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Degree: Biological Sciences (Bachelors) - Durham University
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Dawn (Student) March 7 2016
Lucy (Student) February 2 2016
The cell cycle begins with interphase (G1,S G2) then follows on to mitosis and ends with cytokinesis.
G1 phase - Protein synthesis and preparation for DNA replication
S phase - DNA replication
G2 phase - Organelle replication. Protein and ATP synthesis. Preparation for mitosis.
Mitosis - multiple stages: prophase, metaphase, anaphase and telophase.
Mitosis separates chromatids to create two identical daughter cells.
Cytokinesis - Cytoplasm splits and separates to form to genetically identical cells.
Slow oxidative fibres are designed for aerobic endurance exercise. They use oxygen to work at a moderate rate over a long period. They are red due to the high concentration of blood vessels which deliver a rich supply of oxygenated blood. They have a high resistance to fatigue and are found in high percentages in athletes such as marathon runners.
Fast twitch fibres are designed for anaerobic exercise. They produce small amounts of energy very quickly. Unlike slow twitch they don't use oxygen to produce energy (ATP) so do not require such a rich blood supply. This means they are white in colur not red. They fatigue much more quickly than slow twitch fibres. Athletes in high power sports such as sprinting have high percentages of fast twitch fibres.see more
The systemic circuit carries oxygenated blood from the heart around the body then carries the deoxygenated blood from the body back to the heart. The blood leaves the left ventricle of the heart via an artery called the aorta, it then travels around the whole body where oxygen is exchanged for carbon dioxide at respiring tissues. Deoxygenated blood is transported back to the heart via a vein called the vena cava.
The pulmonary circuit transports blood between the heart and the lungs. The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs. The blood is oxygenated in the lungs where carbon dioxide is exchanged for oxygen. The pulmonary veins then carries the blood back to the heart to be pumped round the body via the systemic circuit.see more