Organizing Genetic Information

Question 1

A & G are double rings which means they are…

Answer 1

purines

Question 2

C & T are single rings so they are…

Answer 2

pyrimidines

Question 3

What is DNA made up of?

Answer 3

deoxyribose/pentose sugar

heterocyclic nucleobase

phophodiester bonds

Question 4

Why are G/C base pairs stronger than A/T base pairs?

Answer 4

becuase G/C has 3 hydrogen bonds vs A/T which only has 2

Question 5

Is DNA a simple double helical structure?

Answer 5

No! It’s a superhelix

Question 6

The conformation of DNA is controlled by which DNA modifying enzymes

Answer 6

Topoisomerase I

Topisomerase II

Helicase

Question 7

What does Topoisomerase I do?

Answer 7

It makes a single strand break in a negatively supercoiled DNA (removes 1 super coil)

Basically uncoils it

Question 8

What does Topoisomerase II do?

Answer 8

Makes a double strand break (removes 2 super coils)

Unwinds it quickly

Question 9

Which histone proteins are included in the histone protein octomer of Eukaryotic DNA?

Answer 9

H1, H2A, H2B, H3, H4

Question 10

What is the purpose of H1?

Answer 10

it helps connect multiple nucleosome units

Question 11

What is considered the 1st level of DNA packaging?

Answer 11

Formation of the nucleosome unit - packaging into a tight unit

Question 12

What do chromosomes contain?

Answer 12

highly condensed double stranded DNA molecules and associated proteins

Question 13

Describe the process of DNA organization

Answer 13

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

Question 14

True or False

Somatic cells in any individual of a given eukaryotic species typically have the same characteristic number of paired chromosomes

Answer 14

True

Question 15

What is a karyotype?

Answer 15

the full complement of chromosomes in an organism that is stained so you can distinguish between chromosomes

Question 16

Do different species have different Karyotypes?

Answer 16

yes

Question 17

Do females vs. males have different karyotypes within species?

Answer 17

yes

Question 18

What is an autosome?

Answer 18

All chromosomes other than the sex chromosomes

Question 19

What three things differ about chromosomes between species?

Answer 19

Number

Shape

Size

Question 20

What was the point of discussing chromosome segment homology accross speices?

Answer 20

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

Question 21

What does comparative genomics data tell us?

Answer 21

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

Question 22

Do all species have the same number of extrons on their chromosomes?

Answer 22

in general yes

Question 23

Do all species have the same number of introns on their chromosomes?

Answer 23

No, it differs among species

Question 24

What is the main take-home point about amion acids across species?

Answer 24

Amion acid conservation among species is very high

Question 25

How do you acomplish genome sequencing?

Answer 25

Take a genome and chop it up into very small fragments (put it in a machine and apply a force to shear it)

Question 26

Why do we use sequencing? - which example was given in class?

Answer 26

DFTD - Devil Facial Tumor Disease - sequence their DNA to find resistance factors to help population