Cells, Development, Biodiversity and Conservation

Worked examples (6)

• 1Matching organelles to functions (2 marks)
• 2Identifying ribosome size (2 marks)
• 3Ordering the secretory pathway (3 marks)
• 4Calculating actual size from a micrograph (4 marks)
• 5Comparing eukaryotic and prokaryotic cells (6 marks)
• 6Explaining organelle abundance in a secretory cell (4 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 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer 10

Worked examples (6)

• 1Haploid, diploid and the outcome of meiosis (2 marks)
• 2Defining a homologous pair (2 marks)
• 3Calculating chromosome combinations (3 marks)
• 4Describing crossing over (4 marks)
• 5Comparing the outcomes of mitosis and meiosis (4 marks)
• 6Identifying recombinant gametes from linkage data (4 marks)

Model answers (10)

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

Worked examples (6)

• 1Magnification versus resolution (2 marks)
• 2Converting between mm, µm and nm (2 marks)
• 3Calculating actual size with M = I/A (3 marks)
• 4Light, TEM and SEM compared (4 marks)
• 5Calibrating an eyepiece graticule (4 marks)
• 6Actual size from a scale bar (4 marks)

Model answers (10)

• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style (levels-based)
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Core Practical 5 style (levels-based)
• ✓Model answer — Edexcel IAL Biology Unit 2 style (data interpretation)
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style (evaluate)

Worked examples (6)

• 1Relating sperm structure to function (2 marks)
• 2Function of the oocyte food reserves (2 marks)
• 3The acrosome reaction in order (4 marks)
• 4Restoring the diploid number (3 marks)
• 5Preventing polyspermy (6 marks)
• 6Comparing sperm and oocyte structure (6 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 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer 9
• ✓Model answer — Edexcel IAL Biology Unit 2 style (suggest / applied context)

Worked examples (6)

• 1Same genome, different cells (2 marks)
• 2Classifying potency (2 marks)
• 3Why iPSCs are useful (3 marks)
• 4Effect of DNA methylation (3 marks)
• 5How a cell becomes specialised (4 marks)
• 6Evaluating the ethics of embryonic stem cells (6 marks)

Model answers (10)

• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style

Worked examples (6)

• 1Order and events of the cell cycle (3 marks)
• 2Identifying a stage of mitosis (2 marks)
• 3Calculating a mitotic index (3 marks)
• 4Significance of mitosis (4 marks)
• 5Mitotic index and time in mitosis (4 marks)
• 6Roles of the reagents in the root tip squash (4 marks)

Model answers (10)

• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer 2
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer 4
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer 6
• ✓Model answer — Edexcel IAL Biology Unit 2 CP6 style
• ✓Model answer 8
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer 10

Worked examples (6)

• 1Structures unique to plant cells (2 marks)
• 2Identifying the tonoplast and amyloplast (2 marks)
• 3How cellulose gives the wall strength (4 marks)
• 4Xylem versus phloem function (4 marks)
• 5Designing the tensile-strength practical (CP8) (6 marks)
• 6Calculating actual size from a scale bar (4 marks)

Model answers (10)

• ✓Model answer 1
• ✓Model answer 2
• ✓Model answer 3
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer 5
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer 10

Worked examples (6)

• 1State uses of plant fibres (2 marks)
• 2Identify a mineral deficiency (2 marks)
• 3Explain a nitrate deficiency symptom (4 marks)
• 4Describe how seeds are stored in a seed bank (4 marks)
• 5Evaluate a plant-based plastic (6 marks)
• 6Evaluate seed banks vs in-situ conservation (6 marks)

Model answers (10)

• ✓Model answer — Practice question — spec 4.6
• ✓Model answer — Practice question — spec 4.7
• ✓Model answer — Practice question — spec 4.9
• ✓Model answer — Practice question — spec 4.8
• ✓Model answer — Practice question — spec 4.9
• ✓Model answer — Practice question — spec 4.7
• ✓Model answer — Adapted from Edexcel IAL Biology Unit 2 data-response — spec 4.5/4.6
• ✓Model answer — Practice question — spec 4.6
• ✓Model answer — Practice question — spec 4.9
• ✓Model answer — Practice question — spec 4.8/4.9

Worked examples (6)

• 1Why plants are a source of new antibiotics (2 marks)
• 2Two aseptic steps and their reasons (2 marks)
• 3Calculate the area of a zone of inhibition (4 marks)
• 4Why use a control disc (5 marks)
• 5Placebo and double-blind design (6 marks)
• 6Interpret zone-of-inhibition data (6 marks)

Model answers (10)

• ✓Model answer — Practice question — spec 4.10
• ✓Model answer — Practice question — spec 4.11
• ✓Model answer — Practice question — spec 4.13
• ✓Model answer — Practice question — spec 4.11 (CP9)
• ✓Model answer — Practice question — spec 4.12
• ✓Model answer — Practice question — spec 4.13
• ✓Model answer — Practice question — spec 4.10/4.11
• ✓Model answer — Adapted from Edexcel IAL Biology Unit 2 data-response — spec 4.11
• ✓Model answer — Practice question — spec 4.10/4.13
• ✓Model answer — Practice question — spec 4.11 (CP9)

Worked examples (6)

• 1Defining a species (2 marks)
• 2Binomial name and ranks (2 marks)
• 3Natural vs artificial classification (4 marks)
• 4Why three domains replaced five kingdoms (5 marks)
• 5Cytochrome c relatedness (6 marks)
• 6Difficulties of the species concept (6 marks)

Model answers (10)

• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer 2
• ✓Model answer 3
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style
• ✓Model answer — Edexcel IAL Biology Unit 2 style

Worked examples (6)

• 1The three levels of biodiversity (3 marks)
• 2Species richness vs species diversity (2 marks)
• 3Calculate the index of diversity (4 marks)
• 4Compare two habitats using D (4 marks)
• 5Heterozygosity index calculation (6 marks)
• 6Evaluate in situ vs ex situ conservation (6 marks)

Model answers (10)

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