Module 2.3 EXTRA Flashcards
EXTRA
How to use methyl green pyronin stain to show the distribution of DNA and RNA within cells
-DNA takes up the methyl green and RNA takes up the pyronin . You can make slides of root tips of bean or onion roots to stain them to show DNA is in the nuceli and RNA is in the cytoplasm (and nucleous ) .
How to use methyl green pyronin stain to show the distribution of DNA and RNA within cells (1)
Use a clean sharp scalpel or raor blade and cut thin longitudinal section sof the tip of the fixed root . Each section should be about mm long .
How to use methyl green pyronin stain to show the distribution of DNA and RNA within cells (2)
Place the sections on a microscope slide and cover with methyl green pyronin stain for 30 minutes .
How to use methyl green pyronin stain to show the distribution of DNA and RNA within cells (3)
Use a pipete to remove the stain , and then add distilled water to the root tips .
How to use methyl green pyronin stain to show the distribution of DNA and RNA within cells (4)
change the water several times to wash the root tip sections .
How to use methyl green pyronin stain to show the distribution of DNA and RNA within cells(5)
add a drop of distilled water and a coverslip .
How to use methyl green pyronin stain to show the distribution of DNA and RNA within cells (6)
observe cells in the sections under low power and then under high power .
How to use methyl green pyronin stain to show the distribution of DNA and RNA within (7)
you should see DNA stained blue - green in cells nuclei and RNA are stained red in the cytoplasm.
why is protease enzymes added
to break up proteins associated with DNA / histones .
for forming dna why is temp key
temperature has to be low enough to reduce enzyme ctivity .
why does every third amino acid being glycine help
glycine small r group so allows closeness when teisting tightly , corss links and staggerrd
misconception cleared up about the strucutrue of dna
-SUGAR phospahte ackbone held with phsophodiester bonds .
-HDYORGEN BONDS , between compeltnary bases
-phosphodiester bonds between nucloetined .
Polnucleotide strans are antiparallel .
similarities / differen ces between atp and dna
- both contain nucleotide
pentose suar
atp two pshophate
BUT
atp has ribose instead of deoxyrbibose
what does completemnaty base pairing suggest
ATCG , is correct butalso the idea
a PURINE can only bind witha purine as they are on different strands .
-IF one base is nown ir can onl bind with one other base .
AT 2bonds
CG 3 BONDS BOTH SUE HYDGEN BONDS .
FOR SOMETHIGN to be visible using light m icorscope what dye should you use
methlene blue
do phosphodiester bonds break during dna replkciation and re they in the same direction
-phosphodiester bonds DO NOT BREAK onl hdyorgen bonds .
PHOSPHODIESTER BONDS OCCUR IN THE SAME REACTION .
URACID adenine all example of
Pyrimidines .
what happens in semi conseervative replicaiton
after two replications two DNA moelcules will have one original and onenew srand .
-Two dna moleucles will have two new strands .
-After three replications there are ight DNA moelcules , onlyt wo of which have trands from the original DNA .
what stage of the cell cycle does dna repliction occur in
s phse / during nterpahse
why should every dell be replcilated exactly
every cell has to have the idenitcal gene content of the parent cell
what is the function of dna polymerase
dna polymerase forms new DNA from activated nucleotides by forming phophodeister bodns of complenary bases EXPOSED to nucleotides
What enzmes help with transcription of dna
gyrae and helicse
IGNORE THE RNA PLOYMERASE BIT .
how is peptide bond formed in transltion
via condensation reaction
ATP IS needed .
what is the fucntion of ligase
it joins fragemns amde on LAGGING STAND / formaiton of phosphodiester bonds between sugar + phospahte .
what may a change in DNA BASES DO
transcribed change in mrna codons , mamy alter the sequence of amino acids ina protein ,t herefore altering the primary strcuture .
-may chage the bonds in r groups of amino acids to other r groups of amino acids disuflide
-therefore tertiary sturcutre (quaternary also if needred ) also altered ,t herefore not carryign out funciton .
how may an adult insect and a larva have diferent protein sturcuture
larval gene off in adult and adult geen off on larva vice cera .
rna product of one gene may udnero different post tranciption and trnaslational modification in alrva and in adults .
egens for lysosome on more in adult exampe ..
wht ios meant by degenrae geneti code
64 different combiantions of bases but only 20 ma mino zi ds so some amino acids ode for more thn one amino acid .
thids REDUCES the chance of point mutations in the amino acid eqnece therefore tertiary strucutre is unafected .
