chapter 8 objectives

Question 1

what is the griffith experiment; role in discovering DNA

Answer 1

s. pne could either be smooth with capsule (more virulent) or rough without capsule

Question 2

contribution of oswald with streptococcus pneumoniae

Answer 2

found that animals survived when they targeted DNA and that DNA was key to transformation of rough to smooth

Question 3

overview of hershey chase experiment

Answer 3

proved that dna was hereditary material becayse when bacteriophages infect host only their DNA enters cell

Question 4

contributions of watson and crick

Answer 4

they founded the structure of DNA shape (double helix)

Question 5

4 nitrogenous bases in rna

Answer 5

purines: adenine and guanine
pyrimidines: uracil, cytosine

Question 6

sugar in rna

Answer 6

ribose

Question 7

dna vs rna

Answer 7

function: molecule of inheritance (d) protein synthesis (r)
location: nucleiod (d) proteins (r)
bases: a,g,c,t (d) a,g,c,u (r)
sugar: deoxyribose, ribose
structure: double stranded vs single stranded

Question 8

central dogma

Answer 8

DNA–> RNA–> proteins

Question 9

why is dna semi conservative

Answer 9

one strand is used as a template, while the other remains as an original strand

Question 10

2 types of bacterial dna replication

Answer 10

bidirectional replication:
rolling circle replication

Question 11

steps of bacterial dna replication

Answer 11

topoismerases unwinds dna, helicases breaks down bonds, binding proteins keep strands apart, dna poly III adds nucleotides, rna primase adds primers, ligase brings together okazaki fragments

Question 12

what direction does dna polymerase II read

Answer 12

it reads in a 3’ to 5’ direction

Question 13

synthesis of leading/lagging strands during dna replication

Answer 13

leading strand is sythesized 5’ to 3’ while lagging strand is synthesized 3’ to 5’

Question 14

enzymes and the role they play in dna replication

Answer 14

Helicase: unzipping the DNA helix
Gyrase: helping to untangle the DNA supercoils
Primase: synthesizing an RNA primer
DNA polymerase III: adding bases to new DNA chain; proofreading the chain for mistakes
DNA polymerase I: removing primer, closing gaps, repairing mismatches
Ligase: final binding of nicks in DNA during synthesis and repair
Topoisomerases I and II: supercoiling and untangling

Question 15

structural/functional differences between rna and dna

Question 16

transcription

Answer 16

dna–> rna
initiation: sigma determines transcription starting pt
elongation: sigma released, rna polymerase moves along strand
termination: termination sequence tells rna polymerase to stop adding

Question 17

three types of rna involved in traslation

Answer 17

mRNA, tRNA, rRNA

Question 18

wobble

Answer 18

multiple codons can code for the same amino acid because only the first two nucleotides are required to encode the correct amino acid, the third will not change its sense

Question 19

codon

Answer 19

3 bases that code for one amino acid

Question 20

anticodon

Answer 20

carried by tRNA and contains complementary nucleotides to the codon in mRNA

Question 21

three start and stop codons

Answer 21

start: AUG
stop: UAA, UAG, and UGA

Question 22

locations of promoter, start codon, and a/p sites during translation

Answer 22

promoter: DNA
start: on mRNA
A site: holds the next amino acid
P site: holds growing polypeptide chain

Question 23

transcription/translation bacteria vs. eukaryotic

Answer 23

eukaryotic: transcription happens in nucleus, separate process, translation on 80s ribosomes
bacteria: happens simultaneously in cytoplasm using 70s ribosomes