Respiration Flashcards

All 10 cards in this deck

True or false? Respiration makes energy.

False. Respiration releases energy — it is an exothermic reaction happening continuously in all living cells.

Give three uses of the energy released by respiration.

Movement (muscle contraction), keeping warm, and building larger molecules from smaller ones.

What is the word equation for aerobic respiration, and where in the cell does it happen?

glucose + oxygen → carbon dioxide + water (energy is released); in the mitochondria.

What are the word equations for anaerobic respiration in muscle cells and in yeast?

Muscle cells: glucose → lactic acid.
Yeast (fermentation): glucose → ethanol + carbon dioxide.

State two differences between aerobic respiration and anaerobic respiration.

Aerobic uses oxygen, anaerobic does not; aerobic releases more energy than anaerobic.
Products: aerobic gives carbon dioxide and water, anaerobic (in muscle) gives lactic acid.

Why do an athlete's muscles produce lactic acid when running very fast?

There is not enough oxygen in the muscles, so they respire anaerobically.
The lactic acid builds up, causing muscle fatigue and cramp.

What are the steps to measure the rate of respiration of small living organisms with a respirometer?
e.g. maggots in a sealed test tube

1. Seal the maggots in a tube with soda lime (absorbs carbon dioxide), joined to a capillary tube holding a drop of coloured liquid.
2. Keep at a constant temperature and record the starting position of the drop.
3. After a set time, measure how far the drop has moved towards the tube (oxygen used).

Describe a suitable control for an investigation of respiration using hydrogencarbonate indicator.

The same test tube, gauze and bung with the same indicator, but containing no living organisms (or an inert object, e.g. glass beads or dried peas).

When comparing the respiration rates of different organisms using hydrogencarbonate indicator, give three variables that must be controlled.

Same mass of organisms; same volume and concentration of indicator; same temperature (and same size of test tube).

What colour change in hydrogencarbonate indicator shows that more carbon dioxide is present?

Red to yellow.