DNA REPLICATION AND PROTEIN SYNTHESIS
Each somatic cell in the human body contains identical DNA. This DNA controls the synthesis
of
all proteins required for the structure and functioning of the human body. Describe how DNA
controls protein synthesis with the assistance of other nucleic acids found in the human cell.
Also describe how DNA is replicated before the start of cell division to ensure that all body
cells
contain identical genetic information.
Protein synthesis
Transcription
• DNA double helix unwinds
• weak hydrogen bonds of DNA break
• forming two single strands of DNA
• One strand acts as template
• to form a complementary strand which is mRNA / (A – U; G – C )
• using free RNA nucleotides from the nucleoplasm
• Three adjacent bases on mRNA make up a codon
• which codes for an amino acid.
• mRNA moves out of the nucleus
• through the nuclear pore
• into the cytoplasm
• where it attaches to a ribosome
Translation
• according to the codons of mRNA
• t-RNA molecules with complementary anticodons
• bring the required amino acids to the ribosome
• The amino acids link together by peptide bond
• to form the required proteins.
DNA replication
• DNA double helix unwinds
• weak hydrogen bonds between nitrogenous bases break
• and the two DNA strands unzip/separate
• Each original DNA strand serves as template to form a new strand
• by attaching to free nucleotides from nucleoplasm
• to form complementary strands
• Each DNA molecule now consists of one original strand and one new strand.
• The result is two genetically identical DNA molecules.
Content 17
Synthesis - relevance 1
- Logical sequence 1
- Comprehensiveness 1
Total = 20
Each somatic cell in the human body contains identical DNA. This DNA controls the synthesis
of
all proteins required for the structure and functioning of the human body. Describe how DNA
controls protein synthesis with the assistance of other nucleic acids found in the human cell.
Also describe how DNA is replicated before the start of cell division to ensure that all body
cells
contain identical genetic information.
Protein synthesis
Transcription
• DNA double helix unwinds
• weak hydrogen bonds of DNA break
• forming two single strands of DNA
• One strand acts as template
• to form a complementary strand which is mRNA / (A – U; G – C )
• using free RNA nucleotides from the nucleoplasm
• Three adjacent bases on mRNA make up a codon
• which codes for an amino acid.
• mRNA moves out of the nucleus
• through the nuclear pore
• into the cytoplasm
• where it attaches to a ribosome
Translation
• according to the codons of mRNA
• t-RNA molecules with complementary anticodons
• bring the required amino acids to the ribosome
• The amino acids link together by peptide bond
• to form the required proteins.
DNA replication
• DNA double helix unwinds
• weak hydrogen bonds between nitrogenous bases break
• and the two DNA strands unzip/separate
• Each original DNA strand serves as template to form a new strand
• by attaching to free nucleotides from nucleoplasm
• to form complementary strands
• Each DNA molecule now consists of one original strand and one new strand.
• The result is two genetically identical DNA molecules.
Content 17
Synthesis - relevance 1
- Logical sequence 1
- Comprehensiveness 1
Total = 20
