Biology B3 predictions - Edexcel 20 June 2016Watch
- What is a culture medium and how is that different to a culture?
Also with the fungus fusarium, is it used to produce mycoprotein or is it mycoprotein and needs to be put into a fermenter to grow it?
Also why does Fusarium need to respire aerobically?
Hi, if the structure of the nephron did come up, would we need to mention the specific names of the tubes and loops, like loop of Henle? Or just describe ultrafiltration, reabsorption etc in detail? Because I know the processes really well, but I don't quite know how to mention the loops and that into it. Good luck everyone
Yes, just like the involvement of the glomerulus and the bowman's capsules in ultrafiltration, mention the sizes of molecules - that only small sized molecules diffuse into the nephron. Then the selective reabsorption of water (dependent on ADH levels), salts & all of the glucose. And include the structures where reabsorption occurs - the loop of Henlé and the convoluted tubules. Then finally talk about the release of waste substances (urea, excess water etc) through the collecting duct, then the ureters, into the bladder and past through the urethra as urine. Just talk about this but in more detail Good luck for tomorrow!
There are 3 stages of how the kidney filters urea and other substances out of the blood.
Blood travels through the renal artery and reaches to the glomerulus. The blood contains urea (solid made in the liver where amino acids react with co2 to make urea) ,water,glucose,red blood cells and proteins. The glomurulus is a network of capillaries and is present inside the bowmans capsule. The bowmans capsulle has tiny holes to let small molecules pass through like urea,glucose,water. These small molecules then diffuse into it and go through the convoluted tubules and henlest tube. The larger molecules like the red blood cells and glucose stay in the blood and are taken by the renal vein towards the heart.
2) Selective reabsorption of glucose and excess water
While the fluids flow through the convoluted tubules some useful substances like glucose and the water get reabsorbed back into the blood. Almost all glucose and all water molecules are reabsorbed. This is called selective reabsorption. The amount of water reabsorbed depends on how much the body needs. This is called osmoregulation
3) Removal of excess water in urine
At the end of the nephron the urea and remaining water go to the ureter (it takes urine from kidneys to bladder). The urea dissolves in the water to form urine.
In the fermentation question that asked what gas is added for the growth. What was the answer? I put oxygen then changed it to nitrogen in the last 10 mins of the exam! Because oxygen is added but for respiration. But I know nitrates are added which are converted to nitrogen for growth