Molecular Genetics Lecture 21

A mutation in the lacZ gene, preventing the production of the enzyme beta-galactosidase.

A mutation in the lacY gene, preventing the production of lactose permease, a protein responsible for transporting lactose into the cell.

A mutation in the lacP promoter, disrupting the binding site for RNA polymerase, resulting in reduced transcription of the lac operon.

A mutation in the lacI gene, resulting in a non-functional LacI repressor protein, which cannot bind to the lacO operator, leading to constitutive expression of the lac operon.

In the absence of lactose, the LacI repressor binds to the lacO operator, preventing RNA polymerase from transcribing the lac operon.

When both glucose and lactose are present, LacI does not bind to lacO, but the affinity of RNA polymerase for the lacP promoter is low. Only a few transcripts are produced.

In the absence of glucose and presence of lactose, the LacI repressor does not bind to the lacO operator. The cAMP-CAP complex binds to the lacP promoter, enhancing RNA polymerase binding and transcription.

The lac operon is efficiently transcribed when lactose is available and glucose is absent. This ensures that the cell only utilizes lactose as a carbon source when glucose is scarce.

A modification of a cytosine base where a methyl group (CH3) is added to the 5' position of the cytosine ring. This alters the structure of the cytosine base.

Proteins that recognize and bind to methylated DNA, particularly 5-methylcytosine.

The modification of cytosine to 5-methylcytosine doesn't change how it pairs with guanine in DNA.

Enzymes involved in removing acetyl groups from histone proteins.

The process of silencing or repressing gene expression.

Set of techniques to manipulate DNA sequences, including locating, isolating, altering, amplifying and studying.

A method used to separate DNA fragments based on their size. Smaller DNA fragments move faster through the gel than larger fragments.

The application of Recombinant DNA technology to solve practical problems in medicine, agriculture, biotechnology.

A molecule that binds to DNA and makes it visible under UV light. This allows researchers to see the DNA fragments after they are separated by electrophoresis.

A molecule that is used as a reference point to determine the size of other DNA fragments.

Field focused on designing and creating new biological systems with functions not found in nature.

A set of biochemical tools that cut DNA at specific sequences.

A small piece of DNA that is inserted into a vector to create a recombinant DNA molecule.

A DNA molecule that carries and replicates the gene of interest in a host organism.

A vehicle used to transport and replicate DNA inserts. Vectors are often plasmids or viruses.

Process of making identical copies of a specific DNA fragment using vectors and host cells.

The process of creating a recombinant DNA molecule by joining a DNA insert into a vector.

A technique that separates DNA fragments based on their length and electric charge.

A molecule of DNA that contains both the vector and the insert. It's a combination of two different DNA molecules.

A technique that uses a thermal cycling process to amplify a specific DNA sequence.

The process of transferring DNA into cells. This allows the cells to produce the protein encoded by the DNA.

A process where acetyl groups are added to histone tails, making DNA more accessible to transcription factors, leading to increased gene expression.

A modification to DNA where a methyl group is added, making DNA less accessible to transcription factors, leading to decreased gene expression.

Heritable changes in gene expression that do not involve alterations to the DNA sequence. These modifications can be passed on through cell division and, in some cases, across generations.

Proteins associated with DNA that help regulate gene expression.

A stable, inactive form of chromatin, characterized by tightly packed DNA, making it difficult for transcription factors to access genes.

A highly active form of chromatin, characterized by loosely packed DNA, making it easy for transcription factors to access genes.

During early development, in females, one of the two X chromosomes is randomly inactivated and condensed into a Barr body, making it inactive.

A mosaic pattern in females where different cells express genes from either one or the other X chromosome due to X chromosome inactivation.

A short segment of DNA that can replicate independently within a host cell. It is used to carry and amplify a specific gene or DNA fragment in genetic engineering.

A specific DNA sequence within a plasmid that initiates DNA replication, allowing the plasmid to multiply within a host cell.

A gene within a plasmid that provides resistance to a specific antibiotic, allowing selection for bacteria containing the plasmid.

A region within a plasmid containing multiple restriction enzyme recognition sites, allowing the insertion of foreign DNA at specific locations.

A DNA sequence that controls the expression of a gene. It is found upstream of the target gene in a plasmid.

A process that inserts a fragment of DNA into a plasmid vector, creating a recombinant molecule.