Nucleic Acid Flashcards
what structures are made from DNA and where are they found
double helix structures (chromosones) are made from DNA and are found in the nucleus
what type of protein is also contained in a chromosone and what does it do
histones
holds DNA during replication
what are the monomers of DNA and RNA called
nucloetides
what reaction joins the components of a nucleotide together
condensation reaction to form phosphodiester bonds
name the 4 nitrogenous bases in DNA
cytosine
guanine
thymine
adenine
name the 4 nitrogenous bases in RNA
cytosine
guanine
adenine
uracil
what is one side of a chromosone called
a chromotid
what two things make up a chromotid
DNA tightly coiled round a histone
what 3 parts make up DNA
phosphate group
deoxyribose sugar
nitrogous base
what are the differences between DNA and RNA
DNA
double strand
A,T,C,G
dexoyribose
very stable
contains hereditary material
RNA
single strand
A,U,C,G
ribose
used in protien synthysis
short lived
how many more oxygen does RNA have than DNA
1
how many hydrogen bonds can form between base pairs
3 between C and G
2 between A and T
is DNA parallel or antiparallel
anti parallel
will C-G bonds or A-T bonds be stronger and why
C-G becuase they have more hydrogen bonds
why is it a good thing that the DNA is very stable
to passes from generation to generation and rarely mutates
why is it good that they two polynucleotide strands are linked only by hydrogen bonds
during replication and protein synthesis strands are easily separated
why is it a good thing that DNA is a huge molecule
it can store lots of information
why is it a good thing that DNA is coiled into a double helix with a sugar - phosphate backbone
the information is protected a bit within the coil
why are base pairing good in DNA
allows DNA to replicate and transfer RNA as info
what does in vivo mean
by a living organism (rather than a lab )
how was the fact that DNA was hereditary material tested
mice were injected with harmful and safe pneumonia
both mice remained healthy
then the mice are given both types of pneumonia and they become ill
what were the three theories that explained why the mice became ill from the two types of pneumonia
- experimental error ( harmful pnemonia wasnt killed )
- safe bacteria mutated into harmful bacteria
- pneumonia is caused my toxins. harmful bacteria knows how to kill but is dead so cant. safe bacteria doesnt know how to kill but is alive. but this info may have been transfered to the safe pneumonia making it capable to kill
how was theory 3 tested in pneumonia in mice
harmful bacteria was purified and added to safe bacteria
the substances which then became harmful was DNA because the info had been passed on in replication
how was DNA as a hereditary material tested with a virus
the proteins and DNA were taken from a virus and radioactive material was attached
they both infected a bacteria
the bacteria was tested to see which one became radio active
the answer was the one with radio active DNA
what 4 conditions must be met for DNA replication to happen
1 a pool of free nucleotides must be present
2 both strands of DNA must be copied as a template
3 the enzyme DNA polymerase and DNA helicase must be present
4 atp needs to drive the process
what type of replication is it and why
semi conservative
because one original strand remains in tact and a new complementary strand is formed
how is the leading strand (towards the fork)
replicated
continuously
how is the lagging strand (away from the fork) replicated
discontinuously
explain the meselson and stahl experiment
grew ecoli in heavy nitrogen
all DNA was heavy nitrogen
moved ecoli to light nitrogen so any new DNA would be light nitrogen
after 1 generation bacteria and DNA was removed
do another cycle and repeat
the samples were spun in a centrifuge so that heavy nitrogen would fall to the bottom
what were the results of meselson and stahls investigation
after first spin - 50 % heavy 50% light nitrogen
after second spin - some heavy but most light
how did meselson and stahls investigation support semi conservative replication
because after more spins occured the amount of light DNA increased proportionally
what is the word equation for the conversion of ATP to ADP
atp - > adp + pi + energy
(hydrolised)
what is the word equation for the conversion of adp to atp
adp +pi -> atp
(phosphorylation)
what two organelles is atp synthesised in
mitrochondria
chloroplast
why is atp and immediate energy source
it is a universal currency
it is released instantly in small amounts
5 main biological functions of atp
1 lower activation energy of molecules because of the inorganic phosphate released during hydroylsis making other compounds reactive
2 metabolic processes
3 changes the shape of carrier proteins in the membrane making active transport possible
4 filaments of muscles slide past each other and shorten the muscle fibre
5 formation of lysomes
why is glucose not a good immediate source of energy
it takes a while to release energy and there is a lot of waste
hydrogen ions info
comes from acids breaking down
high h + conc = low pH
could denature enzymes
magnesium ions info
creates chlorophyll
calcium ion info
nerve communication
releasing nurotransmitter s
muscle contraction
phosphate ion info
cell membrane
phospholipids
atp
what does adhesion mean
water making hydrogen bonds with other structures
what does cohesion mean
water making hydrogen bonds with water
how do water molecules have hydrogen bonds
the molecules are attracted to the sligh opposite charge in the other molecules
but this means bonds are broken easily
why is waters high spesific heat capasity important
acts as a buffer to sudden changes in temp so stops enzymes denaturing, keeps conditions for fish stable
why is water acting as a solvent good
it dissolves things so they can be transported
why is water being transparent good
sea weed and photosynthesise
why is the density of ice good
it is denser than water so acts as an insulator
why is high specific latent heat of water good
it takes a lot of enegry to change state so helps with cooling down our bodies
why are hydrogen bonds in water good
it creates surface tension and allows transport in the xylem
where are inorganic ions found in the body
cytoplasm
what is the function of iron in the body
production of hemoglobin in the red blood cells
what is the function of sodium in the body
co transport of glucose and amino acids across the cell membrane
muscle contractions
nerve impulses
Describe dna replication
1 dna helicase breaks hydrogen bonds
2 exposed base pairs attract new complementary bases and they try and make temporary hydrogen bonds
3 dna polymerase makes new strand
4 new phosphdiester bonds are formed
5 eventually dna separates into two strands of dna
