonds
