genetics 2 Flashcards
DNA full name
Deoxyribonucleicacid
-ATGC
RNA full name
Ribonucleic acid
-AUGC
monomer of RNA and DNA
Nucleotide
Parts of a nucleotide
sugar, phosphate (negative), base
pyrimidines( 1 ring )
Thymine- only in DNA
Cytosine
Uracil- not in dna
purines ( 2 rings )
Adenine
Guanine
3 prime (carbon)
- always connected to hydroxyl
- where bonding (phosphodiester) occurs = dehydration synthesis
side note: DNA lose oxygen( only has H on one)
uprights
- alternating sugar and phosphate
- has strongest bond= phosphodiester (covalent)
rungs
- bases
Hydrogen bonds between
DNA structure bonds
- always purines to pyrimidines(3)
- A to T = weaker- 2 H bonds(DNA)
- A to U= RNA- 2 bonds
- G to c = stronger- 3 H bonds
Fredrick Griffith
- tried to find what gene was made of with the rat experiment
- Found that Heat killed bacteria passed something(DNA) to rough bacteria that killed the rats
Oswald Avery
- did elimination experiment 1 variable at a time to see what exactly was killing the mouse
- discovered it was DNA
Alfred Hershey and Marth Chase
- Validated Avery’s conclusion
- used viruses that attacks bacteria
Erwin Chargaff
- discovered that there are equal #s of As and Ts and equal Gs and Cs
Rosalind Franklin
- x ray crystallography
- found that DNA= 2 stands that coil around each other
Watson and Crick
- **** 1953
- (discovered shape of DNA) 3D molecules of DNA - Double Helix
- hydrogen bonds between purines and pyrimidines
- method of replication
DNA chromosomes (Prokaryotic)
- no nucleus
- circular DNA
DNA chromosomes (Eukaryotic)
- nucleus
- Linear DNA
Nucleosome
section of DNA coiled around Histones
histone
- protein that keeps DNA organized (positive charge)
- can move back and forth
Chromatin
- elongated DNA
- open DNA
- found in interface
- made of coiled nucleosomes
How to makes Chromosomes
- DNA wraps around histones
- DNA + Histones coil into nucleosomes
- Nucleosomes coil tighter into chromatin(2 types)
- super coil
Euchromatin
- open DNA
- Histones are spread apart
- gene on
Heterochromatin
- Closed DNA
- Histones are close together
- Gene off
Epigenetics
Experiences and environment can effect which genes turn off
Aminos
Turn on gene
Methyl’s
turn off gene
when does DNA replication occur
Interphase S
Leading stand VRs Lagging strand
Leading = 3 to 5, one primer lagging= 5 to 3, lots primer
Steps of DNA replication
- create open complex
- add primer (RNA)
- Extension of primer(Replication)
- primer replacement
- proofread
Primase (enzyme)
- adds primer to SS to start the replication process
DNA Helicase (enzyme)
- uncoils and unzips helix (DS)
- creates the open complex ( 2 Replication forks- where replication occurs)
DNA polymerase
- replicates DNA
- replaces primer
- proofreads= backwards to remove mistake, forwards to fix
DNA Ligase
- joins fragments of DNA
- creates final phosphodiester bond
okazaki fragments
- short section of lagging strand that is being looped to add primer
semi consevative
New DNA molecule consists of one old strand and one new strand
Telomere
- found at end of chromosomes, highly repeated/condensed region of DNA
- protects ends from damage
- stops ends of chromosomes from fusing together
End of replication problem
- small section of of DNA is lost from lagging stand because prime cant be added before the start of the chromosome
- can reach critical length( loss of all telomers) cant replicate = cell dies, organism aging
- cell gets sent to G sub O (Go) to get fixed, cell will stay there and age
DNA vs RNA
- both: nucleic acids, monomer= nucleotides, no ose in name
- RNA: SS, can bond to itself, uses ribose, No thymine, has Uracil.
DNA: DS, uses deoxyribose, has all bases but uracil
MRNA
carries DNA message to ribosomes
TRNA
Transfers Amino Acids to Ribosomes
RRNA
Part of ribosome: provides docking point for MRNA + Amino Acids
why do we make MRNA
- we cant just send DNA to the cytosol because it contains exonucleases that can destroy it
- we will no longer have template so we send a copy
- MRNA gets destroyed but makes proteins first
