Honors Bio preparation for big tests!!!

Module 1 DNA Basics

What is the full name for DNA

Deoxyribonucleic acids

What is the full name for RNA

Ribonucleic acids

This is a nucleotide structure, the next 3 questions will go with this

What is A

the sugar

What is c

the nitrogeous base

What is B

the phosphate

How many bases does each nucleotide have?

4 bases (the T,A,C, and G bases)

What is T?

Thymine

What is A?

Adenine

What is C?

Cytosine

What is G?

Guamine

Which base does A match with?

T

What does C match with

G

What shape is DNA in?

A double helix

What are pyrimidines

they’re one ring bases where C and T match

What are purines?

they’re two ring bases where A and G match each other

DNA replication

What is the original DNA helix (think family tree)

The parent DNA

What is a topoisomerase? (it’s like a checkpoint)

an enzyme that loosens out the supercoiled DNA before it goes into the replication fork

What is a helicase?

A ring shaped enzyme that unzips the DNA by breaking up the hydrogen bonds causing the replication fork

What is the replication fork?

The Y shaped structure where the DNA is unzipped

What is DNA polymerase?

its an enzyme responsible for adding nucleotides to the new growing complimentary strand

What are ozaki fragments?

The lagging strand in replication that leaves behind small peices that are the okazaki fragments

What is DNA ligase?

an enzyme responsible for connecting the strands of okazaki fragments together

What are the leading and lagging strands?

The parent helix makes 2 copies called helices that contain new and old strands which commonly are referred to as the leading and lagging strand

Overview of protein synthesis

What happens in step 1 (transcription)

DNA is combined with mRNA as DNA goes from 3’ to 5’ and RNA goes from 5’ to 3’

What happens in step 2 (Post-Transcriptional Modifications)

The introns are removed while the exons are pulled together to create a blueprint while adding a 5’ cap and a poly a tail for stability. (these first 2 steps take place in the nucleus)

What happens in step 3 (translation)

The RNA leaves the nucleous to go to a ribosome as codons enter the ribosome in what's called transfer. RNA (tRNA) then brings proper amino acids and matches the codons with the anti-codons.

What happens in step 4 (Post-Translational Modifications)

Amino acid chain is folded to make a protein as even a carbohydrate lipid or another protein could be added

What are the three types of RNA?

tRNA, mRNA, and RNA

Transcription vs Translation!

Easiest part ever!

What is transcription/ how do you use it?

Transcription makes mRNA and what you do is you replace all A’s with a U in the sequence

What is translation/ how do you use it?

Translation divides the codons from mRNA into amino acids and what you do is use the chart Mr. E gave you (find first 2 letters going horizontally to diagnaly and it will tell you everything!)

Mutations

What are mutations?

A mutation is a change in the DNA

How do mutations happen?

They’re random and increase risk due to mitogens

What is substitution?

The base is changed to a different base (GAC, ATT) —→ (GAC, AAT) (Adenine is exchanged for the 5th base)

What is Insertion

Base is added to DNA (GAC, ATT) —→ (GAC, GATT) (Guamine is added)

What is deletion

Base is removed from DNA (GCA, ATT) —→ (GCA, TT) (Adenine is removed)

Effects of Mutations

What is silent mutation?

The base changes however the amino acid and protein are the same (Original mRNA and A.A: CAC/UAU/GCG—>His/Tyr/ala. Mutated mRNA chain: CAC/UAU/GCA. A.A chain: His/tyr/ala.)

What is Missense Mutation?

One amino acid is changed (Original mRNA and A.A.: CACUAUGCG—> His/Tyr/ala. Mutated mRNA: CUC/UAU/GCG. A.A. Chain: Leu/tyr/ala.)

What is frameshift mutation?

Codons get shifted due to insertion or deletion (Original mRNA: CAC/UAU/GCG. Mutated mRNA: CAC/UUG/ CG (missing the A.) A.A. Chain: His/ Lev/ Stop!)

What is nonsense mutation?

An early stopping codon. (Mutated mRNA: CAC/UAA/UGCG. A.A. Chain: His/Stop.)

Chromosomal Mutations

What is a chromosomal mutation?

A change in a piece of chromosome

What is duplication?

Section of a chromosome is copied x2

What is immersion?

Two sections of a chromosome are flipped

What is deletion?

Section of a chromosome is removed

What is translocation?

A piece of a chromosome is removed and added to another