-
We need your support!
We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
Click here to Donate Now (View Announcement)
Search results
-
-
A level Biology: Post your doubts here!
Well as the question says keystone species are those whose disappearance can change the whole food chain all you have to do.is repeat this and state the effect of loosing seaotters. Like which species will increase as seaotters are gone and which will decrease as their predators have increased... -
A level Biology: Post your doubts here!
In the Dna gene code the the base sequence is changed from CTT TO CAT adenine replaces thymine hence during transcription a different mRna is coded for when this mRna attaches to the subunit of ribosome die to the change I codon a different trna attaches due to specifity therefore different... -
A level Biology: Post your doubts here!
you You will have to explain why like, only 10 percent energy is available from one trophic level to another plus top carnivores are usually at 4 trophic level hence only 0.01 percentage of energy supplied to the ecosystem reaches them.Also as top carnivore are big in size their energy... -
-
A level Biology: Post your doubts here!
Correct me if i am wrong also in anaphase we are able to see cleavege between two cells which is shown here whereas in telophase cytokenesis is more obvious -
-
A level Biology: Post your doubts here!
I think in bio the poly molecules are considered macro the rest are not macro , However you should confirm this first. -
A level Biology: Post your doubts here!
it decreases the haemoglobin(HB) affinity for oxygen, This is known as the BOHR EFFECT. Why does this happen well in water CO2 molecules from carbonic acid H2CO3 which dissociates to form H+ and HCO3 - ions. This is catalysed by the enzyme carbonic anhydrase. H+ ions then react with HB to form... -
Chemistry: Post your doubts here!
because the answer we get is the mole of hydrogen molecules , to find the moles of H atoms we times it by two as each hydrogen molecule has two H atoms. -
A level Biology: Post your doubts here!
yes as they are growing they require energy for replication of dna and protien synthesis. 23 is D because lingin strengthen the xylem vessels so they wont collapse under hydrostatic pressure which in this case is due to high rate of transpiration. -
A level Biology: Post your doubts here!
24 sugar will move out due to energy required by the growing cells for protein sythesis and Q 23 is the answerD -
A level Biology: Post your doubts here!
Question 27 http://maxpapers.com/syllabus-materials/biology-9700/attachment/9700_w14_qp_13/ -
-
A level Biology: Post your doubts here!
qwertypoiu has explained it in detail , so as you can see not everyone has sickle cell anemia and there are people that die due to sickle cell anemia. Plus being a carrier or having sickle cell anemia counts too. Its a kind of compilcated if you want to know more read the chapter on natural... -
A level Biology: Post your doubts here!
Thats unusual becuase the relation in sicke cell anaemia and malaria is part of natural selection which is A2 anyways here is the explaination, People with sickle cell anaemia can not acquire malaria as the sickle plasmodium cannot live in sickle red blood cells hence, people with siclkle cell... -
-
A level Biology: Post your doubts here!
D is not valid while 123 are valid