Biology 210
GENETICS
20 February, 1998

(1 pt.) What is your name?______________________________

1. (3 pts.) what is the MOST important contribution to DNA structure & curvature?

2. How much is the DNA compacted in a typical cell?

2a. (3 pts.) How long would the DNA double helix be, for a single human cell?

b. (3 pts.) What would be the distance of ALL the DNA stretched out in the B-DNA double helical form, for an average person? How many times would this stretch around the earth (circumference = 40,070 km)? How does this number compare with other distances (see "helpful facts below")?

some helpful facts:

• Humans have about 3,000,000,000 bp of DNA per genome.
• The rise in the B-DNA helix is very close to 0.34 nm per bp.
• 1 nm = 1x10^-9 meters
• Remember that humans have TWO copies of chromosomes per cell!
• An average human contains about 0.5 grams of DNA.
• Assume that DNA weighs about 1x10-21 grams/bp
• The distance from the earth to the moon is 382,000,000 meters.
• 1 Astronomical Unit ("AU", the distance from the earth to the sun) is 149,600,000,000 meters

so how do I tell if the DNA is CURVED???  I'm sooo confused!

Last modified on: 2 February, 2000 by Dave Ussery