Biology

• Mitochondria produce energy through aerobic respiration.
• The nucleus is the control centre of the cell, containing genetic material (DNA) that controls all activities within the cell.
• Chloroplasts contain chlorophyll and are involved in photosynthesis.
• Air containing oxygen enters our body through the mouth or nose and is then transported to the lungs
• Air passes down the trachea (windpipe) and into each lung through a tube called the bronchus.
• The bronchi branch into smaller tubes called the bronchioles, which end in air sacks called alveoli.
• oxygen in the air passes into the blood to be transported to body cells through the process of diffusion.
• In order to breathe in, the diaphragm and intercostal muscles need to contract. Your rib cage moves upwards and outwards.
• In order to breathe out, the diaphragm and intercostal muscles need to relax. Your ribcage moves downwards and inwards.
• Inhalation: your diaphragm contracts and flattens, the volume inside your thorax (chest) gets bigger, this lowers the pressure inside your thorax and air is drawn into your lungs.
• exhalation: your diaphragm becomes dome shaped. The volume inside your lungs becomes smaller and air is forced out.
• Exhalation: the pressure inside the thorax increases, the pressure is now higher than the pressure of the air outside your body.
• The movement of air takes place because of differences in pressure.
• the trachea and bronchi need support provided by the rings of cartilage.
• Oxygen dissolves in the layer of moisture, then diffuses from the air (a higher concentration) into the blood (a lower concentration).
• The air content in the alveolus is refreshed with each breath.
• Carbon dioxide goes from the alveolus from the cells, then diffuses from the blood (a higher concentration) into the alveolus (a lower concentration) down a concentration gradient.
• Alveolus adaptations: the alveoli walls are very thin and blood capillaries are close to the alveoli so there is less distance for the gasses to travel (reduces diffusion distance).
• Alveolus adaptations: Large surface area, thin walls, moist lining, and a large blood supply.
• Alveolus adaptations: a good supply/circulation if blood so that oxygen can be removed quickly (increasing the diffusion gradient).
• Alveolus adaptations: tiny (folded) alveoli increases the total surface area so lots of gas particles can pass through (diffuse) at the same time.
• Alveolus adaptations: a thin layer of moisture/water lining the alveoli allowing oxygen to dissolve before diffusing into the blood.
• The respiratory system produces mucus and has ciliated epithelia cells which help to protect the respiratory system as they act as the cleaning mechanism.
• The trachea and bronchi are lined with mucus to trap dust and bacteria.
• The mucus is constantly moved upwards to the back of the throat to be swallowed by cilia which beat back and fourth.
• Parts of a ciliated epithelial cell: cell membrane, cilia (plural), a nucleus and cytoplasm.
• Aerobic respiration is a chemical reaction, which releases energy from food.
• The equation for aerobic respiration: Glucose + Oxygen → Carbon dioxide + Water (energy).
• Respiration= the release of energy. Breathing = the release and intake of air.
• Smoking: cigarettes contain tar - collects in the lungs and contains carcinogens which causes cancer.
• Smoking: cigarettes contain Nicotine - highly addictive and dangerous.
• Smoking: cigarette smoke damages the cilia so that they cannot remove mucus efficiently. Chemicals in tobacco paralyse the cilia preventing their function and therefore leading to increase in risk of disease in the respiratory system.
• Smoking: cigarette smoke leads to coughing which destroys the lung tissue, leading to shortness of breath. This is called emphysema.
• Smoking damages unborn children because it stops them getting as much oxygen.
• Smoking causes heart disease.