Molecules, Diet, Transport and Health

Worked examples (6)

• 1Order the clotting cascade (2 marks)
• 2Calculate BMI (2 marks)
• 3Sequence the atherosclerosis pathway (4 marks)
• 4Evaluate prescribing statins (5 marks)
• 5Interpret risk-factor data — correlation vs causation (6 marks)
• 6Explain HDL vs LDL and diet (6 marks)

Model answers (10)

• ✓Model answer — Practice question — spec 1.11
• ✓Model answer — Practice question — spec 1.12
• ✓Model answer — Practice question — spec 1.10
• ✓Model answer — Practice question — spec 1.14
• ✓Model answer — Practice question — spec 1.15
• ✓Model answer — Practice question — spec 1.16
• ✓Model answer — Practice question — spec 1.14
• ✓Model answer — Practice question — spec 1.14
• ✓Model answer — Adapted from Edexcel IAL Biology Unit 1 data-response — spec 1.14/1.15
• ✓Model answer — Practice question — spec 1.16

Worked examples (6)

• 1Why the model is called 'fluid mosaic' (2 marks)
• 2Orientation of phospholipids in the bilayer (3 marks)
• 3Channel versus carrier proteins (4 marks)
• 4Role of cholesterol at different temperatures (4 marks)
• 5Core Practical 3 — beetroot variables and colorimetry (6 marks)
• 6Interpreting an absorbance–temperature graph (6 marks)

Model answers (10)

• ✓Model answer — Edexcel IAL Biology Unit 1 (style)
• ✓Model answer 2
• ✓Model answer 3
• ✓Model answer — Edexcel IAL Biology Unit 1 (style)
• ✓Model answer 5
• ✓Model answer — Edexcel IAL Biology Core Practical 3 (style)
• ✓Model answer — Edexcel IAL Biology Unit 1 (style)
• ✓Model answer 8
• ✓Model answer — Edexcel IAL Biology Unit 1 (style)
• ✓Model answer — Edexcel IAL Biology Core Practical 3 (style)

Worked examples (6)

• 1Why water is a good solvent (3 marks)
• 2Comparing α-glucose and β-glucose (2 marks)
• 3Condensation reaction forming maltose (4 marks)
• 4Comparing starch and glycogen as stores (5 marks)
• 5Cellulose structure and cell-wall function (6 marks)
• 6Triglyceride formation and fatty-acid type (5 marks)

Model answers (10)

• ✓Model answer 1
• ✓Model answer 2
• ✓Model answer 3
• ✓Model answer 4
• ✓Model answer 5
• ✓Model answer 6
• ✓Model answer 7
• ✓Model answer — Adapted from Edexcel IAL Biology Unit 1
• ✓Model answer — Adapted from Edexcel IAL Biology Unit 1
• ✓Model answer — Adapted from Edexcel IAL Biology Unit 1

Worked examples (6)

• 1Surface area : volume ratio and the need for transport (2 marks)
• 2Artery structure related to function (2 marks)
• 3Reading a cardiac pressure graph (4 marks)
• 4Reading the oxygen dissociation curve (4 marks)
• 5Explaining the Bohr effect (6 marks)
• 6Formation and return of tissue fluid (6 marks)

Model answers (10)

• ✓Model answer 1
• ✓Model answer 2
• ✓Model answer 3
• ✓Model answer — Practice question — Unit 1
• ✓Model answer 5
• ✓Model answer — Practice question — Unit 1 (data interpretation)
• ✓Model answer — Practice question — Unit 1 (levels-based)
• ✓Model answer — Practice question — Unit 1 (levels-based)
• ✓Model answer 9
• ✓Model answer — Practice question — Unit 1 (synoptic / evaluate)

Worked examples (6)

• 1Drawing and labelling an amino acid (2 marks)
• 2Forming a dipeptide by condensation (3 marks)
• 3Bonds maintaining tertiary structure (4 marks)
• 4Identifying levels of protein structure (4 marks)
• 5Comparing haemoglobin and collagen (6 marks)
• 6Why heat denatures an enzyme but not the primary structure (3 marks)

Model answers (10)

• ✓Model answer 1
• ✓Model answer 2
• ✓Model answer 3
• ✓Model answer 4
• ✓Model answer 5
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer 9
• ✓Model answer — Edexcel IAL Biology Unit 1 style

Worked examples (6)

• 1Identifying the transport mechanism (2 marks)
• 2Predicting the direction of osmosis (2 marks)
• 3Channel versus carrier proteins (3 marks)
• 4Why a respiratory inhibitor stops uptake (3 marks)
• 5Applying Fick's law — a proportional calculation (2 marks)
• 6Co-transport of glucose in the intestine (4 marks)

Model answers (10)

• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style

Worked examples (6)

• 1How an enzyme speeds up a reaction (3 marks)
• 2Intracellular vs extracellular enzymes (2 marks)
• 3The induced-fit model (4 marks)
• 4Effect of temperature on initial rate (4 marks)
• 5Calculating initial rate from a tangent (3 marks)
• 6Why the substrate-concentration curve plateaus (4 marks)

Model answers (10)

• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer 2
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer 4
• ✓Model answer — Core Practical 4 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style (levels-based)
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style (levels-based)
• ✓Model answer — Core Practical 4 style

Worked examples (6)

• 1Structure of a mononucleotide (3 marks)
• 2Complementary base pairing and hydrogen bonds (2 marks)
• 3Chargaff base-percentage calculation (3 marks)
• 4Steps of semi-conservative replication (4 marks)
• 5Interpreting the Meselson–Stahl bands (4 marks)
• 6Why C–G-rich DNA is more stable (4 marks)

Model answers (10)

• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer 2
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer 4
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer 6
• ✓Model answer 7
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer 9
• ✓Model answer — Edexcel IAL Biology Unit 1 style

Worked examples (6)

• 1Defining a gene (2 marks)
• 2How RNA differs from DNA (3 marks)
• 3Explaining the three properties of the genetic code (3 marks)
• 4Template strand vs coding strand (4 marks)
• 5Working out a polypeptide from a codon table (4 marks)
• 6Codon-anticodon pairing and the role of tRNA (4 marks)

Model answers (10)

• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style

Worked examples (6)

• 1Classifying gene mutations (3 marks)
• 2Why CF mucus is thick (2 marks)
• 3Full monohybrid genetic diagram (5 marks)
• 4Deducing inheritance from a pedigree (4 marks)
• 5X-linked cross with a carrier mother (6 marks)
• 6Evaluating genetic screening (6 marks)

Model answers (10)

• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer 2
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer 4
• ✓Model answer 5
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer 7
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style
• ✓Model answer — Edexcel IAL Biology Unit 1 style