6 Questions
What is the sugar molecule found in each nucleotide of DNA?
Which of the following base pairing rules is correct?
A-T and G-C are the only possible pairings
What is the result of semi-conservative DNA replication?
Each new DNA molecule consists of one old strand and one new strand
What is the primary function of DNA in cells?
To carry genetic information from one generation to the next
What is the result of a point mutation in DNA?
A single nucleotide change
What is the purpose of PCR (Polymerase Chain Reaction) in DNA technology?
To amplify specific DNA sequences
Study Notes
Structure of DNA
- Double helix model: two complementary strands of nucleotides twisted together
- Each nucleotide consists of:
- Sugar molecule (deoxyribose)
- Phosphate group
- Nitrogenous base (A, C, G, or T)
- Hydrogen bonds between nitrogenous bases hold the two strands together
Nitrogenous Bases
- Adenine (A) pairs with Thymine (T)
- Guanine (G) pairs with Cytosine (C)
- Base pairing rules:
- A-T and G-C are the only possible pairings
- A and G are purines, while T and C are pyrimidines
DNA Replication
- Semi-conservative model: each new DNA molecule consists of one old strand and one new strand
- Process:
- Unwinding of DNA double helix
- Binding of primers to template strands
- Synthesis of new DNA strands by adding nucleotides to primers
- Proofreading and editing to correct errors
DNA Functions
- Carries genetic information from one generation to the next
- Provides instructions for protein synthesis
- Regulates gene expression through transcription and translation
DNA Mutations
- Changes in the DNA sequence
- Types:
- Point mutations: single nucleotide change
- Frameshift mutations: insertion or deletion of nucleotides
- Consequences:
- Genetic disorders or diseases
- Evolutionary changes
DNA Technologies
- Recombinant DNA technology: combining DNA from different sources
- Polymerase Chain Reaction (PCR): amplifying specific DNA sequences
- DNA sequencing: determining the order of nucleotides in a DNA molecule
Structure of DNA
- Double helix model consists of two complementary strands of nucleotides twisted together
- Each nucleotide composed of sugar molecule (deoxyribose), phosphate group, and nitrogenous base (A, C, G, or T)
- Hydrogen bonds between nitrogenous bases hold the two strands together
Nitrogenous Bases
- Adenine (A) pairs with Thymine (T)
- Guanine (G) pairs with Cytosine (C)
- Base pairing rules: A-T and G-C are the only possible pairings
- Purines: A and G
- Pyrimidines: T and C
DNA Replication
- Semi-conservative model: each new DNA molecule consists of one old strand and one new strand
- Process involves: unwinding of DNA double helix, binding of primers to template strands, synthesis of new DNA strands, and proofreading and editing to correct errors
DNA Functions
- Carries genetic information from one generation to the next
- Provides instructions for protein synthesis
- Regulates gene expression through transcription and translation
DNA Mutations
- Changes in the DNA sequence
- Types: point mutations (single nucleotide change), frameshift mutations (insertion or deletion of nucleotides)
- Consequences: genetic disorders or diseases, evolutionary changes
DNA Technologies
- Recombinant DNA technology: combining DNA from different sources
- Polymerase Chain Reaction (PCR): amplifying specific DNA sequences
- DNA sequencing: determining the order of nucleotides in a DNA molecule
Learn about the double helix model of DNA, nucleotides, nitrogenous bases, and base pairing rules.
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