1B Flashcards
What does DNA stands for
deoxyribonucleic acid and it is used to store genetic info for repair and reproduction
what does RNA stand for
ribonucleic acid transfers genetic info from DNA to ribosomes
what is a nucleotide
type of biological molecule
what is a nucleotide made of
a pentose sugar
a nitrogenous base
a phosphate group
describe the nucleotide in DNA
pentose sugar is deoxyribose
4 bases are adenine, thymine, cytosine and guanine
describe the nucleotide of RNA
pentose sugar is ribose
4 bases are adenine cytosine guanine and uracil replaced thymine
what are a group of nucleotides called and how do they join
polynucleotide
condensation reactions
what type of bond is formed between nucleotides
ester and phophodiester is whole thing
describe the structure of DNA
Double helix
bases joined by hydrogen bonds
they have complimentary bases pairs- A-T- 2 bonds
C-G 3 bonds
equal amounts of DNA bases
describe the structure of RNA
single polynucleotide chain
A-U
C-G
much shorter then DNA
describe the process of DNA replication
1) DNA helices breaks hydrogen bonds between bases- unwinds the dna to form 2 strands
2) each original acts as a template for a new strand. complimentary base pairs mean free floating DNA is attracted to exposed bases
3)condensation reaction happens to join nucleotides of new strands together- catalysed by dna polymerase to form new hydrogen bonds
4) each new strand contains one new and one original
why is DNA rep described as semiconservative
this is because it contains 1 new strand and one old
what is meselson and stahl evidence for semi-conservative
look in revision guide
why is water vital to living organisms
its a metabolite so it is important it lots of metabolic reactions
its a solvent
temperature control
very cohesive
describe the structure of water
consists of 2 hydrogen and 1 oxygen joined by shared electrons
its is polar because of the slightly negative and slightly positive charges
attraction is called hydrogen bonding
what is meant by water being a good metabolite
means its involved in condensation and hydrolysis reaction as a water molecule is needed
what is meant by a high latent heat of vaporisation and why is it important
takes alot of energy to break hydrogen bonds between water molecules
this is useful to water loss through evaporation to cool them down
what is meant by specific heat capacity and why is it important
this is the amount of heat needed to cause a temp change. this acts as a buffer against sudden changes
it is important to keep conditions stable within the cell so that it can keep normal function e.g optimum temp for enzyme
what id adhesion
tendency of water molecules to attract other substances- allows water droplets to stick to surfaces of leaves to prevent evaporation
what is cohesion
water molecules sticking together it allows water to be transported
why is water a good solvent and why’s it important
water surrounds ion and dissolves it this allows chemicals to be carried around the body
why is transparency important
means light can pass through easily
what does ATP stand for
adenosine triphosphate
what is the equation for adenine triphosphate to adenine diophosphate
ATP+H20=ADP+PI hydrolysis
ADP+PI=ATP condensation
