Biology respiration

RESPIRATION:

This is the burning of food to release energy. It takes place in the cells of all living organisms all the time.

AEROBIC RESPIRATION:

This is the burning of glucose to release lots of energy by reacting with oxygen:

Glucose + oxygen          carbon dioxide + water
C6H12O6 + 6H2O                     6CO2           + 6H2O

ANAEROBIC RESPIRATION:

This is the breakdown of glucose in the absence of oxygen, producing only a small amount of energy.

In yeast:
Glucose               ethanol  + carbon dioxide
C6H12O6               2C2H6O  +      2CO2
In animals:
Glucose                  lactic acid
C6H12O6                   2C3H6O3

WHY DO ORGANISMS NEED ENERGY?

Reproduction:

-          New cells

-          Lactation

Muscle contraction:

-          Limbs

-          Heart

-          Peristalsis

Growth:

-          Cell division (mitosis, meiosis)

-          Make big molecules:

-          Protein

-          Antibodies

-          Fats

-          Glycogen in animals, starch in plants

Heat:

-          Birds

-          Mammals

Electrical energy:

-          Nerves

Active transport:

-          Digestive system

-          Kidneys

YEAST:

Yeast is a single celled fungus and is only 7/1000 mm across (7 microns.) It is unusual because there are no hyphae (thread things) like most fungi have. It is found naturally on the surface of plums and grapes in particular, as well as some other fruit.

Yeast is a living organism and uses its energy to reproduce by budding off new cells so the yeast culture increases with time.

ANAEROBIC RESPIRATION IN HUMANS:

In a sprint the muscles in the legs need lots of energy from respiration to contract. Oxygen for aerobic respiration is carried to the muscles by the blood. The lungs and heart cannot supply oxygen quickly enough to keep up with the demands of the muscles so an oxygen debt is built up. Extra energy is needed from anaerobic respiration. Lactic acid is produced as a waste product making the muscles ache.

After the race the lactic acid is transported to the liver where it is combined with oxygen and destroyed. The sprinter breathes heavily for a while to pay off oxygen debt.