ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Biology => Topic started by: starbuckscoffee on March 15, 2008, 04:58:07 pm
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Does the tertiary and/or the quaternary structure of a protein determine it's catalytic function? and can u explain
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I would say the tertiary structure determines its catalytic function because that is when a single enzyme(protein) molecule gets it's three dimensional configuration. (The enzyme's amino acid sequence also determines it's function). This means active sites are formed and substrate molecules can fit - hence it can now catalyse reactions.
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its the tertiary structure because thats when the protein has all folded and bended and twisted due to the bonds between the amino acids, and so theres the groove that is the active site that makes reactions go faster. the quarternary structure is just like two or more proteins clumped together such as haemogloebin. so yeah tertiary determines the active site. prob not a flash explanation but eh.
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im pretty sure all enzymes are only made up of one polypeptide chain, so the answer would be tertiary.
Tertiary structure is the overall shape of a protein. Enzyme catalysed reactions are usually very specific; an enzyme will only react on its specific substrate because for an enzyme to act on a substrate it must have a complimentary shape to the molecule its acting on.
*some enzymes however are less specific and can break down specific bonds rather than specific molecules. ie it can break down any molecule containing a certain bond
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sorry guys, but its actually both tertiary and quartenary structure that affect an enzymes function.
a singular protein strand is extremely small and often these globulins bind together (eg haemoglobin is comprised of four identical proteins) but it's active site where it binds with oxygen is found on all four units, but these units do not react in the same way if found singularly)
hope you get that...
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sorry guys, but its actually both tertiary and quartenary structure that affect an enzymes function.
a singular protein strand is extremely small and often these globulins bind together (eg haemoglobin is comprised of four identical proteins) but it's active site where it binds with oxygen is found on all four units, but these units do not react in the same way if found singularly)
hope you get that...
My teacher told me that today, lol.
So it depends on which kind of enzyme/protein it is? - like you said, haemoglobin needs four ... but some will work as a single.
EDIT: added "/protein" since it sounded like I said haemoglobin was an enzyme
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haha. yep. its a really commonly used example.
its totally dependent on the size of the molecule. but if you look at the chemistry of an amino acid, the size of some of them are only 10-15 atoms in size, so using that as a yardstick proteins on their own can be pretty damn small. it is dependent on the individual question, but on an exam i'd put that down as my answer what i told you, gives you the mark for tertiary but also the kudos in the markers mind that you really know your shit and then the will mark more lenient on other questions (TRUTH)
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hmmz i did some experiment today in bio this sounds like some info that adds something extra to the information about enzymes ... ill just copy it
- the activity of some enzymes depends entirely on their structure as proteins, while others require additional non-protein structure for activity. If the extra molecule is loosely attached so that it can diffuse away it is called a co-enzyme (some vitamins are co-enzymes). If it is firmly attacked to the protein it is called a prosthetic group...... there are several heam-dependent enzymes invovled in respiration. Certain ions such as cyanide and azide combine with the iron atom found in haem groups. Poisons such as cyanide and azide combine with the iron atom in the haem group and inactivate the enzyme. Heavy metal ions in solution (like mercury, lead , cadmium) also exert their toxic effect by inhibiting enzymes.