BIOL 1100 Lecture 25: Lecture 25

65 views2 pages

erinpanda559

29 Nov 2016

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Epigenetic inheritance - patterns of inheritance that is not due to differences in gene sequences. Histone code hypothesis: precise patterns of chemical modifications of histones, varies from one cell type to another, contain information that influences gene expression. Mediator - middle man first binds to activator protein and binds basal transcription factors. Gene transcription is initiated by transcription factors that help recruit rna polymerase to the promoter (core promoter sequence - tata box are bound by tbp) Activator: binds to enhancer to activate/turn on genes, binds when dna is opened (chromatin is relaxed) Repressor: binds to silencer to repress/turn off genes. Improving (far away from dna promoter); doesn"t code for any protein. Activator (dna binding protein)binds to enhancers (dna sequence) Repressors bind to silencer sequences to turn off genes. Gene expression requires: opening up chromatin, binding of transcriptional regulators/factors, recruiting rna polymerase to the start site.

Related Questions

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.

- Review the levels of control of gene expression that include:

1. Chromatin structure and role of chemical modifications of DNA and histones, as

the first âonâ switch for turning on eukaryotic gene expression. Define the term

epigenetics.

2. Structural components of eukaryotic genes: coding and proximal and distal

regulatory sequences (enhancers and silencers), and their function. Role and

binding sites of transcription factors and activator and repressor proteins.

3. Transcriptional and post transcriptional levels

4. Pre and post translational control levels

QUESTION 10

If you can drink milk as an adult, it means that you have inherited a mutation in the promoter of your lactase gene (the gene that encodes the enzyme you need to break down lactose). Predict the effect of this mutation:

		The mutation changes the number of domains in the enzyme, which makes it work more efficiently
		The mutation changes the amino acid sequence of the lactase protein
		The mutation increases the number of copies of the lactase gene that will be found in your genome
		The mutation changes whether the lactase sequence is found in an intron or exon
		The mutation affects the expression of the lactase gene

1.2 points

QUESTION 11

A competitive inhibitor is decreasing the activity of an enzyme. Predict the effect of adding more substrate to the reaction.

		The substrate will increase the reaction rate by binding to the allosteric site
		The substrate will increase the reaction rate by competing with the inhibitor for the active site
		The reaction rate will not change unless the inhibitor can be removed
		The enzyme adjusts its shape so that the substrate, but NOT the competitive inhibitor, can bind
		The substrate will bind to the competitive inhibitor and block its ability to bind to the enzyme

1.2 points

QUESTION 12

What determines where in the genome a transcription regulator will bind?

		Transcription regulators bind to the 5' UTR region of a gene
		Regulators bind via complementary base-pairing to certain DNA molecules
		Covalent bonds form between the transcription regulator and the atoms of the DNA backbone
		Every eukaryotic gene has a different transcription regulator that will bind to the 5' end of the gene
		Transcription regulators bind to specific DNA sequences via multiple weak non-covalent interactions

1.2 points

QUESTION 13

What is the basic premise of cell theory?

		DNA -> RNA -> protein
		All cells arise from pre-existing cells
		DNA provides the complete instructions to create a cell
		The identity of a cell is determined through gene expression patterns
		All cells contain the same four basic macromolecules

1.2 points

QUESTION 14

What is the benefit of using BOTH the lac activator and the lac repressor to control gene expression?

		Using both an activator and repressor enables cells to more accurately determine the amount of lactose available in the environment
		Enzymes to digest lactose are only made when energy is low and lactose is available
		The activator can override the inhibition of the lac operon by the repressor
		The repressor can control the enhancer, while the activator can control the promoter
		When neither the lac activator or repressor is present, expression of the lac operon is too high

1.2 points

QUESTION 15

What is the histone code used for?

		Phosphorylation and acetylation of DNA affect its ability to be compacted
		Changes to the sequence of DNA change whether DNA will wrap around histone proteins
		Covalent modifications of histones affect the ability of the transcription initiation complex to form
		Histones provide the codon sequences needed for translation to occur
		The histone code affects which amino acids will get added to a polypeptide

BIOL 1100 Lecture 25: Lecture 25

Document Summary

Get access

Related Documents

Biology 1002B Lecture Notes - Lecture 15: Histone Deacetylase, Hormone Response Element, Chromatin Remodeling

Biology 1002B Lecture Notes - Lecture 15: Steroid Hormone Receptor, Hormone Response Element, Histone Acetyltransferase

BIOLOGY 2C03 Lecture Notes - Lecture 4: Chromosome, Ctcf, Meiosis

Related Questions