Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Community
Ask the community for help and clear up your study doubts
Discover the best universities in your country according to Docsity users
Free resources
Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors
A collection of past paper questions for biology a-level (as) exams. It provides a valuable resource for students preparing for their exams, offering insights into the types of questions they can expect and the key concepts they need to master. Questions on topics such as lipid identification, enzyme action, dna replication, calibration curves, haemoglobin function, tissue fluid accumulation, breathing mechanisms, asthma, leaf surface area, and countercurrent systems in fish. Each question is accompanied by a correct answer, providing students with a clear understanding of the expected responses.
Typology: Exams
1 / 3
Describe how to test for the presence of a lipid - correct answer Add ethanol, then add water, white emulsion shows lipid Describe the induced fit mode of enzyme action - correct answer Active site not complementary to substrate. Shape of active site changes as substrate binds stressing bonds. Why does DNA polymerase work in different directions in DNA replication - correct answer DNA has anttiparallel strands The nucleotides are alligned differently Enzymes have acttive sites with specific shape Only substrates with complementary shape caan bind with ative site of DNA polymerase Describe how to produce a calibration curve and used to obtain results (Benedict's test) - correct answer Make maltose solutions of know concentrations Measure colorimeter value of each soluton and plot calibration curve Find concentration of sample from calibration curve Describe the role of haemoglobin in supplying oxygen to the tissues of the body - correct answer Haemoglobin associates with oxygeen in areas of higher ppO Oxygen dissociates in areas of lower ppO
High blood pressure leads to an accumulation of tissue fluid, explain how
Cut out and count the squares Multiply by 2 for upper and lower surface Describe and explain how the counter current system leads to efficient gas exchange across the gills of a fish - correct answer Water and blood flow in opposite directions Maintains concentration gradient Along whole length of gill Suggest and explain why the combined effects of endopeptidases and exopeptidase are more efficient than exopeptidase on their own - correct answer Exopeptidases remove amino acids at the end Increased surface area