Search found 232 matches

by Navin
Fri Nov 30, 2007 7:22 pm
Forum: Genetics
Topic: Griffith and his role with DNA discovery
Replies: 3
Views: 2209

Yes - I think DNA is heatstable when compared to proteins and RNA. I think its got to do with its unique structure that makes it more stable than RNA (This is why our genome is made of the more stable DNA, not RNA), and we know that most proteins (particularly enzymes) denature at high temperatures ...
by Navin
Fri Nov 30, 2007 3:32 pm
Forum: Genetics
Topic: Genetics related MCQ
Replies: 2
Views: 11689

Not really - besides plasmid transformation, there is also the uptake of naked DNA when bacteria in natural populations are in a state of natural competence. Fragments of chromosomal DNA from lysed bacteria can enter into neigbouring bacteria (then followed by homologous recombination). There is a f...
by Navin
Fri Nov 30, 2007 9:20 am
Forum: Genetics
Topic: Genetics related MCQ
Replies: 2
Views: 11689

Genetics related MCQ

I managed to get my hand on my exam booklet - and here are several qns that stumped me. I'll post the qns first, then followed by my reasoned answers. 1. What process in bacteria ALWAYS allow both chromosomal and non-chromosomal DNA to be transferred? A binary fission B conjugation C transduction D ...
by Navin
Mon Nov 26, 2007 2:12 pm
Forum: Cell Biology
Topic: Creating a markscheme.
Replies: 4
Views: 4761

Oh i think i can help with the 2nd qn too: Possible Answers 1. Cyanide is an inhibitor of the Electron Transport Chain (specifically the enzyme cytochrome c) 2. Hence, ETC cannot proceed, so no oxidative phosphorylation, no regeneration of Hydrogen carriers, no Link Rxn nor Kreb's cycle --> and ulti...
by Navin
Mon Nov 26, 2007 2:04 pm
Forum: Cell Biology
Topic: Creating a markscheme.
Replies: 4
Views: 4761

I can help with the first question: These might be possible answers 1. Pyruvate is the substrate that enters mitochondria and participates in link reaction 2. Glucose can only participate in glycolysis - a process in which the enzymes are present only in the cytoplasm (NOT the mitochondria) 3. Hence...
by Navin
Sun Nov 25, 2007 3:36 am
Forum: Molecular Biology
Topic: Template Re-annealing Problem
Replies: 8
Views: 2692

Thanks!

Yep, i guess C is the limiting step.

In fact - I have done PCR many times - but i didnt question what limited the number of steps! Well, I guess it just pays to be extra inquisitive.
by Navin
Sat Nov 24, 2007 10:33 am
Forum: Molecular Biology
Topic: Template Re-annealing Problem
Replies: 8
Views: 2692

Template Re-annealing Problem

In PCR, after the denaturation step, and then the temaperature is lowered to around 60 degrees celcius for the annealing of the primers, Why is it that the 2 template strands do not re-anneal? This question came out in my exam and some of the available options were; A. The primer is small B. 60 degr...
by Navin
Thu Jul 26, 2007 2:55 pm
Forum: Genetics
Topic: usage of chi square in a genetics cross -how does this work?
Replies: 9
Views: 5122

Oh - what i was taught to do, was this: (number of phenotypes -1)

Since in your case there is a total of 4 phenotpes in the offspring, then the degree of freedom is 4-1 = 3.

Is this an acceptable method?
by Navin
Thu Jul 26, 2007 2:46 pm
Forum: Molecular Biology
Topic: CFTR: transport HCO3- ions?
Replies: 0
Views: 926

CFTR: transport HCO3- ions?

I would like to know if the Cystic Fibrosis Trans-membrane Regulator protein is also involved in HCO3- ion transport in addition to Cl- ion transport? I was doing an A level question - and the data in the question seemed to suggest that HCO3- ion transport decreased upon a mutation in the CFTR. But ...
by Navin
Wed Feb 28, 2007 2:38 am
Forum: Botany Discussion
Topic: Smallest Gametophyte?
Replies: 3
Views: 3912

ah, ok.

So i guess by means of evolution of the reduced gametophyte, then I can say that the angiosperms have the smallest gametophyte.
by Navin
Tue Feb 27, 2007 3:23 pm
Forum: Cell Biology
Topic: Modification to HeLa cells
Replies: 0
Views: 1163

Modification to HeLa cells

The HeLa cell line derived form cervical cancer cells of Henrietta Laques.
Were any modifications done to those cells in order to allow them to grow indefinitely in culture conditions.

Also in tissue culture, what does the term "transformed cell" mean?
by Navin
Tue Feb 27, 2007 3:18 pm
Forum: Botany Discussion
Topic: What part of a dead tree doesn't biodegrade
Replies: 9
Views: 7529

Then it is important to note this irony - that whilst plants served to remove carbon dioxide in the air (especially the petridophytes long time ago) that are then are converted to coal (therby contibuting to global cooling) is now implicated in global warming when the coal (from those plants) is bei...