PLTW BIOMED 2.2.2

Protein types and functions

• Structural proteins (collagen, keratin)

• Enzymes (amylase, DNA polymerase)

• Transport proteins (hemoglobin)

• Hormones (insulin)

• Antibodies (immune response)

Transcription

• Transcription occurs inside the Nucleus_ (cell organelle).

• During transcription, DNA is read by an enzyme called RNA Polymerase and produces __Messenger_  RNA (mRNA).

• This newly created mRNA molecule moves to the Cytoplasm (part of cell) where the process of translation can occur.

• During translation, small organelles called Ribosome read the mRNA sequence.

• These organelles direct transfer RNA, or tRNA, to assemble a specific sequence of amino acids__. A codon is a sequence of three mRNA bases that codes for one amino acid.

• When all the amino acids coded for by a gene link, they fold, and this creates a functional protein.

Base Pairing

A → T
G → C
A → U for RNA

NF1 Gene

A gene that provides instructions for producing a protein called neurofibromin, which helps regulate cell growth and division. Mutations in this gene are associated with neurofibromatosis type 1.

Translation

Process where mRNA leaves nucleus, goes to ribosomes, enters ribosome, and is translated by tRNA into 3 nucleotide groups called codons that code for an amino acid. This amino acid chain then forms a protein.

Types of Gene Mutations

substitutions	One DNA base is exchanged for another, such as switching an A to a G.
insertions	One DNA base is inserted into a gene sequence.
deletions	One DNA base is deleted from a gene sequence.

Point mutation doesnt shift reading frame, Frameshift does.

Sickle Cell mutation?

A specific type of point(substitution) mutation in the HBB gene that leads to the production of abnormal hemoglobin known as hemoglobin S, which causes red blood cells to become rigid and sickle-shaped.

Glutamate → Valine Substitution, A genetic mutation where adenine is replaced by thymine in the HBB gene.

Explain why blood is drawn for genetic testing

Blood sample → DNA extraction → PCR → Gel electrophoresis → Genetic mutation detection

Determine a patient’s NF1 status

• Neurofibromatosis Type 1 (NF1) symptoms: Tumors, café-au-lait spots, freckling

• Caused by NF1 gene mutation (autosomal dominant)