Biological Molecules (Miss Reynolds) Flashcards
What atoms do organic compounds contain?
Carbon, hydrogen and oxygen.
Polymer
A long molecule made of similar/identical units called monomers.
Polysaccharides
Chain of carbohydrates, built from monosaccharides.
Polymer for monosaccharides and example.
Carbohydrate (like starch)
Polymer for amino acids and example.
Protein (e.g Insulin/collagen)
Polymer for fatty acids and example.
Lipids (e.g fats/oils)
Polymer for nucleotides.
DNA
Name an example of a monosaccharide.
Glucose, fructose, ribose.
Name an example of a disaccharide.
Lactose, sucrose.
Name an example of a polysaccharide.
Glycogen, cellulose, starch.
What’s the difference between alpha and beta glucose structurally?
The position of the OH-. In alpha it is below the carbon and in beta it is above.
Which disaccharide out of maltose, sucrose and lactose has a beta glucose bond?
Lactose.
Formula of glucose.
C6H12O6.
Which polysaccharide out of cellulose, starch and glycogen uses beta glucose bonding?
Cellulose.
Which polysaccharide is branched?
Glycogen.
Similarities between all three polysaccharides.
All have glycosidic bonds and are insoluble.
Reduction
A chemical reaction involving the gain of electrons/hydrogen.
How to test for reducing sugars?
At Benedicts solution and if a brick red precipitate forms, reducing sugar is present.
How to test for non-reducing sugars?
If there is no colour on Benedicts Test, add hydrochloric acid, hydrolysing any disaccharides into monosaccharides. Then add sodium hydrogen-carbonate solution to neutralise acid and repeat test.
What is the bond in triglycerides?
Esther bonds.
How do triglycerides form?
Condensation reaction.
Lipids
A diverse group of compounds that are insoluble in water but soluble in organic solvents.
In phospholipids what is hydrophilic and hydrophobic?
The phosphate is hydrophilic and fatty acids hydrophobic.
Hydrophilic
Attracts water.
Hydrophobic
Repels water.
Name two roles of lipids.
An energy source, heat insulation, protection.
Describe the emulsion test for lipids.
Adding ethanol to food sample and shake vigorously. Then add water and a milky layer will form if lipids present.
What is the function of triglycerides?
Energy storage.
Function of phospholipids?
Control what goes in/out of the cell.
Proteins
A diverse group of large/complex polymer molecules.
What are proteins made up of?
Long chains of amino acids.
Structural proteins role.
Main component of body tissues e.g muscle/skin.
Catalytic proteins role.
Biochemical reactions e.g enzymes.
Signalling proteins role.
Cause body changes e.g hormones.
Immunological proteins role.
Fight disease e.g antibodies.
What defines an amino acid?
The R Group.
What does the R Group represent?
A side chain from the central alpha carbon atom.
Polypeptides
Long chains of amino acids.
How do proteins/polypeptides form?
In condensation reactions.
Primary protein structure.
Simple long chains with no intermolecular bonds.
Secondary protein structure.
Hydrogen bonds form causing the molecule chain to either fold/coil. Forms alpha helix.
Tertiary protein structure.
Hydrophilic/phobic interactions, hydrogen bonds, ionic bond and disulphide bonds hold the molecules together.
Quaternary Protein Structure.
Same as tertiary but with two separate polypeptide chains interlinked.
What causes proteins to denature?
The breaking of bonds.
What factors lead to protein denature?
Temperature, pH, concentration.
What happens to fibrous proteins when they denature?
They lose their structural strength and become insoluble and inactive.
Structure of globular proteins.
Polypeptide chains are folded into spherical shapes, with the hydrophilic side chains on the outside, making them soluble.
Structure of fibrous proteins.
Formed of long chains, several polypeptide chains can be cross linked for additional strength. Insoluble and important for structure.
Name an example of a globular protein and fibrous one.
Globular, enzymes, fibrous, collagen/keratin.
Digestion
Large biological molecules are hydrolysed by enzymes into smaller molecules that can be absorbed across the cell membrane.
Amylase
Made by salivary glands and pancreas.
Maltose
Made by small intestines.
Miscelles
Tiny droplets of monoglyceride and fatty acids that release monoglycerids close to the surface of the cell.
Endopeptidase
Hydrolyses peptide bonds within a polypeptide.
Exopetidace
Hydrolyse peptide bonds at the end of the polypeptide.
Endopeptidase
Stomach, produces small chains of amino acids by hydrolysing peptide bonds between amino acids.
Physical Digestion
Breaking large pieces of food into smaller pieces.
Chemical Digestion
Breaking down large molecules e.g starch.
Digestive enzymes for the food groups.
Protein, protease, lipids, lipase, starch, maltose/amylase.
Products of Digestion for each food group.
Protein, amino acids, lipids, fatty acids, starch, glucose.
Membrane Bound Dipeptidase
Enzymes attached to membranes, hydrolyse peptide bonds between dipeptides.
Exopeptidase
Ileum, produces single and pairs of amino acids by hydrolysing peptide bonds on the terminal amino acids.
Dipeptidases
Ileum, produces single amino acids. (Membrane bound)
Lock and Key Theory
The specific action of an enzyme with a single substrate.
Induced-fit Theory
Substrate plays a roll in determining the final shape of the enzyme and that the enzyme is partially flexible.
Rate
Amount of something produced per unit of time.
What factors affect rate of reaction?
Temperature and concentration.
As you increase concentration, rate of reaction increases, why?
More active sites for substrate molecules to react to.
Whats the limiting factor with concentration?
Substrate as eventually there will be a point where there is more substrate than enzyme and the reaction cannot proceed any faster.
Enzymes Inhibitors
Substances that interfere with the functioning of the active site of an enzyme and so reduce it’s activity.
Competitive Inhibitors
Bind to the active site of the enzyme.
Non-competitive inhibitors.
Bind to the enzyme at a position other than the active site.
