Chapter 12 Gene Experssion Flashcards by Syd xxx | Brainscape

Q

The central Dogma

A

DNA —-> RNA —–> protein

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Q

Transcription

A

DNA is transcribed into a pen RNA copy

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Q

Translation

A

mRNA is translated into a polypeptide at the ribosome

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Q

Structural gene

A

Transcribed to produce an MRNA that specifies the amino acid sequence of a polypeptide

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Q

tRNA

A

Translates the language of mRNA into that of amino acids

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Q

rRNA

A

Forms part of ribosomes , which provide the site where translation occurs

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Q

Promoter

A

Signals the beginning of transcription

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Q

Transcribed region

A

Part of this region contains the information that specifies an amino acid sequence

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Q

Regulatory sequence

A

Site for the binding of regulatory proteins. The role of regulatory proteins is to influence the rate of transcription

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Q

Terminator

A

Signals the end of transcription

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Q

Transcription occurs in three stages:

Initiation

A

A recognition step

The pro motor functions as a recognition site for Sigma factor. RNA polymerase is bound to the promoter. Following binding, the DNA is on wound to form an open complex.

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Q

Three steps for translation

2. Elongation

A

Synthesizes the RNA transcript

Sigma factor is released, and RNA polymerase slides along the DNA in an open contacts to synthesize RNA. RNA polymerize slides along the template strand to the 3 to 5 direction well it’s the sizes are they in the opposite, 52 to 3, direction

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Q

Three steps to transcription

3. Termination

A

When RNA polymerase reaches the terminator, it any RNA transcript dissociate from the RNA

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Q

Terminator factors

A

Proteins that influence the ability of RNA polymerase to transcribe genes.

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Q

RNA always synthesizes

A

3 to 5 direction

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Q

Eukaryotic transcription

A

They have three RNA polymerases

Polymerase II transcribes all mRNA
Polymerase I AND III. Transcribe other RNA’s

Instead of sigma factor RNA polymerase requires five general transcription factors to initiate transcription

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Q

Eukaryotic RNA processing

A

Eukaryotic pre mRNA undergoes three types of processing to mature mRNA

5’ capping
3’ splicing to remove introns

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Q

Capping

A

Covalent attachment of 7 - methylguanosine to the 5’ end of the mRNA transcript

Occurs while RNA polymerase is still creating the pre mRNA

Q

Poly A Tail Addition

A

Poly adenylation sequence in mRNA attracts enzyme complex that cuts mRNA and adds 100 to 200 adenines to the 3’ end

Increases mRNA stability

Q

Splicing

A

Removes introns and joins extrons together

Q

Exons

A

Are the RNA sequences found in the mature mRNA

Q

Introns

A

Are intervening untranslated sequences

Q

Sliceosomes are composed of

A

snRNP

Q

Genetic code

A

Specifies the relationship between the sequence of amino acids in a polypeptide

Q

What code name is CCC

A

Proline

Q

What code is GGC

A

Glycine

Q

Translation

Start codon

A

A codon that specifies the first amino acid in a polypeptide sequence

AUG Met/Start

Q

Translation

Coding sequence

A

A series of codons from the start codon to the stop codon that determine the sequence of amino acids of a polypeptide

Q

Translation

Stop codon

A

End of translation

UAA, UAG, UGA

Q

Translation

Reading frame

A

Start codon defines the reading frame of an mRNA

Q

Aminoacyl tRNA synthase charging a tRNA

A

1 a specific amino acid and ATP bind to aminoacyl tRNA synthase

The amino acid is activated by the covalent binding of a AMP, and pyrophosphate is released
The correct tRNA binds to the synthase. The amino acid is covalently attached to the tRNA. AMP is released
The charged tRNA is released

Q

Ribosomes

A

Macromolecular site where translation takes place

Q

P site

A

Peptide site

Q

A site

A

Aminoacyl site

Q

E site

A

Exit site

Q

tRNA

Initiation

A

mRNA and tRNA and ribosomal subunits firm a complex

Q

tRNA

Elongation

A

The ribosome travels in the 5’ to 3’ direction and synthesizes a polypeptide

Q

tRNA

Transcription

A

The ribosome reaches a stop codon , and all of the components disassemble, releasing a completed polypeptide

Q

Which represents the central dogma of gene expression

A

During transcription, DNA codes for mRNA, which codes polypeptides during translation

Q

A mutation prevents a gene from being transcribed into an mRNA. The mutation most likely disrupts

A

The promoter

Q

The functional product of a structural gene is

A

A polypeptide

Q

The part of a mRNA that is complementary to a codon in an mRNA is the

A

Anticodon

Q

During the initiation of translation, the first codon, ______, enters the _______ and associates with the initiator tRNA

A

AUG, P site

Q

During which stage of translation does the synthesis of a polypeptide occur?

A

Elongation