Molecular Biology-מעבדה רפואית

(USMLoid) The DNA polymerases and RNA polymerases of both prokaryotes and eukaryotes make copies of nucleotides sequences - but the RNA polymerases are more prone to error. This doesn't matter because

1

The alanine aminoacyl tRNA synthetase enzyme of E. coli recognizes the alanine tRNA only by an unusual G:U base pair at position 70 in the stem of the tRNA. In the laboratory, you make a copy of the alanine tRNA gene that is identical to the wildtype copy except that the anicodon sequence 5' - IGC -3' is replaced with the sequence 5' - UCA -3'. You then add this mutant tRNA gene back into a wildtype E. coli. As a result,

1

שאלה #39133

		some proteins will be longer than ususal.
		all alanines in newly synthesized proteins will be replaced with serine.
		some alanines in newly synthesized proteins will be replaced with serine.
		nothing will change because the mutant tRNA will not function.
		all proteins will be truncated at the first alanine position.
		proteins will be truncated randomly at different alanine positions.

Core Processes:Translation. This is a difficult one, but is actually basic. Just think the process through. Make diagrams - it may help. This is an example of a difficult question. You can expect one two that demand this level of understanding and analytical skill on the final exam. The correct answer is: some proteins will be longer than ususal.

מיין לפי

Complete the following sentence. The covalent bond between a tRNA and its amino acid is catalysed: השלם את המשפט הבא: הקישור הקוולנטי בין tRNA והחומצה האמינית אליה המתאימה, מזורז -

1

שאלה #39134

		by a ribosomal subunit at the P site. ע"י תת יחידה של הריבוזום באתר P
		by one of the amino acyl tRNA sythetases. ע"י אחד מאנזימי amino acyl tRNA sythetases
		once the correct tRNA has bound the codon in the A site of the ribosome. מיד כאשר ה-tRNA הנכון נקשר אל הקודון באתר A בריבוזום
		None of these, the bond between tRNA and its amino acid is not covalent. אף תשובה אינה נכונה. הקשר בין ה-tRNA לחומצה האמינית המתאימה איננו קוולנטי
		by a nucleolar enzyme. ע"י אנזים המצוי בגרעינון
		such that the amino acid is bound to the 5' end of the tRNA. כך שהחומצה האמינית קשורה לקצה '5 של ה-tRNA

מיין לפי

(USMLoid) You have identified a mutation in a gene transcribed in the liver. At codon 42 of the expected translation product you find 5'-CAT-3' instead of the normal codon 5'-GAT-3'. This same mutation is found associated with type II diabetes in a large kindred. Which of the following best describes the effect of this change on the protein encoded?

1

שאלה #39135

		Addition of amino acid sequence beyond the normal carboxy terminus
		Asp -> His
		Val -> Leu
		Leu -> Val
		His -> Asp

מיין לפי

(USMLoid) Which of the following is a result of the degeneracy of the genetic code?

1

שאלה #39136

		Bacteria and eukaryotes use different codons for the same amino acid
		The same RNA sequence being read by one ribosome may produce a different amino acid sequence when read by another
		Several different amino acids may be specified by the same codon.
		Some amino acids have more than one corresponding tRNA
		A translational proofreading mechanism is implemented to fix the errors caused by the degeneracy.

מיין לפי

In prokaryotes EF-Tu is involved in:

1

שאלה #39137

		translocation of the ribosome.
		bringing charged tRNAs to the P site.
		bringing charged tRNAs to the A site.
		determining translation fidelity.
		covalently linking to the correct amino acid.

מיין לפי

In humans there are 64 codons. 61 of these code for amino acids. There are 20 amino acids. There are 31 tRNAs. How many different amino acyl tRNA synthetases are there?

1

שאלה #39138

		20
		31
		None of these is correct
		1
		64

מיין לפי

Formation of peptide bonds during protein synthesis is catalysed by:

1

שאלה #39139

		one of the ribosomal proteins
		None of these is correct.
		the amino acyl tRNAs.
		one of the ribosomal RNAs.
		amino acyl tRNA synthetase.

מיין לפי

Which of the following are correct? Because of the differences in the translation machinery between Prokaryotes and Eukaryotes:

1

שאלה #39140

		prokaryotes and Eukaryotes use different genetic codes.
		prokaryotic mRNAs are often polycistronic.
		None of these is correct
		some drugs are able to stop translation in bacteria, but not in humans
		eukaryotic mRNAs are often polycistronic.

