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Biology aqa

What is the importance of transfers of substances within organisms and between organisms and their environment
- entry of pathogens
- Gas exchange
- Haemoglobin
- immune response
- replication of DNA

This is an essay question but I don’t really understand what I could write about each of those examples given above. Please share any ideas you may have

Reply 1

macpatgh-Sheldon

- entry of pathogens: (between organisms) - e.g. bacteria need to enter host to live as a parasite
.......…...…………………………………………….. plasmodium (malaria parasite) needs to transfer from blood of infected host to vector (female Anopheles mosquito) then to blood of victim.
- Gas exchange - O2 needs to reach respiring cells; CO2 needs to be extruded to atmosphere to avoid collection in body, which would cause acidosis (CO2 + H2O ----> H2CO3 [carbonic acid]).
- Haemoglobin - for transfer of O2 to tissues from lung - talk about its structure, the adaptation features of red cell, etc
- immune response - immune cells need to travel to site of infection to recognize 2foreign" material and engulf (T cells or macrophages) OR produce antibodies (Ab)
....…...………….. Ab need to travel from production site to location of e.g. bacteria.
- replication of DNA - copied DNA needs to move to nuclei of daughter cells in mitosis

.......…………………. mRNA needs to transfer from nucleus via pores to RER.

THIS WILL ONLY GET YOU ABOUT max 10 out of 20 marks.

OTHER MARKS:
A) transfer of food material: amino acids, glucose, copper (ceruloplasmin), iron (iron binding protein), fatty acids (mention chylomicrons)
B) transfer of waste material to kidneys for excretion e.g. urea [breakdown product of proteins], creatinine, uric acid [breakdown of RNA + DNA via xanthine], excess water, H+, HCO3-, drugs, etc.
C) transfer of hormones from endocrine organs to body by blood - rich blood supply of e.g. adrenal
D) transfer of pollen by wind; animals (bees)
E) seed dispersal by animal eating fruit and pooing seeds; water (coconut).