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B2 Biology Revision, image, image, image, image - Coggle Diagram
B2 Biology Revision
Plants
BAOBAB TRÉ
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The baobab tree has no leaves for most of the year. This is because the heat in Africa causes a large increase in the amount of water the baobab tree loses. The baobab tree must have water in order to survive as water is required for photosynthesis. In order to retain water throughout the hottest months of the year, the baobab tree gets rid of its leaves. The leaves have stomata, which open to allow the diffusion of gases. High heat causes water to be lost through the stomata. So, by losing its leaves, the baobab tree prevents a large amount of water from being lost.
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Xylem
One-way, made of dead cells, carries water and dissolved minerals up from the roots into the plant and its leaves for transpiration
Phloem
Two-way, carries dissolved sugars around the plant for respiration
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Enzymes
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Amylase
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Found in the salivary glands(mouth), pancreas and small intestine
Protease
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Found in the stomach, pancreas and small intestine
Circulatory system
Heart
Deoxygenated blood enters the right atrium via the vena cava. The heart contracts, and the blood moves through the tricuspid valve into the right ventricle. The blood is then pumped through the pulmonary artery into the lungs where the blood is oxygenated.
Oxygenated blood enters the heart through the pulmonary vein which leads to the left atrium. From the left atrium, oxygenated blood is pumped into the left ventricle through the bicuspid valve. The heart contracts, pushing the oxygenated blood out of the heart and to the rest of the body through the aorta. The left side of the heart is more muscular in order to push the blood around the entire body.
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Blood vessels
Arteries
Arteries carry oxygenated blood away from the heart. They have a narrow lumen and thick muscular walls to carry blood at high pressures.
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Composition of blood
Red Blood Cells (RBC)
RBCs carry oxygen around the body using the protein haemoglobin enabling them to carry the maximum amount of oxygen. They also have no nucleus to make more space for oxygen.
They are small, flexible and their biconcave shape gives a larger surface area which allows more oxygen to be absorbed by diffusion
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Platelets
Platelets are small structures which fuse together to form a scab. These platelets start a clotting process.
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Plasma
Plasma is a liquid transport medium. It carries blood cells and other substances, such as:
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Diseases
Tumours
Malignant tumours spread through the lymph system and bloodstream, they are cancerous and can form secondary tumours
Benign tumours barely spread and are non-cancerous, they cannot form secondary tumours and usually aren't as serious as malignant ones
Non-Communicable
Examples: Cancers, HIV, CHD
Cannot be passed on via contact or anything alike, not caused by a pathogen
Communicable
Examples: COVID-19, COVID-20 the squeekwal
Diseases that can be passed on via contact, coughing, sneezing etc. Caused by a pathogen
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