Chapter 13
... In presence of lactose, which is the allosteric effector for the lac Repressor, lactose binds to the allosteric site of lac Repressor & prevents it from binding to DNA. Relief of repression = Induction. Allosteric effectors that cause such relief of repression are called inducers. When lactose is no ...
... In presence of lactose, which is the allosteric effector for the lac Repressor, lactose binds to the allosteric site of lac Repressor & prevents it from binding to DNA. Relief of repression = Induction. Allosteric effectors that cause such relief of repression are called inducers. When lactose is no ...
Aim: What is positive feedback of bacterial operons?
... transcription on. The activator site is next to the promoter site and binds to transcription factors which help RNA polymerase bind more easily to the promoter. This increases the rate of transcription of the operon. ...
... transcription on. The activator site is next to the promoter site and binds to transcription factors which help RNA polymerase bind more easily to the promoter. This increases the rate of transcription of the operon. ...
Bio1A Unit 2-7 Gene Expression Pt 1 Notes File
... • Mutants are almost always “loss of function” whatever you mutated doesn’t work. There are far more ways for things to go wrong than right. The alternative is a “gain of function” mutation. • Think of mutations in terms of an enzyme. ...
... • Mutants are almost always “loss of function” whatever you mutated doesn’t work. There are far more ways for things to go wrong than right. The alternative is a “gain of function” mutation. • Think of mutations in terms of an enzyme. ...
Cellular Control miniQUIZ
... The diagram below illustrates protein synthesis. Label five important stages in this process. ...
... The diagram below illustrates protein synthesis. Label five important stages in this process. ...
Ch 16 Lac Operon
... Now let’s look at 2 specific operons • The Lactose operon • The Tryptophan operon ...
... Now let’s look at 2 specific operons • The Lactose operon • The Tryptophan operon ...
Controlling the Code: molecules at work
... Student answers will vary but should include that RNA is transcribed when lactose is present. It is then that the repressor is released from the operator and no longer blocks the attachment of RNA polymerase to the promoter. This allows transcription to begin. ...
... Student answers will vary but should include that RNA is transcribed when lactose is present. It is then that the repressor is released from the operator and no longer blocks the attachment of RNA polymerase to the promoter. This allows transcription to begin. ...
Worksheet Control Mechanisms
... Now that LacI has been removed for the operator, RNA polymerase can proceed with transcription ...
... Now that LacI has been removed for the operator, RNA polymerase can proceed with transcription ...
The lac Operon
... Gene Expression Gene expression for all genes falls into one of two categories. constitutive expression – ...
... Gene Expression Gene expression for all genes falls into one of two categories. constitutive expression – ...
Chapter 18: Control of Gene Expression in Bacteria
... 7.) The protein coded by the LacI gene can be altered in a way that changes its function. What is the name of this change and what induces the change to this protein? 8.) Is the lac operon an example of positive or negative control? Based on the mechanism, explain why. How can this type of control t ...
... 7.) The protein coded by the LacI gene can be altered in a way that changes its function. What is the name of this change and what induces the change to this protein? 8.) Is the lac operon an example of positive or negative control? Based on the mechanism, explain why. How can this type of control t ...
What happens to the repressor when lactose is present?
... • What happens to the repressor when lactose is present? • Lactose fits into the active site of the repressor protein, which causes it to release from the operator. RNA polymerase can copy the gene. ...
... • What happens to the repressor when lactose is present? • Lactose fits into the active site of the repressor protein, which causes it to release from the operator. RNA polymerase can copy the gene. ...
Gene Regulation - yayscienceclass
... Four of the many different types of human cells: They all share the same genome. What makes them different? ...
... Four of the many different types of human cells: They all share the same genome. What makes them different? ...
Problems in Replication and Protein Synthesis
... and the gene is on, protein production must be stimulated. • Ex. If lactose and glucose are both present E. Coli chooses to use glucose and does not produce enzyme to break down lactose (even though the lactose operon is on) ...
... and the gene is on, protein production must be stimulated. • Ex. If lactose and glucose are both present E. Coli chooses to use glucose and does not produce enzyme to break down lactose (even though the lactose operon is on) ...
Protein Synthesis
... • in eukaryotic cells, there are 4 levels of gene regulation: – transcriptional – post-transcriptional – translational – post-translational ...
... • in eukaryotic cells, there are 4 levels of gene regulation: – transcriptional – post-transcriptional – translational – post-translational ...
presentation source
... – CAP's helix-turn-helix motif binds to DNA near several promoters – Promoters activates, genes transcribed ...
... – CAP's helix-turn-helix motif binds to DNA near several promoters – Promoters activates, genes transcribed ...
Gene Expression
... • DNA bends to allow interaction of enhancer with promoter so RNA polymerase can bind – 1 promoter per gene ...
... • DNA bends to allow interaction of enhancer with promoter so RNA polymerase can bind – 1 promoter per gene ...
gene regulation
... • Positive control when lactose is E. coli’s sole carbon source (but not if glucose also is present). • Catabolite activator protein (CAP) binds cAMP, activates, and binds to a CAP recognition site upstream of the promoter (cAMP is greatly reduced in presence of glucose). ...
... • Positive control when lactose is E. coli’s sole carbon source (but not if glucose also is present). • Catabolite activator protein (CAP) binds cAMP, activates, and binds to a CAP recognition site upstream of the promoter (cAMP is greatly reduced in presence of glucose). ...
