Lesson 2 ·Class 9 · The Respiratory System · Sort Lab

Aerobic and Anaerobic in Humans

Why your muscles ache the next day.

Sort each statement by the type of respiration it describes in humans.

Sorted 0/12

All items sorted — check each bin.

Free play — sort every item into the bin it belongs in; each correct drop tells you why. Switch to when you're ready to test yourself.

In humans the anaerobic product is lactic acid, not alcohol. Yeast makes alcohol; muscle makes lactic acid. Examiners test exactly this.

Stuck? Ask Guru

Selina ICSE: The Respiratory System

What this lesson covers

Why do you keep panting after you stop running? You are repaying the oxygen debt — oxidising the lactic acid that built up.

Sort each statement by the type of respiration it describes in humans.

Aerobic — With oxygen: Oxygen is required (It is the final acceptor in the breakdown.); Glucose is broken down completely (All the way to carbon dioxide and water.); Products are carbon dioxide and water (Both are easily removed by the body.); Releases a large amount of energy per glucose molecule (The complete breakdown yields far more ATP.); Occurs mainly in the mitochondria (Only the first stage, glycolysis, is in the cytoplasm.); Used while walking or resting (Oxygen supply comfortably meets demand.)
Anaerobic — Without oxygen: Proceeds without oxygen (Used when the muscles are working faster than oxygen can be delivered.); Glucose is broken down only partly (Most of the energy remains locked in the product.); The product in muscle is lactic acid (It accumulates in the muscle and causes cramp and fatigue.); Releases only a small amount of energy (A fast but very inefficient emergency measure.); Occurs entirely in the cytoplasm (It never gets as far as the mitochondria.); Used by a sprinter in the last part of a race (The lungs cannot supply oxygen fast enough, so an oxygen debt builds up.)

In humans the anaerobic product is lactic acid, not alcohol. Yeast makes alcohol; muscle makes lactic acid. Examiners test exactly this.