Cellular Respiration: Aerobic vs. Anaerobic

• Respiration involves releasing energy from food.

Respiration Process

• Taking in oxygen into cells
• Releasing energy by burning food
• Eliminating waste products
• Glucose (food) + Oxygen yields carbon dioxide + water + energy
• This occurs in a cell

Aerobic Summary

• The breakdown of food in cells to release energy.

Aerobic vs. Anaerobic Respiration

• Aerobic involves oxygen
• Anaeorobic does not involve oxygen

Aerobic Respiration

• Breakdown of food occurs using oxygen.
• Most organisms carry out this form of respiration, dogs, cats and lions

Anaerobic Respiration

• The breakdown of food occurs without oxygen.
• Organisms like yeast respire this way
• Glucose (food) yields carbon dioxide + alcohol + energy

Yeast

• Yeast is an anaerobe
• It is a single-celled organism
• Yeast converts glucose into alcohol
• It is used to make wine, beer, and bread

Anaerobic Respiration in Muscles

• Oxygen in muscle cells gets used up faster.
• It takes place during vigorous physical activity when oxygen gets used up faster than the muscle cells can be supplied by the blood
• During the process, glucose is partially broken down to form lactic acid and gives some energy.
• Glucose yields lactic acid + energy

Muscle Cramps and Breathing

• The accumulation of lactic acid in muscles causes cramps.
• Breathing is the process by which oxygen is taken in and carbon dioxide is expelled.
• Inhaling allows the body to supply oxygen to all cells and tissues.

Oxygen and Altitude

• Mountaineers carry oxygen tanks because higher altitudes contain less air.

Breathing Rate

• Average adult breathes 15-18 times per minute.
• Breathing rate may change according to bodily needs.
• During heavy exercise, humans can breathe up to 25 times per minute.

How We Breathe

• The breathing rate of children is higher than adults.
• Lungs are connected to the nostrils through the nasal passage and windpipe.
• Lungs hang in an airtight space in our body called the chest cavity.
• The rib cage forms the sides of the chest cavity with sheets of muscle between ribs.
• At the bottom of the chest cavity is a curved sheet of muscle called the diaphragm.
• Rib cage moves outward and upward during the breathing process.
• The diaphragm moves downward.

Air Composition

• Air inhaled is different from the air exhaled:
  • Inhaled Air: Oxygen 21%, CO₂ 0.04%, Water Vapour (a little)
  • Exhaled Air: Oxygen 16.4%, CO₂ 4.4%, Water Vapour (a lot)
• When exhaling on a mirror, moisture forms due to water vapor.

Respiration in Humans

• The respiratory system consists of the nose, nasal passage, trachea, bronchi, lungs, and diaphragm.
• Nasal passage joins the nose to the windpipe (trachea).
• Upper end of the trachea has a voice box called the larynx.
• The trachea branches into two smaller tubes named bronchi.
• Each bronchus divides in the lungs to form bronchioles.
• Bronchioles have air sacs at their ends known as alveoli.
• The exchange of gases takes place in the walls of alveoli.

Breathing in Animals

• Animals like lions, cows, goats, and frogs have lungs.
• A cockroach has small openings called spiracles.
• Insects have a network of air called trachae
• Oxygen rushes through spiracles into trachae and diffuses into the tissue.
• The skin of earthworms feels moist and allows air to pass through.
• Frogs also breathe through their skin.

Breathing Underwater

• Gills are projections of the skin.
• They are supplied with blood vessels for the exchange of gases.

Respiration in Plants

• Root cells need oxygen to generate energy.
• Roots take up air spaces present between the soil particles.

NCERT Notes

• Amoeba exchange gases through the general body surface.
• Air becomes warm after passing through the nasal cavity.
• Hot water baths relieve cramps, improves circulation and oxygen supply, and breaks down lactic acid.
• Root oxygen in the soil particles diffuses into root hair and reaches all cells of the body.
• Hemoglobin is a pigment that carries oxygen to all parts of the body.