Transcription Initiation in Prokaryotes and Eukaryotes

<p>5</p> Signup and view all the answers

<p>50nt / sec</p> Signup and view all the answers

<p>10%</p> Signup and view all the answers

<p>3'-end</p> Signup and view all the answers

<p>24,000-31,000</p> Signup and view all the answers

<p>Cloverleaf</p> Signup and view all the answers

<p>Complementary codon recognition</p> Signup and view all the answers

<p>To restore methylation patterns on newly synthesized DNA</p> Signup and view all the answers

<p>Silencing cascade resulting in closed chromatin</p> Signup and view all the answers

<p>DNA is largely lacking of methylation</p> Signup and view all the answers

<p>It is deacetylated and then methylated to silence gene expression</p> Signup and view all the answers

<p>DNMT3A and DNMT3B</p> Signup and view all the answers

<p>Faithful replication of methylation patterns</p> Signup and view all the answers

<p>Triggering hydrolysis of peptidyl-tRNA at the ribosomal peptidyl transferase center</p> Signup and view all the answers

<p>It forms the large ribosomal subunit</p> Signup and view all the answers

<p>A higher S value indicates a denser particle</p> Signup and view all the answers

<p>Eukaryotes have a single precursor RNA, while prokaryotes have multiple precursors</p> Signup and view all the answers

<p>Transcription is coupled to translation</p> Signup and view all the answers

<p>80-90%</p> Signup and view all the answers

<p>It results in the loss of a few nucleotides</p> Signup and view all the answers

<p>50 nucleotides</p> Signup and view all the answers

<p>90-100%</p> Signup and view all the answers

<p>New DNA synthesis occurs on both strands</p> Signup and view all the answers

<p>Homology-directed repair results in gene conversion, while homologous recombination results in new genetic combinations</p> Signup and view all the answers

<p>Crossover</p> Signup and view all the answers

<p>Histone H1 stabilizes both nucleosome structure and higher-order chromatin architecture.</p> Signup and view all the answers

<p>It forms a nucleosome.</p> Signup and view all the answers

<p>It produces the chromatid of a chromosome.</p> Signup and view all the answers

<p>It links the histone cores.</p> Signup and view all the answers

<p>It makes approximately 2 complete turns.</p> Signup and view all the answers

<p>Chromosomes need to be less condensed in the form of chromatin fibers to allow for gene expression.</p> Signup and view all the answers

<p>To unwind the double-stranded DNA template</p> Signup and view all the answers

<p>It blocks mtSSB binding, allowing POLRMT to initiate primer synthesis</p> Signup and view all the answers

<p>To initiate primer synthesis</p> Signup and view all the answers

<p>At the 3′-end of the primer, after about 25 nt</p> Signup and view all the answers

<p>To bind and protect the exposed parental H-strand</p> Signup and view all the answers

<p>Enzymes and transport, defense, and regulatory proteins are globular in nature, making them soluble, while structural and motility proteins are fibrous and insoluble.</p> Signup and view all the answers

<p>It marks the start of polypeptide synthesis and ensures that the translation process begins with a methionine residue.</p> Signup and view all the answers

<p>It means that base substitution does not necessarily change an amino acid.</p> Signup and view all the answers

<p>The quaternary structure of hemoglobin, with its four Fe2+-containing heme groups, allows it to bind oxygen and transport it efficiently.</p> Signup and view all the answers

<p>The energy source required is ATP, which is used to activate the amino acid and attach it to the tRNA, facilitating the first step in polypeptide synthesis.</p> Signup and view all the answers

<p>It is aligned with the next codon, which will be bound with the anticodon of the next tRNA.</p> Signup and view all the answers

<p>The combinatorial nature of protein function allows for a vast range of possible functions without a corresponding increase in gene number, contributing to the genetic complexity of higher organisms.</p> Signup and view all the answers

<p>It is where the uncharged tRNA is moved to and released from the ribosome.</p> Signup and view all the answers

<p>The primary structure is the amino acid sequence, the secondary structure is the local spatial arrangement of the backbone, the tertiary structure is the 3D structure of the entire polypeptide, and the quaternary structure is the arrangement of subunits in a multi-subunit protein.</p> Signup and view all the answers

<p>They signal the termination of the amino acid chain when the ribosome encounters a termination codon.</p> Signup and view all the answers

<p>Oligomers are proteins that work together, composed of individual monomers, which are the component proteins that make up the oligomer.</p> Signup and view all the answers

<p>It is done by initiating factors that participate in the formation of the ribosome complex.</p> Signup and view all the answers

<p>It activates the initiator caspase after binding of Fas ligand to Fas death receptors.</p> Signup and view all the answers

<p>It forms an apoptosome with Apaf1, leading to the activation of the initiator caspase.</p> Signup and view all the answers

<p>They bind to cell-surface death receptors, leading to the formation of the DISC and activation of the initiator caspase.</p> Signup and view all the answers

