Karteikarten
OCR A2 Biology: Excretion
Karten in diesem Stapel (31)
- 1What is excretion?The removal of the waste products of metabolism from the body
- 2What is the function of the liver?1. Break down metabolic waste products into less harmful products
- 3What does the hepatic artery do?Supply the liver with oxygenated blood from the heart
- 4What does the hepatic vein do?Takes deoxygenated blood away from the liver
- 5What does the hepatic portal vein do?Brings blood from the duodenum and ileum (parts of the small intestine), to the Liver, so it can break down ingested and harmful substances.
- 6What does the bile duct do?Takes bile to the gall bladder to be stored
- 7What is bile?A substance produced by the liver to emulsify fats
- 8What is deamination?The process which removes nitrogen-containing amino acids from excess amino acids
- 9What does deamination produce?Ammonia and organic acids
- 10What happens to the organic acids?1. Respired to give ATP
2. Converted to a carbohydrate and stored as glycogen - 11Why does ammonia enter the ornithine cycle?It is too toxic to excrete directly
- 12What in the ornithine cycle combines with ammonia?Carbon Dioxide
- 13What does this produce?Citrulline
- 14What happens to the Citrulline next?It is combined with more Ammonia
- 15What does ammonia and citrulline produce?Arginine
- 16What combines with Arginine?Water
- 17What does water and Arginine produce?Urea and ornithine
- 18What is detoxification?The process in which harmful substances, such as alcohol, are broken down into less harmful compounds in order to be excreted
- 19What is alcohol broken down into?Acetic acid
- 20What can excess alcohol lead to?Cirrhosis of the Liver (The cells die and scar tissue blocks the blood flow)
- 21What can excess paracetamol lead to?Liver and Kidney failure
- 22What can excess insulin lead to?A lack of blood glucose
- 23What is ultrafiltration?The filtering of the blood into the Kidneys
- 24How does ultrafiltration work?1.Blood enters the glmoerulus from the wide afferent arteriole.
2. The narrow efferent arteriole that take blood away causes the glomerulus to be under high pressure
3. This forces small substances like urea out of the blood capillaries. - 25What three layers do filtered substances pass to enter the Bowman's capsule?1. Capillary endothelium
2. Basement membrane
3. Podocytes, epithelium of the Renal Capsule - 26What is selective reabsorption?The reabsorption of useful substances from the kidney nephrons back into the blood
- 27What is selectively reabsorbed in the PCT?1. Amino acids
2. Glucose
3. Vitamins
4. Salts
5. (Some) Urea - 28How do these get reabsorbed back into the blood?Active transport
(Urea is by diffusion) - 29Where is water reabsorbed?The Loop of Henle, DCT and the Collecting Duct
- 30What do the descending limb and ascending limb form?A counter-current multiplier mechanism
- 31—
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- A-Level Biology Karteikarten am OCR A2 Biology: Excretion, erstellt von hannawin98 am 17/05/2016.
- Erstellt von
- hannawin98 · Mai 2016
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- 19 Okt 2016
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