Edexcel A Level Biology A (Salters-Nuffield)
Edexcel A Level Biology A (Salters-Nuffield) Topic 2: Proteins and Enzymes Exam Questions
Free Edexcel A Level Biology A (Salters-Nuffield) exam questions on Topic 2: Proteins and Enzymes, with mark schemes. Covers amino acids, peptide bonds, protein structure, enzymes, activation energy and enzyme practicals.
Topic 2: Proteins and Enzymes exam questions
These packs of real past exam questions cover the whole of Topic 2: Genes and Health, including Topic 2: Proteins and Enzymes. Work through every question on this sub-topic, then mark your answers against the mark scheme.
StemUp mark scheme flashcards
Edexcel A Level Biology A (SNAB) 9BN0 Flashcards (Anki & Quizlet)
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Use them on Anki or Quizlet, then test yourself with the questions on this page.
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About Edexcel A Level Biology A (Salters-Nuffield) Topic 2: Proteins and Enzymes
This part of Topic 2 covers protein structure and how enzymes work. Expect questions on bonding, specificity and the effect of conditions on enzyme activity.
What you need to know
- Protein structure Amino acids join by peptide bonds in condensation reactions. Primary, secondary, tertiary and quaternary structure, held by hydrogen, ionic and disulfide bonds.
- Globular and fibrous proteins Globular proteins such as haemoglobin are soluble; fibrous proteins such as collagen give strength.
- Enzymes Biological catalysts that lower activation energy. The active site is complementary to the substrate.
- Rates of reaction Measure initial rates and know the effect of enzyme concentration, substrate concentration, temperature and pH.
Common mistakes in Topic 2: Proteins and Enzymes
- Saying enzymes are killed instead of denatured.
- Describing the active site as the same shape as the substrate rather than complementary.
- Confusing peptide bonds with hydrogen bonds.
Try three Topic 2: Proteins and Enzymes exam-style questions
1. Name the bond that joins amino acids. (1 mark)
Show the mark scheme answer
Peptide bond.
2. Explain how high temperature reduces enzyme activity. (3 marks)
Show the mark scheme answer
Bonds holding the tertiary structure break (1), so the active site changes shape (1) and the substrate can no longer bind, forming fewer enzyme-substrate complexes (1).
3. Explain how enzymes speed up reactions. (2 marks)
Show the mark scheme answer
They provide an alternative pathway (1) with lower activation energy (1).
Topic 2: Proteins and Enzymes FAQs
What does this part of SNAB Topic 2 cover?
Protein structure, enzymes and factors affecting enzyme activity.
Is there a core practical?
Yes, investigating the effect of enzyme and substrate concentration on the initial rate of reaction.
Do I need the induced fit model?
Know the lock and key and induced fit ideas of how the substrate binds.
Revise this topic with flashcards: Edexcel A Level Biology A (SNAB) 9BN0 Flashcards, with mark scheme answers for Anki and Quizlet.
