Exam Questions Flashcards
Name the covalent bond between 2 adjacent amino acids in a chain of amino acids
-peptide
Name the type of reaction involved in breaking peptide bonds
-hydrolysis
-adding water to break the H bonds
Describe how an enzyme breaks down
-substrate is complementary to active site
-substrate fits onto active site
-induced fit
-forms enzyme substrate complex
-destabilises bonds
-amino acids leave active site
Describe how to do the emulsion test for lipids and how a positive result would be identified
-add ethanol
-goes cloudy
How might lipid content of mycoprotein differ from food that comes from animals?
-less lipid
-less fat
-more unsaturated
Describe the formation of H bonds between 2 molecules of water and explain why water can form these bonds
-hydrogen binds to oxygen molecules
-electropositive
-polar molecule
Why is the ability of water to act as a solvent important for the survival of organisms?
-medium for reactions
-allows ionic compounds to separate
-transport in xylem + phloem
Describe the structure of collagen molecule
-peptide bonds
-helix
-3 polypeptide chains
-H bonds between chains
-no hydrophilic groups on outside
-cross links
-fibril
What bond joins monosaccharides together?
glycosidic
How is cellulose formed?
-condensation polymerisation of beta glucose
What role does hydrogen play in helping cut flowers last longer?
-to regulate pH
What role does sodium play in helping cut flowers last longer?
-to regulate water potential
Explain how properties relating to the density of water contribute to the survival of organisms
-ice is less dense than water = floats
-animals can float
-ice provides a habitat for some species
-ice insulates water below
Outline the properties of water which make it an ideal habitat for an amphibian
-high specific heat capacity
-high density = buoyancy
Explain how the structure of phospholipids allow them to form the bilayer of a plasma membrane
-hydrophilic head = attracts water forming H bonds
-hydrophobic head = forms bilayer as they repel water
-polar molecule
Describe and explain how the structure and properties of different carbs and lipid molecules suit them to their role as energy storage molecules in plants and animals
carbs
-polymers of glucose - used to release energy
-1-4 glycosidic bonds = easy to make + break = glucose
-coiled shape = take up less space
-unbranched amylose = no need for rapid release of monomers in plants
-glycogen more branched = more rapid release in animals
-fats insoluble - don’t affect WP
Name 3 functions of triglycerides in living organisms
- energy storage
- thermal insulation
- energy source for respiration
Explain how the fatty acids in phospholipids allow the formation of membranes
-fatty acid tails = hydrophobic
-repels water molecules
-forms bilayer by facing inwards
What is meant by hydrolysis in terms of triglycerides molecules?
-uses water to break 3 ester bonds
Describe how a method that uses Benedict’s reagent and a colourimeter could be calibrated to measure the concentration of lactose in an unknown sample
-set to 0
-using blank
-use known contractions of glucose
-construct calibration curve
-read from curve to determine concentration
Suggest how you could test for the prescene of a disaccharide
-benedicts test
-boil with HCL and retest with benedicts
What bond holds together alpha glucose and fructose?
1-6 glycosidic bond
State the name of the monomer in cellulose
-beta glucose
What bond joins monosaccharides together?
-glycosidic
