Correction to 2002-2011 Worked Solutions Book

Hi all, 

due to printing error, please make the corrections to the following: 

1) 2002-2011 Worked Solutions Book (green cover): 

N11/P3/Essay Question 5c

The corrections are highlighted in yellow

2) 2002-2011 Topical Series Book (dark pink cover)

Answers for MCQ are: 

(1) D  (2) B  (3) B  (4) C  (5) C  (6) B  (7) A  (8) D  (9) A  (10) A      (11) A  (12) B  (13) A  (14) B  (15) A  (16) D  (17) D  (18) C  (19) B  (20) C  (21) B  (22) D  (23) B  (24) B  (25) A  (26) C  (27) D  (28) B  (29) D  (30) C  (31) A  (32) D  (33) C  (34) C  (35) C  (36) D  (37) A  (38) A  (39) D  (40) B 

To all 2012 A level candidates - All the best! 

Bioichy ;-)

List of Enzymes Arranged in Topical Format

Hi all,
this is the list of enzymes mentioned in the 100 Model Essay Book which we hope will be useful to you.
[Advertisement: We also provide a compilation of Structured Questions and Model Answers nicely arranged in topical format. However, we do charge a fee for it. The fee includes postage.]

List of enzymes arranged to topics

Note: The enzymes with the asterisk* are important for the A level exams.  

(1)  Core topic: Cellular Functions        

Carbohydrate

*Amylase

(2)  Core topic: DNA and Genomics

DNA Structure & Replication

*DNA ligase

*DNA polymerase

*DNA primase

*Helicase

Protein Synthesis & Gene Mutation

*Amino-acyl tRNA synthetase

*Peptidyl transferase

*RNA polymerase

(3)  Core topic: Genetics of Viruses and Bacteria

Genetics of Viruses

*Integrase

*Neuraminidase

*Topoisomerases

*(β-galactoside) transacetylase

Genetics of Bacteria

*Beta (β) galactosidase

*Permease

*Protease

(4)  Core topic: Organisation and Control of Prokaryotic and Eukaryotic Genome

Endopeptidase

*Guanylyltransferase

*Histone deacetylase

*Histone transacetylase (or acetyltransferase)

*Poly-A polymerase

*Telomerase

(5)  Core topic: Genetic Basis for Variation

Tyrosinase

(6)  Core topic: Cellular Physiology and Biochemistry

Cellular Respiration 

*ATP synthase (complex)

*Dehydrogenase

*Glucokinase

Phosphoglycerate kinase

*Pyruvate decarboxylase

*Pyruvate dehydrogenase

Pyruvate kinase

Photosynthesis

*ATP synthase (complex)

*RuBP carboxylase

Nervous control

*Acetylcholinesterase

Homeostasis & Cell Signaling

*Adenylyl (or adenyl / adenylate) cyclase

*Glycogen synthetase

*Glycogen phosphorylase

*GTPase

*Glucokinase

*Kinase

*Phosphatase

*Phosphodiesterase

*Receptor tyrosine kinase

*Tyrosine kinase

(7)  Core topic: Diversity and Evolution

Nil

(8)  Application topic: Isolating, Cloning and Sequencing DNA

*Beta (β) galactosidase

*DNA ligase

Endopeptidase

Exonuclease

*Restriction enzyme (or endonuclease)

*Reverse transcriptase

RNase

*Taq DNA polymerase

(9)  Application topic: Applications of Molecular and Cell Biology

Nil

URL link to the synthesis of cDNA from mRNA

Hi all, 
this website has the different ways to synthesize cDNA from mRNA. Nice diagrams to help you understand. However, the information presented is beyond the A levels syllabus. It's meant for those who are really interested or/and advanced learners.

http://dwb4.unl.edu/Chem/CHEM869N/CHEM869NLinks/www.dur.ac.uk/~dbl0www/Staff/Croy/cDNAfigs.htm

regards, 

bioitchy ;-)

2004-2010 worked solution - missing Nov 2010 answer

We missed out the answer for Q1b(ii). So, here is the answer:

"The hydrolysis of ATP produced from the mitochondria is used to provide energy for the attachment of the amino acids to their respective transfer RNA and for the formation of peptide bonds. Some of the proteins made by the ribosomes of the rough endoplasmic reticulum are imported into the mitochondrion where they serve as carrier proteins of the electron transport chain."

Correction to the essay worked solution (Nov 2004)

We made a mistake in our answer to the essay on Calvin cycle. We described the Krebs cycle instead (apologies!). Below is the correct answer for the particular essay question.

The Calvin cycle comprises of three stages: (i) carbon fixation, (ii) reduction of glyceraldehyde-3-phosphate (G3P) and (iii) regeneration of RuBP.

Initially, a molecule of carbon dioxide combines with the 5C ribulose bisphosphate (RuBP) in a reaction that is catalyzed by ribulose bisphosphate carboxylase. The product is an unstable 6C compound that immediately breaks down into two 3C molecules of phosphoglycerate (PGA).

In the next stage, PGA is reduced to glyceraldehyde-3-phosphate (G3P) that requires ATP and NADPH (from the light-dependent reactions). For every six CO₂ that enter the cycle, 12 G3P molecules are made of which two are used to synthesize carbohydrate (e.g. sucrose, starch or cellulose).

The remaining G3P molecules undergo reactions to form ribulose phosphates (RuP) which are then phosphorylated to regenerate RuBP required for the cycle to repeat itself.

Hence, for every hexose molecule synthesized, six CO₂ are fixed, phosphates transferred from ATP and electrons from NADPH.


P.S. The essay main points are in the previous post (19 Oct '11) so you may want to refer to it for more effective revision instead. 

Explanation of a past yr multiple choice question

The A Level H2 Biology worked solutions (2002-2010) for Paper 1 are out in Popular Bookshops. We advise you go through every past yr MCQ as questions may be repeated! By the way, the 2002-2010 worked solutions and the 2002-2011 Topical Series questions will be out early next year.

Those who bought the book will encounter a particular question that says "No answer (VOID)". This is because I find the question ambiguous - I have to assume that the molecule does not have anymore EcoR1 or Tac1 elsewhere other than the given section. So total no. of fragments is 5.

If I make the assumption, then the answer is C.