PQ : 2.5 - 2.8 + 2.11 + 2.15 + 2.16 - DNA & Genetics Flashcards
EXAM QUESTION
Describe the process of DNA synthesis during replication. (4 marks)
initiation: DNA helicase unwinds the double helix. (1 mark)
elongation: DNA polymerase adds complementary nucleotides. (1 mark)
leading and lagging strands.(1 mark)
termination: DNA ligase seals the nicks in the backbone. (1 mark)
EXAM QUESTION
Discuss the significance of DNA synthesis in the context of cellular functions. (6 marks)
Genetic inheritance: DNA replication ensures transmission of genetic information.(1 mark)
Cell division: DNA synthesis provides each daughter cell with an identical copy of genetic material.(1 mark)
Maintenance of genetic integrity: DNA synthesis corrects errors and repairs damaged DNA.(1 mark)
Consequences of errors: Discussion of mutations leading to genetic disorders or cancer.(1 mark)
Explaining the importance of minimizing errors.(1 mark)
- minimizing errors in DNA synthesis is essential for preserving genetic stability, maintaining cellular function, preventing disease,
1 mark for discussing broader implications for cellular and organismal survival.
Types of RNA:
- Blurt everything you know bout tRNA.
Transfer RNA (tRNA)
o Carries amino acids to the ribosome during translation
o Contains an amino acid binding site at one end and an anticodon at the opposite end
o Anticodons bind to complementary codons on mRNA to convert the mRNA sequence into a protein’s primary sequence
Types of RNA:
- Blurt everything you know about mRNA
Messenger RNA (mRNA)
o Produces during transcription – RNA polymerase uses DNA as a template to provide mRNA strand
o Carries the genetic code from the nucleus to the cytoplasm – provides the instructions for making a protein on the ribosome in translation
o Read in triplets.
Give three differences between replication of DNA and transcription of DNA.
replication involves DNA
nucleotides whereas transcription involves RNA nucleotides (1)
• replication produces double stranded DNA molecules whereas transcription produces a single stranded
RNA molecule (1)
replication uses DNA polymerase whereas transcription requires RNA polymerase (1)
replication produces identical copies whereas transcription produces a complementary copy (1)
Describe the role of tRNA in the production of the protein part of a glycoprotein.
The synthesis of mRNA occurs in a process called transcription.
Compare and contrast the process of transcription with the process of DNA replication.
(4)
(iii) Explain how a change of one amino acid could lead to a change in the
structure and properties of the haemoglobin protein.
(4)
(ii) Describe the role of tRNA in the production of leptin. (3)
(iii) Describe how the primary structure of leptin enables it to be soluble in water. (3)
One function of DNA is to act as a template for the synthesis of messenger RNA (mRNA)
during transcription.
(i) Describe how mRNA is synthesised at a template strand of DNA. (2)
Describe the roles of transcription and translation in the synthesis of a globular protein by a
muscle cell. (5)
