8.4 Transcription

A pairs with

U

Central Dogma

After the discovery of DNA's structure, Francis Crick defined the central dogma of biology, stating that information flows in one direction from DNA to RNA to proteins.

G pairs with

C

When do these processes occur in Eukaryotes?

In eukaryotic cells, DNA is located inside the nucleus so the processes are separated both in location and time.

2nd Step of Transcription

RNA polymerase uses a section of one strand of DNA as a template and strings together a complimentary strand of RNA. base pair rules are followed except Uracil (U) pairs with A instead of Thymine (T)

What template is used in Transcription?

A short segment of 1 strand of DNA

T pairs with

A

U pairs with

A

Pairs of Bases in RNA

A - U G - C

Bases of RNA

A Uracil C G

What template is used in DNA Replication?

All of each strand of DNA

What is RNA?

An intermediate molecule that takes the information coded by the DNA outside the nucleus to the ribosome where a protein can be made.

Transcription

Converts DNA into RNA

Replication

Copies DNA

What is made in DNA Replication?

DNA

What enzyme is used in DNA Replicatio?

DNA Polymerase, DNA Helicase

Who defined the central dogma?

Francis Crick

C pairs with

G

When do these processes occur in Prokaryotic cells?

In prokaryotic cells, all 3 processes occur in the cytoplasm at approximately the same time.

Translation

Interprets RNA message to make string of amino acids (polypeptide), which makes a protein.

3 Types of RNA

Messenger RNA - mRNA Ribosomal RNA - rRNA Transfer RNA - tRNA

Transcription

Process of copying a sequence of DNA to produce a complimentary set of RNA

What is made in transcription?

RNA

How does RNA differ from DNA?

RNA has one strand of nucleotides, DNA has 2 strands. RNA has a 5-Carbon sugar, ribose, which has one more oxygen atom than Deoxyribose in DNA RNA nucleotides use the nitrogen-base Uracil (U) instead of Thymine.

What enzyme is used in Transcription?

RNA polymerase

1st Step of Transcription

RNA polymerase recognizes the transcription start site of a gene and unwinds the DNA segment

3rd Step of Transcription

RNA strand detaches from the DNA after it has been transcriped and the DNA helix recoils.

Eukaryotic cells - where do these processes each take place

Replication and transcription occur in the nucleus, while translation occurs in the cytoplasm.

3 Processes

Replication, Transcription, Translation

RNA abbreviated for

Ribonucleic acid

Codon

a series of three-nucleotide sequences that correspond to an amino acid, start or stop signal for translation.

RNA polymerase

an enzyme that bonds nucleotides together in a chain to make a new RNA molecule

mRNA

an intermediate message that is translated to form a protein. Instructions are written as codons

tRNA

brings amino acids from the cytoplasm to a ribosome to make a protein.

Translation occurs in the

cytoplasm

rRNA

forms part of the ribosomes

Replication occurs in the

nucleus

Transcription occurs in the

nucleus