DNA Study Guide Biology

Fredrick Griffith

Injected mice with bacteria, killed some bad bacteria with heat (mice survived) but bacteria could still be found, heat killed cells but didn’t destroy their hereditary mechanism

Hersey and Chase

sulfur used to show viral proteins did not enter infected cells, phosphorus used to show viral DNA did not enter infected cells

DNA is responsible for genetic inheritance, not protien

Chargaff

discovered amount of adenine and guanine differs between species but actions of adenine + thymine were the same, as well as guanine+cytosine

Rosalind Franklin

used x-rays to create first clear image of DNA, calculated DNA had molecules have some configuration that constantly repeats

Watson and Crick

used Rosalind’s image to build model of double helix with two strands running in opposing directions

Three parts of a DNA nucleotide

1) ring shaped sugar called deoxyribose

2) phosphate group

3) nitrogenous base

three parts of an RNA nucleotide

1) phosphate group

2) five carbon sugars

3) nitrogenous base

Names of the nucleotides

adenine

Guanine

Cytosine

Thymine

Which nucleotides are paired together?

adenine+thymine

Cytosine + guinine

process of DNA replication/how does DNA replicate so quickly

1) HELICASE unzips DNA down themiddle by breaking Hydrogen bonds.Single-stranded binding (SSB) proteins keep the strands from coming back together.

2) RNA primase must put down RNA primers to start the addition of newnucleotides

3) DNA POLYMERASE I replaces RNA primers with DNA nucleotides. DNA POLYMERASE III moves along the2 strands and base pairs nucleotides to eachoriginal parent strand.

4)Replication moves in only ONE direction. So, small DNA segments called OKAZAKI FRAGMENTS are made on the other strand.

5) DNA LIGASE seals up all of thegaps in the DNA molecule, like theOkazaki fragments.

Lots of DNA copy at the same time

difference between pyrimidines and purines?

Pyrimidines= single ring structure

Purines= double ring structure

Pyrimidines and purines always pair together

which nucleotides are the pyrimidines and which are the purines?

Adenine and guanine→ purine

Thymine and cytosine→ pyrimidines

role of Helicase in replication of DNA

Unwinds parental double

role of DNA polymerase I in replication of DNA

replaces RNA primers with DNA nucleotides

role of DNA polymerase II in DNA replication

Proofreads new DNA to catch most of these mutations and fixes them.

role of DNA polymerase III in replication of DNA

moves along 2 strands and base pairs nucleotides to each profoundly parent strand

role of RNA premade in replication of DNA

puts down RNA primers to start the addition of new nucleotides

role of exonuclease in DNA replication

removes incorrectly paired nucleotides, eliminates RNA primers

role of ligase in DNA replication

Links okazakzi fragments, forms final bonds

Seals DNA

explain the structure of a DNA strand. What sets 3 and 5 reference?

twists like a ladder. Sugar bonds with phosphate groups.

Either 5 or 3, and the opposite on other side

When does DNA replication occur

How does it relate to cell division

In the nucleus

Occurs before a cell divides so each new cell produced has a complete set of chromosomes

difference between the leading strand and the lagging strand in DNA replication?

Why does replication occur differently in these areas?

leading= synthesizes continuously towards replication, or forks

Lagging= synthesized discontinously awzy from fork in fragments called Okazaki fragments

DNA is antiparell and runs in opposite directions )(5→3)

What are some of the differences between DNA and RNA

DNA= double stranded, contains deoxyribose sugar, bonds A+T and C+G, never leaves the nucleus

RNA= single stranded, contains ribose sugar, bonds A+U and C+G, can leave the nucleus

u=uracil

Processes of transcription and translation

To synthesize proteins from genetic code steers in DNA

Transcription→ creates mRNA of gene

Translation→ uses mRNA to assemble amino acids

Decribe the roles of each type of DNA

mRNA→ (messenger) sends messages outside of nucleus to ribosomes (

rRNA→ (ribosomal) makes up ribosomes (opposite+u)

tRNA→ (transfer) trasnfers amino acids deceive building blocks of protien to ribosome (same thing as DNA but w U)

Codon

three letter sequence that codes for different amino acids

what is a start codon

aug

protiens are made of how mnay amino acid building blocks

20

What are the different stop codons

UUA

UAG

UGA

how many genes are located in human cells

20,000

ose

sugar (glucose)

ase

enzyme (ligase)

mono

one, singular (monomer)

poly

many, much (polymers)

anti

against (antiviral)