BIOL 1081 Lecture Notes - Lecture 34: Ubiquitin, Rna Splicing, Intron

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jadecattle874

19 Sep 2017

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Department

Biological Sciences

Course

BIOL 1081

Professor

Dr.Kinkle

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Regulation of gene expression in eukaryotes reading: sections 18. 2-18. 3 in textbook: describe how gene expression can be regulated by modifying access to dna in chromatin. Chromatin modification: the physical state (packing) of dna in or near a gene helps control whether the gene is available for transcription. A genes location relative to nucleosomes can affect whether it is transcribed. The location of a gene s promoter, relative to both placement of nucleosomes and the sites where the dna attaches to the chromosome scaffold, can affect whether the gene is transcribed. In addition, genes within the heterochromatin, which is highly condensed, are usually not expressed. Lastly, certain chemical modifications to the histone proteins and to the dna of chromatin can influence both chromatin structure and gene expression: define what promoters, transcription factors, activators, repressors, and enhancers are. Draw and explain the function of a transcription initiation complex.

Related Questions

17. Which histone is required to compact the âbeads on a stringâ chromatin into higher-order chromatin structures such as the 30 nm fiber?

18. Certain lysine amino acids (Kâs) in the core histone tail can be acetylated. How would this chemical modification of the nucleosome affect the transcription of a gene?

19. Certain protein/protein complexes do not bind DNA, but regulate processes such as transcription and replication. These proteins can associate with the chromatin by recognizing chemical modifications in the core histone tails of the nucleosome. This process represents the âhistone codeâ. Separately, a protein that folds into its three-dimensional functional structures can have different domains with different functions. Assume that a certain protein that increases transcription does not recognize a specific DNA sequence, but rather associates with acetylated lysine amino acids in the histone tails. What domain in this protein would allow it to associate with these acetylated lysine amino acids?

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â¢ Identify the mechanisms for gene expression control in the lac and trp operons

â¢ Explain what transcription factors and regulatory proteins are and how they regulated gene expression in eukaryotes.

â¢ Describe how chromatin structure (DNA methylation and histone modification) can affect gene expression

â¢ Explain the process of protein degradation and its purpose

â¢ Contrast the mechanisms regulating gene expression depending on when they act on: 1) regulating transcription, 2) posttranscriptionally (regulating the mRNA and protein synthesis) and posttranslationally (regulation of protein degradation)

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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

QUESTION 10

If you can drink milk as an adult, it means that you have inherited a mutation in the an enhancer for 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

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

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 1081 Lecture Notes - Lecture 34: Ubiquitin, Rna Splicing, Intron

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