The Central Dogma and Transcription

Practice flashcards based on the lecture notes regarding the Central Dogma, transcription, and mRNA processing.

What is the Central Dogma in biology?

It describes the flow of genetic information from DNA to RNA to protein.

What is the process of Transcription?

Transcription is the process through which DNA is used as a template to create messenger RNA (mRNA).

What enzyme carries out transcription in eukaryotes?

RNA ppolymarse.

Where does transcription occur in eukaryotic cells?

In the nucleus.

What are the four nitrogenous bases found in RNA?

Adenine, Uracil, Cytosine, and Guanine.

How many strands does RNA have?

RNA is single-stranded.

What is the role of helicase in DNA replication?

Helicase unzips the DNA double helix.

What is the function of primase?

Primase signals and lays down an RNA primer for DNA synthesis.

What does DNA polymerase do?

DNA polymerase synthesizes new DNA strands.

What is the role of exonuclease?

Exonuclease removes RNA primers from the newly synthesized DNA.

How does ligase function in DNA replication?

Ligase glues together the Okazaki fragments on the lagging strand.

What is a gene?

A DNA sequence that contains the instructions for making a specific protein.

What are the three regions of a gene?

Promoter sequence, protein-encoding region, and terminator sequence.

What is the function of the promoter sequence?

It is the binding site for RNA polymerase.

What happens during the initiation step of transcription?

RNA polymerase binds to the promoter of a gene and unwinds a small region of DNA.

What occurs during the elongation step of transcription?

RNA polymerase synthesizes a complementary strand of RNA in the 5' to 3' direction.

What signals the termination of transcription?

RNA polymerase reaches the termination site.

What is pre-mRNA?

The initial RNA transcript that requires further processing.

What is mRNA splicing?

The process where introns are removed and exons are joined together.

What is the role of the 5’ cap on mRNA?

The 5' cap protects mRNA from degradation and aids in ribosome binding.

What is the function of the 3’ Poly-A tail?

It helps protect mRNA from degradation and aids in the export from the nucleus.

What is the difference between exons and introns?

Exons code for proteins; introns do not.

What is the relationship between DNA replication and transcription?

Both processes occur in the nucleus and use DNA as a template.

What products result from DNA replication?

Two identical DNA molecules.

What products result from transcription?

Messenger RNA (mRNA).

Which enzyme synthesizes DNA?

DNA Polymerase.

Which enzyme synthesizes RNA?

RNA Polymerase.

What is a transcription bubble?

The unwound region of DNA where transcription occurs.

How are RNA and DNA different in terms of sugar?

RNA contains ribose; DNA contains deoxyribose.

What nitrogenous base is used in RNA but not in DNA?

Uracil.

What is the complementary mRNA sequence for 3’-A T A C G A T G-5’?

5’-U A U G C U A C-3’.

How does transcription differ from DNA replication in terms of product?

Transcription produces mRNA; replication produces DNA.

What role do methylguanosines play in mRNA processing?

They are part of the 5’ cap that protects mRNA.

What is the main purpose of mRNA processing?

To prepare pre-mRNA for translation into a functional protein.

How many adenines are typically in a 3’ Poly-A tail?

About 200 adenines.

Why are introns removed during mRNA processing?

To produce a functional mRNA that codes for proteins.

What happens to RNA polymerase after transcription is completed?

It is destabilized from the DNA and released.

What additional modifications occur to pre-mRNA?

Intron splicing, 5’ capping, and addition of a 3’ tail.

What is the significance of the termination sequence in a gene?

It signals RNA polymerase to stop transcription.

What structure ensures RNA polymerase accurately synthesizes mRNA?

The transcription bubble.

In which step does RNA polymerase unwind DNA?

During the initiation step of transcription.