AQA A-Level Biology Paper 1 Latest Update
A scientist found that leaf-chewers and xylem-sap-feeders had a greater effect on plant growth than phloem-sap-feeders (greater reduction in leaf area).
Other than environmental factors, give two features the scientist would have controlled in his experim...
A scientist found that leaf-chewers and xylem-sap-feeders had a greater effect on
plant growth than phloem-sap-feeders (greater reduction in leaf area).
Other than environmental factors, give two features the scientist would have
controlled in his experiment to ensure this conclusion was valid. [2 marks] -
✔✔✔ANSWER-1. Number/mass/density of insects per plant;
2. Stage of development/size of plants/insects;
A student concluded from a graph of the data in Table 5 that the bacterium lives at
15 °C, which is the optimum temperature for enzyme activity. Do the data support
the student's conclusion? [4 marks] - ✔✔✔ANSWER-Yes:
1. Expect optimum temperature of enzyme to be
same/similar to temperature where bacterium lives;
2. Optimum temperature for enzyme (appears to
, be around) 15 °C;
No:
3. Need data from more temperatures (between
10 °C and 20 °C);
4. Data for only isolated enzyme
OR
Isolation may affect activity;
A student puts amylase and starch inside of Visking tubing in a beaker of water.
She then tests the solution in the beaker with Biuret's, Benedict's and potassium
iodide. Explain the results. /3 - ✔✔✔ANSWER-1. Biuret: protein molecules too
large to pass
through tubing; (not enzyme)
2. Iodine in potassium iodide solution: starch
molecules too large to pass through tubing;
3. Benedict's: starch hydrolysed to maltose,
which is able to pass through tubing (amylase doesn't hydrolyse to glucose)
Before the cell was examined using the electron microscope, it was stained. This
stain caused parts of the structure of the cell-surface membrane to appear as two
dark lines.
Suggest an explanation for the appearance of the cell-surface membrane as two
dark lines. [3 marks] - ✔✔✔ANSWER-1.Membrane has phospholipid bilayer;
2.Stain binds to phosphate/glycerol;
3.On inside and outside of membrane;
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller NURSING2EXAM. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $10.49. You're not tied to anything after your purchase.
