SI worksheet #1
September 3rd
1. What is the difference between a genome and a karyotype?
Genome is complete set of genes for an organism and Karyotype is picture of all the chromosomes
2. Tables are a great way to organize your notes! Fill in the below table about model organisms!
Scientific Name (Genus species OR G. species)
Arabidopsis thaliana
“Common” Name (and type of organism)
Thale cress plant (eukaryote)
Eschericha coli
Bacteria (prokaryote)
Mus musculus
House mouse (eukaryote)
Saccharomyces cerevisiae
Baker’s yeast (multi cell fungus)
Caenorhabditis elegans
Nematode worm (eukaryote)
Drosophila melanogaster
Fruit fly (eukaryote)
3. Fill in the blanks: E.coli has about 5 million base pairs while humans have 6 billion. This means that
there is a [three] fold difference in the amount of base pairs each organism has and that human’s
genome is [1000] times larger.
4. What is the difference between a chromatosome and a nucleosome?
Nucleosome is DNA wrapped around 8 core histones. That plus 1 linker histone (H1 in humans NOT H5)
forms chromatosome
5. Fill in the blank: 5 [chromatosome units] coil into 30nm fiber known as a solenoid which can then
continue to coil into [300] nm loops. 6 loops connect to form a [rosette] that continues to super coil. This
super coiling is stabilized by [scaffold proteins] which are non-histone. [700] nm is the highest level of
chromatid you will see.
6. Explain the difference between a centromere and a kinetochore.
Centromere (important for cell cycle is if damaged cell replication wont complete) is DNA fragment that
happens to be in the middle while kinetocore is protein structure that binds spindle fibers
7. Fill in the below table!
Property
Is the DNA highly condensed?
Heterochromatin
YES
Euchromatin
NO
Is the DNA usually
transcriptionally active?
When the chromosome is
stained, does this region appear
light or dark?
NO
YES
DARK
LIGHT