Year 12s: what will be the first way you research your future options? >>

Could you mark my a level biology essay

The importance of nitrogen containing substances in living organisms
Nitrogen is useful for living organisms as it is present in the amine group (-NH2)- which along with the carboxyl group (-COOH) and an R group (a variable side group) to create the structure of amino acids which in turn forms proteins made up of polypeptides- where more than two amino acids join together. Nitrogen is vital in order to make proteins which a variety of different functions such as: enzymes; antibodies; transport proteins and structural proteins.
Enzymes are needed to break down large food molecules and other enzymes help to synthesise large molecules. If nitrogen was not present then there will be no enzymes to aid with metabolism.
Antibodies are involved the immune response which are essential in keeping the organism alive and survive to reproduce and so forth.
Transport proteins are significant- for example- channel proteins present in cell membranes- these proteins transport molecules and ions across membranes- without nitrogen containing substances an organism will not survive. In the placenta, the transport proteins more in for example- glucose into the foetus, helping the growth of the foetus. Without the presence of nitrogen- mammalian organisms that carry their offspring in the womb which is vital in the development of offspring. Without nitrogen substances both reproduction and growth will not be possible.
Structural proteins are physically strong and are found in keratin and collagen. Keratin is found in the horns of rhinos which serves as a defence against predators. Furthermore, without nitrogen- collagen which is found in connective tissue would means the skin cells will not be able to renew and repair itself. Skin which is a physical barrier and the first line of defence against pathogens would mean that organisms would struggle to defend themselves from bacteria more.
Nitrogen is needed in the structure of nucleotides. A nucleotide is a monomer that’s structure is made up of pentose sugar, a nitrogen-containing organic base and a phosphate group. Nucleotides make up DNA and RNA and without nitrogen- a nucleotide would not be able to form. In DNA the base codes for adenine, guanine, thymine and cytosine. In RNA, however uracil replaces thymine. Nitrogen is needed to make up DNA and RNA. DNA is used to store genetic information- all the instructions needed for an organism to grow and develop from a fertilised egg to a fully grown adult. One of the main functions of RNA to transfer genetic information from the DNA to the ribosomes, which then go on to make polypeptides (proteins) in translation. Without nitrogen none of these functions can go on. It also means that living organisms will not be able to grow and reproduce- mitosis and meiosis would not occur and living organisms would not exist due to nitrogen being fundamental as it is what comprises heredity material for example gametes would not function properly due to no nitrogen so no fertilisation occurs and a zygote would not be able to divide- mitosis would not occur.
All amino acids- the monomers they are made from contain nitrogen. This is why growing plants need a source of nitrogen unlike animals- that absorb amino acids to make necessary proteins such as enzymes by consuming and digesting proteins in other organic matter- they must make their own by absorbing nitrogen in the form of nitrates from the ground. Leguminous plants that have nitrogen fixing bacteria at the end of the roots in a symbiotic relationship in which the bacteria receive glucose from the plants and the plants receive nitrogen from the rhizobium. This normally occurs through the nitrogen cycles, the movement of nitrogen through ecosystems. For example, nitrogen fixing bacteria turn atmospheric nitrogen gas into ammonia, which can be used by plants, and nitrates in dead plants and animals are turned into ammonia in ammonification and then nitrates in nitrification. Nitrogen is also used by farmers artificially to soils, through fertilisers that improve growth and to increase yield which in turn is important in sustaining organisms.

Reply 1

ZedTV

Wow! Im overwhelmed by the amount of detail! Do you have a mark scheme/ exam board? or both?

Reply 2

coffee alert

my exam board is aqa and here's the link:
https://filestore.aqa.org.uk/sample-papers-and-mark-schemes/2017/june/AQA-74023-WRE-JUN17.PDF

Reply 3

macpatgh-Sheldon

Please find at-d marked essay with detailed feedback
Best of luck & be safe!

M

Reply 4

macpatgh-Sheldon

@coffee alert

Wakie wakie!!!

marked essay above

Reply 5

coffee alert

thank you so much!!!!

Reply 6

coffee alert

Original post by coffee alert

thank you so much!!!!

oh my god there is so much helpful feedback that i could cry right now

Reply 7

macpatgh-Sheldon

Original post by coffee alert

oh my god there is so much helpful feedback that i could cry right now

I am trying to stuff some tissues into my CD drive - Alas looks like they will not get to you - that technology is not here yet!! Please don't :cry:

lol!

Reply 8

macpatgh-Sheldon

Original post by coffee alert

thank you so much!!!!

My pleasure!

Reply 9

Reality Check

Just for the benefit of others who may be reading this thread, please note that we do not award marks for SPAG - spelling, punctuation and grammar. You can go so far as to spell things phonetically, like 'fotosinthusis' and, so long as it can't be confused with another process, concept or molecule, we would completely ignore the mis-spelling when marking via a Level of Reponse MS.

Reply 10

macpatgh-Sheldon

Original post by Reality Check

Hi, thanks for this comment @Reality Check; I was under the impression that in the synoptic Q, there were 2-3 marks assigned to command of English and logical flow of ideas.

Reply 11

Reality Check

Original post by macpatgh-Sheldon

Hi, thanks for this comment @Reality Check; I was under the impression that in the synoptic Q, there were 2-3 marks assigned to command of English and logical flow of ideas.