100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
Previously searched by you
Previously searched by you
logo
Over 2000 A level biology questions- mainly for aqa but can also be great practice for other exam boards £18.39
Add to cart
Quickly navigate to
Preview
  2.  
  3. AQA
  4.  
  5. A Level Biology
  6.  
  7. Biology

Exam (elaborations)

Over 2000 A level biology questions- mainly for aqa but can also be great practice for other exam boards
 0 purchase
  • Institution
  • AQA

If you are struggling with biology you need this pack with over 2000 questions with markschemes. you won't find these questions on websites so you're best bet is to download these and study the hell out of them to get that A*

Preview 4 out of 1197  pages

Document information

  • July 8, 2021
  • 1197
  • 2020/2021
  • Exam (elaborations)
  • Questions & answers

Subjects

Written for

All documents for this subject (40)

Seller

avatar-seller
ainhoa1

Content preview

ATP Questions 1
1. The diagram shows the flow of energy through a marine ecosystem.
–2 –1
The units are kJ m year .

Light energy measured at sea surface
12.5 × 10 5

6250

1000 Respiration 1250
Producers

4000

500 Respiration 2800
Primary consumers

700

100 Respiration 550
Secondary consumers

50

Energy in faeces
and dead organisms
which fall to the bottom


(a) (i) Calculate the percentage of the light energy at the sea surface which is converted
into chemical energy in the producers. Show your working.
(2)

(ii) The percentage of the light energy at the sea surface which is converted into
chemical energy in the producers is very small. Give two reasons for this.
(2)

(b) Use the information in the diagram to explain why marine ecosystems such as this rarely
have more than five trophic levels.
(2)

(c) What happens to the energy in faeces and dead organisms which fall to the bottom of the
sea?
(2)




1

,(d) Light energy is important in the light-dependent reaction of photosynthesis. The energy
changes which take place in the light-dependent reaction are shown in the diagram.

Chain of
electron
carriers

Chain of
electron
carriers

Energy Reduced
Level NADP NADP

ATP
Light
ADP + Pi

Chlorophyll

Light

Chlorophyll

(i) Describe what happens to the chlorophyll when it is struck by light.
(2)

(ii) The weedkiller DCMU blocks the flow of electrons along the chains of electron
carriers. Describe and explain the effect this will have on the production of triose
phosphate in the light-independent reaction.
(3)

(e) Living organisms release energy from organic molecules such as glucose during
respiration.
Much of this energy is used to produce ATP.
Explain why ATP is better than glucose as an immediate energy source for cell
metabolism.
(2)

(f) The production of ATP is said to be coupled to the transport of electrons along the carrier
chain. Normally, electrons are only passed along the carrier chain if ADP is being
converted to ATP at the same time. When the amount of ADP in a cell is low, electrons do
not flow from reduced coenzyme to oxygen.

(i) Suggest how the rate of respiration is linked to the needs of the cell.
(3)

(ii) DNP is a substance which allows electron transport to take place without the
production of ATP. When DNP is given to rats, their body temperatures rise.
Explain why.
(2)
(Total 20 marks)




2

,2. The diagram gives an outline of the process of aerobic respiration.


Glucose
2 ATP
Stage C



Stage A 2 reduced NAD 6 ATP



4 ATP


2 Pyruvate

2 CO 2
2 reduced NAD 6 ATP


2 Acetylcoenzyme A
2 Coenzyme A




6 reduced NAD 18 ATP

Stage B 2 reduced NAD 4 ATP

2 ATP



4 CO 2


H + ions and electrons


(a) (i) Complete the table by naming stages A and B and giving the location of each stage
in a cell such as a liver cell.

Stage Name of stage Location in cell
A
B

(2)

(ii) How many carbon atoms are there in each pyruvate ion? ...............................(1)

3

, (iii) What happens to the H+ ions and electrons released in stage C?

..........................................................................................................................

..........................................................................................................................

..........................................................................................................................
(2)

(b) In aerobic conditions, ATP is produced by substrate-level phosphorylation and by
oxidative phosphorylation. Use information in the diagram to find the net yield of
molecules of ATP per molecule of glucose by

(i) substrate-level phosphorylation; .....................................................................

(ii) oxidative phosphorylation. ..............................................................................
(2)

(c) (i) One mole of glucose releases 2880 kJ of energy when burned completely in
oxygen. Hydrolysis of one mole of ATP to ADP and phosphate releases 31 kJ of
energy. Use your answers from part (b) to calculate the percentage efficiency of
energy transfer from glucose to ATP by aerobic respiration. Show your working.




Percentage efficiency = .......................................%
(2)

(ii) What happens to the energy which is not transferred to ATP?

..........................................................................................................................
(1)

(iii) Explain why ATP is better than glucose as an immediate energy source for cell
metabolism.

..........................................................................................................................

..........................................................................................................................

..........................................................................................................................

..........................................................................................................................
(2)




4

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

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

Quick and easy check-out

You can quickly pay through credit card for the summaries. There is no membership needed.

Focus on what matters

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 ainhoa1. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for £18.39. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

66184 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy revision notes and other study material for 15 years now

Start selling
£18.39
  • (0)
Add to cart
Added