Podcast
Questions and Answers
What is the primary role of transfer RNAs (tRNAs) in protein synthesis?
What is the primary role of transfer RNAs (tRNAs) in protein synthesis?
Which of the following statements best describes the differences between prokaryotic and eukaryotic DNA?
Which of the following statements best describes the differences between prokaryotic and eukaryotic DNA?
What type of bond connects complementary nitrogenous bases in DNA?
What type of bond connects complementary nitrogenous bases in DNA?
Which of the following is NOT a type of RNA produced in cells?
Which of the following is NOT a type of RNA produced in cells?
Signup and view all the answers
During cell division, chromosomes are formed from which cellular structure?
During cell division, chromosomes are formed from which cellular structure?
Signup and view all the answers
What distinguishes the B form of DNA from the other forms?
What distinguishes the B form of DNA from the other forms?
Signup and view all the answers
Why is antiparallel arrangement essential for DNA replication?
Why is antiparallel arrangement essential for DNA replication?
Signup and view all the answers
What role did Rosalind Franklin play in the discovery of DNA's structure?
What role did Rosalind Franklin play in the discovery of DNA's structure?
Signup and view all the answers
Which of the following correctly describes a characteristic of nucleotides?
Which of the following correctly describes a characteristic of nucleotides?
Signup and view all the answers
How many base pairs does the A form of DNA contain compared to the B form?
How many base pairs does the A form of DNA contain compared to the B form?
Signup and view all the answers
Study Notes
DNA and RNA Composition and Structure
- Nucleic acids are biopolymers, large biomolecules made of monomers called nucleotides.
- Two types of nucleic acids:
- Deoxyribonucleic acid (DNA)
- Ribonucleic acid (RNA)
History of DNA
- Genetic research began with Gregor Mendel, the "Father of Genetics," who experimented with plants in 1857.
- DNA was first observed by Friedrich Miescher in 1869.
DNA Structure
- DNA is a double-stranded helix.
- James Watson and Francis Crick determined the 3-dimensional structure of DNA in 1953, based on Rosalind Franklin's work.
DNA Composition
- DNA is a long polymer made of repeating nucleotides.
- Nucleotides consist of a sugar (deoxyribose), a phosphate group, and a nitrogenous base.
- Nitrogenous bases in DNA: Adenine (A), Thymine (T), Guanine (G), Cytosine (C)
- Base pairs:
- Adenine pairs with Thymine (A-T)
- Guanine pairs with Cytosine (G-C)
- The base pairs form a spiral staircase in the interior of the double helix.
- Hydrogen bonds connect the base pairs. Millions of weak hydrogen bonds hold the two strands together in the DNA double helix.
Forms of DNA
- B-form: Right-handed helix with 10 base pairs per turn (described by Watson and Crick).
- A-form: More compact than B-form.
- Z-form: Left-handed helix and bases are positioned more toward the periphery.
DNA Orientation
- Strands run from 5' to 3' and are antiparallel. This arrangement is necessary for DNA replication.
Chemical Bonds in DNA
- Covalent bonds: Between sugar and phosphate groups of two nucleotides (phosphodiester bonds).
- Hydrogen Bonds: Between complementary nitrogenous bases.
DNA in Prokaryotes and Eukaryotes
- Prokaryotic DNA: Smaller, circular, located in the cytoplasm.
- Eukaryotic DNA: Larger, arranged on chromosomes, located in the nucleus.
DNA vs RNA
-
DNA:
- Site: Nucleus
- Sugar: Deoxyribose
- Nucleotides: A, T, G, C
- Arrangement: Double helix
- Types: One
- Synthesis: By replication
- Function: Storage and transfer of genetic and hereditary characters
-
RNA:
- Site: Cytoplasm
- Sugar: Ribose
- Nucleotides: A, U, G, C (Uracil replaces Thymine)
- Arrangement: Single helix
- Types: mRNA, tRNA, rRNA
- Synthesis: By transcription
- Function: Protein synthesis by translation
DNA Denaturation and Renaturation
- Denaturation: Alkali or heat causes the DNA strands to separate.
- Renaturation: If DNA strands are separated (by heat), and the temperature decreases, base pairs reform, and the complementary strands come back together.
- Hybridization: A single strand of DNA or RNA pairs with complementary bases on another strand.
Mitochondrial DNA
- Mitochondrial DNA (mtDNA) is a double-stranded circular DNA molecule in the mitochondrial matrix.
- mtDNA has a different genetic code than genomic DNA.
- mtDNA codes for 13 protein subunits of the electron transport chain, a large and small ribosomal RNA (rRNA), and 22 transfer RNAs (tRNAs).
- mtDNA is maternally inherited.
- mtDNA has a higher mutation rate than nuclear DNA. (about 5-10 times higher).
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz explores the composition and structure of DNA and RNA, including their historical background and significance in genetics. Key topics include the discovery of DNA, its double-helix formation, and the roles of different nucleotides. Test your knowledge on the fundamental concepts of nucleic acids.
