DNA Organistaion Flashcards
(17 cards)
what are the 3 different types of living things
bacteria
archaea
eucarya
what are the two groups the living things are put into
prokaryotes
eukaryotes
what are the prokaryotes
oldest forms of life and are often the simplest for. They are the most common organism which have no nucleus (before nucleus). bacteria and archaea come under this group
where do you find them
heat springs well over 100 degrees desicated areas like desserts subglacial leeks sea vents bottom of sea bed if we found life on another planet it would be this
How is DNA organized in prokaryotes
they have singular circular chromosomes that are loosely gathered into the nucleus (free in the cytoplasm). they also have smaller circular sections of DNA called plasmids which can carry extra coding
what are plasmids
small circular sections of DNA that are in the cytoplasm that can carry extra coding and can give the cell more functions
why does thinking of a phone work with prokaryotes
the chromosome is like the operating system of the ‘phone’- without it the phone wont work. the plasmids are like the apps - they give you extra things to do (extra functionality) and we can alter plasmids like writing a new app.
what do eukaryotes have that prokaryotes have not
nucleus and mitochondria
apart from bacteria and archaea what is everything else made of
1 or more eukaryotic cells
what is the advantages to eukaryotes of having a nucleus
it allows jobs to be carried out more efficiently by the cells as they have specific areas.
what are the disadvantages to eukaryotes of having a nucleus
if an organ fails there is no backup to do its jobs because each cell/organ has a certain role. e.g kidneys and filtering.
since our cells are so complex and have to be replicated perfectly, cell division takes a lot longer.
what are the deference in shapes of chromosomes in eukaryotes and prokaryotes
eukaryotes have linear chromosomes
prokaryotes have circular chromosomes
how is DNA organized in a eukaryote
they have linear chromosomal DNA which are tightly packed into the nucleus and have to be organized in a way that they wont tangle up. the DNA wraps itself around proteins called histones. they create something like ‘beads on s string’ which is then neatly stacked on top of each other
what charge do histones have and why
histones have a positive charge because they have to be able to stick to the DNA and we already know that the phosphate in DNA has a very powerful negative charge so histones need to be positive to form a bond
do eukaryotes have circular chromosomes?
yes but only in mitochondria and chloroplasts
what is so special about yeast
although yeast is a eukaryote it still contains plasmids. This is useful when it comes to genetic engineering because if we put some of our genetic material into a prokaryote then it might not do what we want it to do because they don’t contain all the special things we have.
what shape are the chromosomes in eukaryotes and prokaryotes
Linear in eukaryotes
circular in prokaryotes
