BSCI 105 Lecture Notes - Lecture 24: Start Codon, Molecular Machine, Signal Peptide

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mauvewater-buffalo154

30 Nov 2016

School

University of Maryland

Department

Biological Sciences Program

Course

BSCI 105

Professor

Norma Allewell

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Document Summary

Prokaryotic transcriptions at different times, blobs: ribosomes. Held together with mrna: the big strand at the top is dna. Wobbly making it possible for some amino acids to interact with more than one t-rna and creating redundancy in the genetic code trna structure: anti-codon is complementary to corresponding rna. Charing the trna: connecting the amino acid to the trna: catalyzed by enzymes called aminoacyl-trna synthetases, one synthetases for each amino acid. The ribosome: two subunits (large and small) each made up of a large number of proteins and 3- Protein:rna = 1:3: assembled in the nucleolus. Proteins made in cytoplasm and imported to nucleus; rrna made in nucleus: prokaryotic and eukaryotic ribosomes are similar but eukaryotic ribosomes are larger and more complex. Differences can be exploited in antibiotic development: amino acids in, polypeptide out, three trna binding sites. Three major steps in protein synthesis: initiation, elongation, termination. Forming the initiation complex: step 1:

Related Questions

Please please please I reallly need help with the following 5 questions.

Question 1

Which of the following is responsible for directing the prokaryotic ribosome to the +1 start site:

	a.	the 3' UTR
	b.	the AUG codon
	c.	Kozak sequence
	d.	Okasaki fragment
	e.	Shine Dalgarno sequence

Question 2

In translation, mRNAs are READ in the:

	a.	5' to 3' direction and polypeptide chains are synthesized amino to the carboxyl ends
	b.	5' to 3' direction and polypeptide chains are synthesized carboxyl to the amino ends
	c.	3' to 5' direction and polypeptide chains are synthesized carboxyl to the amino ends
	d.	3' to 5' direction and polypeptide chains are synthesized amino to the carboxyl ends

Question 3

Which of the following terms describes a tRNA to which an amino acid has been added:

	a.	charged tRNA
	b.	activated tRNA
	c.	stimulated tRNA
	d.	hydrolyzed tRNA

Question 4

The ability of some tRNA to recognize more than one codon in mRNA is explained by which of the following:

	a.	a reading frameshift
	b.	a reading mistake
	c.	Redundancy Theory
	d.	Wobble Hypothesis

Question 5

One essential component in eukaryotic mRNAs recognized by translation initiation factors is the

	a.	TATA box
	b.	AUG initiation codon
	c.	7-methylguanosine cap
	d.	Shine-Dalgarno sequence

blackporcupine6

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

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

BSCI 105 Lecture Notes - Lecture 24: Start Codon, Molecular Machine, Signal Peptide

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