I just want to make sure that my hw problems are correct.thk

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I just want to make sure that my hw problems are correct.thk

Post by maya786 » Tue Sep 16, 2008 2:22 am

Why does water expand upon freezing?
a. Dissolved air is released from the water, making bubbles in the ice that cause it to expand
b. When water freezes, the covalent bonds lengthen and crystals form.
c. When water freezes, it forms a crystalline structure in which the hydrogen bonds are perfectly aligned. This alignment causes the water molecules to be held at "arm's length" from one another.

*The answer I got is C

Which of the following is an example of an amino acid with a nonpolar (hydrophobic) R group
a. glutamic acid
b. isoleucine
c. serine
d. cysteine
e. lysine

*The answer I got is a

Which type of bond is most responsible for the following properties of water:
cohesion, moderation of temperature, expansion upon freezing, and its ability to act as an excellent solvent.
a. The polar covalent bond connecting the oxygen to the hydrogen
b. The hydrogen bond that connects the oxygen on one water molecule to the hydrogen on another

*The answer I got is b

A cell has a nucleus, ribosomes, golgi bodies, mitochondria, and chloroplasts. What kind of cell is this likely to be?
a. Prokaryotic
b. eukaryotic (animal)
c. eukaryotic (plant)

*The answer I got is a

Two different proteins are loaded into different lanes of a gel which has been prepared at a physiological pH. An electric field is applied such that the electrode placed near the origin of the gel is positive and the one placed at the far end of the gel is negative. After 2 hrs, the electric current is shut off and the position of the two proteins is analyzed. Protein A has not moved very far from its original position while Protein B has moved toward the negative electrode. What does this tell you about the net charge of Protein A with respect to Protein B?
a. Protein A is less charged than Protein B. Protein B has a net positive charge.
b. Protein A is less charged that Protein B. Protein B has a net negative charge.
c. Protein A is more charged than Protein B. Protein A has a net positive charge.
d. Protein A is less charged than Protein B. Protein A has a net negative charge.

*The answer I got is d

Thanks in advance...I just want to know if these answers are correct and if not which is the correct answer and thanks

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Post by mith » Tue Sep 16, 2008 4:36 am

You have 3 problems wrong.
Living one day at a time;
Enjoying one moment at a time;
Accepting hardships as the pathway to peace;

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Post by lansden » Sat Oct 18, 2008 7:08 pm

yeh the second one is isoleu. not glu
the fourth is plant
last one is b is pos a is less charg
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Post by ChinnRod » Wed Oct 22, 2008 1:24 pm

Well,you have 3 problems wrong.
No.2: b is right
isoleucine,It's R group is
:D :D C
:D :D
It's a hydrophobic group

No.4: c is right
only eukaryotic cell has chloroplasts.chloroplasts link to photosynthesis,release oxygen.

No.5: b is right
Great China!We are all human.No politics here.

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