Applied Science AQA/Breathing

Topic Title
THIS TOPIC MIGHT BENEFIT FROM BEING BROKEN UP INTO SMALLER CHUNKS

Setting Applied context
An understanding of respiration is vital to many scientists and healthcare professionals. Biochemists can analyse the rates of cellular respiration in samples of tissues. Sport physiologists can determine whether an individual is respiring aerobically or anaerobically using non-invasive methods. Engineers use their understanding of cellular respiration to clean up contamination in the environment, using cells which convert contaminants into energy.

Exploration of key ideas (must be original text, not C&P) – level checked by AQA
In general, point students towards the approach to take, as opposed to just giving them information.

Concept 1
Glycolysis Glycolysis- splitting of glucose

Reactants

Glucose

2NAD

2ATP

4ADP

Products

2 Pyruvate- go to link reaction

2 redNAD- to electron transport chain

4ATP- used by cells for energy Net ATP= 2ATP (two used as reactant)

Concept 2
Link reaction Text BoxTakes place in the matrix of the mitochondria

ShapeText BoxShape

ShapeShape2 x Pyruvate (3C) [Symbol] 2 x acetyl CoA (2C)

2NAD        2NADH

reduction

Reactants

2 Pyruvate

2 NAD

Products

2 Acetyl CoA

2 ReducedNAD

2 CO2

Co-enzymes are substances that are required in addition to the substrate to allow Enzymes to function.

NAD

FAD

These enzymes are hydrogen acceptors and they mop up excess hydrogen ions- electron carriers when reducuced

Takes place in the matrix of the mitochondria

Concept 3
Krebs Cycle

The 2-carbon acerylcoenzyme A from the link reaction combines with a 4-carbon molecule to produce a 6-carbon molecule.

In a series of reactions this 6-carbon molecule loses carbon dioxide and hydrogen to give a 4-carbon molecule and a single molecule of ATP produced as a result or substrate-level phosphorylation (Topic 2.3).

The 4-carbon molecule can now combine with a new molecule of acetylcoenzyme A to begin the cycle again.

Reactants

Oxaloacetate (4C)

Acetyl CoA (2C)

2ADP

6NAD

2FAD

Products

Citrate (6C)

4CO2- Waste

2 ATP- used by cell

6 NADH- to ETC

2 FADH2- to ETC                (Per 2 turns of the kerb cycle)

Concept 4
Electron Transport Chain Generates 34 ATP molecules

Requires oxygen

Takes place on the inner mitochondrial membranes

Uses reduced electron carriers: NAD and FAD from the Krebs cycle, link reaction and glycolysis

Reactants

NADH

FADH2

Oxygen

ADP

Products

NAD

FAD

Water

Electrons are carried along the ETC by NADH and FADH. The H+ ions cannot get to the electrons, but they are attracted to them so are pulled through the H+ pump.

Study Task
Work to do to understand this topic e.g. research, analysis

Careers and Organisations
Carry out some research into these jobs in this area. (Feel free to add other jobs you find.)

Relevant practical/s
– relating to criteria skills

Exam-style questions
– can we use old AQA qs… e.g. from more than 5 years ago? With Examiner comments

Links
to other sections within this book

to good external websites (including AQA website, wikipedia, relevant applications / companies) - also considering links in spec

References / Bibliography
of recommended text books

including mapped refs to existing books

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