16 O&C of Eukaryotic Genome Notes 2024

Acetylation of free lysine residues.

By blocking the binding of transcription factors and inducing heterochromatin formation.

A highly condensed chromosome structure at mitosis.

It recognizes and binds to regions with methylated DNA, inducing histone deacetylation.

Half-life of RNA and initiation of translation.

It pairs with the telomere sequence to allow extension.

A longer poly-A tail acts as a buffer against degradation, allowing the mRNA to remain functional for more translation.

Proteins that bind to specific DNA sequences, known as control elements, to control the rate of transcription.

By preventing fusion of chromosomal ends with other chromosomes.

The remainder of the DNA not wound around histones that joins adjacent nucleosomes.

It enables the synthesis of many more proteins than would be expected from its 20,000 protein-coding genes.

A specific nucleotide sequence located just upstream of a gene that initiates transcription.

Post-transcriptional modifications, including alternative splicing, occur in eukaryotes.

Post-translational modifications and protein degradation.

To form functional proteins through the addition of chemical groups.

The promoter to initiate transcription at a basal rate.

It prevents the formation of the transcription initiation complex.

It determines how long mRNA remains available for translation, influencing the amount of protein produced.

To bind to specific non-coding DNA sequences to regulate the rate of transcription.

The addition of hydroxyl groups, such as in collagen polypeptides forming hydroxyproline and hydroxylysine.

It uses the short RNA molecule as a template to extend the telomere length.

Eukaryotic genomes are generally much larger and consist of linear chromosomes, while prokaryotic genomes are smaller and typically circular.

Both use translational repressors or RNA complementary to the Shine-Dalgarno sequence/5' UTR.

A complex of proteins that forms at each centromere and serves as the attachment point for spindle fibers.

Sections of non-coding DNA within eukaryotic genes.

Prokaryotes do not package DNA as chromatin and do not have histone modifications, while eukaryotes use chromatin remodeling involving histone acetylation and DNA methylation.

They catalyze histone deacetylation, reverting histones to a positively charged state.

Non-coding DNA includes portions that do not encode protein or RNA, such as introns, centromeres, telomeres, promoters, enhancers, and silencers.

At different levels including chromatin level, transcriptional level, and post-transcriptional level.

It appears as darkly-stained regions.

It binds to the site where DNA enters and exits the nucleosome, stabilizing it.

The binding of specific transcription factors to DNA control elements.

By methylating CpG-rich sites where many transcription factors bind, preventing their attachment.

A specific nucleotide sequence that suppresses transcription by binding to repressor proteins.

Contains genes that are actively transcribed or destined to be transcribed.

A regulation mechanism that allows different combinations of exons to be joined, producing multiple protein variants from a single gene.

Genes that are continuously expressed and involved in general cell maintenance and activity.

In specific regions, including centromeres and telomeres.

Germ (sex) cells.

Through chemical modification of DNA and histone proteins, such as methylation.

A modification of DNA structure through the addition of methyl groups, catalyzed by DNA methyltransferase, without altering the DNA sequence.

A state where the number of chromosomes is not a multiple of the haploid set.

It allows greater accessibility to the underlying DNA sequence.

It generally enhances transcription by making DNA more accessible.

No, it often requires additional factors for a sufficient effect.

Activators needed for the expression of the crystallin gene.

To remove proteins that are no longer required and recycle raw materials like amino acids.

Through ubiquitinylation and proteasome action.

Telomerase.

Chromatin remodeling, transcription, post-transcription, translation, and post-translation.

More than 90% does not code for protein or RNA.

Ubiquitinylation and protein degradation by the proteasome.

They bind to the 5' UTR of mRNA, preventing ribosome binding and formation of the translational initiation complex.

Sister chromatid adhesion and kinetochore formation.

In transcriptionally inactive regions of the genome.

Central nuclear matrix scaffold proteins.

Euchromatin and heterochromatin.

Heterochromatin.

A variety of transcription factors that bind to specific control elements in the genome.

The close packing of DNA around histones in nucleosomes.

Promoters, silencers, and enhancers.

They are usually transcriptionally inactive.

A process where one of the two X chromosomes in female mammals remains as heterochromatin.

A 'bead-like' structure formed by DNA winding around a core of histone proteins.

Certain hormones and specific proteins that bind to the 3' UTR of mRNA can stimulate or retard degradation.

Formation of a stem-loop at the 3' end, which prevents digestion by 3' exonucleases.

They may increase or decrease the rate of transcription of the target gene.

Improper chromosomal alignment and segregation, resulting in aneuploidy.

The helical structure formed by the coiling of nucleosome 'beads'.

They take advantage of changing environmental conditions, such as food sources, to respond efficiently and economically.

The addition of short carbohydrate chains to proteins, forming glycoproteins.

Ubiquitin is covalently added to the N-terminus of the protein to mark it for degradation.

It activates enzymes like phosphatase that remove phosphate groups from proteins.

No, post-translational modifications do not occur in prokaryotes.

They upregulate the activity of RNA polymerase.

Increased or decreased rate of transcription.

Telomeres.

A modification that involves the addition of methyl groups to DNA, influencing gene expression.

No, they do not occur in prokaryotes.

It allows organisms to respond efficiently to changing environmental conditions and maintain homeostasis.

Remodeling of chromatin to be more closely packed, leading to transcriptionally inactive regions.

