Module 2.3 EXTRA

Question 1

How to use methyl green pyronin stain to show the distribution of DNA and RNA within cells

Answer 1

-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 ) .

Question 2

How to use methyl green pyronin stain to show the distribution of DNA and RNA within cells (1)

Answer 2

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 .

Question 3

How to use methyl green pyronin stain to show the distribution of DNA and RNA within cells (2)

Answer 3

Place the sections on a microscope slide and cover with methyl green pyronin stain for 30 minutes .

Question 4

How to use methyl green pyronin stain to show the distribution of DNA and RNA within cells (3)

Answer 4

Use a pipete to remove the stain , and then add distilled water to the root tips .

Question 5

How to use methyl green pyronin stain to show the distribution of DNA and RNA within cells (4)

Answer 5

change the water several times to wash the root tip sections .

Question 6

How to use methyl green pyronin stain to show the distribution of DNA and RNA within cells(5)

Answer 6

add a drop of distilled water and a coverslip .

Question 7

How to use methyl green pyronin stain to show the distribution of DNA and RNA within cells (6)

Answer 7

observe cells in the sections under low power and then under high power .

Question 8

How to use methyl green pyronin stain to show the distribution of DNA and RNA within (7)

Answer 8

you should see DNA stained blue - green in cells nuclei and RNA are stained red in the cytoplasm.

Question 9

why is protease enzymes added

Answer 9

to break up proteins associated with DNA / histones .

Question 10

for forming dna why is temp key

Answer 10

temperature has to be low enough to reduce enzyme ctivity .

Question 11

why does every third amino acid being glycine help

Answer 11

glycine small r group so allows closeness when teisting tightly , corss links and staggerrd

Question 12

misconception cleared up about the strucutrue of dna

Answer 12

-SUGAR phospahte ackbone held with phsophodiester bonds .

-HDYORGEN BONDS , between compeltnary bases

-phosphodiester bonds between nucloetined .

Polnucleotide strans are antiparallel .

Question 13

similarities / differen ces between atp and dna

Answer 13

1. both contain nucleotide
   pentose suar
   atp two pshophate

BUT

atp has ribose instead of deoxyrbibose

Question 14

what does completemnaty base pairing suggest

Answer 14

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 .

Question 15

FOR SOMETHIGN to be visible using light m icorscope what dye should you use

Answer 15

methlene blue

Question 16

do phosphodiester bonds break during dna replkciation and re they in the same direction

Answer 16

-phosphodiester bonds DO NOT BREAK onl hdyorgen bonds .

PHOSPHODIESTER BONDS OCCUR IN THE SAME REACTION .

Question 17

URACID adenine all example of

Answer 17

Pyrimidines .

Question 18

what happens in semi conseervative replicaiton

Answer 18

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 .

Question 19

what stage of the cell cycle does dna repliction occur in

Answer 19

s phse / during nterpahse

Question 20

why should every dell be replcilated exactly

Answer 20

every cell has to have the idenitcal gene content of the parent cell

Question 21

what is the function of dna polymerase

Answer 21

dna polymerase forms new DNA from activated nucleotides by forming phophodeister bodns of complenary bases EXPOSED to nucleotides

Question 22

What enzmes help with transcription of dna

Answer 22

gyrae and helicse

IGNORE THE RNA PLOYMERASE BIT .

Question 23

how is peptide bond formed in transltion

Answer 23

via condensation reaction
ATP IS needed .

Question 24

what is the fucntion of ligase

Answer 24

it joins fragemns amde on LAGGING STAND / formaiton of phosphodiester bonds between sugar + phospahte .

Question 25

what may a change in DNA BASES DO

Answer 25

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 .

Question 26

how may an adult insect and a larva have diferent protein sturcuture

Answer 26

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 ..

Question 27

wht ios meant by degenrae geneti code

Answer 27

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 .