GN311 Homeworks 7-9

Which of the following statements are true of the poly(A) tail added to the 3" end of eukaryotic mRNA? a) translates into a long stretch of repeated amino acids, b) stabilizes mRNA transcripts in the cytoplasm, c) folds into a cloverleaf structure, d) facilitates the attachment of the ribosomes to the mRNA, e) contains introns and exons

b) stabilizes mRNA transcripts in the cytoplasm and d) facilitates the attachment of the ribosomes to the mRNA

What component/protein/subunit is present in the holoenzyme but is not present in the core enzyme in prokaryotes?

sigma

What are the components of a nucleoside?

sugar + base

What are the components of a nucleotide?

sugar + base + phosphate

For a sequence of mRNA, how many reading frames are possible?

three

In eukaryotic DNA replication, what is the role of licensing factor?

to ensure all DNA is only replicated once

If the nucleosome core occupies 147 bp of DNA and the organism has a linker DNA length of 43 bp, then what is the maximal number of nucleosomes that can occupy a 10962 bp segment of DNA? Your answer must be a whole number.

(147+43)/10962 = 57.69 --> ~57

If the nucleosome core occupies 147 bp of DNA and the organism has a linker DNA length of 87 bp, then what is the maximal number of nucleosomes that can occupy a 14564 bp segment of DNA? Your answer must be a whole number.

(147+87)/14564 = 62.24 --> ~62

What is the distance between base pairs?

.34 nm

Regarding transcription in prokaryotes, list the 4 steps and if they require the holoenzyme or core enzyme for proper completion.

1. Template Binding - holoenzyme, 2. Initiation - holoenzyme, 3. Elongation - core enzyme, 4. Termination - core enzyme

How many base pairs are in one turn of DNA?

10 bp

If a DNA molecule consists of 15% Adenine, what is the % of each of the other bases?

15% Adenine, 15% thymine, 35% cytosine, and 35% guanine

How many hydrogen bonds are between adenine and thymine?

2 hydrogen bonds

How many hydrogen bonds are between guanine and cytosine?

3 hydrogen bonds

In transcription, to which end of the elongating strand are nucleotides always added?

3'

All DNA polymerases synthesize new DNA by adding nucleotides to the _____ of the growing DNA chain.

3' -OH

Antiparallel describes the fact that one DNA strand reads 5' to 3' and the other reads __________ if one reads the sequence from left to right across the molecule.

3' to 5'

If one strand of a double stranded DNA molecule has the sequence below, what is the sequence of the complementary strand? Label the ends of the strand. 5' - GTACCAGTT - 3'

3'- CATGGTCAA -5'

What is the distance for 1 turn of DNA?

3.4 nm

If a DNA molecule is 300 bp long and has 20 complete turns, then is the DNA positive supercoiled, negative supercoiled, or neither?

300 bp/10bp = 30 bp/turn. 30 bp > 20 bp so the DNA is underwinded (negative supercoiled).

For the following tRNA anticodon, list the possible codon(s) each could base pair with and their corresponding amino acids. 3' AAU 5'

5' UUA 3' = leu(L) and 5' UUG 3' = leu(L)

Identified DNA as the transforming principle

Avery, McCarty, and MacLeod

Identified that DNA for yeast consisted of equal amounts of purines and pyrimidines

Chargaff

Used x-ray diffraction to determine that DNA was helical, distance between base pairs, length of one turn of DNA, and diameter of DNA

Franklin and Wilson

Demonstrated the phenomenon of transformation, but did not identify DNA as transforming principle

Griffeth

Which of the following enzyme or enzymes do aid in unwinding of DNA for replication? Transferase, Primase, Synthetase, Gyrase, Helicase, single-stranded binding proteins

Gyrase, Helicase, single-stranded binding proteins

In a typical eukaryotic cell, would you expect to find more molecules of the H1 histone or more molecules of the H2A histone?

