Molecular Biology-מעבדה רפואית

(USMLoid) Which of the following is responsible for determining the amino acid sequence of a protein being synthesized by a ribosome.

1

(USMLoid) The single tyrosine tRNA recognises both of the tyrosine codons - UAU and UAC. Which of the following is therefore the anticodon sequence of this tRNA? את שני הקודונים עבור טירוזין – UAU, UAC – מזהה tRNA יחיד. אם כך, מי מהבאים הינו רצף האנטי-קודון של tRNA זה?

1

שאלה #39143

		5' - GAG - 3'
		5' - GUA - 3'
		5' - UUA - 3'
		5' - AAA - 3'
		5' - AAG - 3'

This is a question about the wobble position - and yes, it corresponds almost exactly to a USMLE question. However, you can answer it without remembering almost anything about that table of non-canonical base-pairings at the wobble position. Just think it through. All the choices except the correct one are eliminated even if you just remember that a base never base-pairs with itself. The correct answer is: 5' - GUA - 3'

מיין לפי

Under highly stressful circumstances E. coli is able to down regulate almost all of the normally active genes and initiate transcription of stress response genes. This event is due to which one of the following?

1

שאלה #39144

		Stress activated phosphorylation of the normal RNA polymerase (σ) subunit.
		Transcription of small basic proteins (SBPs) which bind most of the E. coli genomic DNA into an inaccessible higher-order structure resembling eukaryotic chromatin.
		An increase in cAMP, which is a prokaryotic starvation signal. As a result, the CAP protein initiates transcription of a small subset of response genes.
		Degradation of the normal β subunits of RNA polymerase and their replacement with a second copy of β'.
		The transcription of the heat-shock genes.
		None of the above.

Gene Regulation If you wanted to change the binding of the E.coli RNA polymerase, which subunit would you work with?

מיין לפי

Tevel Bruckner 1 נקודות · יותר מ-6 חודשים

מוניטין: 45

טעות, קליי תיקן. אף תשובה לא נכונה.

In the context of prokaryotic gene regulation, an operator is the:

1

שאלה #39145

		part of the operon encoding the repressor.
		DNA sequence where transcription of the operon begins.
		DNA sequence which binds the repressor.
		DNA sequence which binds the RNA polymerase.
		protein which regulates transcription from the promoter.

מיין לפי

Isca Kaszovitz 0 נקודות · יותר מ-6 חודשים

מוניטין: 201

יש באחד השחזורים שהתשובה היא רצף DNA איפה שהשעתוק של האופרון מתחיל אז לא סגורה כרגע מה התשובה הנכונה

You create an E.coli bacteria that is diploid for the Lac operon by placing a second copy of the operon on a plasmid. The chromosomal lac operon is I+ P+ O- Z+ Y+ A+. The plasmid copy is I+ P+ O+ Z+ Y+ A+. You grow these bacteria on plates that contain glucose and X-gal (which turns blue when cut by β -galactosidase), and on plates containing lactose and X-gal. The bacteria will:

1

שאלה #39146

		Form blue colonies on the lactose plates and die on the glucose plates.
		Die on both plates
		. Form white colonies on the glucose plates and blue colonies on the lactose plates.
		Form blue colonies on both plates.
		Form white colonies on both plates.
		Form white colonies on the lactose plates and die on the glucose plates
		Die on the lactose plates and form white colonies on the glucose plates.

מיין לפי

In the context of prokaryotic gene regulation, a repressor is:

1

שאלה #39147

		a cis-acting DNA sequence which binds the operator.
		the DNA sequence which binds the repressor.
		the DNA sequence where transcription of the operon begins.
		a protein which regulates transcription from the promotor.
		a protein which binds to the RNA polymerase.

מיין לפי

(USMLoid) A researcher has discovered a strain of E.coli bearing a mutant RPOD gene, resulting in the production of an altered RNA polymerase sigma factor. This mutation would most likely affect recognition of which of the following cis-acting regulatory sequences?

