the importance of microbes and how they can affect the lives of humans and other organisms Flashcards
the importance or microbes in humoral response
-in clonal selection, specific B cells bind to antigens on the surface of a pathogen
and are stimulated by the release of cytokines by helper T cells
-this causes the b cells to divide rapidly by mitosis to form clones in clonal expansion
-the B cell differentiates into plasma cells for the primary immune response as they secrete large amounts of monoclonal antibodies into the blood
-some B cells differentiate into B memory cells for the secondary immune response so upon reinfection antibody production is faster and at a higher concentration
-the humoral response has been manipulated into medicine as vaccines involve the injecting of weak or dead pathogens into the body to stimulate the production of memory cells against that specific antigen. this means the pathogen will be quickly destroyed upon reinfection
the importance of microbes in nitrogen cycle
-in nitrogen fixation the nitrogen fixing bacteria in the root nodules of legumes and free living bacteria in the soil use the enzyme nitrogenase to reduce gaseous nitrogen into ammonia. an example of this is the mutualistic bacteria rhizobium which forms a symbiotic relationship with the plant
-the rhizobium provides the plants with nitrogen compounds and the hyphae increase the surface area of the root network to increase the water uptake by osmosis
-in return the plant provides the bacteria with carbohydrates formed through photosynthesis
-in ammonification the saprobiotic microorganisms feed on the dead organisms and faeces to release ammonia ions back into the soil through breaking down organic nitrogen containing compounds
-in nitrification the ammonia ions are oxidised into nitrite ions by nitrifying bacteria and more nitrifying bacteria oxidise the nitrite ions into nitrate ions
-microbes enable nitrogen to be absorbed by plants in the form of nitrates which is integral for plant growth and production of essential compounds like proteins and DNA
the importance of microbes in vivo cloning
-restriction endonuclease which often come from bacteria are used to create a staggered cut at the recognition site on a DNA strand
-this creates sticky ends as there are exposed unpaired bases at each end of the DNA fragment
-the plasmid sourced from a bacterium is cut open using the same restriction endonucleases that was used to isolate the DNA fragment containing the target gene
-this ensures the sticky ends of the dna fragment and the plasmid are complimentary to each other
-the vector DNA and DNA fragment are mixed together with DNA ligase which joined the sticky ends together to form recombinant DNA
-in transformation the vector needs to be inserted into the host cell which is a bacteria where the gene in the DNA fragment will be expressed to create a protein
-bacteria are used as the host cell for in vivo cloning due to their ability to quickly duplicate in medium meaning large quantities of the desired gene are produced. this means that in vivo cloning allows large quantities of insulin to be produced rapidly to treat type 1 diabetes through injections.
the importance of microbes in succession
-seeds and spores are carried by the wind and land on exposed rock
-the first species to grow and colonise the land are referred to as pioneer species which are typically moss and lichens
-lichens are a mutualistic symbiosis between fungi and algae as the fungus release enzymes extracellularly to break down minerals in rocks which provides a source of mineral ions to the plant whilst the plant provides the fungus with carbohydrates produced from photosynthesis
-this enables the species to survive in harsh abiotic conditions at the start of succession
-as these pioneer species die and decompose, the dead organic matter forms humus which creates a basic soil
-this means the microbe are important for creating change in the abiotic conditions to allow small plants and grasses to colonise which increases biodiversity and make the environment more stable