Dr Ishtiaq Regulation of gene expression
... into glucose and galactose. • lacY encodes β-galactoside permease (LacY), a membrane-bound transport protein that pumps lactose into the cell. • lacA encodes β-galactoside transacetylase (LacA), an enzyme that transfers an acetyl group from acetyl-CoA to βgalactosides. • Only lacZ and lacY appear to ...
... into glucose and galactose. • lacY encodes β-galactoside permease (LacY), a membrane-bound transport protein that pumps lactose into the cell. • lacA encodes β-galactoside transacetylase (LacA), an enzyme that transfers an acetyl group from acetyl-CoA to βgalactosides. • Only lacZ and lacY appear to ...
Lecture 10/11/06
... These cells respond to the environment and communicate with each other with incredible efficiency. For example, take cells that make their own light: They won’t do it unless there are other cells of the same type around. It only works if there’s a certain density. They send out signals that act ...
... These cells respond to the environment and communicate with each other with incredible efficiency. For example, take cells that make their own light: They won’t do it unless there are other cells of the same type around. It only works if there’s a certain density. They send out signals that act ...
4-5
... Both of these mutations put an Adenine (A) where it doesn’t belong in the code. Which of these would result in more disruption in the amino acid sequence of the protein this gene codes for? EXPLAIN YOUR ANSWER ___________________________________________________________________________________ ______ ...
... Both of these mutations put an Adenine (A) where it doesn’t belong in the code. Which of these would result in more disruption in the amino acid sequence of the protein this gene codes for? EXPLAIN YOUR ANSWER ___________________________________________________________________________________ ______ ...
OPERONS NOTES
... The lacI regulatory gene is called the lacI regulator gene. Regulatory genes are not necessarily close to the operons they affect. The general term for the product of a regulatory gene is a regulatory protein. -The Lac regulatory protein is called a repressor because it keeps RNA polymerase from tra ...
... The lacI regulatory gene is called the lacI regulator gene. Regulatory genes are not necessarily close to the operons they affect. The general term for the product of a regulatory gene is a regulatory protein. -The Lac regulatory protein is called a repressor because it keeps RNA polymerase from tra ...
The Jacob-Monod Hypothesis of Gene Action in Bacteria
... The bacteria will grow rapidly in a culture medium containing glucose (as the energy source) and inorganic salts. If, however, lactose is substituted for glucose, E. coli will not grow immediately but after a short time lag it begins to show growth rate as for a glucose medium. Lactose is a sugar fo ...
... The bacteria will grow rapidly in a culture medium containing glucose (as the energy source) and inorganic salts. If, however, lactose is substituted for glucose, E. coli will not grow immediately but after a short time lag it begins to show growth rate as for a glucose medium. Lactose is a sugar fo ...
Discussion of control of the lac operon and mutational analysis
... I s=inducer binding region mutated Inhibits transcription, even with inducer ...
... I s=inducer binding region mutated Inhibits transcription, even with inducer ...
check understanding 13.4 gene regulation
... 1. A tiny bacterium like E. coli contains more than 4000 genes. The bacterium does not need all these genes to be active at the same time, so it turns many of them off until needed. This method of switching genes on and off is known as gene ______________________________. 2. In prokaryotes, gene exp ...
... 1. A tiny bacterium like E. coli contains more than 4000 genes. The bacterium does not need all these genes to be active at the same time, so it turns many of them off until needed. This method of switching genes on and off is known as gene ______________________________. 2. In prokaryotes, gene exp ...
Bio 102 Practice Problems
... 1. Testosterone (shown at right) is a hormone that plays important roles in male development and reproduction. Among other things, it stimulates germ cells in the seminiferous tubules of the testes to divide by meiosis and produce sperm. a. Like all hormones, testosterone travels in the blood throug ...
... 1. Testosterone (shown at right) is a hormone that plays important roles in male development and reproduction. Among other things, it stimulates germ cells in the seminiferous tubules of the testes to divide by meiosis and produce sperm. a. Like all hormones, testosterone travels in the blood throug ...
Lac operon
lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria. Although glucose is the preferred carbon source for most bacteria, the lac operon allows for the effective digestion of lactose when glucose is not available. Gene regulation of the lac operon was the first genetic regulatory mechanism to be understood clearly, so it has become a foremost example of prokaryotic gene regulation. It is often discussed in introductory molecular and cellular biology classes at universities for this reason.Bacterial operons are polycistronic transcripts that are able to produce multiple proteins from one mRNA transcript. In this case, when lactose is required as a sugar source for the bacterium, the three genes of the lac operon can be expressed and their subsequent proteins translated: lacZ, lacY, and lacA. The gene product of lacZ is β-galactosidase which cleaves lactose, a disaccharide, into glucose and galactose. LacY encodes lactose permease, a protein which becomes embedded in the cytoplasmic membrane to enable transport of lactose into the cell. Finally, lacA encodes galactoside O-acetyltransferase. Layout of the lac operon.It would be wasteful to produce the enzymes when there is no lactose available or if there is a more preferable energy source available, such as glucose. The lac operon uses a two-part control mechanism to ensure that the cell expends energy producing the enzymes encoded by the lac operon only when necessary. In the absence of lactose, the lac repressor halts production of the enzymes encoded by the lac operon. In the presence of glucose, the catabolite activator protein (CAP), required for production of the enzymes, remains inactive, and EIIAGlc shuts down lactose permease to prevent transport of lactose into the cell. This dual control mechanism causes the sequential utilization of glucose and lactose in two distinct growth phases, known as diauxie.