Gene Regulation and Expression

What is methylation, and how does it affect transcription?

Methylation is the addition of a methyl group (-CH3) to histone tails or DNA, resulting in more packing of chromatin and reduced transcription.

What roles do histones play in gene regulation?

Histones are proteins that package and order DNA into structural units called nucleosomes, which can be modified through methylation and acetylation to regulate gene expression.

What is acetylation and its effect on transcription?

Acetylation is the addition of an acetyl group (-CH2CH3) to lysine in histone tails, leading to less packing of chromatin and an increase in transcription.

Define genomic imprinting.

Genomic imprinting is an epigenetic influence that occurs during critical periods, typically during embryonic development or gamete formation, affecting gene expression.

What is epigenetics?

Epigenetics refers to environmental factors or external influences that affect gene expression without changing the DNA sequence.

What are the two types of ncRNA?

The two types of non-coding RNA are small interfering RNA (siRNA) and microRNA (miRNA), both of which block translation or degrade proteins.

What is RNA interference (RNAi)?

RNAi is a biotechnology technique used to silence gene expression.

What occurs during the translocation of a gene?

Translocation occurs when a gene moves from one location to another within the genome.

What is the impact of gene amplification?

Gene amplification results in multiple copies of the same gene, leading to increased cell division.

What are point mutations?

Point mutations are changes in a single nucleotide of a gene or its regulatory elements.

What is the composition of a virus?

A virus is composed of a genome (single or double-stranded RNA/DNA) and a capsid, which is an outer protein coat made of capsomeres.

What are glycoproteins in relation to viruses?

Glycoproteins are proteins with carbohydrate chains that can be present on the surface of viruses, contributing to their structure and function.

What distinguishes lytic viruses from lysogenic viruses?

Lytic viruses immediately infect the host and cause cell lysis, while lysogenic viruses integrate into the host genome and remain dormant until triggered.

What is a retrovirus?

A retrovirus is a type of virus, such as HIV, that uses reverse transcriptase to replicate its RNA into DNA.

How does normal viral replication differ from retrovirus replication?

Normal replication follows DNA --> RNA, while retrovirus replication goes from RNA --> DNA via reverse transcriptase.

What is the difference between viroids and prions?

Viroids are naked RNA that infect plants, whereas prions are misfolded proteins that infect animals and are resistant to treatments.

What are restriction enzymes?

Restriction enzymes are molecular scissors that cut DNA at specific recognition sequences.

What is CRISPR technology used for?

CRISPR is a gene editing technology used to modify DNA sequences in organisms.

What does PCR stand for and its purpose?

PCR stands for polymerase chain reaction, and it is used to amplify specific DNA sequences.

What is gel electrophoresis?

Gel electrophoresis is a technique used to separate DNA fragments by size, where longer fragments travel slower than shorter ones.

Define transformation in bacteria.

Transformation is the process by which bacteria uptake plasmids or small DNA fragments from their environment.

What are operons?

Operons are clusters of genes under the control of a single promoter in prokaryotic cells, allowing coordinated regulation of gene expression.

What is the lac operon?

The lac operon is an example of negative gene regulation in bacteria, controlling the metabolism of lactose.

What is the trp operon?

The trp operon is a prokaryotic operon used in the biosynthesis of tryptophan, illustrating negative gene regulation.

What is positive gene regulation in the lac operon?

Positive gene regulation in the lac operon involves an activator that binds to DNA to enhance the likelihood of transcription.

What is the role of the p53 pathway?

The p53 pathway is involved in tumor suppression by regulating the cell cycle and preventing the proliferation of damaged cells.

What is the function of the RAS pathway?

The RAS pathway is a G-protein signaling pathway that regulates cell division and growth.

What type of genome do bacteria have?

Bacteria have a circular genome that can contain supplementary genetic elements called plasmids.

What are R plasmids?

R plasmids are plasmids that confer antibiotic resistance to bacteria.

What is an F plasmid?

F plasmids are involved in bacterial fertility, facilitating the transfer of genetic material during conjugation.

What did the recombinant DNA in Bacteria lab focus on?

The lab focused on methods to manipulate and study recombinant DNA in bacterial systems.

What is the main focus of the stickleback gene activity?

The stickleback gene activity explores genetic variations and their impacts on phenotype within stickleback populations.

Define silencing gene in the context of methylation.

Silencing gene refers to the effect of methylation that leads to reduced transcription and gene inactivity.

What environmental factors influence epigenetics?

Environmental factors such as diet, stress, and exposure to toxins can influence epigenetic changes that affect gene expression.

What two features characterize small interfering RNA (siRNA)?

siRNA blocks translation and degrades mRNA, effectively silencing gene expression.

How do glycoproteins affect viral infections?

Glycoproteins on the virus surface aid in attachment to host cells, facilitating infection.

What is the significance of using reverse transcriptase in retroviruses?

Reverse transcriptase is significant for retroviruses as it allows RNA to be converted into DNA, which can integrate into the host genome.

What are the main parts of a virus?

The main parts of a virus are the genome and the capsid, which protects the genome.

What is a key mechanism for the production of proteins in a positive gene regulation context?

In positive gene regulation, an activator binds to DNA, increasing the likelihood of transcription and leading to protein production.