Biology Unit 3 Questions Megathread

[WhoTookMyUsername]

Yeah i saw that, but that doesn't say anything about beta elasticity though, but they ARE elastic?

[WhoTookMyUsername]

Do lipids need to be converted into glucose before their energy can be released?

[shinny]

Do lipids need to be converted into glucose before their energy can be released?

No, lipids are mostly converted into acetyl-CoA which feeds directly into Krebs' cycle and hence by-passes glycolysis.

[HERculina]

Yeah i saw that, but that doesn't say anything about beta elasticity though, but they ARE elastic?

According to answer.yahoo.com they are incredibly elastic: http://answers.yahoo.com/question/index?qid=20101016151853AAZNper
 

[Russ]

RE: beta sheets, I don't think it's particularly important but at a guess, the extra elasticity is derived from the fact that they're aligned with H-bonds between them, which allows for sliding of the sheets relative to each other.

Or something like this I guess

Hm, polar molecules have no overall charge cause theyre made from covalent bonds? :/
... not made of charged ions? :O

Just because they contain covalent bonds, doesn't mean they can't have an overall charge?

[WhoTookMyUsername]

Wouldn't that be ionic AND covalent bonding though? (does that occur?)



How do water molecules get through the phospholipid bilayer (cos they are small, ? could they get in without aquaporins?)


Q
In eukaryotic cells the conversion of ADP and phosphate into ATP occurs:

A) Only in the mitochondria, and requires energy.
C) In both the mitochondria and the cytoplasm, and requires energy (i.e. draws energy from other exergonic reactions?)

[shinny]

How do water molecules get through the phospholipid bilayer (cos they are small, ? could they get in without aquaporins?)

Q
In eukaryotic cells the conversion of ADP and phosphate into ATP occurs:

A) Only in the mitochondria, and requires energy.
C) In both the mitochondria and the cytoplasm, and requires energy (i.e. draws energy from other exergonic reactions?)

Predominately through aquaporins, although some can leak through the plasma membrane despite being charged given its size.

C. Glycolysis occurs in the cytoplasm, while the ETC is obviously in the mitochondria. Glycolysis also requires energy as stated in C. It actually produces 4 ATP, but consumes two, leading to a net production of 2 as you should be familiar with.

[WhoTookMyUsername]

Thanks
Another one (of an infinite amount :S)

I think the answer is D but not 100% sure

Process of anaerobic respiration is different in plants and animals because:

C) Contain Different organnelles
D) Contain different enzymes


Also shinny, can ADP + Pi form ATP by reactions such as the breaking of peptide or polysaccharide bonds (right name? :S)


Thirdly
Do Cyanobacteria have chlorophyll?

[shinny]

It would be D. Anaerobic respiration doesn't really require any organelles.

Not sure if the catabolism of polypeptides themselves can create ATP, I don't think they can, but the individual AAs resulting can be metabolised in the liver into acetyl-CoA which once again feeds directly into Krebs' cycle. AAs can also be turned into glucose.

[WhoTookMyUsername]

Okay thankyou. In some TSFX notes i bought it says all catabolic reactions are exergonic and create ATp but that doesn't sound right..

Also i'm very confused about this whole naming system for WBC and all the names like leukocytes, lymphocytes etc.
Is there a flow chart anywhere on the site?
thankyou

[HERculina]

You should check out the biozone website. it has kool animation links. does anyone else know a good biology site?

[TrueLight]

Also i'm very confused about this whole naming system for WBC and all the names like leukocytes, lymphocytes etc.
Is there a flow chart anywhere on the site?
thankyou

leukocytes are the same thing as white blood cells, its just the scientific way of saying it

just google 'Hematopoiesis', there should be a few around
eg: http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A40/?report=objectonly
also natural killer cells are part of the lymphoid lineage
or this one from wiki
http://en.wikipedia.org/wiki/File:Hematopoiesis_(human)_diagram.png

[WhoTookMyUsername]

lol does anyone know the answer to


whether all non - polar molecules have ph of 7 (or vice versa) thanks

a polar molecule must be charged.

Acidic or Basic substances must have an excess of H or OH as charge?

So does that mean all acidic or basic substances are charged?

[pi]

pH depends a lot on temperature. Just because something has a pH of 7, doesn't necessarily mean it is 'neutral'.

Polar molecules are not 'charged' but rather have uneven distribution of charge in certain covalent bonds creating polar region (due to differing electronegativities of O-H, N-H and F-H).

Acidic or Basic substances must have an excess of H or OH as charge?

Have no idea what you mean there.

So does that mean all acidic or basic substances are charged?

Ditto, but I am inclined to say 'no'.


You really need to know the meaning of 'charged' before posting these question...

[HERculina]

lol does anyone know the answer to


whether all non - polar molecules have ph of 7 (or vice versa) thanks

a polar molecule must be charged.

Acidic or Basic substances must have an excess of H or OH as charge?

So does that mean all acidic or basic substances are charged?

im not 100% sure on what you mean by these q.s, but i do know that:
* Water has a tendency to ionize, split into H+ and OH- ions
 = pH is therefore the concentration of Hydrogen (H+) ions per litre of solution and hence is a measure of the acidity or alkalinity state of a solution