OCR Biology F214 Communication, Homeostasis and Energy Wed 25 Jan 2012

Scroll to see replies

What are the different terms and their meaning...?

Glycogenesis, gluconeogenesis... argh what are the others and the meaning of them all??

Reply 1001

The Illuminati

Original post by xRainbowx

I know there are cells lining the Proximal convoluted tubule, but is the actual tubule itself made up of cells or is it just a space?

The wall of the tubule is made up of epithelial cells. The "space" is the lumen that contains the filtrate from the Bowman's capsule.

Reply 1002

Chris P Chicken.

Original post by Claudine

evidence for chemiosmosis anyone?!

Only one I can think of is a lower PH in the thykaloid space which indicates the presence of H+ ions.

Reply 1003

Claudine

Original post by Chris P Chicken.

Only one I can think of is a lower PH in the thykaloid space which indicates the presence of H+ ions.

There are experiments that prove it, but I dont know about them :O exam is tomorrow!! scary :L

Reply 1004

Chris P Chicken.

Original post by TourettesUnicorn

What are the different terms and their meaning...?

Glycogenesis, gluconeogenesis... argh what are the others and the meaning of them all??

There's three.

Glycogenesis - Glucose is converted into glycogen.
Glycogenolysis - Glycogen is converted into glucose.
Gluconeogenesis - Fatty acids or Amino acids are converted into glucose.

I think... :s-smilie:

Reply 1005

Chris P Chicken.

Original post by Claudine

There are experiments that prove it, but I dont know about them :O exam is tomorrow!! scary :L

Just hope it doesn't come up... :tongue:

Reply 1006

Bubbles94

Original post by Claudine

There are experiments that prove it, but I dont know about them :O exam is tomorrow!! scary :L

i can type out the whole experiment if you want :L

Reply 1007

The Illuminati

Original post by Claudine

evidence for chemiosmosis anyone?!

page 93. It was just to show where the different parts of respiration happened as if they removed a certain part, one process would stop.

Original post by TourettesUnicorn

What are the different terms and their meaning...?

Glycogenesis, gluconeogenesis... argh what are the others and the meaning of them all??

Insulin does the following.......
glycogenesis= making glycogen from glucose

Glucagon does the following........
gluconeogenesis= making glucose from other molecules such as amino acids and proteins
glycogenolysis= breaking down glycogen to make glucose

Reply 1008

Straight up G

So, I literally just understood photosynthesis in the last half hour, and Respiration at 4 o clock. And I have the end of excretion still to cover and I have to remember the first topic later tonight as well.

Retake all the way, cheers

Reply 1009

xRainbowx

Original post by The Illuminati

The wall of the tubule is made up of epithelial cells. The "space" is the lumen that contains the filtrate from the Bowman's capsule.

Thanks, thats what the text book seems to suggest but just wanted to confirm :smile:

Reply 1010

Dan12

Original post by Bi0logical

What is the role of the Kidneys in osmoregulation?

changes in water potential is detected by the osmoreceptors in the hypothalamus.
If the water potential of the blood is too low, water will leave the osmoreceptors by osmosis and causes them to shrink. This stimulates the neurosecretory cells to make and secrete ADH (anti-diuretic hormone). ADH travels along the axon to the posterior pituitary glands where it is stored.
ADH binds to its specific receptor on the collecting duct. this activates adenyl cyclase which converted ATP to cAMP. cAMP activated enzyme catalysed reactions.
This causes aquaporins to be inserted which makes the collecting walls more permeable. More water is reabsorbed.

if the water potential is too high, water will enter the osmoreceptors by osmosis. This stimulates the neurosecretory cells to stop making ADH.
Plasma membrane in the collecting ducts fold inwards to remove aquaporins. Less water is reabsorbed from the collecting duct.

Reply 1011

sophieisabella

Are we required to know why the hydrogen atoms accepted by FAD are passed back into the mitochondrial membrane (instead of being pumped into the inter membrane space)?

Reply 1012

Dan12

Original post by Chris P Chicken.

Lol, what is brown fat?

And is this from a paper or stretch and challenge question?

I made it up.

Reply 1013

Chris P Chicken.

Original post by Straight up G

Need to revise all of respiration till midnight where I have my cut off point. :wink:

Reply 1014

Chris P Chicken.

Original post by Dan12

I made it up.

Oh ok, I was getting worried there.

Reply 1015

Bubbles94

OKAY.

evidence fore chemiosmosis;

An experiment concerning the mitochondria in the chloroplasts and the rate of ATP production.
A sample of mitochondria is submerged in a high PH solution (8) and left for a set time so the ph in the inner membrane space is the same as the solution outside (all is Ph 8)

This sample is compared to another that is exactly the same, but the Ph used is low (2)

The lower the Ph the greater the dissociation into Hydrogen ions (protons) which are needed in ATP production, where they are actively pumped into the inner membrane space, and diffuse back into the matrix via ATPase channels in stalked particles to produce ATP.

The high Ph solution showed no ATP production, the lower one did, supporting chemiosmosis.

High glucose concentration is detected by the Beta cells, as more glucose enters the beta cell by facilitated diffusion, more is phosphorylated and converted into glycogen, increasing the rate of respiration inside the cell, and increasing the amount of ATP released. This causes potassium channels to close, causing potassium to build up inside the cell depolarizing it. The change in voltage causes Ca2+ voltage gated channels to open, and calcium diffuses into the cell, causing vesicles containing insulin to bind with the plasma membrane, and release the insulin by exocytosis.

Gluconeogenesis is the formation of glucose by breaking down Glycogen.

Glycogen is released by the alpha cells in the islets of Langerhans in the pancreas. It circulated in the blood and binds to receptors in target cells. It catalyses reactions inside the cell into breaking down glycogen by activating various enzymes.

Now my hand aches :L

(edited 12 years ago)

Reply 1016

TourettesUnicorn

What do you think is better, revising late into the night or a good night's sleep?

Reply 1017

--NWzD9--

Original post by sophieisabella

Are we required to know why the hydrogen atoms accepted by FAD are passed back into the mitochondrial membrane (instead of being pumped into the inter membrane space)?

All we need to know is that Red. FAD donates its protons to oxygen, as oxygen reacts with protons and electrons to form water, and that Red. FAD donates its electrons to the electrons carriers.

(edited 12 years ago)

Reply 1018

The Illuminati

Original post by xRainbowx

Thanks, thats what the text book seems to suggest but just wanted to confirm :smile:

It took me ages to understand the picture but it makes sense once you realise what all the bits are

Reply 1019

Bubbles94

Original post by TourettesUnicorn

What do you think is better, revising late into the night or a good night's sleep?

Good night sleep. forget that type of revision. Odds are if you don't know it now, you wont have time to process the information and keep it in the long term memory for tomorrow..
Plus its a 9.15 exam, so you need to be awake for it.