<p>They release cytochrome c, which forms an apoptosome with Apaf1, leading to the activation of the initiator caspase.</p> Signup and view all the answers

<p>It leads to the controlled death of the cell through the cleavage of key proteins.</p> Signup and view all the answers

<p>They provide two distinct mechanisms for the controlled death of cells in response to different apoptotic signals.</p> Signup and view all the answers

<p>Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA)</p> Signup and view all the answers

<p>A 5-carbon sugar (pentose), a nitrogenous base, and a phosphate group</p> Signup and view all the answers

<p>A nucleoside is a sugar moiety with a nitrogenous base, while a nucleotide is a nucleoside with a phosphate group attached</p> Signup and view all the answers

<p>In DNA, the sugar moiety is 2-deoxyribose, while in RNA, it is ribose</p> Signup and view all the answers

<p>Phosphorylation</p> Signup and view all the answers

<p>It is responsible for encoding genetic information</p> Signup and view all the answers

<p>DNA methylation regulates gene expression by recruiting proteins that bind to methylated DNA, which form complexes with histone deacetylases, resulting in deacetylated histones and compact and silent chromatin.</p> Signup and view all the answers

<p>Selective methylation of homologous genes during gametogenesis ensures balanced gene expression by marking imprinted genes, which are crucial for normal growth and development.</p> Signup and view all the answers

<p>Methylated C residues in the promoter regions of tumor suppressor genes lead to gene inactivation, contributing to cancer development by silencing tumor suppressor genes.</p> Signup and view all the answers

<p>Epigenetic reprogramming in early embryogenesis erases adult patterns of methylation, allowing for the establishment of new gene expression patterns necessary for development.</p> Signup and view all the answers

<p>DNA methylation dysregulation in disease states can lead to aberrant gene expression, contributing to the development and progression of diseases, including cancer.</p> Signup and view all the answers

<p>DNA methylation maintains genomic stability by regulating gene expression and chromatin structure, ensuring proper gene expression patterns and preventing aberrant gene expression.</p> Signup and view all the answers

<p>TWINKLE is a DNA helicase that travels in front of POLγ to unwind the double-stranded DNA template during mtDNA replication.</p> Signup and view all the answers

<p>L-strand DNA synthesis occurs after about 25 nt, when POLγ replaces POLRMT at the 3′-end of the primer, and POLγ synthesizes the new DNA strand.</p> Signup and view all the answers

<p>The stem-loop structure formed at OL blocks mtSSB binding, allowing POLRMT to initiate primer synthesis and L-strand DNA synthesis to occur.</p> Signup and view all the answers

<p>POLRMT initiates primer synthesis, while POLγ synthesizes the new DNA strand. POLRMT acts first, followed by POLγ, which replaces it at the 3′-end of the primer after about 25 nt.</p> Signup and view all the answers

<p>mtSSB protects the exposed, parental H-strand from degradation, allowing it to serve as a template for DNA synthesis and ensuring the integrity of the genetic material.</p> Signup and view all the answers

<p>Proofreading and 3' to 5' exonuclease activity</p> Signup and view all the answers

<p>Primase intersperses RNA primers in the lagging strand; leading strand requires only one priming event</p> Signup and view all the answers

<p>In prokaryotes, it removes RNA primers; in eukaryotes, enzymes such as FEN1 and RNase H perform this function</p> Signup and view all the answers

<p>Okazaki fragments are short, discontinuous DNA fragments formed on the lagging strand during DNA replication</p> Signup and view all the answers

<p>Leading strand synthesis occurs in the 5' to 3' direction, while lagging strand synthesis occurs in short, discontinuous fragments</p> Signup and view all the answers

<p>Exonuclease activity removes incorrect nucleotides, ensuring the accuracy of DNA synthesis</p> Signup and view all the answers

<p>The primary function of the checkpoints in the cell cycle, specifically the G1 and G2 checkpoints, is to ensure that the cell is ready to proceed to the next stage of the cell cycle, and if the cell is not ready, it may be signaled to undergo apoptosis.</p> Signup and view all the answers

<p>If a cell fails to pass the G1 checkpoint, it may be signaled to undergo apoptosis.</p> Signup and view all the answers

<p>Apoptosis plays a crucial role in the development of digits, as seen in the interdigital cell death, by eliminating excess tissue between the developing digits, allowing for proper formation and separation of the digits.</p> Signup and view all the answers

<p>If a cell fails to pass the G2 checkpoint, it may be signaled to undergo apoptosis.</p> Signup and view all the answers

<p>Apoptosis plays a crucial role in the regulation of cell growth and development by eliminating damaged or defective cells, allowing for proper tissue formation and development.</p> Signup and view all the answers

<p>The key morphological features of a cell during the events of apoptosis include cell shrinkage and condensation, flipping of the plasma membrane, collapse of the cytoskeleton, disintegration of organelles, disassembly of the nuclear envelope, condensation and break-up of chromatin, and formation of apoptotic bodies.</p> Signup and view all the answers