Unit 4 - Concept 2

Protein Synthesis

Describe the relationship between genes and proteins.

Genes provide the code for creating proteins, and proteins have functions that affect an organism’s traits.

Explain the central dogma.

The central dogma is a theory that says genetic information flows in one direction: DNA to RNA (through transcription) to protein (through translation).

What are the three types of RNA?

mRNA, tRNA, and rRNA are the three types of this molecule.

What is mRNA? (Find a pic)

This is the messenger RNA. It copies the instructions in DNA and carries it to the ribosomes and tRNA in the cytoplasm.

What is tRNA? (Picture)

This is the transfer RNA. It carries amino acids to the ribosome and mRNA according to the instructions brought by the mRNA.

What is rRNA? (Picture)

This composes the ribosomes.

Where does transcription take place?

This process takes place in the nucleus.

Why does transcription happen in the nucleus?

This process happens in the nucleus because DNA can’t leave the nucleus.

What happens during transcription?

A specific gene/piece of DNA is copied into mRNA.

* RNA Polymerase unzips the DNA needed.
* Following complementary base-pair rules, RNA Polymerase matches DNA’s nucleotides.
* The mRNA molecule is complete and released, DNA is zipped up again, and mRNA leaves the nucleus to go to the cytoplasm for Transcription.

\*What enzymes are involved with transcription?

RNA Polymerase is used in this process.

Where does translation happen?

This process happens in the cytoplasm.

What happens during translation?

During this process, the instructions carried by the mRNA are read to make proteins.

* mRNA attaches to a ribosome, which reads the codons mRNA has in the 5’ to 3’ direction, starting with codon AUG.
* tRNA picks up and drops off amino acids that match the codons read off by mRNA. The ribosome binds the amino acids together as it does so.
* When “STOP” codon is read, the ribosome releases the completed protein.

\*What enzymes are involved with translation?

Ribosomes are involved in this process.

What would happen if a mistake is made during protein synthesis?

An error in protein creation, resulting in it being deformed, mutated, or toxic, that leads to degenerative disorders and diseases like Parkinson’s or Alzheimer’s are all possible if this happens.