Biochemistry 2280A Chapter Notes - Chapter 7: Cytosol, Reading Frame, Peptidyl Transferase

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periwinklefrog466

22 Nov 2017

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From rna to protein mrna sequence is decoded in sets of 3 nucleotides. Transcription as information transfer is easy to understand- dna and rna are similar & dna acts as a template for rna synthesis. Some trnas only require accurate base-pairing at the first 2 positions of the codon & can tolerate a mismatch (wobble) at the third: explains why many alternative codons only differ in the third position. Large subunit shifts forward, moving the previous trna on the p site to the e site. Ribosomes are ribozymes: ribosomes contain 2/3 rna and 1/3 protein. Small subunit binds to the 5" end of mrna molecule (marked by the 5" cap) Small subunit moves along the mrna until it encounters the first aug. Several translation initiation factors dissociate to make room for the large subunit to bind. For pro, the ribosomes can also start translating before the transcription of the mrna is complete.

Related Questions

Fill in the blank. Elongation during translation does NOT involve ____________.

Question 16 options:

	the translation of codons according to the genetic code
	the formation of bonds catalyzed by the ribosome
	complementary base pairing between RNA molecules
	amino acids being linked together in a polypeptide
	reading the DNA template 3' to 5'

For a given gene, what establishes the reading frame for translation?

Question 17 options:

	the location of the enhancer relative to the gene
	the first three nucleotides at the 5' end of the mRNA
	the first three nucleotides at the 3' end of the mRNA
	the start codon in the mRNA
	the location of the promoter relative to the gene

Which of the following is the LEAST likely direct consequence of a substitution mutation?

Question 18 options:

	changing the length of a protein coded for by a gene
	changing one amino acid in a protein
	creating a stop codon
	eliminating a start codon
	changing the length of the DNA molecule containing a gene

Suppose that the pre-mRNA transcript from a eukaryotic gene is 30,000 nucleotides long, and the gene codes for a sequence of 300 amino acids. What is the best explanation for the relationship between these numbers?

Question 19 options:

	only the first 900 nucleotides of the pre-mRNA transcript are translated
	it takes 100 nucleotides to specify a single amino acid
	300 of the nucleotides in the transcript are important, and the rest are "junk"
	only the last 900 nucleotides of the pre-mRNA transcript are translated
	large portions of pre-mRNA transcripts are cut out during RNA processing

Suppose an individual is born into a population with a novel mutation. Is the new mutation an evolutionary change, and why?

Question 20 options:

	no, because it is not a big enough change to count
	yes, because new mutations are always adaptive
	yes, because the appearance of a new genetic variant is a genetic change in a population
	no, because not enough individuals have the mutation for it to matter
	no, because most mutations are not adaptive

RNA has many different roles in gene expression. Check all thatapply.

mRNA defines the polypeptide to be formed

DNA defines the polypeptide to be formed

rRNA, along with proteins, forms the ribosome

mRNA delivers the appropriate amino acid to the ribosome

tRNA delivers the appropriate amino acid to the ribosome

Translation is appropriately named because the process transfersthe code from DNA to RNA, though in complementary fashion.

True

False

The template strand is to the sense strand as the coding strandis to the antisense strand.

True

False

The phenomenon symbolized by DNA â RNA â Protein is referred toas the Central Dogma because it is true for all organisms.

True

False

The reading frame refers to the selection of the correct tripletof nucleotides by selecting the correct beginning point. If thebeginning point is wrong, all nucleotides will be clustered intothe wrong codons.

True

False

Activating enzymes need to recognize only one anticodon.

True

False

coffeehorse275

A single strand of bacterial DNA contains the base sequence:

5â CGT GTA TTC ACA CTG GTG AGC CAC TAT CGT ATA TTC CCT GAG TGA GCA TTG 3â

A. What is the complementary sequence? Write this sequence below with its polarity.

B. Write the 6 reading frames below (group nucleotides in codon, i.e. ACGCVGTG â¦ = ACG CVG TG. ...) ?

C. Is there an open reading frame (ORF) at least 4 codons long? If yes, what is the reading frame (+1,+2,+3, -1,-2 or -3) for the ORF?

D. Does the strand of the DNA given in (a) serve as the coding strand or template strand for the synthesis of the RNA transcript?

Biochemistry 2280A Chapter Notes - Chapter 7: Cytosol, Reading Frame, Peptidyl Transferase

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