Anaerobic respiration in yeast cell Yeast breakdown glucose

Anaerobic respiration in yeast cell • Yeast breakdown glucose in the absence of oxygen to get energy along with the production of alcohol and carbon dioxide. Glucose in the absence of oxygen alcohol + carbon dioxide + energy Anaerobic respiration in muscle cell During hard physical exercise, muscle cells will not get sufficient oxygen for aerobic respiration. So muscle cells perform anaerobic respiration. The glucose is broken down into lactic acid and energy, in the absence of oxygen. Glucose in the absence of oxygen lactic acid + energy

MUSCLE CRAMPS • The accumulation of lactic acid in muscle cells causes muscle cramps. • Hot water bath or massage causes increased blood supply and oxygen content and lactic acid is completely broken down into carbon dioxide and water.

BREATHING The process in which oxygen rich air is taken in and carbon dioxide rich air is given out is called breathing. Breathing involves Inhalation (Inspiration) and Exhalation (Expiration) Inhalation The intake of oxygen rich air is called inhalation. Exhalation. The out giving of carbon dioxide rich air is called exhalation. Breathing rate. Number of breathes in a minute is called breathing rate. Average breathing rate of an adult human resting time: 15 – 18 per minute. Breathing rate increases during hard physical exercises.

BREATHING MOVEMENTS INHALATION • • • Diaphragm moves down. Ribs move up and out. Space inside the lungs increases. pressure decreases in the lungs. Air comes in EXHALATION • • • Diaphragm moves up. Ribs move down and in. Space inside the lungs decreases. pressure increases in the lungs. Air goes out.

HUMAN RESPIRATORY SYSTEM Human respiratory system consists of the respiratory organ lungs and different tubes which carry air to lungs. It includes: Nostrils: opening of nose. Nasal cavity: space inside the nose. The cavity is lined with hairs and mucus to trap unwanted particles in air. Pharynx: common route for air and food. Wind pipe (trachea): carry air to lungs. Lungs: helps in exchange of oxygen and carbon dioxide.

ACTIVITY TO PROVE CABON DIOXIDE IS ELIMINATED DURING EXHALATION • Take little freshly prepared lime water (calcium hydroxide) in a test tube. • Blow air into it using a straw. Observation The lime water changes into milky colour. Reason Carbon dioxide in the exhaled air reacts with calcium hydroxide to produce calcium carbonate which is milky in colour. Calcium hydroxide( Ca(OH)2 + CO 2 Calcium carbonate (Ca. CO 3) + H 2 O

BREATHING IN OTHER ANIMALS Examples for animals having lungs as respiratory organ. Elephant, lion, cow, goat, snakes, birds, crocodiles, frog, whale etc.

BREATHING IN COCKROACH (INSECTS) • Cockroach has a tracheal system for breathing. • It consists of small openings called spiracles and a network of air tubes called tracheae. • Oxygen rich air enters through spiracles in to tracheal tubes, diffuses into cells and tissues. • Carbon dioxide from the cells enter tracheal tubes and moves out through spiracles.

Breathing in earthworm Earthworm has a moist and slimy skin. Oxygen from the surrounding diffuses in to the body and carbon dioxide from the body diffuses out through the skin. Frogs also can breathe through their moist skin. But they have lungs as the major respiratory organ.

BREATHING IN FISHES • • Fishes have gills as the respiratory organ. Gills are supplied with blood vessels. The fishes take water through mouth and eliminates through gill slits. During this time, oxygen from the water diffuses in to blood vessels of the gills and carbon dioxide from the body diffuses out of the gills.

BREATHING IN PLANTS Different plant parts can take oxygen and release carbon dioxide. Leave takes oxygen and remove carbon dioxide through stomata. The stem takes oxygen and remove carbon dioxide through lenticels. The root takes oxygen from the air space in the soil through root hairs and also release carbon dioxide through root hairs.