Respiration

Respiration

The release of energy from food is called respiration

Pathways- Breakdown of Glucose

After Glucose is broken down into Pyruvate,

If oxygen is present it gets converted into carbon dioxide, water and energy in mitochondria.

In the absence of oxygen pyruvate gets converted into ethanol, carbon dioxide and energy in yeast

In the absence of oxygen, pyruvate gets converted into lactic acid and energy in our muscles

ATP- Energy currency of the cell

The energy released during cellular respiration, is used to make a molecule called ATP(Adenosine Tri Phosphate) from ADP and inorganic phosphate.

When the terminal phosphate bond of ATP is broken energy is released for cellular use.

Breathing Organs- Plants

Since aerobic respiration takes place in the presence of oxygen, different organisms have different breathing organs to take in oxygen

In plants- stomata helps to exchange oxygen and carbondioxide .

During day time carbon dioxide is used by plants to make carbohydrates during photosynthesis. Oxygen gas is released at this time.

At night carbon dioxide release occurs mainly.

Breathing Organs- Animals

• Fishes- Gills- Water containing dissolved oxygen passes through mouth , flows over gills , oxygen gets absorbed by blood supplying gills during the process. Water then flows out of gills

• Humans- lungs are the breathing organs

• Air is taken through nostrils into the body, then through the throat and into lungs.

• Fine hairs and mucus lining the air passage filters dust and germs. Rings of cartilage present in throat ensure that the air passage do not collapse.

Breathing system- Humans

The throat(trachea) divides into two bronchi that enters each lung.

Each bronchi divides into bronchioles.

Bronchioles enter into balloon like structures called alveoli.

Alveoli contain blood vessels.

When we breathe in , our ribs will get lifted, and diaphragm lowered down, chest cavity becomes larger

Oxygen will reach alveoli and passes into blood vessels. from the blood vessels carbon dioxide will get into alveoli.

When we breathe out, our ribs will go down and diaphragm goes up , our chest cavity becomes smaller. Carbon dioxide rich air goes out of alveoli through nostrils. We breathe out air.

Respiratory Pigment

Since humans are multicellular, exchange of gases by simple diffusion is not possible.

The respiratory pigment called hemoglobin present in red blood cells will attract oxygen from air and carry it to tissues that need oxygen for respiration and release of energy.

Carbon dioxide is carried in blood in the dissolved form. That is , carbon dioxide dissolves in blood plasma.