Unit 1 Flashcards
(30 cards)
Explain five properties of water that make it important for organisms
-a metabolite in condensation reactions
-high heat capacity so buffers any changes in temperature
-a solvent so allows transport of substances
-large latent heat of vaporisation so provides a cooling effect through evaporation
-cohesion between water molecules so supports columns of water in plants
testing for lipids
-add ethanol to sample, then water and shake
-milky white emulsion forms to show a positive result
testing for non-reducing sugar
-do a benedicts test for a negative result - boil with excess benedicts
-heatl with acid then neutralise with alkali
-boil with benedicts and a red/orange precipitate forms to show a positive result
testing for reducing sugar
add excess benedicts to the test solution
-boil the mixture
-positive result show from a colour change from blue to brick red
testing for starch
-add potassium iodide solution to sample
-positive result shown from a colour change from orange to blue-black
Describe the formation of a triglyceride (3)
-one glycerol and three fatty acids
-condensation reaction and the removal of three water molecules
-ester bonds formed
testing for proteins
-add biurets solution to the sample
-positive result shown through a colour change from blue to lilac
Compare DNA and RNA
-DNA has two strands, RNA has one strand
-DNA is long, RNA is short
-DNA contains the bases: adenine, thymine, guanine and cytosine, RNA contains: adenine, uracil, guanine and cytosine
-DNA stores genetic information, RNA transfers genetic information in the formation of proteins and helps forms ribosomes
Whats the function of Na+
-used in the co-transport of glucose in the small intestine
Whats the function of H+
-changes the pH of solutions by making them more acidic
describe the structure of amylose and it’s function
-insoluble
-helical shape, makes it very compact so can store lots in the cell
-contains 1,4 glycosidic bonds
describe the structure of amylopectin and it’s function
-insoluble
-highly branched, this provides lots of ends which can be easily hydrolysed to release glucose for use in respiration
-contains both 1,4 and 1,6 glycosidic bonds
describe the structure of glycogen and it’s function
-insoluble
-highly branched (more than amylopectin), this provides lots of ends which can be easily hydrolysed to release glucose for use in respiration
-contains both 1,4 and 1,6 glycosidic bonds
describe the structure of proteins
-polymer of amino acids
-joined by peptide bonds
-formed by condensation reactions
-primary structure is the order of amino acids
-secondary structure forms when the primary structure folds/twists to for beta pleated sheets and alpha helices, these are held together through hydrogen bonds between the R groups
-tertiary structure is formed by further folding int a 3D shape held together by hydrogen and ionic bonds and disulphide bridges between R groups
-quaternary structure is two or more polypeptide chains
Describe the roles of iron ions, sodium ions, and phosphate ions in cells.
Iron ions- haemoglobin loads oxygen
Sodium ions- co-transport o glucose/amino acids intocells because sodium moved out by transport
Phosphate ions - used to produce ATP, phosphorolates other compounds, joins nucleotides
By phosphodiester bonds.
Describe the structure of DNA related to it’s function
- Weak hydrogen bonds so easily broken for replication.
-coiled so compact - large molecule so can store lots of information.
- double stranded so strands can act as templates.
- sugar phosphate backbone provides strength
- base sequence codes for animo acids
Describe the role of DNA polymerase in DNA replication
-joins adjacent DNA nucleotides
- catalyses condensation reactions
-Forming phosphodiesterbonds.
Describe how DNA is replicated.
-DNA helicase breaks hydrogen bonds between bases.
- strands separate
- each strand acts as a template
- free nucleotides attach to the exposed bases
- through complementary base pairing
- DNA polymerase join adjacent nucleotides through pnosphodiester bonds
-Hydrogen bonds form between bases.
Describe the test for amylase
-add biuret reagent and becomes lilac
-add starch, leave then test for reducing sugar (absence of starch)
Describe the test for proteins
-add biuret solution to sample
-solution will change from blue to lilac if protein is present
Describe how enzymes lower the activation energy
- bending the bonds in the substrate, putting strain on the bonds and making them more likely to break
- bringing two molecules close together, overcoming the natural repulsion between two molecules, making a bond between the two molecules more likely.
describe the role of a competitive inhibitor
-they have similar shapes to the substrate
-so they can fit and bind to the active site, blocking the substrate from binding
-this reduces the number of enzyme substrate complexes that form and reducing the rate of reaction.
Describe the role of a non-competitive inhibitor
-they bind to the enzyme on an area away from the active site - the allosteric site
-this causes a change in the shape of the active site, so it is no longer complementary to the substrate
-this reduces the formation of enzyme substrate complexes and reduces the rate of reaction
what is maltose formed form and where is it found
-two alpha glucose
-in germinating seeds
