Cells and Living Organisms

• A cell membrane controls what enters and leaves the cell.
• A cytoplasm is the jelly like liquid in a cell where chemical reactions take place.
• A mitochondria releases energy from food (glucose) by aerobic respiration.
• A cell wall (which is only found in plant cells) is made from cellucose and gives rigid support to the cell.
• A vacuole (which is normally found in plant cells) contains a watery liquid called sap. It keeps the cell firm.
• A nucleus stores information (in DNA) and controls what happensin the cell.
• A Chloroplast (which is only found in plant cells) contains green chlorophyll that absorbs light energy to allow plants to make their own food (photosynthesis).
• Unicellular cells have just one cell.
• Unicellular cells sometimes can miss a feature as they are not a plant or an animal cell.
• Bone cells are part of the skeletal system.
• Blood cells are part of the circulatory system.
• Nerve cells are part of the nervous system.
• Sperm cells in the reproductive system.
• Diffusion is a way that substances enter and leave cells.
• Diffusing surfaces always move from where there is a lot of the substance (high concentration) to where there is very little (low concentration).
• The human skeleton has 4 main different function: supports the body and gives the body its shape, acts as a framework that enables muscles to move around the body, protects parts of body (e.g skull protects the brain etc) , makes blood cells in the bone marrow of the long bonesm (e.g femur).
• Two muscles working together are called an antagonistic pair of muscles (e.g triceps and biceps)
• Bones connect to a bone by a ligaments.
• Muscles connect to a bone by tendons.
• The ends of each bone are covered with cartilage.
• Arthiritis is when the cartilage wears of and the bones rub causing pain.
• Osteoporosis is when the density of the bones become low and drop below a healthy level making it prone to fractures.
• The 4 types of drugs are painkillers, depressants, stimulants and hallucinogens.
• Painkillers reduce pain by blocking the pain messages so that they don't reach the brain.
• Depressants make a person relaxed and drowsy by decreasing their heart rate.
• Stimulants make a person alert and energetic by increasing the heart rate.
• Hallucinogens make a person hear and see things more intensely by hallucinations.
• All types of drugs are addictive.
• All drugs have side-effects.
• Drugs that are taken for non-medical reasons are called recreational drugs. (e.g alcohol)
• Smoking makes you cough tar.
• Smoking gives you a higher risk of lung cancer, heart disease, and stroke.
• Alcohol in the short term can slow down reactions, reduce coordination, alter people's behaviour.
• Alcohol in the long term can cause liver failure, brain damage, increased risk of strokes and heart attacks and anxiety and depression.
• If you are addicted to a drug you may have sweating, shivering, headaches, muscle pain and sickness.
• Nicotine increases heart rate and blood pressure and is found in tobacco which is in cigarettes.
• A cranium is the skull.
• A femur is your thigh bone.
• Ulna and Radius is your 2 bones in your forearm.
• Respiration is the process organisms release energy from food.