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Biology homework

KyleH123

POSTER

(edited 7 years ago)

Reply 1

CheeseIsVeg

@wolfmoon88 erm biology people erm
ermmmmmm idk
:bump:

anyway

Reply 2

macpatgh-Sheldon

Hi,
a) Google Images - search glucose sructure and use structural formula with C toms shown - same with fructose (glucose has a hexagonal ring made with 5 Cs and one O. The carbons are numbered with [1] being the rightmost one and going clockwise so that the left one is C4. (Fructose has a pentagonal ring)). Explain all these facts. Perhaps show alpha AND beta glucose wich just have one pair of -H and -OH groups interchanged

b) The two polymers found in starch are amylose and amylopectin (amylose has alpha glucose; amylopectin has beta). Amylose is a straight chain molecule. This occurs due to a glycosidic bond between the rightmost C (C1) of one glucose and leftmost of the next (C4). You can show a diagram with the two side by side with C1 of the one the left adjacent to C4 of the one on the right. You can imagine that if all glucodse molecules are bonded with these (1,4 glycosidic bonds), it will form a straight chain ONLY.

To produce branching, you need extra bonds in a different directiion (obviously) - this is achieved by 1, 6 glycosidic bonds. C1 (on the right bonds with the C6 [topmost] of the glucose molecule below, so the chain progresses "vertically" downwards. (check diagrams in your book to understand)

c) Glycerol is a triple alcohol (think of it as even stronger than a double whisky lol) i.e. it has three alcohol groups (-OH groups) in its structure (Google it)

|-- CH2OH
|-- CHOH
|-- CH2OH

Fats in general are produced when 1, 2, or ALL 3 of these OH groups react with an acid group of (a) fatty acid(s) to form ester bonds (C=O-O-)
If one -OH group is used thus, you get monoglyceride; two -OH groups: diglyceride three -OH groups (maximum): triglyceride. Google oleic acid to work out that particular example.

d) Mention that insulin is a protein hormone secreted by beta cells of the Islets of Langherhans in the pancreas. It reduces blood glucose levels, and deficiency of insulin causes diabetes. I believe insulin has 56 amino acids (check it out!). Describe primary secondary, tertiary structure with reference to insulin. Insulin breks of from pro-insulin (87 a.a. -s??), leaving C peptide (31 a.a.-s) as residue.

i) the fact that a peptide bond links two amino acids (bond berween amino group of one a.a. (-NH2) with carboxyl group (-COOH) of next giving -CONH- bond. Two a.. (in this case valine and glutamic acid) give a dipeptide.

ii) Two a.a. joine by peptide bond

iii) depeptidation (opposite of formation of peptide bond)

iv) cystine is an a.a. that contains a sulphur atom (so is methionine) - it can form disulphide bridge (-S-S-)with another sulphur-containg a.a., so there's a kind of cross-linkage which will help strengthen any folding or twisting of the polypepptide chain rather like the rungs of a ladder. (This is ane example of secondary or tertiary structure of a protein).

OK I HAVE DONE IT ALL for you, but I will not be doing exams in May, it will be you, so read up more detail, check several diagrams, think about all you learn, associating various facts to aid memory, look at the attached Powerpoint file (which is one I created for teaching), test yourself without cheating, and MAKE YOUR POSTER USING YOUR IMAGINATION AND CREATIVITY.

Good luck!

Mukesh (Specialist Biology Tutor)

CHOs New.pptx195.2KB

Reply 3

KyleH123