Starr Biology

Transcription occurs in the nucleus.

DNA in the NUCLEUS is unzipped by RNA polymerase.
This enzyme produces mRNA, which then leaves the nucleus through the nuclear pore.

Translation occurs in the cytoplasm.

mRNA is read by the RIBOSOME in the CYTOPLASM of cells. The tRNA brings amino acids that code for the three-nucleotide CODONS and chain them together.
This is a POLYPEPTIDE CHAIN, or a PROTEIN.
These PROTEINS show our traits.

Genetic Expression

The sequence of nucleotides determines our traits. The genes can be expressed (turned on) or unexpressed (turned off) based on environmental factors.

Types of Gene Mutations

• Point Mutations: Single base pair changes
• Insertions: Addition of extra base pairs
• Deletions: Removal of base pairs
• Duplications: Replication of base pairs
• Inversions: Reversal of base pairs
• Translocations: Movement of base pairs between chromosomes

Impact of Gene Mutations

Trivia: Gene mutations can alter the structure and function of proteins, leading to various diseases. This can include conditions like cystic fibrosis, sickle cell anemia, and Huntington's disease. Mutations can disrupt the normal folding of proteins or change their active sites, affecting their ability to perform vital functions in the body.

Silent Mutations

Not all mutations cause proteins to change. Because multiple mRNA codons code for amino acids, sometimes mutations are silent.