Module 9- The central dogma

The bonds that hold DNA and RNA backbones together are known as __________.

3'-5'-phosphodiester linkages

During the transcription process in bacteria, what happens once the sigma factor leaves the core enzyme?

The core enzyme continues RNA elongation.

Which of the following is a DNA nucleotide?

a phosphate group, guanine and deoxyribose

Sequences of DNA that are conserved and seen upstream of a transcription initiation site in roughly the same location from gene to gene in bacteria are called ________.

consensus sequences

The enzyme that is responsible for the synthesis of RNA from a DNA template is called _______.

DNA-dependent RNA polymerase

The site where RNA polymerase attaches to a DNA molecule to begin transcription is the:____________

promoter

Which enzyme transcribe most of the large ribosomal RNA in eukaryotic cells?

Polymerase I

Which of the following scientists generated this X-Ray diffraction that led to the discovery of the DNA molecule?

Rosalind Franklin

Which of the following is NOT part of the translation process in the Central Dogma?

Kinesins

Purines

A type of nitrogenous base that includes adenine (A) and guanine (G), characterized by a two-ring structure.

Pyrimidines

A type of nitrogenous base that includes cytosine (C), thymine (T), and uracil (U), characterized by a single-ring structure.

Gene expression

The process by which information from a gene is used to synthesize functional gene products, usually proteins.

Ribosomal RNA

A type of RNA that, together with proteins, makes up the ribosomes, the site of protein synthesis.

Transfer RNA

A type of RNA that transports amino acids to the ribosome during protein synthesis, matching them to the coded mRNA sequence.

RNA polymerase

An enzyme that synthesizes RNA from a DNA template during the process of transcription.

Proofreading

The process by which DNA polymerase checks and corrects errors during DNA replication.

Transcript unit

The segment of DNA that is transcribed into RNA, including the gene and its regulatory elements.

rDNA

Ribosomal DNA, the DNA sequences that code for ribosomal RNA.

Nucleoli

Small, dense structures within the nucleus where ribosomal RNA is synthesized and ribosome assembly begins.

Split genes

Genes that are interrupted by non-coding sequences (introns) that are removed during RNA processing.

Intervening sequences

Non-coding regions of a gene that are transcribed into RNA but are removed during RNA splicing.

Methylguanosine cap

A modified guanine nucleotide added to the 5' end of mRNA, important for stability and initiation of translation.

3' Poly(A) tail

A stretch of adenine nucleotides added to the 3' end of mRNA, enhancing stability and facilitating export from the nucleus.

RNA splicing

The process of removing introns and joining exons in a pre-mRNA transcript to produce mature mRNA.

RNA interference

A biological process in which RNA molecules inhibit gene expression or translation by targeting specific mRNA molecules.

siRNA

Small interfering RNA, a class of double-stranded RNA molecules that play a role in RNA interference and gene silencing.

microRNA

Small, non-coding RNA molecules that regulate gene expression by binding to complementary sequences in mRNA.

CRISPR

A revolutionary gene-editing technology that allows for precise modifications to DNA sequences in organisms.

tRNA

Transfer RNA, the molecule that carries amino acids to the ribosome during protein synthesis.

Anticodon

A sequence of three nucleotides in tRNA that is complementary to a corresponding codon in mRNA.

Initiation factor

Proteins that assist in the initiation of translation by helping the ribosome assemble on the mRNA.

A, P, and E site

The three binding sites on the ribosome: the A (aminoacyl) site, P (peptidyl) site, and E (exit) site, involved in translation.

Translocation

The process during translation where the ribosome moves along the mRNA, shifting the tRNA and the growing polypeptide chain.

What is the Watson-Crick proposal?

The Watson-Crick proposal refers to the model of DNA structure that describes it as a double helix, where two strands are held together by complementary base pairing between adenine-thymine and guanine-cytosine.

What are the relationships among genes, proteins, and RNAs?

Genes are segments of DNA that encode instructions for synthesizing proteins. RNA serves as a messenger between DNA and proteins, with messenger RNA (mRNA) transcribing the genetic information and transfer RNA (tRNA) assisting in translating that information into proteins.

What is the flow of information through the cell?

The flow of information in a cell typically follows the central dogma of molecular biology: DNA is transcribed into RNA, which is then translated into proteins. This process involves replication, transcription, and translation.

What is the role of polymerases in transcription?

Polymerases are enzymes that synthesize RNA from a DNA template during transcription. RNA polymerase binds to the promoter region of a gene and catalyzes the formation of RNA by adding complementary RNA nucleotides.

What is transcription in prokaryotic and eukaryotic cells?

Transcription in prokaryotic cells occurs in the cytoplasm and involves a single RNA polymerase. In eukaryotic cells, transcription occurs in the nucleus and involves multiple RNA polymerases, with additional processing steps for mRNA before it exits to the cytoplasm.

What are eukaryotic nuclear RNA polymerases?

Eukaryotic nuclear RNA polymerases are enzymes that transcribe different types of RNA in eukaryotic cells. There are three main types: RNA polymerase I (for rRNA), RNA polymerase II (for mRNA), and RNA polymerase III (for tRNA and other small RNAs).

What is the synthesis and processing of eukaryotic ribosomal and transfer RNAs?

Eukaryotic ribosomal RNA (rRNA) is synthesized in the nucleolus and undergoes processing to form the ribosomal subunits. Transfer RNA (tRNA) is also synthesized in the nucleus and requires processing, including splicing and the addition of a CCA tail, before it is functional.

What is the initiation of transcription from a eukaryotic polymerase II promoter?

Initiation of transcription from a eukaryotic polymerase II promoter involves the binding of transcription factors to the promoter region, followed by the recruitment of RNA polymerase II, which begins RNA synthesis after the DNA strands are unwound.

What is the structure of messenger RNA?

Messenger RNA (mRNA) is a single-stranded molecule that carries genetic information from DNA to the ribosome. It has a 5' cap, a coding region that contains codons, and a poly-A tail at the 3' end, which aids in stability and translation.

What are introns and splicing machinery?

Introns are non-coding sequences within a gene that are removed during RNA processing. The splicing machinery, including spliceosomes, recognizes introns and exons (coding sequences) to join exons together, forming mature mRNA.

What is the processing of eukaryotic mRNAs?

Processing of eukaryotic mRNAs includes capping at the 5' end, polyadenylation at the 3' end, and splicing to remove introns, resulting in a mature mRNA that can be translated into a protein.

Wobble hypothesis, U anticodon pairs with? and G with? and I with?

U: A or G, G: C or U, I: A C U