It regulates gene expression at the processing of pre-mRNA, including splicing, polyadenylation, and 5' capping.

It activates many transcription factors and proteins involved in cell signaling.

At the transcriptional level, often using the operon system.

It changes their charge, affecting the association between DNA and histone proteins.

Eukaryotes involve a unique combination of control elements, including enhancers and silencers that are distal to the genes.

For recognition and binding to a specific DNA sequence.

They can interact directly to block further assembly or prevent the release of RNA polymerase.

About 220 nucleotides.

A modification that involves the addition of acetyl groups to histone proteins, affecting gene expression.

In prokaryotes, transcription and translation occur simultaneously, while in eukaryotes, they are separated by the nuclear envelope.

It activates transcription by binding to activator proteins, located far from the transcription start site.

Telomeres.

It switches off gene expression due to lower accessibility of proteins to DNA.

Transcriptionally active regions usually contain acetylated histones.

It causes telomeres to shorten during DNA replication in eukaryotes.

A post-translational modification that can affect DNA packaging and transcription.

5′ - TTAGGG - 3′ repeats.

Through biochemical modifications and proteolytic cleavage.

Involves a single operator that is proximal to the genes under its control.

Monocistronic mRNA, where each gene is controlled by its own promoter.

Eukaryotic repressors have many more mechanisms of action and do not directly block RNA polymerase binding.

A condition where the number of chromosomes is abnormal due to extra or missing chromosomes.

Euchromatin.

The appropriate activator or repressor proteins must be present at a precise time or in a specific cell type.

As lightly-stained regions.

They undergo apoptosis (programmed cell death).

Histone modification and DNA methylation.

They include proteins such as activators and repressors that regulate gene expression.

By regulating the rate of transcription to control the amount of mRNA produced.

They can increase or decrease transcription by affecting DNA packaging.

It plays a crucial role in regulating access to DNA and thus influences gene expression.

To protect genes from being eroded via successive rounds of replication.

For interaction with other proteins of the transcriptional machinery.

It consists of two identical sister chromatids joined at the centromeres.

It refers to the regulation of a gene by multiple enhancers or silencers, each active at different times or in different cell types.

CpG-rich sites.

DNA/RNA, single/double-stranded, number of nucleotides, packing of DNA, linearity/circularity, and presence/absence of introns.

It can regulate transcription through chromatin remodeling.

Chromatin.

Approximately 10%.

It is essential for the activation of proteins like p53 and stabilizing microtubules.

General transcription factors recognize and bind to the promoter via the TATA box and recruit RNA polymerase.

It shields the mRNA against degradation by 5' exonucleases, increasing its half-life.

Specialised DNA sequences that form the ends of linear DNA of eukaryotic chromosomes.

DNA binding domain and activation domain.

They prevent the machinery from recognizing and sticking together the ends of chromosomes when there are breaks.

It allows a single gene to code for more than one protein by including or excluding particular exons.

They allow for alternative splicing, enabling one gene to code for more than one polypeptide.

To distinguish its genome from viral genomes as part of a protection mechanism against viral infection.

The types of activator and repressor proteins expressed in each cell type determine which genes are expressed.

Activators needed for the expression of the albumin gene.

Approximately 50 rounds.

No, they do not need to express all genes all the time or in all cells.

Proximal to the gene it regulates.

Eukaryotic repressor proteins have more complex interactions and regulatory mechanisms compared to prokaryotic ones.

During cell differentiation.

To fold into functional proteins.

51 amino acids, which is less than half of the original translation product.

They limit the lifespan of cells.

Both positive regulation (via catabolite activator protein) and negative regulation (via repressor).

A regulated process that produces different mature mRNA sequences from the same pre-mRNA coded by the same gene.

It lowers the affinity due to decreased positive charge.

They have a more significant effect than the presence of a single unique control element.

It directs the development of the organism and maintains homeostasis.

Promoter, Enhancer, Silencer.

Different cell types express different genes to make different proteins, serving specialized functions.

It is a protease complex that degrades proteins marked by ubiquitin.

It allows the mRNA to remain in the cytoplasm longer and serve as a template for more protein translation.

Involves removal of the signal peptide and C-chain, forming active insulin from pre-proinsulin.

5’ - TTAGGG - 3’ repeated 100 - 1000 times.

The end-replication problem, which causes DNA to shorten after each replication.

By binding to and masking the activation domain of an activator protein.

They suppress the expression of particular genes, such as the albumin gene in lens cells.

Post-translational modifications of histones and modifications of DNA residues.

It consists of two or more linear chromosomes bound by the nuclear membrane, each containing a double-stranded DNA molecule associated with histones.

A DNA looping mechanism aided by DNA bending proteins.

It makes the extended portion of the telomere double stranded.

Polycistronic mRNA, where multiple structural genes are controlled by the same promoter.

It leaves the nucleus to be translated in the cytoplasm.

They downregulate the activity of RNA polymerase.

Eukaryotic mRNA has a 5' cap and a 3' poly-A tail, increasing its half-life, while prokaryotic mRNA is typically less stable.

They are recognized as defective by cellular DNA repair machinery.

5’ capping, splicing, and 3’ polyadenylation.

Heterochromatin is a tightly packed form of DNA that is resistant to transcription, and eukaryotic repressors can package chromatin into this form.

Block the binding of an activator protein to the enhancer sequence.

By recruiting histone deacetylases to condense the chromatin at the promoter region, making it less accessible.