Question

1)Where do the rRNA and ribosomal proteins synthesis take place, what processes made them and where do the subunits get assembled? Organize this information into a flow chart or CONCEPT MAP. (Draw a CONCEPT MAP).

2)How will you design drugs that would easily go through the cell membrane, and some that will not easily enter through the cell membrane?

Answer 1

1) The ribosomal proteins are present in the cytoplasm where the protein synthesis takes place after the process of the arrangement of ribosomes on the rough endoplasmic reticulum required for the synthesis of different proteins. mRNA template is formed for the synthesis of proteins with the help of enzyme RNA polymerase-II. This template then leads to the synthesis of different proteins outside the nucleus in the cytoplasm. The synthesized ribosomal proteins and 5s rRNA reach the nucleolus region where they form a complex ribosomal machinery. The cleavage of the precursor RNA takes place in the nucleolus leading to the synthesis of different protein complex particles like 28S, 5.8S and 5S rRNA. The assembled ribosomal fractions of different proteins then leaves the nucleolus and nucleus region and enters the cytoplasm for the protein synthesis mechanism to take place.

The concept map diagram is given below as follows:

RNA C pt Map RNA can be tRNA mRNA rRNA also called which functions to also called which functions to also called which functions to Carry instructions Messenger Ribosomal Combine with Brings amino acids Transfer RNA RNA RNA protein to the ribosome to make up from to DNA Ribosomes Ribosomes

source-chapter 13 -Levine Biology

The diagram showing the synthesis and formation of different rRNA and ribosome particles is depicted below in the form of a diagram as follows:

Nucleolus Nucleus rDNA 5S rRNA Pre-rRNA Ribosomal proteins 285 -5.8S 18S 55 Preribosomal particles 28S 18S 5.8S 40S subunit 5S Cytoplasm 60S subunit

Source- Cooper, The cell book.

2) PepT1 transporter is used for the transport of certain antibiotics from the outside of the cell to the interior of the cell by the process of transport across the channel present in the membranes of human cells. The alpha Amanitin drug inhibits the enzyme RNA polymerase and enters the interior of the cell. There are other receptors present in the membrane like ATP binding cassette and P-glycoproteins which help in the transport of drugs across the membrane of the mammalian cell. There is docking of different drugs on specific sites of ribosomes which block the synthesis of proteins inside the cell and lead to the synthesis of antibiotic peptides inside the cell. There are other drugs which bind to cholesterol moiety inside the cell membrane and enter the interior of the cell. The movement of drugs and peptides depends upon the structure and the specificity of the condensed molecules in the drug which either allow or prohibit the entry of the drug molecules through the cell membrane. There is Lipinski rule of 5, which is used for analyzing the properties of the drug molecule inside the membrane along with analysis of physicochemical parameters which are meant to be identified. If the value of clogP is over 5, then it means that there is poor absorption of drug in the membrane of the cell. The other factors for low solubility of drugs are if the molecular weight is over 500, presence of more than 500 hydrogen bond donors in the cell, and presence of more than 10 hydrogen bond acceptors in the cell.