5 interactive labs · AS & A Level Biology 9700
· Couple ATP hydrolysis to active transport, movement and synthesis, compare carbohydrate, lipid and protein as fuels, and balance equations to find RQ.
Couple ATP hydrolysis to active transport, movement and synthesis, compare carbohydrate, lipid and protein as fuels, and balance equations to find RQ.
You will be able to
Syllabus learning outcomes: 12.1.1, 12.1.2, 12.1.3, 12.1.4, 12.1.5, 12.1.6
· Trace the six carbons of one glucose through glycolysis, the link reaction and two turns of the Krebs cycle, with an ATP, reduced NAD and CO2 ledger.
Trace the six carbons of one glucose through glycolysis, the link reaction and two turns of the Krebs cycle, with an ATP, reduced NAD and CO2 ledger.
You will be able to
Syllabus learning outcomes: 12.2.1, 12.2.2, 12.2.3, 12.2.4, 12.2.5, 12.2.6
· Step hydrogen along the electron transport chain, build the proton gradient, and test what oxygen, a leaky membrane and the cristae do to ATP synthesis.
Step hydrogen along the electron transport chain, build the proton gradient, and test what oxygen, a leaky membrane and the cristae do to ATP synthesis.
You will be able to
Syllabus learning outcomes: 12.1.3, 12.2.7, 12.2.8, 12.2.9
· Switch off the oxygen in a muscle cell and a yeast cell, then flood a rice plant, to see what fermentation does and what it cannot do.
Switch off the oxygen in a muscle cell and a yeast cell, then flood a rice plant, to see what fermentation does and what it cannot do.
You will be able to
Syllabus learning outcomes: 12.2.10, 12.2.11, 12.2.12
· Plan and run respirometer and yeast-indicator investigations: choose controls, temperature and repeats, calculate RQ, and judge the spread of your results.
Plan and run respirometer and yeast-indicator investigations: choose controls, temperature and repeats, calculate RQ, and judge the spread of your results.
You will be able to
Syllabus learning outcomes: 12.1.7, 12.2.13, 12.2.14
Each link is a piece of biology that carries an idea from one lab into another. Follow one to use what you found here in a new setting.
A sprinter's leg muscles go from rest to maximum effort in a few seconds. Follow oxygen from the alveoli to the mitochondria and ATP to the sarcomere.
Ventilation rate and blood flow to the lungs both rise. Why does that keep oxygen uptake high?
Fresh air keeps the alveolar partial pressure of oxygen high and flowing blood keeps the capillary partial pressure low, so a steep diffusion gradient is maintained across the thin squamous epithelium.
Working muscle has a higher partial pressure of carbon dioxide. How does that change oxygen unloading?
More carbon dioxide gives more hydrogen ions (carbonic anhydrase), which bind haemoglobin and lower its affinity for oxygen: the Bohr shift moves the curve right, so more oxygen is released at the same partial pressure.
Where is that oxygen used, and why is it essential for ATP synthesis?
On the inner mitochondrial membrane oxygen accepts electrons at the end of the chain and forms water; without it the chain stops, protons are no longer pumped and ATP synthase has no gradient to use.
Oxygen supply cannot keep up. How does the muscle still make some ATP?
Pyruvate is reduced to lactate, which regenerates NAD so glycolysis can continue; only the ATP from glycolysis is made, so the yield per glucose is far smaller.
What does each contraction cycle use ATP for?
ATP binds the myosin head so it detaches from actin, and its hydrolysis re-cocks the head; calcium ions released from the sarcoplasmic reticulum expose the binding sites.
