Lesson 4 Genetics

Small nuclear RNAs (snRNA)

component of small nuclear ribonucleoproteins; known as “snurps”

Small nucleolar RNA (snoRNA)

Process and assemble rRNA (think organize)

Small cytoplasmic RNA (scRNA)

Found in eukaryotic cells; varied and unknown function

MicroRNA (miRNA) & small interfering RNA (siRNA)

play regulatory role by degrading mRNA

Piwi-interfering RNA (piRNA)

Inactivate the transposons

Origin of replication

DNA sequence where replication begins

Initiator proteins

Bind the origin and cause the DNA to begin opening, allowing replication machinery to assemble

Helicase

Unwinds the DNA strands

Primase

Makes short RNA primers that provide a free 3’-OH for DNA polymerase

Gyrase

Relieves twisting/supercoiling ahead of the replication fork by cutting and rejoining DNA

SSBs

Binds separated DNA strands and prevent them from reannealing

DNA Pol 3

Main DNA building enzyme; adds DNA nucleotides 5’ to 3’

DNA Pol 1

Removes RNA primers and replaces them with DNA

DNA ligase

Seals the remaining nicks in the sugar-phosphate backbone; joins Okazaki fragments