Qualification > Sciences
Edexcel BIOLOGY Doubts!!!!
-Cornea:
Captive breeding programs-this is done by keeping animals in zoo or in national parks,keeping a record of their genetic information in the studbooks and allowing them to breed with individuals which is different from the previous mating or with different species increasing genetic diversity and gene pool size the genes are swapped with different zoos to maxmise genetic variation hence increasing allele frequency and providing right conditions for them to mate they sometimes use the cross cloning species after this process they are then re-introduced into the wild to restore their original population and to acclamtize to their original habitat.By keeping them in the zoos they increase the public awareness of the people and keeps them away from the predators and poachers (the reasons of their extinction in the first place )
-Cornea:
Point 6- one of the most important characteristic of meiosis that it produce tetra(4 cells) which contains haploid number of chromose 23 yes the sperms has a nucleus but it contains only 23 chromosome so during fertilization it can restore the diploid number ,and the gametes are produced by MEIOSIS !
-Cornea:
I forget to mention this in my last post
If the cell is damaged or repair the new cells must have the same structure and function as the old ones or else the tissue won't function as effective as before MITOSIS ensures this :D
-Cornea:
Don't mix up between kingdoms and domains consider them as two separate things the domains are archae bacteria and eukaryotes you don't need to know much just a couple of differences between each of them and you need to know that ARCHAE AND EUKARYOTES are more closely related than ARCHAE AND BACTERIA :D
-Cornea:
the last point - you need to obtain the plant material first crush it 10 cm^3 of industralised denatured alcohol to kill any bacteria that might be contaminated with the extract shake the test tube from time to time pippete 0.1 cm^3 of plane extract onto filter paper discs and place it in a petri dish incubate it at 25 degree Celsius for 24 hours tape the petri dish but do not tape it in a way that might lead to the growth of anaerobic bacteria and of course you know that the petri dish contains agar with a microbial lawn growing on it .The plant extract will diffuse from the paper disc and it will inhibit the growth of the bacteria to a certain extent this area which appears to be clear is known as the ZOI(ZONE OF INHIBITION) it can be measured using a ruler if it regular and then repeat the measurements and take the average if it's irregular take the readings from different angles or there is another method in which u use the graph papers and counting the surface area(which i have no idea about it)
and about the manila you don't need to know the name of different fibers you just to need to know how to extract the plant fibers and how to measure the tensile strength !
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