Solution to Midterm #1

I don't have both versions, so here's the questions and their answers:

Q: DNA molecules play a critical role....in addition to reproduction?

(/6)

DNA governs the synthesis of protein

Q: Why do many biologists....a world have existed

(/9)

precursor of DNA

simpler molecule

can perform the same functions

4 - 3.8 billion years ago

Q: What is a peptide...Name a protein

(/10)

peptide - 2 or more amino acids joined together after giving up H2O molecule

peptides link together to make a protein

proteins are workhorses of the cell

hemoglobin, insulin, cytochrome c, etc.

Q: suppose that the Universe....not have any edges

(/7)

analogy to the surface of a sphere is a 2-D imbedded in 3-D, our universe could be a 3-D analogue of a sphere embedded in 4-D space.

Q: What do cosmologists...such dark matter

(/9)

dark matter interacts with ordinary matter only via gravitation, it's non-luminous

rotation curves of galaxies indicate that most of the mass in galaxies is in the form of dark matter

Q: Do we live in....the evidence?

(/9)

We don't know.

The experimental results for the total density of the universe are so close to critical density that it could be either way.

(You got full credit for also saying yes, and explaining that the density of the universe is greater than critical, or saying no and that the density of the universe is less than critical)

Q: What are believed to be....4 billion years ago?

(/6)

outgassing

impacts of planetesimals (comets, asteroids)

Q: What is meant by free energy...creatures on Earth?

(/6)

free energy is needed by organisms in order to decrease the entropy so as to retain the high degree of order needed for life.

e.g.: sunlight, lightening, volcanoes

Q: Describe how scientists measure the age of old rocks.

(/7)

radioactive dating

taking the relative ratio of the parent to daughter isotopes, and from knowing the half life, deduce the age of the sample.

Q: What force holes the3He...hydrogen atom?

(/6)

Q:Suppose that you point a radio....at what rate of speed?

(/14)

It is coming towards us.

v = (1.3 - 1.2)/1.3 * C

v = 0.077 c

Q: What happens to a water...after emission?

(/4)

the molecule rotates more slowly due to the conservation of energy

Q: Is water an organic molecule? Why?

(/7)

No

organic molecules contain Carbon, or, Carbon and Hydrogen.