IQ 3 - Protein Synthesis Module 1

what are proteins

A protein is a fully folded, functional molecule made up of one or more polypeptide chains. Proteins have a specific 3D shape that determines their function (e.g., enzymes, hormones, or structural proteins).

what is a gene

A gene is a portion of DNA which codes for proteins

What is the role of mRNA in protein synthesis?

a gene (a segment of DNA) in nucleus is copied by polymerase into a complementary mRNA strand. This mRNA sequence mirrors the DNA coding strand but uses uracil (U) instead of thymine (T). mRNA molecule then carries the genetic code from the nucleus to the ribosome, where tRNA molecules, carrying specific amino acids, bind to the corresponding codons on the mRNA, and the ribosome links the amino acids together to form a protein

Transcription

In the nucleus, a gene (a segment of DNA) is copied by a polymerase enzyme into a complementary mRNA strand. This mRNA sequence mirrors the DNA coding strand but uses uracil (U) instead of thymine (T).

Which enzyme is used to make an mRNA copy of a gene

RNA polymerase is used to copy genes into mRNA

tRNAs

tRNA molecules consist of nucleic acid, and they have an anticodon and an amino acid binding region. The amino acid binding region is specific to only one type of amino acid.

It binds to its amino acid in the cytoplasm. Then, the anticodon recognises and binds to its complementary codon sequence on the mRNA as it is being translated at the ribosome. The ribosome attaches the amino acid to the growing polypeptide chain, in accordance with the mRNA sequence. will stop producing a polypeptide when it reaches a stop codon on the mRNA

what is an enzyme 

Enzymes are proteins that speed up chemical reactions in the body, such as amylase breaking down starch into sugar.

Structural proteins

provide support and strength to cells and tissues such as Collagen in skin and bones.

synthesis of an enzyme. (steps of  making DNA into protein)

Sep  1) transcription -  the gene form the enzyme is copied from DNA onto a strand of mRNA in the nucleus. The mRNA  contains the genetic code ( sequence if bases that determine the order of amino acids . 

step 2) mRNA processing and transport - the mRNA leaves nucleus through a nuclear pore and travels to a ribosome in the cytoplasm.

Step 3) translation: At the ribosomes, the mRNA code is read in triplets ( codons). each codon specifies a particular amino acid.

step 4) tRNA tole :tRNA reads codon and brings the correct amino acids to the ribosome, matching  each codon with its complementary anticodon. 

step 5) polypeptide formation) the ribosome joins the amino acids together with peptide bonds, forming a polypeptide chain 

step 6: Folding and activation: the polypeptide chain folds into a specific 3D shape forming the active site of the enzyme. this folded protein becomes a functional enzyme 

what does synthesis mean 

when cells build complex molecules (like proteins, DNA, or enzymes) from simpler components.e.g

•  Protein synthesis = making proteins by joining amino acids together.

• Photosynthesis = plants make glucose using sunlight, water, and carbon dioxide.

polypeptides

A polypeptide is a chain of amino acids joined together by peptide bonds. It is the first product made during translation.