ATAR Notes: Forum
Uni Stuff => Science => Faculties => Biology => Topic started by: purple_rose on March 21, 2009, 08:55:47 pm
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In the process of carbon fixation, RuBP attaches a CO2 to produce a 6 carbon molecule, which is then split in two. After phosphorylation and reduction, what more needs to happen in the Calvin cycle?
a a gain of NADPH
b regeneration of ATP from ADP
c. regeneration of rubisco
d. inactivation of RuBP carboxylase enzyme
e. addition of a pair of electrons from NADPH
Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?
a. a deletion of 2 nucleotides
b. a substitution of the first nucleotide of a GGG codon
c. a substitution of the third nucleotide in an ACC codon
d. an insertion of a codon
e. a deletion of a codon
thanks,
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The first question seems to be way out of the VCE syllabus.
Question 2: A
This is because all the other mutations only affect a single amino acid. This (I think) is referred to as a point mutation. However, A causes all subsequent amino acids to be shifted and hence the translation 'reading frame' is moved as well, causing basically every single subsequent amino acid to change as well. These VERY drastic mutations are known as 'frame shift mutations'.
EDIT: Whoops this was in the tertiary section, hang on, I'll check my notes.
Question 1: Pretty sure it's C. The Calvin Cycle occurs in three basic steps; 1. Carbon fixation, 2. Reduction, 3. Regeneration of Ribulose. I assume the first two steps mentioned in the question refer to steps 1 and 2, so all that's left is the third step for which C seems to fit best since ribulose something something becomes RuBP again after a few steps.
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Yea it's right. Thanks for the quick reply.