You have correctly selected 1. The correct answers are: prokaryotic mRNAs are often polycistronic., some drugs are able to stop translation in bacteria, but not in humans.

מיין לפי

The following piece of DNA codes for an mRNA. The top strand is the template strand. The initiation and terminations codons are in the sequence. 5'-AATTACCATGAAATTGTCATCTACTTGTTGATTA-3' 3'-TTAATGGTACTTTAACAGTAGATGAACAACTAAT-5 The sequence of the protein encoded by this transcript is:

1

שאלה #39141

		None of these is correct
		COOH-Met-Lys-Leu-Ser-Ser-Thr-Cys-NH2
		NH2-Met-Thr-Ile-Ser-Trp-COOH
		NH2-Met-Lys-Leu-Ser-Ser-Thr-Cys-COOH
		COOH-Met-Thr-Ile-Ser-Trp-NH2

מיין לפי

		Errors introduced into protein sequence usually have no effect on function.
		RNA molecules are smaller than DNA molecules.
		mRNAs bearing mutations are usually degraded before they can be translated
		The errors occurring during RNA synthesis are repaired later.
		The copies are not incorporated into the genetic material of the next generation.

Molecular Biology-מעבדה רפואית

Discuss, Learn and be Happy דיון בשאלות

(USMLoid) The DNA polymerases and RNA polymerases of both prokaryotes and eukaryotes make copies of nucleotides sequences - but the RNA polymerases are more prone to error. This doesn't matter because

שאלה #39132

שאלה #39133

Complete the following sentence. The covalent bond between a tRNA and its amino acid is catalysed: השלם את המשפט הבא: הקישור הקוולנטי בין tRNA והחומצה האמינית אליה המתאימה, מזורז -

שאלה #39134

שאלה #39135

(USMLoid) Which of the following is a result of the degeneracy of the genetic code?

שאלה #39136

In prokaryotes EF-Tu is involved in:

שאלה #39137

In humans there are 64 codons. 61 of these code for amino acids. There are 20 amino acids. There are 31 tRNAs. How many different amino acyl tRNA synthetases are there?

שאלה #39138

Formation of peptide bonds during protein synthesis is catalysed by:

שאלה #39139

Which of the following are correct? Because of the differences in the translation machinery between Prokaryotes and Eukaryotes:

שאלה #39140

The following piece of DNA codes for an mRNA. The top strand is the template strand. The initiation and terminations codons are in the sequence. 5'-AATTACCATGAAATTGTCATCTACTTGTTGATTA-3' 3'-TTAATGGTACTTTAACAGTAGATGAACAACTAAT-5 The sequence of the protein encoded by this transcript is:

שאלה #39141

Molecular Biology-מעבדה רפואית

Discuss, Learn and be Happy דיון בשאלות

(USMLoid) The DNA polymerases and RNA polymerases of both prokaryotes and eukaryotes make copies of nucleotides sequences - but the RNA polymerases are more prone to error. This doesn't matter because

Complete the following sentence. The covalent bond between a tRNA and its amino acid is catalysed: השלם את המשפט הבא: הקישור הקוולנטי בין tRNA והחומצה האמינית אליה המתאימה, מזורז -

(USMLoid) Which of the following is a result of the degeneracy of the genetic code?

In prokaryotes EF-Tu is involved in:

In humans there are 64 codons. 61 of these code for amino acids. There are 20 amino acids. There are 31 tRNAs. How many different amino acyl tRNA synthetases are there?

Formation of peptide bonds during protein synthesis is catalysed by:

Which of the following are correct? Because of the differences in the translation machinery between Prokaryotes and Eukaryotes:

The following piece of DNA codes for an mRNA. The top strand is the template strand. The initiation and terminations codons are in the sequence. 5'-AATTACCATGAAATTGTCATCTACTTGTTGATTA-3' 3'-TTAATGGTACTTTAACAGTAGATGAACAACTAAT-5 The sequence of the protein encoded by this transcript is:

בקשה לשינוי התשובה / תיקון שאלה gavel

בקשה למחיקת השאלהmood_bad

בקשה לשינוי התשובה / תיקון שאלה

בקשה למחיקת השאלה