Eduqas A Level Biology
Eduqas A Level Biology AS Component 1: Basic Biochemistry and Cell Organisation Exam Questions
Free Eduqas A Level Biology exam questions for AS Component 1: Basic Biochemistry and Cell Organisation, with a mark scheme for every pack. Covers carbohydrates, lipids, proteins, water and ions, cell structure, membranes and transport, enzymes, DNA and cell division.
AS Component 1: Basic Biochemistry and Cell Organisation exam questions
6 question packs of real past exam questions, each with its mark scheme. Do not stop after a few: answer as many as you can without notes, then mark every answer with the mark scheme. The more questions you do, the more quickly you will spot how examiners ask about each idea.
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A-Level Biology Flashcards for 2027 Onwards
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Then test yourself with the questions on this page.
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About Eduqas A Level Biology AS Component 1: Basic Biochemistry and Cell Organisation
AS Component 1 of Eduqas AS Biology, Basic Biochemistry and Cell Organisation, is the foundation of the whole course. It covers the biological molecules that make up living things, the structure of prokaryotic and eukaryotic cells, how substances cross membranes, how enzymes work, the structure and function of DNA and RNA, and the cell cycle. Every later topic, from respiration to inheritance, depends on it. Examiners like questions that link molecular structure to function, water potential and osmosis problems, enzyme rate graphs, protein synthesis sequences and magnification or mitotic index calculations.
What you need to know
- 1.1 Monosaccharides join by glycosidic bonds in condensation reactions; starch and glycogen are storage polysaccharides of alpha glucose, cellulose and chitin are structural. Triglycerides form from glycerol and three fatty acids by ester bonds, phospholipids have a hydrophilic head, and proteins have primary to quaternary structure held by peptide, hydrogen, ionic and disulfide bonds.
- 1.2 Organelles in eukaryotic cells (nucleus, mitochondria, chloroplasts, ER, Golgi body, lysosomes, ribosomes), differences from prokaryotic cells and viruses, and levels of organisation from cells to organ systems.
- 1.3 The fluid mosaic model; diffusion, facilitated diffusion, osmosis, active transport, endocytosis and exocytosis. Water potential of a plant cell = solute potential + pressure potential.
- 1.4 Enzymes lower activation energy; the induced fit model; effects of temperature, pH, substrate and enzyme concentration; competitive and non-competitive inhibition; immobilised enzymes and their uses.
- 1.5 Nucleotide structure, DNA as a double helix with complementary base pairing, semi-conservative replication (Meselson and Stahl), the genetic code, transcription and translation.
- 1.6 The cell cycle and the stages of mitosis and meiosis, the significance of each, and how uncontrolled mitosis leads to tumours.
Common mistakes in AS Component 1: Basic Biochemistry and Cell Organisation
- Saying denatured enzymes are killed. Enzymes are not alive; high temperature breaks hydrogen and ionic bonds so the active site changes shape and substrates no longer bind.
- Writing that water moves from low to high water potential. Water moves by osmosis from higher (less negative) to lower (more negative) water potential across a partially permeable membrane.
- Confusing alpha and beta glucose in polysaccharides. Starch and glycogen are made of alpha glucose, while cellulose is made of beta glucose with alternate molecules inverted.
- Saying tRNA carries a codon. mRNA carries codons; tRNA has the complementary anticodon and carries a specific amino acid.
- Giving a magnification answer with mismatched units. Convert image and actual size to the same unit (for example micrometres) before dividing.
Try three AS Component 1: Basic Biochemistry and Cell Organisation exam-style questions
1. A cell has a solute potential of -800 kPa and a pressure potential of 300 kPa. Calculate its water potential and state the direction of water movement if it is placed in a solution of -700 kPa. (2 marks)
Show the mark scheme answer
-800 + 300 = -500 kPa; water moves out of the cell into the solution because -500 kPa is higher than -700 kPa.
2. Explain how a competitive inhibitor reduces the rate of an enzyme-controlled reaction. (3 marks)
Show the mark scheme answer
Inhibitor has a similar shape to the substrate; binds to the active site; fewer enzyme-substrate complexes form; effect reduced by increasing substrate concentration.
3. Describe the process of transcription. (4 marks)
Show the mark scheme answer
DNA helicase breaks hydrogen bonds and unwinds part of the DNA; one strand acts as a template; free RNA nucleotides pair with complementary bases (uracil with adenine); RNA polymerase joins nucleotides with phosphodiester bonds; mRNA leaves the nucleus through a nuclear pore.
AS Component 1: Basic Biochemistry and Cell Organisation FAQs
What does Eduqas AS Biology Component 1: Basic Biochemistry and Cell Organisation cover?
Biological compounds, cell structure and organisation, cell membranes and transport, enzymes, nucleic acids, and cell division.
Is this content also needed for A Level?
Yes. The AS content underpins the A Level components and can be assessed synoptically in the A Level papers.
Which practicals link to Basic Biochemistry and Cell Organisation?
Key practicals include food tests, measuring water potential using potato or onion tissue, investigating enzyme activity, and preparing a root tip squash to observe mitosis.
