Lecture 19: Gene to Protein

What are the steps:enzymes of DNA Replication?

Unwinding:helicase, Prevent Supercoiling:topoisomerase, Starting points for replication:primase, Copy the new DNA: DNA polymerase, and Glue pieces:ligase

When does DNA Replication occur?

it occurs in the S phase of mitosis/meiosis

What is a replication bubble?

the area where the parental strands are seperated

What is replication fork?

the edges of the bubble where the helicase are unwinding

What is parental strand?

the two strands we start with

What is daughter strands?

the two new strands that form

What is a leading strand?

part of a daughter strand that forms continuously

What is a lagging strand?

part of a daughter strand that forms in pieces (okazaki fragments)

What is Semi-Conservative replication?

when each double helix has half of the parent and half of the daughter

What is DNA transcription?

1 enzyme, single gene, mRNA copy, has Uracil, cell needs a protein to start, starts at promoter

What is DNA replication?

5 enzyme, whole genome, DNA copy, has thymine, S phase, starts at ori

What is RNA polymerase?

the note taker that goes to the nucleus to copy the DNA recipe

What is the difference between DNA and RNA?

DNA is deoxyribose and RNA is ribose. DNA has thymine whereas RNA has Uracil

What is the origin of replication (Ori)

Where DNA replication always start at

What is a promoter?

a cell that needs a protein to start

What is mRNA?

tells ribosomes exactly what amino acids to use and in which order to make the protein

What is rRNA?

single stranded polynucleotide, wraps itself to form two subunit: large and small subunits

What is tRNA?

what carry amino acids to the ribosomes

What does the ribosome large subunit look like?

usually on top and it is one of the biggest sites. Has A site —> P site —> E site

What does the ribosome small subunit look like?

the smaller one and it hover below large subunits

What are codons?

nucleotides and their base pairs

What are anticodons?

set of three nucleotides at the base of rRNA

What is the start codon?

it is a three nucleotide code to start DNA translation.

What is the stop codon?

it is a three nucleotide code to end DNA translation.

What are the three steps of DNA translation?

initiation, elongation, and termination

What occurs in initiation?

mRNA transcript attaches to a small subunit of ribosomes which search for the start codon. Once the start codon is found the large subunit clamps down and mRNA is pulled through to be transferred

What occurs in elongation?

tRNAs bring amino acids and polypeptides are built. each three nucleotides codes for another amino acid

What occurs in termination?

ribosome knows when to stop when it hits a stop codon. Once the ribosome reaches the stop codon subunits separate, polypeptide chain detaches, and mRNA is released