DNA/RNA

Question 1

What were the results for the mice injections in the Griffith Experiment?

Answer 1

live pathogenic strain=mice die
live nonpathogenic strain (no protein coat)=mice live
heat-killed pathogenic strain=mice live
mix of heat-killed pathogenic and nonpathogenic strains=mice died

Question 2

What is transformation?

Answer 2

the transfer of genetic material from one cell to another which can alter the genetic makeup of the recipient cell

Question 3

What is a bacteriophage?

Answer 3

a virus that attacks bacteria

Question 4

What is a purine?

Answer 4

a base-double carbon ring. Adenine and Guanine

Question 5

What is pyrimidine?

Answer 5

base-single carbon ring. Cytosine, thymine (uracil in RNA)

Question 6

phosphodiester bond

Answer 6

holds sugars to phosphates on the sides of the DNA (RNA)

Question 7

hydrogen bond

Answer 7

holds the bases together to make the “rings” of the DNA ladder

Question 8

Chargaff’s Rule

Answer 8

A’s pair with T’s; G pairs with C’s
There is always an equal portion of A’s to T’s and of G’s to C’s. A:T and G:C
The base pairing is also known as being complementary

Question 9

semiconservative replication

Answer 9

the way DNA actually copies itself. copying genetic information is complementary
DNA unzips- one side serves as the template for the new strand being built

Question 10

Conservative Replication

Answer 10

parent DNA stays intact and makes new copies of DNA

Question 11

Dispersive Replication

Answer 11

parent DNA is dispersed throughout new DNA so each strand is a mix of old and new

Question 12

What are the three things that replication requires?

Answer 12

something to copy-parental DNA molecules serve as a template
something to do the copying-enzymes
building blocks-nucleotides

Question 13

Where does replication begin?

Answer 13

replication forks

Question 14

What enzyme glues new nucleotides to the growing strands

Answer 14

DNA polmerase 3

Question 15

What is the RNA primer

Answer 15

the anchor. the enzyme RNA primase builds a piece of RNA primer about 10 RNA nucleotides long. DNA Polymerase 3 recognizes the primer and starts to build new DNA strand

Question 16

leading strand

Answer 16

the DNA strand elongating toward the replication fork

Question 17

continuous replication

Answer 17

new DNA is built continuously by simply adding nucleotides to the 3 end

Question 18

lagging strand

Answer 18

the DNA strand elongating away from the replication fork

Question 19

discontinuous replication

Answer 19

new DNA is built in pieces

Question 20

Okazaki Fragments

Answer 20

segments of DNA about 100-20 nucleotides long

Question 21

What unwinds the DNA

Answer 21

helicase

Question 22

how are DNA strands kept open?

Answer 22

single-strand binding proteins

Question 23

DNA polymerase 1

Answer 23

removes primers and fills in gaps between Okazaki fragments

Question 24

DNA Ligase

Answer 24

rejoins the parent strand

Question 25

DNA Gyrase

Answer 25

releases tension in the DNA

Question 26

Primosome

Answer 26

composed of primase and helicase and accessory proteins

Question 27

Describe the Griffith Experiment

Answer 27

Griffith was trying to make a vaccine against the flu which was thought at the time to be caused by a bacterium called Streptococcus pneumoniae The bacteria comes in two forms: virulent (disease causing), makes deadly polysaccharide coat that causes blood poisoning -"S" form nonvirulent- no polysaccharide coat -"R" form (shouldn't kill)

Question 28

rRNA

Answer 28

ribosomal RNA- makes up ribosomes and provides a place to make proteins

Question 29

mRNA

Answer 29

messenger RNA- long piece of RNA transcriped/made from DNA -a "xerox" copy of a gene which leaves the nucleus and goes to a ribosome to direct the making of a protein. copies genes in the nucleus and takes it to the ribosome in the cytoplasm so it takes it out of the nucleus

Question 30

Codons

Answer 30

genetic information exists in blocks of genetic information

Question 31

Nonsense Codons

Answer 31

code for nothing

Question 32

reading frame

Answer 32

the order in which the nucleotides of DNA are read

Question 33

Transcription

Answer 33

1. 1st phase of gene expression 2. when a sequence (piece) of DNA is transcribed into a mRNA sequence (piece) 3. RNA polymerase- the enzyme that starts transcription

Question 34

How does transcription happen?

Answer 34

RNA polymerase binds to a special binding site (PROMOTOR) RNA polymerase moves along the DNA strand into the gene as it encounters each DNA nucelotide, it adds the corresponding complimentary RNA nucleotide to the growing mRNA copy RNA polymerase arrives at a stop signal at the end of the gene and drops off the DNA new mRNA is released

Question 35

Initiation

Answer 35

start reading the mRNA copy

Question 36

elongation

Answer 36

bring amino acids to the protein chain and make it grow

Question 37

termination

Answer 37

release the protein from the ribosome

Question 38

What is the process of translation?

Answer 38

rRNA molecule binds to "START" codon of mRNA ribosome moves along mRNA, 3 nucleotides (1 codon) at a time tRNA gets its amino acid attached to it by protein tRNA's add their amino acids to growing protein chain ribosome goes until it encounters a STOP codon ribosome drops off of mRNA and releases the completed protein

Question 39

What does translation start with

Answer 39

the formation of an initiation complex

Question 40

What is the elongation process?

Answer 40

Ribosome exposes codon next to the start codon the tRNA carrying the corresponding amino acid binds its ANTICODON with the mRNA's codon with help of proteins called ELONGATION FACTORS The ribosomes rolls and exposed the next codon. The met-tRNA is in the old A SITE which is now called the P SITE. The newly exposed codon is in the A site. THe tRNA that matches the new exposed codon brings in its amino acid. Met joins to the newly added amino acid via a PEPTIDE BOND and its released from its tRNA Process repeats. Old P site is now an E site (empty) old a site is now the p site. new codon is exposed in the a site this continues, ribosomes moves along ribosome, exposing 3 nucleotides at a time (TRANSLOCATION)

Question 41

How are stop codons recognized?

Answer 41

proteins called release factors