Organizing Genetic Information Flashcards
(26 cards)
A & G are double rings which means they are…
purines
C & T are single rings so they are…
pyrimidines
What is DNA made up of?
deoxyribose/pentose sugar
heterocyclic nucleobase
phophodiester bonds
Why are G/C base pairs stronger than A/T base pairs?
becuase G/C has 3 hydrogen bonds vs A/T which only has 2
Is DNA a simple double helical structure?
No! It’s a superhelix
The conformation of DNA is controlled by which DNA modifying enzymes
Topoisomerase I
Topisomerase II
Helicase
What does Topoisomerase I do?
It makes a single strand break in a negatively supercoiled DNA (removes 1 super coil)
Basically uncoils it
What does Topoisomerase II do?
Makes a double strand break (removes 2 super coils)
Unwinds it quickly
Which histone proteins are included in the histone protein octomer of Eukaryotic DNA?
H1, H2A, H2B, H3, H4
What is the purpose of H1?
it helps connect multiple nucleosome units
What is considered the 1st level of DNA packaging?
Formation of the nucleosome unit - packaging into a tight unit
What do chromosomes contain?
highly condensed double stranded DNA molecules and associated proteins
Describe the process of DNA organization
1) Naked DNA with no histones merge into the nucleosome where where DNA is wrapped around a histone octomer
2) Histone octomer then coupled with H1 proteins start wrapping around each other on that H1 backbone to make increasingly larger filaments that package together in to a huge complex called a Solenoid
3) Solenoids gather together to make more complex strands of DNA which are used to form chromosomes
True or False
Somatic cells in any individual of a given eukaryotic species typically have the same characteristic number of paired chromosomes
True
What is a karyotype?
the full complement of chromosomes in an organism that is stained so you can distinguish between chromosomes
Do different species have different Karyotypes?
yes
Do females vs. males have different karyotypes within species?
yes
What is an autosome?
All chromosomes other than the sex chromosomes
What three things differ about chromosomes between species?
Number
Shape
Size
What was the point of discussing chromosome segment homology accross speices?
During evolution the genome has been chopped up and reordered to create different species
Even as humans we have many similar genes as chickens - some of them are reserved and have been relocated
What does comparative genomics data tell us?
Chromosomes of different species contain large tracts of of similar DNA sequences
Chromosome segments have likely been rearranged over speciation and evolution
The karyotype of humans and gorillas is more similar than pigs and cattle
Do all species have the same number of extrons on their chromosomes?
in general yes
Do all species have the same number of introns on their chromosomes?
No, it differs among species
What is the main take-home point about amion acids across species?
Amion acid conservation among species is very high
