3a biology Flashcards
What causes Type 1 Diabetes? How can it be controlled?
Caused by a lack of insulin
Can be controlled by injecting a needle that has insulin
Describe what happens when blood glucose level is too high.
1) Insulin secreted by the pancreas.
2) Glucose is removed by the liver
3) Stored as glycogen
What are the advantages and disadvantages of a kidney transplant over dialysis?
Advantages - long term solution, cheaper, one time settlement, does not cause blood clots, drugs can suppress the immune system.
Disadvantages - can be rejected, infection, bleeding, damage to surrounding organs.
How does kidney dialysis work?
When your kidneys fail, dialysis keeps your body in balance by: removing waste, salt and extra water to prevent them from building up in the body. keeping a safe level of certain chemicals in your blood, such as potassium, sodium and bicarbonate. helping to control blood pressure.
Explain why sugars doesn’t simply diffuse back into the blood from the nephrons
The glucose does not diffuse it moves by active transport into the blood stream because there is a higher concentration of glucose in the blood stream than in the nephrons
Name three things that that are reabsorbed by
kidneys
Glucose, water, ions
What is the difference between diffusion and osmosis?
the differences between osmosis and diffusion it that diffusion refers to the movement of any chemical from one place to another, whereas osmosis exclusively refers to the movement of water across a membrane. also diffusion is the movement of molecules
Why should a long distance runner choose an isotonic drink rather than water?
because the drink will provide and replace the lost mineral ions through sweating and breathing. The isotonic drink has the same concentration of minerals in body as it does in the drink whereas the cola will not replace any of the ions lost from the body
Describe 2 adaptations of the villi which help the small intestine to function.
To get a big surface area, the inside wall of the small intestine is lined with tiny villi. These stick out and give a big surface area. They also contain blood capillaries to carry away the absorbed food molecules.
Describe how the leaf and roots are adapted for efficient exchange
The mineral ions are transported around the plant where they serve a variety of functions, whilst the water is transported to be used as a reactant in photosynthesis, as well as to cool the leaves by evaporation and support the leaves and shoots by keeping cells rigid.
