biological molecules: nucleic acids

Question 1

what are nucleic acids

Answer 1

large molecules that were discovered in cell nucleic
DNA and RNA
have roles in the storage and transfer of genetic information and the synthesis of polypeptides

Question 2

components of an individual nucleotide

Answer 2

pentose monosaccharide containing 5 carbon atoms
phosphate group, an inorganic molecule that is negatively charged
nitrogenous base

Question 3

bonds of nucleotides

Answer 3

linked together by condensation reaction to form polynucleotides
phosphate group at the fifth carbon of the pentose sugar (5’) forms a covalent bond with the hydroxyl group at the third carbon (3’) of the pentose sugar
these bonds are called phosphodiester
can be broken by hydrolysis which is the reverse of condensation reaction

Question 4

deoxyribonucleic acid DNA

Answer 4

the sugar in dna is deoxyribose contains one less oxygen then RNA
the nucleotides in DNA each have 1 of 4 different bases

Question 5

groups and bases of DNA

Answer 5

pyrimidines - the smaller bases contain a single carbon ring structure
thymine and cytosine
purines - the larger bases which contain a double carbon ring structure
adenine and guanine

Question 6

the double helix

Answer 6

DNA molecule is made up of 2 strands of polynucleotides coiled togther in a helix
2 strands are held together by hydrogen bonds between the bases
each strand has a phosphate group at one end (5’) and a hydroxyl group at the other (3’)
strands are arranged in opposite directions - anti parallel

Question 7

base pairing rules

Answer 7

adenine and thymime - 2 hydrogen bonds
guanine and cytosine - 3 hydrogen bonds
sequences of bases along DNA strand carries the genetic information of an organism in the form of a code

Question 8

what is RNA and its primary function

Answer 8

ribonucleic acid transfers genetic informtion from DNA to the proteins in the body
involved in protein synthesis translating genetic code from DNA to be used in cellular functions

Question 9

how is genetic information passed through generations

Answer 9

dna stores all the genetic info needed by an organism and passes down through generation
found in chromosomes made up of hunreds of genes but cant leace the nucleus

Question 10

why cant DNA directly participate in protein synthesis outside the nucleus

Answer 10

dna is a long molecule that cant leave the nucleus so rna copies sections of dna and transports the info outside the nucleus

Question 11

how does mRNA solve the issue of DNA not leaving the nucleus

Answer 11

mRNA transcribes a short section of DNA and transports it outside the nucleus for protein synthesis
mRNA molecules are much shorter then chromosomes

Question 12

what base does rna replace

Answer 12

uracil replaces thymine

Question 13

how are RNA polymers formed

Answer 13

rna nucleotides form polymers through phosphodiester bonds

Question 14

what happens to RNA after protein synthesis

Answer 14

rna molecules are degraded in the cytoplasm phosphodiester bonds are broken and rna nucleotides are reused

Question 15

dna extraction steps

Answer 15

1. grind sample in mortar and pestle to break down cell walls
2. mix sample with detergent to break down cell membrane and release contents into solution
3. add salt to break hydrogen bonds between dna and water molecule
4. add protease enzyme to break down the proteins associated with DNA
5. add layer of alcohol on top of sample to cause dna to precipitate out of solution
6. dna will be seen as white strands forming between sample and layer of alcohol
   can be picked up by spooling it onto a glass rod