H2A

Identified DNA as the genetic material in bacteriophages

Hershey and Chase

What are the main differences of eukaryotic replication from prokaryotic replication?

In eukaryotes, a) there are many origins of replication, b) the origins must be licensed for replication, c) is linear instead of circular, d) has lots of different DNA polymerase molecules with various roles, e) replicates the telomeres, and f) nucleosome assembly immediately follows replication

First to isolate DNA

Miescher

Demonstrated that changes in DNA and protein are co-linear

Yonofsky

Anticodon: 3' U C I 5' Could this tRNA conform to the nearly universal genetic code?

No. Codon(s): AGA, AGU, or AGC. AGU and AGC are ser(S) but AGA is arg(R)

Which of the following are required for transcription? Promoter, Ribonucleotides, RNA primers, Polymerase, DNA template

Promoter, Ribonucleotides, Polymerase, DNA template

In eukaryotes, which RNA polymerase(s) transcribes the genes that encode proteins?

RNA polymerase II

Telomeres exist to help with the __________ of the ends of eukaryotic chromosomes.

replication

A plectonic coil...

requires the strands to be unwound before they can be separated.

What component/protein/subunit is sometimes required for proper termination of transcription in prokaryotes?

rho

Determined the structure of DNA

Watson and Crick

Anticodon: 3' A G I 5' Could this tRNA conform to the nearly universal genetic code?

Yes. Codon(s); UCA, UCU, or UCC. All of these code for ser(S)

Does DNA polymerase III have a) 5'->3' polymerase activity, b) 3'->5' exonuclease activity, or c) 5'->3' exonuclease activity?

a) yes, b) yes, c) no

Does DNA polymerase I have a) 5'->3' polymerase activity, b) 3'->5' exonuclease activity, or c) 5'->3' exonuclease activity?

a) yes, b) yes, c) yes

Which of the following are characteristics of heterochromatin? a) contains few genes, b) usually contains condensed chromatin, c) hotspot for recombination, d) contains many actively transcribed genes, e) replicates early in S phase, f) seen in barr bodies

a, b, and f

Which of the following are characteristics of histones? a) highly conserved, b)negatively charged, c) bind to negatively charged DNA, d) eight histones and 147 bp of DNA are required to form the nucleosome core particle

a, c, and d

What enzyme is responsible for joining the tRNA molecule with its amino acid?

aminoacyl synthetase

In a typical eukaryotic cell, would you expect to find more molecules of the H2A histone or of the H3 histone?

same amount

During gel electrophoresis, the __________ DNA fragments migrate the fastest.

shortest

The bases directly across from one another in the DNA molecule are __________.

complementary

In eukaryotic cells, where does the basal transcription apparatus bind?

core promoter

In humans, telomerase activity is most likely to be found in which cells?

germ cells

Which one of the following is the main force stabilizing the DNA double helix?

hydrophobic interactions

As DNA is heated, UV absorption __________.

increases

Which of the following elements would NOT be typically found in an mRNA molecule? a) Start and stop codons, b)Protein-coding region, c) Promoter, d) 3′ untranslated region, e) 5′ untranslated region

just c) promoter

On which molecule is the Shine-Dalgarno sequence found?

mRNA

A portion of the template strand of DNA has the following sequence: 5'- ATA ATC GCG CGC ATG -3' Assume the first codon for the peptide begins with the first nucleotide of the portion of mRNA and there are no introns (May not start at AUG). Enter the mRNA and amino acid sequence below. Use the one letter abbreviations for the amino acids

mRNA codons: 5'- CAU GCG CGC GAU UAU -3' Amino acids: NH2 - H A R D Y - COOH

During gel electrophoresis, the DNA fragments migrate toward the __________ pole.

positive

What was originally thought to be the genetic material of organisms and what was its case?

proteins, which are very abundant and have a lot of variability. Nucleic acids was believed to be too simple to account for variability.