DNA Replication

What is the structure of DNA?

Double Helix

What is the building block of DNA?

Nucleotides

What is the compliment nitrogenous base to adenine?

Uracil & Thymine

When in the cell cycle does DNA Replication occur?

Synthesis phase in Interphase

How many replication forks are in the replication bubble?

2

What is responsible for adding support or stabilizing the newly opened DNA?

Single strand binding protein

What is the compliment nitrogenous base to Guanine?

Cytosine

What molecule is responsible for "un-zipping" DNA?

Helicase

What type of macromolecule is Helicase?

Protein

What enzyme is responsible for adding nucleotides to the separate strands of DNA?

DNA Polymerase

What is the compliment nitrogenous base to Cytosine?

Guanine

What enzyme puts down the RNA primer so DNA Polymerase can "print" on the 5' side of DNA?

Primase

What are the sections of DNA(in-between the RNA primers) that are synthesized on the 5' side called?

Okazaki Fragments

What enzyme is responsible for putting the Okazaki fragments together?

Ligase

What is the compliment nitrogenous base to Thymine?

Adenine

The result of DNA Replication is half parent, half newly synthesized. For this reason, DNA Replication is considered____?

Semi-Conservative

The components of DNA are similar for all living organisms?

True

Prokaryotes have multiple sites of origin.

False

When a single base is changed this is called a ____?

Point Mutation

How many nucleotides are in a codon?

3

Several different codons code for the same amino acid.

True

An Insertion Mutation causes a frame-shift.

True

What type of RNA is responsible for bringing the temple to a ribosome for protein synthesis?

tRNA

This is the process of building Protein.

Translation

This is the process of mRNA copying DNA to make a template.

Transcription

What is the function of DNA?

Storage of genetic information

What are the building blocks of DNA?

DNA is Nucleic Acid(RNA), so building blocks are Nucleotides

When does DNA Replicate?

S- phase of Interphase

Occurs before the cell divides so each of the two cell made will have a complete copy of the genetic info

Where does DNA replicate?

Eukaryotic: Nucleus

Prokaryotes: cytoplasm

Wherever DNA is located in an organism

What is Polymerase?

it compliments the DNA during replication. it adds nucleotides to the copying strand of DNA

It helps synthesize the mRNA during transcription

What is Helicase?

it is the enzyme responsible for opening or unzipping the double strand of DNA

What is Primase?

It puts down the RNA Primers that allow DNA Polymerase to compliment the lagging strand(5' side)

What is Ligase?

It re-combines the Okazaki fragments on the lagging strand of DNA.

What are the correct DNA compliments ?

DNA

A-T

GC

RNA

A-U

G-U

What is the result of DNA Replication?

Two daugther DNA strand

1 parent double strand of DNA turns into 2 daughter double strands of DNA. They should be identical

What is a codon?

It is part of an RNA temple

it is made of 3 nitrogenous bases

it is responsible for making proteins

if there are 15 nucleotides in a gene. how many amino acids will be produced?

5

What is unique about RNA?

it is a single strand and doesn't have thymine(replaced by uracil)

How many RNA molecules are there?

mRNA(messenger RNA, transcription)

tRNA(transfer RNA, bringing amino acid to ribosomes)

rRNA(ribosomal RNA, made up of what a ribosome is)

How are proteins made?

DNA is copied by mRNA. that template is transferred to a ribosome so a protein can be built.

Prokaryotes: Co-translation: transcription is being performed at the same time as translation(protein synthesized)

Eukaryotes: Transcription --> translocation (the movement at the newly synthesized mRNA to a ribosome)- >> translation

The genetic code is universal, although no organism has identical DNA, each organism uses the same components: ATGC

true

What is the point of origin?

It is the site of DNA Replication

At this site there is a Replication Bubble that is formed

The Replication Bubble has TWO(2) Replication forks

Prokaryotes. only have 1 point of origin

Eukaryotes can have many points of origin.

What is the purpose of the cell membrane?

Cell protection, selective permeability( letting things in and out of cell)

What is the purpose of enzymes?

Speed up reactions and lower activation energy

How many chromatids in a chromosome?

2

Direction of synthesis

5 to 3

what does dna polymerase need to add new nucleotides

OH group

what does new nucleotides add too

3” end OH

what direction does dna polymerase read the template stand

3-5

but synthesizes 5 to 3

Leading stand

synthesized continuosly 5-3

Lagging strand

synthesized discontinuously 5 to 3

DnaA proteins

bind to dnaa box sequences with origin of replication to initiate dna replication

Dna polymerase 1

removes rna primers, fills in gaps with dna

AT rich regions

dna strands separate, origin of replicationG

GATC methylation

regulate dna replication

Proofreading direction

Exonuclease

3 to 5

3 mechanisms for replication accuracy

base pair specificity, proofreading, mismatch repair

Eukaryotic replication

Multiple origins

slower than bacteria

different polymerase

Alpha polymerase

eukaryotes only

primer synthesis (stater polymerase)

dna rna hybrid primer

Delta polymerase

replication of lagging strand

Epsilon polymerase

eukaryotes only

replication of leading strand

gamma polymerase

mitochondrial dna

end replication problem

lagging strand cannot be fully replicated

solved by telomerase

telomerase extends telomeres using RNA template

Sanger Sequencing

uses ddNTPs to terminate DNA synthesis at specific bases

determine the exact sequence of nucleotides in a DNA molecule

ddNTP

lacks OH chain stops

dNTP

3’ OH chain continues

Sanger sequencing steps

1. divide dna into 4 tubes (ATCG ddntp)

2. incubate with same primer

3. separate via gel

PCR

dna amplification

PCR process

denaturation

dna replication

elongation and cooling

USES taq polymerase (heat stable enzyme) and primers

Bidirectional

bubbles merge and end up wither 2 sister chromatids during s phase

ARS elemnts

function as origins of replication and contain lots of AT

G quadruplux

4 guanines and hydrogen bonding

NFR

near replication origin

helps regulate replication

Constituitve OR

origins used all the time

flexible or

used in random manner

most common

dormant or

only specific stages of development and cell differentiation

Assembly or prereplication complex occurs when

g1

what binds to orc to start replication

cdc6 cdt1

MCM helicase

If telomeres are too short they become

senescent

Fidelity mechanisms

stability of base pairing

structure of the dna polymerase active site

proofreading function of DNA polymerase

Stability of base pairs

complementary bp more stable than mismatched

Meselson and stahl experiment

determines how dna replicates

conservative, semiconservative, dispersive

Stalh Conservative

Gen 1: 1heavy 1 light

Gen 2: w heavy 1 light

Stahl semiconservative

1 hybrid gen 1

1hybrdi 1 light gen2

Stalh dispersive

1 intermediate gen 1

1 intermiediate that gets lighter over time gen 2