1. Biological Molecules Flashcards
Complete to spec.
Name three disaccharides
Maltose sucrose and lactose
What monosaccharides make up sucrose
Glucose + fructose
What monosaccharides make up maltose
Glucose + glucose
What monosaccharides make up lactose
Glucose + galactose
Describe a hydrogen bond
A weak electrostatic force between two dipolar molecules
What is the primary structure of a protein. What type of bond is involved
The order of specific amino acids, held by peptide bonds
What is the secondary structure of a protein
When H-bonds form between the amino causing either:
an alpha-helix shape
or a beta-pleated sheet
what is the territory structure of a protein? what bonds are involved
The 3d shape of the polypeptide is dependent on the secondary structure
- h bonds
- ionic
- di sulfide
What does hydrophilic mean
Molecule has a charge, so it’s attracted to water
Describe the differences in alpha and beta glucoses
A-glucose has H group on top and OH bottom
B-glucose has H group on bottom and OH on top
Draw the structure of a protien
R
|
H2N——C—-COOH
|
H
What are the 4 uses of lipids
- Waterproofing
- Energy source
- Insulation
- Protection
Why are triglycerides better at storing energy than carbohydrates
High ratio of c-h (stores energy)
Give three properties of triglycerides relating to its function
Low energy to mass ratio, good for storage, storing a lot in small masses
Large, non polar = insoluble in water. Do not effect osmosis or water potential of cell
High ratio of h:o = source of water when oxidised
Describe the test for lipids
- 2cm of sample, 5cm of ethanol, shake
- Add water and shake
- Milky white emulsion indicates the presence of a lipid
Repeat with control, water instead of sample
What is the difference between reducing and non-reducing sugars?
a reducing sugar is able to donate electrons.
Describe structure of glycogen
- a-glucose polymer
- 1-4 glycosidic + 1-6
- ## highly branched
what is cellulose, and how does its structure help its function
Single, unbranched chain of alternating b glucoses
H bonds form between rows, tensile strength
Makes up microfibril in plant walls
what are the 5 components of an amino acid?
central carbon, R group, hydrogen, carboxyl group (COOH), amino group (HNH)
describe the test for NON-reducing sugars
- Add dilute hydrochloride acid to sample
- Neutralise solution with sodium hydrogen-carbonate
- Use litmus paper to identify when the solution has been neutralised,
- add a little more sodium hydrogen-carbonate
- Then carry out Benedict’s test as normal;
- positive = brick red
describe the INDUCED-FIT MODEL
active site and substrate have complementary shapes, active site must change slightly to bind to fit substrate and bind to form ENZYME-SUBSTRATE COMPLEX.
what bond is formed between two monosaccharides?
glycosidic.
what is an isomer? apply to glucose.
- molecule with same molecular formula but structurally different
- ## a-glucose, b-glucose
draw the structures of a-glucose and b-glucose.
OH on bottom of a-glucose, top on b
structure of starch
- amylose, 1-4 glycosidic
- amylopectin, 1-4 + 1-6
What is the function of starch? give three features that help function.
Store of glucose in plants
- helix, fit a lot in small space
- branched molecule, SA for hydrolysis
- insoluble, no effect on water pot.
How does glycogens structure help its function?
Store of glucose in animals, muscle and liver cells.
- Branched structure, SA for hydrolysis
- insoluble, no effect on water pot
Structure of cellulose (4)
- b-glucose
- long, straight chains
- every other molecule inverted 180
- chains held together in parallel by hydrogen bonds to form fibrils
Role of cellulose.
- Provide strength to cell wall
Describe the use of benedict’s reagent to test for the presence of REDUCING SUGARS.
- 2cm of
- equal volume of benedict’s reagent
- water bath for 5 mins
Benedict’s test for NON-REDUCING SUGARS
- add dilute HCL to sample and heat in a water bath, close to boil
- neutralise with sodium hydrogen carbonate.
- use litmus paper to test that solution is slightly alkaline
- benedict’s solution as normal
triglycerides are made up of…
One glycerol molecule and three molecule of fatty acids.
What reaction and bond joins a glycerol and a fatty acid?
- condensation
- ester bond
Describe the quaternary structure of proteins.
Association of multiple polypeptide chains and non-protein (prosthetic) groups.
Describe the biuret test
- Equal volumes sample and sodium hydroxide at room temp.
- Add a few drops of copper2 sulfate, mix
- purple coloration indicates presence of peptide bonds, blue if negative.
Name the bond that joins amino acids together
Peptide
amino acids are joint by…
condensation reaction.
Role of enzymes
lowers activation energy of the reaction it catalyses.
Explain the effect that a high PH has on an enzyme controlled reaction
- PH alters charges of amino acids, substrate cannot bind to active site
- Tertiary structure may be changed, active site changed shape (ionic bonds)
