BIO SCI 93 Lecture Notes - Lecture 13: Reading Frame, Polysome, Transfer Rna

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olivecod766

19 Aug 2016

School

UC-Irvine

Department

Biological Sciences

Course

BIO SCI 93

Professor

Busciglio/ Wood/ Green

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BIO SCI 93 Full Course Notes

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Cell translates mrna message into protein with aid of trna. Molecules of trna not the same: each carries specific amino acid on one end, each has anticodon on other side. Accurate translation requires two steps: correct match between trna and amino acid, done by enzyme aminoacyl-trna synthetase, correct match between trna anticodon and mrna codon. Wobble: flexible pairing at third base of codon. Allows some trnas to bind to more than one codon. Three stages of translation: initiation, elongation, termination, all require protein factors that help during process. Number of ribosomes can translate single mrna at the same time: forms polysome or polyribosome. Enables cell to make many copies of polypeptide very fast. Translation often not sufficient to make a functional protein. Completed proteins targeted to specific sites in cell. Clicker question: certain antibiotics work by targeting the ribosome, which is slightly different in prokaryotes.

Related Questions

3. Describe the aminoacylation of a tRNA reaction being careful to include information about how one particular amino acid is attached to a particular tRNA.

4. All of the following steps are part of the process of gene expression in eukaryotes. Number them toreflect the approximate order in which each occurs during this process.
a) Introns are removed from the original transcript of the gene.

b) A 5â cap is added onto the mRNA.

c) A specific aminoacyl-tRNA synthetase charges Val-tRNA.

d) Val-tRNA enters the A site of the ribosome.

e) The mRNA is cleaved near the poly(A) site in its 3â UTR.

f) A translation release factor binds to the stop codon.

g) RNA polymerase II initiates mRNA synthesis

h) The mRNA is transported out of the nucleus into the cytoplasm.

i) An activator protein binds to an enhancer.

1. _________________________ is the name of the process that produces proteins using RNA molecules.

a.Transcription

b Translation

c. Replication

d. Mutagenesis

2. The peptide bonding site on the ribosome:

a. A site

b. P site

c. E site

d. D site

3. The name given to the bond formed between two amino acids.

a. Hydrogen bond

b. Double bond

c. Peptide bond

d. Negative bond

4. __________________________ is the movement of the mRNA molecule on the ribosome to open up the A-site for the new incoming amino acid.

a. Transformation

b. Mutation

c. Translocation

d. Initiation

5. What does the term semi-conservative mean.

a. Replication of RNA is semi-conservative, each new strand consists of one old strand of RNA and one new strand of RNA.

b. Replication of DNA is semi-conservative, each new strand consists of one old strand of DNA and one new strand of DNA.

c. Replication of DNA is semi-conservative, each new strand consists of new strands of nucleotides.

d. Transcription of RNA is semi conservative.

6. This molecule functions during protein synthesis to recognize the codon and bring the proper amino acid back to the ribosome for translation.

a. mRNA

b. tRNA

c. rRNA

d. DNA polymerase

7. What is meant by the base-pairing rule.

a. Bases on a single strand of DNA are always found as pairs

b. Adenine always base pairs with guanine; cytosine with thymine

c. Adenine always base pairs with thymine; cytosine with guanine

d. Bases on a single strand of RNA are found in pair.

8. In this step of protein synthesis, amino acids are added to a growing polypeptide chain.

a. Initiation.

b. Elongation.

c. Termination.

d. Transpiration.

9. Three complementary bases found in a mRNA are called ____________________.

a. Anti-codon.

b. Triplet.

c. Doublet.

d. Codons.

10. Which statement best describes the job or function of the messenger RNA.

a. Carries the map of the gene sequence in the form of codons to the cytoplasm

for translation of the protein.

b. It transfers amino acids to the ribosome for protein synthesis.

c. It forms the ribosomes.

d. It helps replicate DNA.

ceruleangnat663

If one is testing a goodness of fit to a 9:3:3:1 ratio, how many degrees of freedom would be associated with the Chi-square?

not enough information to determine

Which of the following choices does not describe a type of posttranslational modification of proteins?

The amino terminal methionine may be removed.

Glycoproteins are produced by the attachment of phosphates to newly synthesized proteins.

Precursor proteins are cleaved and trimmed by protease enzymes to produce a functional protein.

Molecular chaperones help proteins fold correctly.

Amino acids in the amino terminal of the protein can be acetylated.

A eukaryotic DNA sequence that affects transcription at distant promoters is called a(n)

long distance promotor

regulator

operon

enhancer

DNA methylation may be a significant mode of genetic regulation in eukaryotes. Meythylation refers to

altering RNA polymerase activity by adding methyl-groups

changes in DNA-DNA hydrogen bonding

altering translation activity via methylated tRNAs

adding methyl groups to certain cytosines in DNA

If a nucleotide lacks a 3â-OH group, what will happen?

itâs transformed into RNA

another nucleotide can bond at the 3â site during replication

replication will halt

no effect

Which of the following describe posttranscriptional modifications commonly seen in mRNA of eukaryotes?

5â capping, 3â-poly-A tail addition, splicing

3â capping, 5â poly-A tail addition, splicing

heteroduplex formation

5â capping, 3âpolyA tail addition, removal of exons

In birds, females are the heterogametic sex. This means that

females have chromosomes in pairs.

emales produce eggs.

females determine the gender of their offspring.

males have two identical sex chromosomes (ZZ)

An anticodon on a tRNA has the sequence 5'âGCAâ3'. What would be the effect on translation if the G in the anticodon were mutated to a U?

The anticodon could pair to the serine codon 5'âUCAâ3', and a cysteine would be incorporated at all points where a serine should have been incorporated.

The anticodon could pair to the threonine codon 5'âACUâ3', and a threonine would be incorporated at all points where a cysteine should have been incorporated.

The anticodon could pair to the serine codon 5'âAGUâ3', and a serine would be incorporated at all points where a cysteine should have been incorporated.

The anticodon could pair to the stop codon 5'âUGAâ3', and instead of stopping translation, a cysteine would be incorporated and translation could continue.

BIO SCI 93 Lecture Notes - Lecture 13: Reading Frame, Polysome, Transfer Rna

BIO SCI 93 Full Course Notes

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