IAL Biology Specification Checklist for Unit 5 Topic 7

(i) Understand the overall reaction of aerobic respiration as splitting of the respiratory substrate to release carbon dioxide and reuniting hydrogen with oxygen to release energy.
(ii) Understand that respiration is a stepped process catalysed by specific intracellular enzymes (names not required).

Understand roles of glycolysis in aerobic and anaerobic respiration , including phosphorylation of hexoses , production of ATP by substrate level phosphorylation , reduced coenzyme , pyruvate and lactate (details not required).

Understand roles of the link reaction and Krebs cycle in oxidation of glucose , forming CO₂ by decarboxylation , ATP by substrate level phosphorylation , reduced NAD and FAD by dehydrogenation in mitochondria (compared to cytoplasmic glycolysis ).

Understand how ATP is synthesised by oxidative phosphorylation in the electron transport chain of mitochondria , including roles of chemiosmosis and ATP synthase .

Understand what happens to lactate after anaerobic respiration in animals.

Understand what is meant by respiratory quotient (RQ) .

Use an artificial hydrogen carrier (redox indicator) to investigate respiration in yeast.

Use a simple respirometer to determine rate of respiration and RQ of a suitable material (e.g. germinating seeds or small invertebrates).

Know how muscles , tendons , the skeleton and ligaments interact to enable movement including antagonistic pairs , extensors and flexors .

(i) Know structure of mammalian skeletal muscle fibre .
(ii) Understand differences between fast and slow twitch fibres .

Understand sliding filament theory of skeletal muscle contraction and roles of actin , myosin , troponin , tropomyosin , Ca²⁺ , ATP and ATPase .

(i) Know the myogenic nature of cardiac muscle .
(ii) Understand how the SAN , AVN , bundle of His and Purkyne fibres coordinate the heartbeat .
(iii) Know how ECGs aid diagnosis of abnormal heart rhythms.

(i) Be able to calculate cardiac output .
(ii) Understand how variations in ventilation and cardiac output aid gas exchange and roles of control centres in the medulla oblongata .

Understand role of adrenaline in the fight or flight response .

Investigate effects of exercise on tidal volume , breathing rate , minute ventilation and oxygen consumption using spirometer traces .

(i) Understand negative and positive feedback control.
(ii) Understand how negative feedback maintains systems within narrow limits.

Understand homeostasis and its importance in maintaining dynamic equilibrium during exercise, including role of hypothalamus in thermoregulation .

Know the gross and microscopic structure of the mammalian kidney .

Understand how urea is produced in the liver from excess amino acids and removed via ultrafiltration .

Understand selective reabsorption in the proximal tubule and role of the loop of Henle as a countercurrent multiplier for water reabsorption .

Understand how the pituitary gland , osmoreceptors and ADH provide negative feedback control of plasma concentration and blood volume .

Understand how genes are switched on/off by DNA transcription factors , including roles of peptide and steroid hormones .

EDEXCEL IAL BIOLOGY

Specification 2025 - 2026

Unit 5

Topic 7 – Respiration, Muscles and the Internal Environment

7.1 Aerobic Respiration

7.2 Glycolysis

7.3 Link Reaction and Krebs Cycle

7.4 Oxidative Phosphorylation

7.5 Fate of Lactate

7.6 Respiratory Quotient (RQ)

7.7 CORE PRACTICAL 15

7.8 CORE PRACTICAL 16

7.9 Muscles, Tendons, Skeleton and Ligaments

7.10 Structure of Skeletal Muscle Fibre

7.11 Contraction of Skeletal Muscle

7.12 Myogenic Nature of Cardiac Muscle

7.13 Cardiac Output and Ventilation

7.14 Role of Adrenaline

7.15 CORE PRACTICAL 17

7.16 Feedback Control

7.17 Homeostasis

7.18 Structure of the Mammalian Kidney

7.19 Production and Removal of Urea

7.20 Reabsorption in the Kidney

7.21 Control of Plasma Concentration and Blood Volume

7.22 Gene Regulation

All Units (Unit 1 → Unit 6)