This site is 100% ad supported. Please add an exception to adblock for this site.

Harris Chromosome structure


undefined, object
copy deck
During most of the cell cycle DNA is present in the nucleus as______.
Histones + DNA =
How's eukaryotic DNA different?
Highly repetitive DNA sequences (near centromeres or in telomeres)
Contain introns (really long)
Exons: pretty small 
Lessons from Human Genome project.

Only 2% DNA is protein coding sequence.

Functions unknown for over 1/2 discovered genes

Many animals/plant have more DNA than humans.

T/F: Genes evely spread on chromosomes in humans.
T/F: Human genes are about 99.9% the same
Tell me about bent DNA.

Found with long stretches of AT; Around a protein; With a drug

DNA is flexible 

What are centromeres?
Near midpoint of chromosomes; attach to mitotic spindle; consist of highly repetitive DNA sequences
What are histones? (made of)

Basic proteins

lots of lys and arg; (+) at pH 7.4

5 classes: H1, H2a, H2b, H3, H4

Bind compactly to DNA

Are acetylated and ppylt'd 

What are nucleosomes (specific)?
146 BP of DNA.  2 molecules Each of H2A, H2B, H3, and H4
What are protein scaffolds?

Form domains of nucleosomes.

Turn beads-on-string to a solenoid. 

What are telomeres?

At the end of liner DNA w/ TTAGGG-3' repeats

Maintain integrity at chromosome ends

What comprises chromosomes?

DNA (a chromatid = single, linear DNA)



What does H1 do?
Wrap DNA around the other histones
What kinds of DNA are there?



What winds up DNA?
Enzymes.  (Like topoisomerase II)
What's A DNA?

Found when DNA binds w/ RNA.

Also when DNA binds in high humidity. 

Fatter, bigger hole in center. 

What's B DNA?
What Watson and Crick discovered.  Generally what we find.
What's supercoiling?

1 way to bend DNA.

Negative (right handed) is easier to separate into single strands.  Underwind

(+) - left handed; overwind 

They are topoisomers 

What's Z DNA?

Left-handed.  Skinner.

Zig Zag helix. 

Not found in vivo. 

Deck Info