Respiration

There are two types of respiration:

Aerobic Respiration - Uses oxygen. Creates significantly more ATP than anaerobic respiration, and does not produce lactic acid

It occurs in the mitochondria

Anaerobic Respiration - Does not use oxygen. Create significantly less ATP than aerobic respiration and produces lactic acid with is toxic to the body.

It occurs in the cytoplasm

Lactic acid can be removed through exhalation.

Equations

Aerobic Respiration:

602 + C6H12O6 → 6CO2 + 6H20 + ATP

Oxygen + Glucose → Carbon Dioxide + Water + Energy

Anaerobic Respiration in animals

C6H12O6 → Lactic acid + ATP

Glucose → Lactic Acid + ATP

Anaerobic Respiration in plants and fungi (fermentation):

Glucose → Ethanol + Carbon Dioxide + ATP

Carbon Dioxide Test

Wood lice

  • Put hydrogen carbonate indicator in a test tube

  • Put a wire gauze with wood lice in the test tube

  • If there is a colour change of red to yellow, carbon dioxide is present.

  • It should turn from red to yellow as the woodlice are respiring

Seeds

  • Place germinating seeds and boiled seeds in two separate thermal flasks

  • Place a thermometer in the test tube

  • Respiration releases heat.

  • Germinated seeds should emit heat because they are respiring, and boiled seeds shouldn’t as they are dead and not respiring

Muscles

When exercising at high intensity, your muscles will require more oxygen to aerobically respire

The lungs won’t be able to supply enough oxygen to aerobically respire

Less aerobic respiration will mean less energy will be produced.

Anaerobic respiration will begin, and lactic acid will be produced and less energy will be produced.

This could cause cramps. Remove lactic acid through exhalation.

Lungs

Thorax - Chest

Gas exchange

Ventilation - Breathing. Moving air in and out of the lungs

This required a difference in air pressure and relies on the thorax being an airtight cavity ( no air) .

Movements of the intercostal muscles and the diaphragm cause the change in volume inside the cavity and therefore the air pressure.

Inhalation

  • Intercostal muscles contract

  • Ribs move up and out

  • Diaphragm contracts and flattens

  • Volume of air in the thorax increases which reduces the pressure

  • Air rushes into the lungs

Exhalation

  • Intercostal muscles relax

  • Ribs move down and in

  • Diaphragm relaxes and returns to dome shape.

  • Volume of thorax decreases and therefore the pressure increases

  • Air is forced out of the lungs

Alveoli

The lungs contain 700,000,000 tiny air sacs called alveoli.

They are surrounded by a network of blood capillaries

Gasses diffuse into and out of the blood based on concentration gradients.

Oxygenated blood travels back to the heart to be pumped around the body

Adaptations for gas exchange

  • They have a large surface area for diffusion

  • They are moist to help dissolve gases to increase the rate of diffusion

  • Rich blood supply for a steep diffusion gradient

  • Walls are permeable

  • One cell thick cell walls

Breathing rate experiment

  • Measure resting breathing rate

  • Run on the spot for 5 minutes

  • Measure breathing rate immediately after exercise

  • Wait 5 minutes then measure breathing rate again

  • Repeat thrice

  • Ensure that the people doing the experiment are the same gender, age, and fitness level. Ensure the room’s temperature is the same, food and drink before is the same and time spent exercising is the same.

Smoking

Smoking contributes to the following lung conditions:

Lung Cancer

  • Tobacco contains carcinogens (stuff that mutates stuff into cancerous tumors).

Chronic Bronchitis

  • In healthy lungs, the cells lining the bronchi and bronchioles have cilia, cells that waft mucus that traps bacteria and dust up the lungs.

  • Goblet cells secrete (produce and discharge) mucus

  • The cilia waft the mucus up to the throat where it can be swallowed and destroyed in the stomach acid.

  • Tar in cigarettes damages and paralyses the cilia.

  • Bacteria builds up in the lungs and causes chest infections.

  • The tar irritates the lining encouraging more mucus to be produced

  • The smoker develops a heave cough called smoker’s cough and chronic bronchitis

Emphysema

  • Smoke damages the alveoli walls to burst and fuse

  • This greatly decreases surface area for gas exchange

  • The victim is unable to carry out basic tasks like walking due to lack of oxygen.

  • There is no cure.

Coronary Heart Disease

  • Coronary heart disease is when you get fatty deposits in the wall of the coronary arteries which normally supply your heart with oxygen.

  • Eventually these can get blocked entirely with a clot and some oxygen will not get to the heart.

  • This is called a heart attack.

  • Carbon monoxide in smoke binds to haemoglobin in the blood instead of oxygen.

  • Therefore the heart has to work harder, beat faster and with a higher pressure

  • This damages the artery wall making clots more likely to happen.

  • Nicotine makes blood cells more sticky and narrows blood cells (vasoconstriction)

  • These things increase the effects of CHD and makes a heart attack more likely.