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 ;-)

Q) Explain how neutral mutations may be used as molecular clock to date evolutionary events

Since neutral mutations do not confer selective advantages or disadvantages to the individuals, it is assumed the rate of such mutations are fixed at a relatively constant rate. If the ancestral fossil of a particular species is available, the rate of mutation could be determined.

Hence, neutral mutations could be used as a molecular clock to date evolutionary events. For example, by comparing the DNA sequences of two related species of birds, the number of genetic differences between them could be used to calculate the length of time that has elapsed since divergence occurred.

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."

Tuition Advertisement

This post is for students (e.g. private candidates or mainstream students) considering tuition. Ignore the rest of this post if you are not looking for one.

Our previous batch of JC2 and O level students have graduated and we are available for a new intake.

JC biology - We have an experienced current teacher on board but his availability is limited due to the existing guidelines from MOE. Email bioichiban@gmail.com if you need JC biology tuition. Please note he will not start tuition until both parties corresponded with each other and are sure the match is good. If you are keen, you ought to provide the information - (1) Most recent exam grades including non-biology subjects (2) What kind of help do you need (3) School / year (4) General residential area and (5) available days/time slots

Topic Biomolecule (Lipid) Essay - Main Points!

Q) Lipids is a better energy storage molecule than carbohydrates. Despite this, explain why, unlike animal cells, plant cells tend to store carbohydrates.

Main points
Key idea:	Varied functions of lipids in animals
Triglycerides ·Energy store ·Buoyancy (for aquatic animals e.g. whales) ·Thermal insulation (for animals living in cold climate) ·Source of metabolic water (for animals living in the desert) ·Protects internal organs
Key idea:	Advantage of lipids over carbohydrates in terms of energy storage capacity
·Lipid stores more energy per unit mass compared to carbohydrate ·Hence, greater mobility for animals
Key idea:	Possible reason why plants can afford to store their energy as carbohydrates
·Plants are not mobile
Comments: (i) Visualize the answer with the aid of a labelled diagram (ii) Verbalize the answer + write down the main points w/o referring to the answer (use abbreviations) (iii) Read again within the next 24h & once more within 72h (do not spend more than 10min) (iv) Lipids store more energy per unit mass than carbohydrates because it has a higher proportion of H to O atoms per unit mass. Hence, they are easily oxidized and produce more ATP compared to an equivalent mass of carbohydrate (eg. glycogen)