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MBG 1000 Chapter Notes - Chapter 10: Ribosomal Rna, Intron, Uracil

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limecicada923
17 Apr 2016
School
University of Guelph
Department
Molecular Biology and Genetics
Course
MBG 1000
Professor
Christine Schisler

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Document Summary

Chapter 10: gene action- from dna to protein. Rna is single-stranded, has uracil and ribose, and has different functions than dna. Each three mrna bases in a row form a codon that specifies a particular amino acid. Ribosomal rna and proteins form ribosomes, which physically support protein synthesis and help catalyze bonding between amino acids. Transfer rnas connect mrna codons to amino acids. In more complex organisms, cascades of transcription factors control gene expressions. Rna polymerase inserts complementary rna bases opposite the dna template strand. Messenger rna (mrna) gains a modified nucleotide cap and a poly a tail. Introns are transcribed and cut out, and exons are reattached. Introns are common and large in human genes. Certain genes are processed into different-sized rnas in different cell types. Dna: usually double-stranded, thymine as a base, deoxyribose as the sugar, maintains protein-encoding information, cannot function as an enzyme, persists.

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Related Questions

5. Alpha amanitin is a drug that binds RNA polymerase andprevents it from functioning in the cell (this is the compound thatis found in poison mushrooms). The reason people die when theyconsume alpha amanitin is:

a) Alpha amanitin prevents gene expression from occurring in thecell

b) DNA replication is directly inhibited by alpha amantin

c) Alpha amanitin binds tightly to the messenger RNAs that aremade in the cell, preventing translation

d) Alpha amanitin binds to nuclear pores preventing thetransport of messenger RNA into the cytoplasm

6. In order for transcriptional initiation to begin in E. colithe following elements are needed:

a) an origin and RNA polymerase

b) initiator protein and a promoter

c) the sigma subunit of RNA polymerase and an RNA template

d) RNA polymerase and a promoter

e) helicase and primase

Questions 7 and 8. You are studying two species of closelyrelated snakes, one species lives in sandy desert area and has paletan skin and the species lives in a volcanic rock area and has darkbrown skin. You a sequence the DNA from each type of snake anddiscover a gene encoding a protein that transports pigment into theskin cells. The pigment transporter protein is responsible for skincolor. When you analyze the DNA coding sequence of the pigmenttransporter from each snake you find these two DNA sequences (hashmarks have been added to indicate the reading frame):

pale tan snake: GCG/TTG/GAC/TGC/ACC (DNA template strand)CGC/AAC/CTG/ACG/TGG (complementary strand) dark brown snake:ACG/TTG/GAC/TGC/ACC (DNA template strand) TGC/AAC/CTG/ACG/TGG(complementary strand)

7. From these sequences you conclude:

a) that the amino acid sequence of the pigment transporters forthe two proteins are almost identical

b) that the amino acid sequence of the pigment transporters forthe two proteins are very dissimilar

c) that the amino acid sequence of the pigment transporters forthe two proteins are identical

8. Since the skin color is different in each snake, you concludefrom the sequence data above that:

a) the genetic code in the skin cells in each of these snakes isdifferent

b) the DNA sequence encoding the entire gene for pigmenttransporters in these two snakes is different

c) that one of the codons in the gene for the pigmenttransporter in these two snakes is different

9. You are analyzing eukaryotic cells that have been exposed tothe radioactive uracil. In most cells the radioactive uracil isinitially localized in the nucleus and then moves from the nucleusto the cytoplasm. However, you observe that in some cells theradioactive molecules stay in the nucleus and never arrive in thecytoplasm. This is most likely a defect in:

a) the transcription of the DNA

b) the processing of the mRNA

c) the translation of the RNA

d) the labeling of the RNA

e) the replication of the DNA

10. Which of the following is true of both eukaryotic andbacterial transcription? (select all that are true)
a) Transcription factors must bind the promoter before RNApolymerase initiates transcription

b) Messenger RNAs must be spliced before translation begins inorder to produce the appropriate gene product

c) During transcription only one DNA strand is used as atemplate to make the messenger RNA

d) Termination of transcription occurs when the RNA polymerasetranscribes a hairpin structure in the RNA followed by a string ofU

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.

DNA Structure and Function LabReport

  1. DNA Structure
  2. Which two scientists are credited with discovering DNA?
  1. Name the nitrogen bases that are purines.
  1. Which nitrogen base pairs with thymine?
  1. List the three components of a nucleotide.
  1. DNA Replication
  2. What is the purpose of DNA replication?
  1. How many times does replication occur in the life of acell?
  1. In the Lab, Exercise 2, the original strand on the left had thebases shown below. Input the new bases that correctly pair with theoriginal strand.

Original

New

C

A

G

T
  1. RNA Structure
  1. Describe the structure and function of RNA.
  1. Refer to Exercise 3 and record the bases of the RNA strandproduced from the replicated DNA strand.

DNA

RNA

C

A

G

T

  1. Record the differences between DNA and RNA in the tablebelow.

DNA

RNA

Sugars

Bases

Strands

  1. RNA Synthesis

  1. The process of assembling RNA is called _________.
  1. How is replication different from transcription?
  1. Refer to Exercise 4. Write the letters for the base sequence ofmRNA in the spaces below DNA. Note that the order is reversed;start with the 3’ end of the DNA strand and the 5’ end of the mRNAstrand. Transcription is DNA to mRNA. Note RNA contains Uracilinstead of Thymine; There is no thymine in RNA.

DNA

3’

C

G

T

C

G

T

C

C

A

A

T

T

5’

mRNA

5’

3’

  1. Protein Synthesis

  1. What type of RNA provides amino acids to build polypeptidechains?

  1. If a mRNA strand has the bases 5’ CUC 3’, what amino acid willbe translated? Refer to the printable chart in Exercise 5.

  1. Where in the cell does translation occur?
  1. Genes

  1. What could be the problem if there is a change in the basesequence of a gene as it is passed down to the offspring?
  1. Give an example of a disorder that results from changes in theamino acid sequence.
  1. What causes sickle cell anemia?
  1. Gene Cloning
  1. What is the function of a plasmid?
  1. Print the document from Lab, Exercise 6. Complete the activityalong with the video demonstration. Sign, date, and take an imageof your final product and include with this lab report.