BIOL 116 Lecture Notes - Lecture 21: Lac Operon, Lactose Permease, Beta-Galactosidase

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blackchinchilla342

28 Nov 2016

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Flow of info from dna to rna to activation of the final gene product occurs in 3 steps: Dna mrna protein activated protien. Most genes expressed only when needed (except housekeeping genes, consecutive expression) Avoid making mrnas for enzymes, regulatory proteins affect the rna polymerase"s ability to bind to promoter and initiate transcription. Translational control mrna transcribed, prevent being translated to protein. Alter length of time mrna survives before degradation, or affecting translation initiation, or elongation factors. Dna -x- mrna protein activated protein. Dna mrna -x- protein activated protein. Dna mrna protein -x- activated protein. Proteins made in an inactive form and must be activated by chemical modifications, ex addition of phosphate group. Metabolizing lactose - a model for studying regulation of gene expression. Enzymes for lactose utilization: permease (lac y) and beta galactosidase (lac z) Lac y, lac z, lac a, located close and transcriptionally regulated together (1 mrna, same promoter) = lac operon.

Related Questions

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

BIOL 116 Lecture Notes - Lecture 21: Lac Operon, Lactose Permease, Beta-Galactosidase

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