AP Bio unit 6

Addition of poly-A tail

makes mRNA more stable

Addition of GTP cap

Helps with ribosomal recognition

Alternative Splicing

Let your ex stay, and put the Inteligence away

• Removal of Introns

• Keeping extrons

Purines

A, G base pair, has a double ring structure

Pyrimidine

T, C, U base pair, has a single ring structure

Base Pair rules

A-T/U with 2H bonds. C-G with 3H bonds.

Directionality

• DNA is read 3’ to 5’

• Synthesize 5’ to 3’

Sideness

• 5’ end: phosphate

• 3’ end: hydroxyl group

Promoter

site where RNA polymerase binds to start transcription

DNA polymerase

1. Reads the Template: DNA polymerase moves along an existing DNA strand, using it as a blueprint.

2. Adds New Bricks: It brings in free-floating DNA building blocks (nucleotides).

3. Builds a New Strand: It links these new nucleotides together in the correct order, forming a new, identical DNA strand. 

RNA polymerase

• Reads DNA: It finds a gene on the DNA strand.

• Unwinds DNA: It temporarily separates the two strands of the DNA double helix.

• Builds RNA: It synthesizes a new strand of RNA by matching complementary bases (A-U, G-C) to the DNA template.

• Produces various RNAs: It creates messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA), and other functional RNAs. 

mRNA

Carries the genetic code from DNA to the ribosome

rRNA

Makes up the ribosome and helps assemble proteins

tRNA

rings amino acids to the ribosome during protein building

codon

3 bases on mRNA that codes for an amino acid.

anticodon

3 bases on tRNA that matches the codon.

Point mutation

one nucleotide has been substituted for a different nucleotide

Missense, Nonsense, Silent

Missense: one amino acid changes

Nonsense: causes a premature stop

Silent: no effect on the amino acid sequence

Frameshift mutation

one or more nucleotide are inserted or deleted, causing the reading frame to be shifted