1

שאלה #39148

		Operator
		Attenuator
		Catabolite-activator protein (CAP) binding site
		Promoter
		Enhancer

מיין לפי

(USMLoid) Transcription in eukaryotes is often regulated by promoter sequence and enhancer elements. Which of the following best describes enhancers?

1

שאלה #39149

		Zinc-finger family transcription factors that bind the TATA box
		Short DNA sequences located before or after the promoter.
		Nascent mRNAs that bind to promoters
		DNA sequences that bind histones
		Nuclear hormone receptors that bind to DNA

מיין לפי

Embryonic development and cell differentiation are largely driven by gene regulation. The most common mechanism is at which of the following levels?

1

שאלה #39150

		Protein degradation
		Alternative RNA splicing
		Initiation of RNA synthesis
		Initiation of protein synthesis
		Protein modification

מיין לפי

Acetylation of histones often results in: אצטילציית היסטונים מביאה לרוב ל:

1

שאלה #39151

		proteolytic degradation of the histones דגרדציה פרוטאוליטית של ההיסטונים
		increased transport of RNA polymerase II into the nucleus עליה בטרנספורט RNA Pol-II אל תוך הגרעין
		None of these is correct. אף תשובה אינה נכונה
		decreased nucleosome density and increased transcription ירידה בצפיפות הנוקלאוזומים ועליה בשעתוק
		decreased nucleosome density and decreased transcription ירידה בצפיפות הנוקלאוזומים וירידה בשעתוק
		decreased transport of RNA polymerase II into the nucleus ירידה בטרנספורט RNA Pol-II אל תוך הגרעין

מיין לפי

		mRNA
		aminoacyl tRNA
		Elongation factor G
		Peptidyl Transferase
		Ribosomal RNA

Molecular Biology-מעבדה רפואית

Discuss, Learn and be Happy דיון בשאלות

(USMLoid) Which of the following is responsible for determining the amino acid sequence of a protein being synthesized by a ribosome.

שאלה #39142

שאלה #39143

Under highly stressful circumstances E. coli is able to down regulate almost all of the normally active genes and initiate transcription of stress response genes. This event is due to which one of the following?

שאלה #39144

In the context of prokaryotic gene regulation, an operator is the:

שאלה #39145

שאלה #39146

In the context of prokaryotic gene regulation, a repressor is:

שאלה #39147

(USMLoid) A researcher has discovered a strain of E.coli bearing a mutant RPOD gene, resulting in the production of an altered RNA polymerase sigma factor. This mutation would most likely affect recognition of which of the following cis-acting regulatory sequences?

שאלה #39148

(USMLoid) Transcription in eukaryotes is often regulated by promoter sequence and enhancer elements. Which of the following best describes enhancers?

שאלה #39149

Embryonic development and cell differentiation are largely driven by gene regulation. The most common mechanism is at which of the following levels?

שאלה #39150

Acetylation of histones often results in: אצטילציית היסטונים מביאה לרוב ל:

שאלה #39151

Molecular Biology-מעבדה רפואית

Discuss, Learn and be Happy דיון בשאלות

(USMLoid) Which of the following is responsible for determining the amino acid sequence of a protein being synthesized by a ribosome.

Under highly stressful circumstances E. coli is able to down regulate almost all of the normally active genes and initiate transcription of stress response genes. This event is due to which one of the following?

In the context of prokaryotic gene regulation, an operator is the:

In the context of prokaryotic gene regulation, a repressor is:

(USMLoid) A researcher has discovered a strain of E.coli bearing a mutant RPOD gene, resulting in the production of an altered RNA polymerase sigma factor. This mutation would most likely affect recognition of which of the following cis-acting regulatory sequences?

(USMLoid) Transcription in eukaryotes is often regulated by promoter sequence and enhancer elements. Which of the following best describes enhancers?

Embryonic development and cell differentiation are largely driven by gene regulation. The most common mechanism is at which of the following levels?

Acetylation of histones often results in: אצטילציית היסטונים מביאה לרוב ל:

בקשה לשינוי התשובה / תיקון שאלה gavel

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