MOL100H23 lecture 8 transcription translation

Central Dogma of Molecular Biology

The concept that genetic information flows from DNA to RNA to protein.

DNA

Deoxyribonucleic acid, a polymer composed of nucleotides that carries genetic information.

RNA

Ribonucleic acid, a nucleic acid polymer made of nucleotides that plays a role in protein synthesis.

Transcription

The process of synthesizing RNA from a DNA template.

Translation

The process of synthesizing protein from an RNA template.

Replication

The process of copying DNA to produce an identical copy.

Reverse transcription

The process of synthesizing DNA from an RNA template.

Nucleic acid structure

The structure of DNA and RNA, composed of nucleotides.

Nucleotide

The monomer unit of DNA and RNA, consisting of a sugar, phosphate group, and nitrogenous base.

Phosphodiester bond

The covalent bond that links nucleotides together in a DNA or RNA strand.

Purines

A type of nitrogenous base found in DNA and RNA, including adenine and guanine.

Pyrimidines

A type of nitrogenous base found in DNA and RNA, including thymine, cytosine, and uracil.

Watson-Crick base pairs

The specific base pairing rules in DNA, where adenine pairs with thymine and guanine pairs with cytosine.

Double helix

The structure of DNA, consisting of two anti-parallel strands twisted together.

Major groove

A larger indentation in the double helix structure of DNA.

Minor groove

A smaller indentation in the double helix structure of DNA.

Flexible

DNA's ability to bend and twist.

Francis Crick

One of the scientists credited with discovering the structure of DNA.

James Watson

One of the scientists credited with discovering the structure of DNA.

Maurice Wilkins

One of the scientists credited with discovering the structure of DNA.

Rosalind Franklin

One of the scientists credited with contributing to the discovery of the structure of DNA.

DNA vs RNA

The differences between DNA and RNA in terms of structure and function.

5' end

One end of a DNA or RNA strand that has a free phosphate group.

3' end

One end of a DNA or RNA strand that has an OH group on the sugar.

mRNA processing

The modifications made to the primary transcript of mRNA in eukaryotes.

5' Cap

A modified guanine nucleotide added to the 5' end of mRNA.

Poly(A) tail

A string of adenine nucleotides added to the 3' end of mRNA.

Introns

Non-coding sequences in the primary transcript of mRNA that are removed during splicing.

Exons

Coding sequences in the primary transcript of mRNA that remain in the mature mRNA.

Alternative splicing

The process by which different combinations of exons are included in the mature mRNA, leading to the production of different protein isoforms.

Genetic code

The set of rules that determines how the information in DNA or RNA is translated into protein.

Codon

A three-letter combination of nucleotides that encodes for a specific amino acid.

Start codon

The codon (AUG) that signals the start of protein synthesis and codes for methionine.

Stop codon

The codon (UAA, UAG, or UGA) that signals the end of protein synthesis.

Reading frames

The three possible ways to "read" an mRNA sequence.

Start codon

The first codon (AUG) in an mRNA sequence that indicates the correct reading frame and where translation begins.

tRNAs

Transfer RNAs, a class of non-coding RNA that have anti-codons complementary to mRNA codons and are attached to amino acids.

Anti-codon loop

Part of the tRNA structure that contains the anti-codon sequence.

Acceptor stem

Part of the tRNA structure where the amino acids are bound.

Aminoacyl-tRNA synthetases

Enzymes that link tRNA to amino acids via a high-energy ester bond, generating aminoacyl tRNA.

Translation

The process of "reading" mRNA and converting it into a sequence of amino acids to form a protein.

Ribosome

A large complex of protein and RNA (rRNA) that translates mRNA into protein.

Ribozyme

The RNA component of the ribosome that has catalytic activity.

GTPases

Enzymes that hydrolyze guanosine triphosphate (GTP) and act as quality control switches at different stages of translation.

Preinitiation complex

The complex assembled before translation initiation, consisting of the small ribosomal subunit, Met-tRNAiMet, eIF2-GTP, and other factors.

Translation initiation

The process of starting translation, involving the recognition of the start codon and the assembly of the initiation complex.

Translation elongation

The process of adding amino acids to the growing polypeptide chain during translation.

E site

The tRNA binding site on the ribosome where the tRNA exits.

P site

The tRNA binding site on the ribosome where the tRNA attached to the previously added amino acid is located.

A site

The tRNA binding site on the ribosome where new tRNAs enter.

Translation termination

The process of ending translation, triggered by stop codons and the binding of release factors.

Polysomes

Multiple ribosomes translating the same mRNA simultaneously.

PABPC

A protein that binds to the 3' end of mRNAs and the 5' cap, facilitating the re-use of ribosome subunits for a new round of translation.

mRNA

Messenger RNA that carries the genetic information from DNA to the ribosome for protein synthesis.

Ribosome

A ribonuclear protein composed of RNA (rRNA) and proteins, responsible for translating mRNA into protein.

rRNA

Ribosomal RNA, a type of RNA found in the ribosome that helps in protein synthesis.

Initiation

The first stage of translation, where the ribosome forms on the mRNA and recognizes the start codon.

Start codon

A specific sequence of nucleotides on mRNA (usually AUG) that signals the start of protein synthesis.

Elongation

The second stage of translation, where the ribosome moves along the mRNA, reading each codon and adding the corresponding amino acid to the growing protein chain.

Codon

A sequence of three nucleotides on mRNA that codes for a specific amino acid.