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Respiration

Respiration is the process by which living cells break down nutrient molecules to release energy, primarily in the form of ATP, which is essential for various bodily functions. There are two types of respiration: aerobic, which requires oxygen and releases a large amount of energy, and anaerobic, which occurs without oxygen and releases a smaller amount of energy, often leading to lactic acid buildup in muscles. Additionally, yeast undergoes anaerobic respiration during fermentation, which is utilized in processes like bread making and brewing to produce carbon dioxide and ethanol.

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6 views4 pages

Respiration

Respiration is the process by which living cells break down nutrient molecules to release energy, primarily in the form of ATP, which is essential for various bodily functions. There are two types of respiration: aerobic, which requires oxygen and releases a large amount of energy, and anaerobic, which occurs without oxygen and releases a smaller amount of energy, often leading to lactic acid buildup in muscles. Additionally, yeast undergoes anaerobic respiration during fermentation, which is utilized in processes like bread making and brewing to produce carbon dioxide and ethanol.

Uploaded by

Badejo Anthony
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOCX, PDF, TXT or read online on Scribd
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Respiration

Respiration releases energy from food

Respiration is the chemical reactions that break down


nutrient molecules in living cells to release energy.

In humans, our cells need energy (ATP) for:

• muscle contraction
• making protein molecules: linking together amino
acids into long chains
• cell division: to repair damaged tissues and so that
we can grow
• active transport
• transmitting nerve impulses
• maintenance of constant body t°

All this energy comes from the food we eat. Water soluble
molecules are absorbed from the intestine into the blood.

The main energy–providing nutrient: glucose (contains a


lot of chemical energy).

There are 2 types of respiration:


Aerobic and anaerobic respiration

Respiration releases energy from food.

There are 2 kinds of respiration: Aerobic and


Anaerobic. The main difference between them is that
aerobic respiration involves oxygen and anaerobic
respiration does not!

A. Aerobic respiration

The release of a relatively large amount of energy in


cells by the breakdown of food substances in the
presence of O2.

B. Anaerobic respiration

Anaerobic respiration: the release of a relatively small


amount of energy by the breakdown of food substances
in the absence of O2.

Anaerobic respiration in muscles during exercise:

Anaerobic respiration in yeast:


Muscles respire anaerobically when exercising vigorously,
because the blood cannot supply enough oxygen to
maintain aerobic respiration. However, the formation and
build-up of lactic acid in muscles causes cramp (muscle
fatigue).

The lactic acid that is made is transported to the liver, and


later is broken down by combining it with O 2. This extra O2
is breathed in after the exercise has stopped, and it is
known as the oxygen debt.

Bread making

- yeast is mixed with water to activate it


then added to flour to make dough

- mixture -----> warm place ------> rise

- yeast releases CO2 ------> dough rises * a


warm to is important because
fermentation is controlled by enzymes

- when dough is cooked, high to kills yeast


and evaporates any formed ethanol
- air spaces are left where CO2 was trapped

Brewing

- yeast is added to a source of sugar


(fruit juice or germinated barley
grains) and kept in warm conditions

- fermentation (yeast respires the


sugar) occurs ------> ethanol is
formed making the drink alcoholic
- CO2 makes the drink fizzy + sharp
Flavour.

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