Topic 1-Biological molecules Flashcards
Why do leaves get greener, and plants don’t grow until then?
-Magnesium needed for chlorophyll synthesis
-Nitrates needed for growth
-Time taken for chlorophyl to be made
-Can’t grow until it photosynthesises
How does water enable muscles to push against body fluid
-tightly bonded to each water molecule
-by hydrogen bonds
-incompressible
-shape of body changes as the volume of water doesn’t change
Why is 30 degrees a suitable temp for different fish?
-High enough so it doesn’t die but low that it still has enough oxygen
-if too high, enzymes would denature and will not have enough oxygen for respiration
-if too low, enzymes won’t have enough energy to collide
Why is protein soluble in water?
-protein folded so hydrophilic group is in the outside
-exposed R groups are polar
-water can form hydrogen bonds with polar/charged particles
-as water is a polar solvent
Why does drought affect quality of food for herbivores?
-less water taken from the soil
-less water in the plant
-less ions such as nitrates/magnesium
-less water for photosynthesis
-less glucose produced
-less biomass of plant
Difference between glucose and ribose
-glucose is hexose sugar, ribose is pentose
-glucose has formula C6H12O6 whereas ribose has c5H10O5
Structure of glycogen
-branched molecule of 1,4 bonds
-compact for energy storage
-1,6 glycosidic bond
-easy breakdown
-insoluble so doesn’t affect osmosis
-large so doesn’t leave cells
Accuracy when measuring mass
-Increase drying time so all solvent is dried
-repeat to reduce standard deviation
-rinse off all precipitate from filter paper so they all get measured
Compare monosaccharides and disaccharides
Different general formula
disaccharides have glycosidic bonds
Starch function and structure
-plants only
-large so insoluble and not osmotic
-many glucose so compact and good energy storage
Cellulose
-hydrogen bonds
-straight chain
-mesh like/parallel structure
-lignin holds mesh like structure
-prevent cell bursting
phospholipids
-bilayer
-hydrophilic head on the outside to interact with aqueous environment
Phospholipids and triglycerides difference
Phospholipids are polar and triglycerides are not
Triglycerides and other molecules
Triglyceride hydrophobic so repels water (good energy source as there isn’t water)
Other molecules are hydrophilic so dissolves in water
Importance of primary structure protein
-determines tertiary shape
-r groups determine position of bonds (ionic/covalent)
Collagen
-3 polypeptide bonds
-helices joined together
-hydrogen bonds
Hydrolysis
-breakdown of glycosidic bonds
-water needed
Optimum plant growth
-contain all mineral ions
-at optimum concentration
-nitrate and magnesium
Protein synthesis
-peptide bonds between amino and carboxylic group to make primary structure
-further folding into secondary and tertiary, ionic/disulfide/hydrogen bonds between R groups
Lipids as energy storage
-insoluble
-high hydrogen content
-insulation as don’t conduct heat
-large molecules loosely packed
Variation in DNA sequence
-more triplet codes than amino acids
-code is degenerate
-Same AA have different codes
-Help maintain structure in case of a mutation
Comparing AA sequences
-No. of bases/codons
-type of AA made
-sequence of AA
tRNA + mRNA reading
5’ tp 3’
Structure of DNA
-Double helix composed of 2 strands
-nucleotides held by phosphodiester bonds
-complementary bases held by hydrogen bonds
Effect of chemical in DNA
-Double helix can’t be unzipped to form templates
-transcription can’t occur
-both cells affected
Effect of inhibitors in protein synthesis
-Some pre made RNA still exists
-Some synthesis takes place
Translation steps
- mRNA attaches to ribosomes
- tRNA attaches to ribosomes
- mRNA codons and tRNA anticodons attach through complementary base pairing
- Instructions translated
- Amino acids join with peptide bonds between amino and carboxylic group
- Start and stop codons involved
Role of ribosomes
Translation-holds mRNA and tRNA together
Enzyme inhibitors
-similar structure
-bind to active site
Controlling temperature
Use a THERMOSTICALLY CONTROLLED water bath
Rate of reaction with enzymes
-Substrate used up so less substrate left to collide with enzyme
Hydrogen peroxide potato experiment
More O2 produced as more potato is added and SA increase
may level off as substrate is in excess
Practicals concerning rate
-control of ph and temperature
-Initial rate should be measured
-a range of concentration should be used (over 5)
-collect volume using gas syringe
-replace bung quickly
Graph that levels off quicker
Non competitive inhibitor as reaction doesn’t reach rate w/o inhibitor
It changes active site
Reasons for measuring initial rate with enzymes
-As soon as the reaction starts rate substrate is broken down
-substrate conc no longer controlled
-Sustrate shouldn’t be limiting
Protease
Digests other enzymes as it is a protein
Globular protein
-hydrophyllic group on outside
-hydrogen bond with water
-water is a polar solvent
Enzyme effect
-lowers activation E
-as a large no. of ATP molecules used
-as reaction requires lots of E
-to make up for nitrogen being unreactive
Benedicts test on sugars
-linear increase until 12 as all glucose reacts
-stops increasing linear from 12
-as glucose in excess
Saturated lipid
fatty acid chains associate with each other more easily
Protein bond
Between R groups
