13.2.1

Protein Synthesis

Test yourself on Protein Synthesis

After reading these notes, test your knowledge with free interactive questions on Seneca — used by over 10 million students.

Protein Synthesis

Protein synthesis is the process of making proteins in the cells.

The genome

The genome

  • The genome is the complete set of genes in an individual's DNA.
  • The genes in the genome encode the different proteins a cell needs.
  • The proteome is the full range of proteins an individual can produce.
Base sequence

Base sequence

  • DNA is made from a combination of four different bases (A, T, C, G).
  • A specific sequence of three bases (called a codon) encodes a specific amino acid.
  • The order of the bases on the DNA tells us the order for combining amino acids to create particular proteins.
Processes

Processes

  • There are two processes involved in synthesising protein from a base sequence. These are:
    • Transcription.
    • Translation.

Types of RNA

RNA is a single-stranded nucleic acid molecule that is made from the same bases as DNA except for uracil (U) which is used instead of thymine (T). There are different types of RNA:

mRNA

mRNA

  • Messenger RNA (mRNA) is transcribed from DNA in the nucleus to produce a single-stranded RNA.
  • The mRNA strand is complementary to the DNA base sequence.
  • mRNA travels from the nucleus to the ribosomes in the cytoplasm.
  • Ribosomes are proteins that translate mRNA into amino acids and synthesise the polypeptide.
tRNA

tRNA

  • Transfer RNA (tRNA) forms a clover-like shape and is vital for translation.
  • tRNA reads the mRNA codons and brings the corresponding amino acid into the ribosomes.
Accuracy of tRNA

Accuracy of tRNA

  • It is important that the correct amino acid is brought to the ribosomes by tRNA so that the protein is assembled correctly.
  • Each tRNA molecule has an anticodon which is complementary to a specific codon on mRNA.
  • The amino acid that corresponds to a specific anticodon binds to a specific attachment site on the tRNA molecule.
DNA → amino acid

DNA → amino acid

  • There are many processes in producing an amino acid from the original DNA sequence.
  • If the original DNA sequence has the codon GCC, the codon in each step is:
    • DNA codon: GCC.
    • mRNA complementary codon: CGG.
    • tRNA anticodon: GCC.
    • Amino acid: Arginine.
Jump to other topics
1

Unity & Diversity - Molecules

2

Unity & Diversity - Cells

3

Unity & Diversity - Organisms

4

Unity & Diversity - Ecosystems

5

Form & Function - Molecules

6

Form & Function - Cells

7

Form & Function - Organisms

8

Form & Function - Ecosystems

9

Interaction & Interdependence - Molecules

10

Interaction & Interdependence - Cells

11

Interaction & Interdependence - Organisms

12

Interaction & Interdependence - Ecosystems

12.1

Populations & Communities

12.2

Transfers of Energy & Matter

13

Continuity & Change - Molecules

14

Continuity & Change - Cells

15

Continuity & Change - Organisms

16

Continuity & Change - Ecosystems

Practice questions on Protein Synthesis

Can you answer these? Test yourself with free interactive practice on Seneca — used by over 10 million students.

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
Answer all questions on Protein Synthesis

Unlock your full potential with Seneca Premium

  • Unlimited access to 10,000+ open-ended exam questions

  • Mini-mock exams based on your study history

  • Unlock 800+ premium courses & e-books

Get started with Seneca Premium