AS biology aqa resit

what did people put for the why youd use a pH meter instead of pH indicator question?

what did people put for the why youd use a pH meter instead of pH indicator question?

triglyceride is hydrolysed to a glycerol and fatty acids, since fatty acids contain the carboxyl group it can dissociate into H+ ions hence lowering the pH is what i put

That answer is good but seems more chemistry related lol. Biology is usually more simple

Unofficial mark scheme of what I can remember, I can't remember the exact order of the questions though so i've done them randomly, feel free to correct me and fill in some of the questions.

1) mitochondria question
- it was 2.8 for actual size
- It was either that mitochondria have its own DNA or that they have circular DNA
-

2) heart question
- it was A and C (cant remember which order)
-

3) lungs question
- When breathing out the diaphragm relaxes and reverts to its original dome shape, the volume in the thorax decreases and the pressure in the thorax increases. Air leaves lungs down pressure gradient.
- Continuing smoking had decrease, stopping smoking had increase then decrease
- Alveoli are damaged, goblet cells produce more mucus so airways narrower

4) enzyme question protease
- Made in ribosomes in pancreas
- It was inactive in the pancreas since pancreas has important enzymes such as amylase which are proteins and if the protease was in an active form it would hydrolise and digest the enzymes before they left the pancreas
- One of the answers was peptide bond

5) enzyme question pH
- Graph had a shallower gradient and reached plateau at the same pH but later on in time
- pH decreases because when the triglyceride is hydrolysed it takes up a water molecule (something like that)

6) Immunity
- Blood transfusion would provide passive immunity and provide the individual with memory cells which would recognise the ebola virus and initiate an immediate immune response producing antibodies rapidly and in large amounts to destroy the virus before it could damage the host cells
- Vaccine wouldnt work due to antigenic variability so memory cells would not recognise antigen. The virus used in the vaccine could also mutate and become active causing serious side effects. (cant remember what else i put)

8)
- Sodium ions that are already present in epithelial cells are actively transport against the concentration gradient into the blood via a carrier protein. The soidum ion conc in the epithelial cells is now lower than that of the lumen of the SI. So Sodium ions are diffused into the epithelial cells, but before doing so bind with glucose. They pass through the cell-surface membrane via a co-transport protein. (not those words exactly, but something like that)
- Chloride ions are too large, charged and not lipid-soluble so pass by facilitated diffusion via protein channel. Oxygen is pretty much the opposite. (I couldnt think of what they would want for 5 marks.

Was the answer for the protease question definitely ribosomes, its what i put, just some people in my year disagreed?

I'm almost certain since ribosomes synthesise proteins and it is a protein. I guess they would condone RER. What did people say it was?

Was the answer for the protease question definitely ribosomes, its what i put, just some people in my year disagreed?

It's ribosomes or rough endoplasmic reticulum, since those are the only organelles capable of synthesising proteins.

The graph question temperature change was asked but it was a pH graph so wouldn't it remain the same

okay this has reassured me as i put ribosomes but a few people in my year said lysosomes? Also what did people put for the question about holes between the ventricles?

okay this has reassured me as i put ribosomes but a few people in my year said lysosomes? Also what did people put for the question about holes between the ventricles?