IBDP Biology Chapter 7 Notes



These notes have specially been curated by expert teachers to simplify and enlighten concepts given in IB Biology HL. The notes are comprehensive in nature and are sufficient to study the chapter in depth and one need not look for other resources beyond the notes provided on our website which can be accessed for free. The notes for Cell Biology IBDP HL are available on our official website and can be downloaded for free. You are one click away from obtaining all that you need to score well in IB Biology HL.

The material made available on Tychr’s website is available for all IBDP subjects and is specially curated after an extensive amount of effort to ensure that the notes are in consonance with the IB curriculum and are an amalgamation from various textbooks prescribed by the IBO.Students often face a challenge understanding concepts, especially concepts that are new and tricky. These IB Biology Notes will help the student cover the chapter of Cell Biology entirely while explaining each and every concept in a detailed and easy way.

This unit aims to explain the genetic material of living organisms and understand the process of protein formation. DNA was confirmed as genetic material by Hershey and Chase’s experiment, whereas Watson and Crick discovered the double-helix structure of DNA wherein two strands of DNA are linked by hydrogen bond between bases and the nucleotides are connected by phosphodiester bonds.

DNA (negatively charged) is packaged with the help of histone proteins(postively charged). DNA replication is a semi-conservative process principle mediated by DNA polymerase and various other enzymes(helicase, ssBP, RNA primase), 3′ to 5′ being the leading strand and 5′ to 3′ lagging strand. Transcription and translation are involved in protein synthesis. Transcription involves RNA polymerase and is done with the help of the formation of mRNA from the sense strand.

The mRNA is then spliced as a part of the post transcriptional modifications. The codons in the spliced mRNA (mature mRNA) are translated into a polypeptide chain with the help of ribosomes in the cytoplasm. This process of translation occurs in 4 steps: initiation, elongation translocation and termination. initiation occurs with the use of start codon AUG and termination with the help of stop codons UGA UAGand UAA.

These polypeptides that are formed can take four levels of structure primary, secondary (alpha helix or beta-pleated sheath), tertiary(most enzymes) and quarternary(haemoglobin.PA proteome is the unique set of proteins that an individual can synthesise, and it depends on the genome.