Protein synthesis Grade 12 Life Sciences Study Notes. Protein biosynthesis (or protein synthesis) is a core biological process, occurring inside cells, balancing the loss of cellular proteins (via degradation or export) through the production of new proteins. Proteins perform a number of critical functions as enzymes, structural proteins or hormones.
Protein synthesis Grade 12 Life Sciences Study Notes
Protein synthesis is the process by which proteins are made in each cell of an organism to form enzymes, hormones and new structures for cells.
There are two main processes involved in protein synthesis, namely transcription and translation.
Transcription (takes place in the nucleus)
- DNA unwinds and splits.
- One DNA strand acts as a template for forming mRNA.
- Free nucleotides arrange to form mRNA according to the DNA template. This process is called transcription.
- The mRNA leaves the nucleus through the nuclear pores. Stage B now takes place when mRNA in the cytoplasm attaches to the ribosome.
Translation (takes place in the cytoplasm on the ribosome)
- Each tRNA brings a specific amino acid to the mRNA. This is called translation.
- The amino acids are linked together to form a particular protein.
Protein Synthesis Video Lesson
TIP:
DNA – double-stranded; look for presence of thymine; found in nucleus only.
Nuclear membrane – has nuclear pores through which mRNA moves.
mRNA – single-stranded; look for presence of uracil; contains a triplet of bases (codon) found in nucleus and cytoplasm.
Ribosome – usually mRNA attached to it.
tRNA – contains a triplet of bases (anticodon); look for attached amino acid
Question and Answers Activities:
Find short and long questions for Grade 12 Life Sciences, which will help you to prepare for the exams, tests, practical tasks, and assignments.
EXAM TIP: The structure of the DNA and RNA molecule is very important and is often examined almost every year in Grade 12. Make sure that you know the labels of each component. Remember to label the diagram first and then move onto the questions