A-Level Biology AQA 2017 Paper 1: Practice Questions and Answers, Exams of Advanced Education

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A-level biology AQA 2017 paper 1

give the two types of molecule from which a ribosome is made - - protein

• RNA describe the role of a ribosome in the production of a polypeptide - - mRNA binds to ribosome
• idea of two codons/ binding sites
• allows tRNA with anti-codons to bind/associate
• catalyses formation of peptide bonds between amino acids held by tRNa molecules
• moves along mRNA to the next codon
• polypeptide produced describe the structure of glucose - - polysaccharide of many alpha glucose molecules
• joined by glycosidic bonds with a branched surface. how does glycogen act as a source of energy... do not include transport across membranes - - hydrolysed to glucose
• glucose used in respiration suggest and explain two ways the cell-surface membranes of the cells lining the uterus may be adapted to allow rapid transport of nutrients - - membrane folded so increases/large surface area for fast rate of diffusion
• large number of channel/carrier proteins in the membrane for facilitated diffusion NHE3 actively transports one sodium ion into the cell in exchange for one proton out of the cell...how... -
• co transport
• uses ATP (hydrolyses it)
• sodium ion and proton bind to protein
• protein changes shape to move the sodium ion across the membrane.

tenapanor does reduce salt absorption in the gut... info provided... explain how reached this conclusion -

• tenapanor causes a significant increase
• there is less than 0.05 probability that the difference is due to chance
• more salt in the gut reduces water potential in the gut
• so less water absorbed out of gut by osmosis high absorption of salt from the diet can result in higher than normal concentration of salt in the blood plasma entering capillaries. this can lead to a build up of tissue fluid... - - higher salt= low w.p of tissue fluid
• so less water returns to capillary by osmosis at venule end describe how bacteria divide - - binary fission of prokaryotic
• replication of circular DNA
• division of cytoplasm to produce 2 daughter cells
• each with single copy of DNA explain the shape of the curves at 50 and 60 degrees - - both denatured by high temperature
• denaturation faster at 60 degrees due to more kinetic energy
• breaks hydrogen bonds
• change in shape of the active site, no longer complementary so fewer enzyme-substrate complexes formed. advantage of a bacterium of secreting an extracellular protease in its natural environment - - to digest protein so they can;
• absorb amino acids for growth/ protein synthesis
• can destroy a toxic substance/ protein. describe the action of membrane bound dipeptidases and explain their importance - - dipeptidases hydrolyse dipeptides into single amino acids by breaking peptide bonds. important as amino acids can cross the membrane.

equation which represents the reaction catalysed by ATP synthase - ADP + Pi= ATP + H2O suggest why human ATP synthase is not inhibited and bacterial synthase is inhibited - - human ATP synthase has a different tertiary structure to bacterial ATP synthase explain why scientists suggested that people newly diagnosed with this bladder infection should be treated with both the current antibiotic and the new antibiotic... - - new/old antibiotic does not kill all bacteria

• resistance bacteria will reproduce to produce more resistant bacteria
• one antibiotic will kill bacteria resistant to the other antibiotic is use both. give 3 environmental variables that should be controlled when growing the plants before treatment with the different sprays - - concentration of mineral ions
• soil pH
• temperature
• light intensity
• distance between seeds
• volume of water given
• CO2 concentration
• humidity suggest one reason why the scientists ensured the temperature remained constant and one reason why the leaf discs were shaken - - temperature: so that the rate of diffusion of ions out of cells remains constant
• shaken: so all surfaces of the leaf discs are exposed so all submerged. collagen... suggest how the immune response to this viral protein can result in the development of RA. -
• the antibody against virus antigen will bind to collagen
• this results in the destruction of the human cells/collagen

what do these classifications suggest about evolutionary relationships between these species of snake?: classification X - without genetic analysis, Mackloti and Olivaceus have a more recent common ancestor with each other. what do these classifications suggest about evolutionary relationships between these species of snake?: classification Y - genetic analysis indicated that papuana and Mackloti have a more recent common ancestor with one another state 3 comparisons of genetic diversity that the scientists used in order to generate classification Y - - the base sequence of DNA

• the base sequence of mRNA
• the amino acid sequence of proteins explain three ways in which an insects tracheal system is adapted for efficient gas exchange: - - tracheoles have thin walls so short diffusion distance to cells -highly branched/ large number of tracheoles so short diffusion distance to cells
• highly branched/ large number of tracheoles so short diffusion distance to cells. explain how the presence of gills adapts the damselfly to its way of life - - Damselfly larvae has higher metabolic/ respiratory rate so uses more oxygen, which the gills help to get from the water. suggest 2 ways the student could improve the quality of her scientific drawing of this gill - - don't use shading
• use only single lines
• add further labels and annotations
• don't cross label lines
• add a scale bar