BIOLOGY 151 Lecture Notes - Lecture 23: Lac Operon, Tata-Binding Protein, Cistron

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26 Apr 2017

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Holds information that makes proteins that have various functions. Do they want to be expressing all their genes. No don"t want to be expressing all their genes all the time. Rna is a non-sequence specific dna binding protein. Transcription factors are sequence specific dna binding proteins. In both prokaryotes and eukaryotes, rna polymerase cannot bind to dna on its own. Sigma factors are less specific baseline transcription factors. Eukaryotic rna polymerase requires basal transcription factors. Trying to get rna polymerase to every promoter in the cell. Regulatory transcription factors are required to control differential gene expression in all organisms. Much more gene specific than sigma and basal factors. Transcription factors can exert either negative or positive control. Negative control occurs when a regulatory protein binds to dna and down- regulates (decreases) the amount of transcription from a particular gene. Positive control occurs when a regulatory protein binds to dna and up-regulates (increases) the amount of transcription from a particular gene.

Related Questions

Answer the following True or False questions and briefly explain your answers.

True or False EXPLAIN: Most human cells, in a single individual, contain the same amount and type of DNA

True or False EXPLAIN: Most human cells, in a single individual, contain the same amount and type of protein.

True or False EXPLAIN: Once a gene is transcribed, it is always translated immediately.

True or False EXPLAIN: RNA polymerase binds to the promoters of all genes at all times, so that it is prepared for transcription.

True or False EXPLAIN: Some transcription factors are general (they play a role in the transcription of most or all genes), while other transcription factors are specific to just a few genes.

True or False: EXPLAIN Turning genes on at the right time and place requires both specific regulatory DNA sequences and specific regulatory proteins.

1 DNA sequences found in introns provide [A] amino acid sequence information.

[B] regulatory information.
[C] no known useful information.

[D] structure for the gene.
[E] alternative DNA splicing possibilities.

3. The TATA box is a(n)
[A] sequence close to the promoter region of many genes.
[B] square-shaped sequence.
[C] enhancer consensus sequence.
[D] activator sequence necessary for proper translation.
[E] None of the above

5. Regarding genes and gene expression, which of the following is not a difference between prokaryotes and eukaryotes
[A] Eukaryotic DNA does not contain a TATA box close to the initiation site as does prokaryotic DNA.

[B] In eukaryotes, RNA polymerase requires

'transcription factors'or initiation.

[C] Prokaryotic genes are often grouped together in

operons.

[D] In eukaryotes, the regulation of several genes at once requires common control elements in each of the genes.
[E] There is a diversity of eukaryotic polymerases that is reflected in the diversity of eukaryotic promoters.

10) In eukaryotic cells, a repressor

[A] is made of DNA.
[B] binds to the enhancer region to block transcription. [

C] is located both upstream and downstream from the promoter.
[D] binds to the operator to block RNA polymerase.

[E] binds to a silencer to reduce transcription rates.

Coordinated regulation of genes in eukaryotic cells [A] is the result of positioning the same regulatory sequence in front of each gene.
[B] results from all of those genes being under the control of one promoter.

[C] occurs because related genes all have the same

operons.
[D] occurs because enhancers cause DNA to bend.

QUESTION 1

How is a bone marrow transplant able to treat someone with leukemia?

		The donor blood contains antibodies that destroy cancer cells
		Donor blood contains stem cells that regenerate cells in the immune system
		Bone marrow contains induced pluripotent stem cells that turn into red blood cells
		Bone marrow contains tumor supressor genes that slow down leukemia growth
		Bone marrow contains pluripotent human embryonic stem cells

1.2 points

QUESTION 2

What would happen if siRNAs designed to target mRNA from an oncogene were introduced into cancer cells?

		Increased genomic instability would result from adding foreign nucleic acids
		New mutations would arise in the oncogene
		The oncogene would be converted back into a proto-oncogene
		The siRNAs would compete with the oncogene's active site
		Production of the oncogene protein would decrease

1.2 points

QUESTION 3

What is the purpose of chromatin-remodeling enzymes in human cells?

		The enzymes control the rate of translation of an mRNA transcript
		The enzymes add phosphate or methyl groups to histone tails
		The enzymes slide nucleosomes farther apart or closer to each other
		The enzymes send damaged proteins to the proteasome for degradation
		The enzymes cause DNA looping to occur

1.2 points

QUESTION 4

If you wanted to resurrect the mammoth, how would you do it?

		Use somatic cell nuclear transfer to insert the mammoth genome into the egg of an elephant
		Use transcription factors to re-program adult cells from elephants into mammoth cells
		Change the gene expression patterns of elephants to increase production of mammoth genes
		Use siRNAs to decrease expression of elephant-specific genes in an elephant embryo

1.2 points

QUESTION 5

How is eukaryotic transcription initiated?

		RNA polymerase is recruited to the start codon by transcription factors
		RNA polymerase begins transcription at the enhancer sequence
		RNA polymerase is activated by binding to GTP
		An initiator tRNA binds to the ribosome
		A complex of proteins forms at the promoter of a gene

BIOLOGY 151 Lecture Notes - Lecture 23: Lac Operon, Tata-Binding Protein, Cistron

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