Lesson 13 (11/11/14)

Date : 7/11/14

Topic : Structure and function of genetic material

Activities

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Notes
Genome = genetic information in a cell

Chromosomes = structures containing DNA that carry genetic information

Genes = segments of DNA that code for functional products

Genotype = genetic composition of an organism ; information that codes for all characteristics

Phenotype = actual expressed properties of an organism

Functions of DNA
1. Store genetic information
2. Self-duplication and inheritance
3. Expression of genetic message

Types of RNA
1. mRNA : contains genetic information to encode a particular protein
2. rRNA : forms integral part of ribosomes
3. tRNA : an adaptor molecule used in translation

Central dogma of genetics is a one way transfer of genetic information from nucleic acid to protein. It includes DNA replication, transcription and translation.
For prokaryotes, translation can begin before transcription is completed because no membrane is separating the chromosomes from cytoplasm.
For eukaryotes, transcription and translation are spatially separated. Exons and introns are present in primary transcript (pre-mRNA), but then introns are removed to form functional mRNA.

Origin of replication > replication forks >  lagging strand & Okazaki fragment + leading strand
RNA primers are removed by DNA polymerase and DNA ligase joins the newly made DNA fragment with the previous one

Replication site > promoter site (promoter) > termination site (terminator)

The Wobble Hypothesis explains why multiple codons can code for one single amino acid. One tRNA molecule (with one amino acid attached) can recognize and bind to more than one codon, due to the less-precise base pairs that can arise between the third base of the codon and the fist bsae of the anticodon. (according to wikipedia)

Name of microbes
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Random facts
A&T have 2 hydrogen bonds
G&C have 3 hydrogen bonds

DNA replication is very accurate because it is proofread by DNA polymerase.

In E.coli, the synthesis of nucleotides during replication can reach up to 1000 nucleotides per second at 37 degree Celcius.

Muddiest point
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My own exploration
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Reflection on this topic

The topic of genetics has been covered in Form Six syllabus, so most of the information still can be handled, just that need some more revision on the topic.