Podcast
Questions and Answers
In 1953, which scientists proposed the molecular structure for deoxyribose nucleic acid?
In 1953, which scientists proposed the molecular structure for deoxyribose nucleic acid?
- James Watson and Maurice Wilkins
- James Watson and Francis Crick (correct)
- Francis Crick and James Watson
- Rosalind Franklin and Maurice Wilkins
The central dogma of molecular biology states that information can be transferred from protein to nucleic acid.
The central dogma of molecular biology states that information can be transferred from protein to nucleic acid.
False (B)
According to the central dogma, what is the primary direction of information flow in biological systems?
According to the central dogma, what is the primary direction of information flow in biological systems?
DNA to RNA to protein
A nucleic acid is a linear ______ which consists of a base, pentose, and phosphate group.
A nucleic acid is a linear ______ which consists of a base, pentose, and phosphate group.
Match each nitrogenous base with its corresponding category.
Match each nitrogenous base with its corresponding category.
Which of the following is a pyrimidine base found in nucleic acids?
Which of the following is a pyrimidine base found in nucleic acids?
Deoxyribose is the pentose sugar found in RNA.
Deoxyribose is the pentose sugar found in RNA.
What is the name of the bond that links nucleotides together in a nucleic acid chain?
What is the name of the bond that links nucleotides together in a nucleic acid chain?
A nucleotide is composed of a nitrogenous base, a ______ sugar, and a phosphate group.
A nucleotide is composed of a nitrogenous base, a ______ sugar, and a phosphate group.
Match each component to its corresponding role in a nucleotide.
Match each component to its corresponding role in a nucleotide.
Which of the following bases is unique to RNA, and not found in DNA?
Which of the following bases is unique to RNA, and not found in DNA?
DNA is typically single-stranded, while RNA is typically double-stranded.
DNA is typically single-stranded, while RNA is typically double-stranded.
What type of bond stabilizes the double helix structure of DNA?
What type of bond stabilizes the double helix structure of DNA?
In a DNA double helix, adenine pairs with ______, while guanine pairs with cytosine.
In a DNA double helix, adenine pairs with ______, while guanine pairs with cytosine.
Match the components with whether they are a feature of DNA or RNA.
Match the components with whether they are a feature of DNA or RNA.
Which term describes the arrangement of DNA strands in a double helix where one strand runs 5' to 3' and the other 3' to 5'?
Which term describes the arrangement of DNA strands in a double helix where one strand runs 5' to 3' and the other 3' to 5'?
In a DNA molecule, the amount of adenine is always equal to the amount of guanine.
In a DNA molecule, the amount of adenine is always equal to the amount of guanine.
What is the approximate twist angle between adjacent base pairs in a DNA double helix?
What is the approximate twist angle between adjacent base pairs in a DNA double helix?
Linear DNA molecules are typically found in ______, while circular DNA molecules are found in prokaryotes and some viruses.
Linear DNA molecules are typically found in ______, while circular DNA molecules are found in prokaryotes and some viruses.
Match each type of RNA with its primary function.
Match each type of RNA with its primary function.
Which type of RNA molecules catalyze the formation of peptide bonds during protein synthesis?
Which type of RNA molecules catalyze the formation of peptide bonds during protein synthesis?
RNA structure is less varied than DNA structure due to its simpler chemical composition.
RNA structure is less varied than DNA structure due to its simpler chemical composition.
Give one example of a regulatory RNA molecule and its function.
Give one example of a regulatory RNA molecule and its function.
The major groove in the DNA double helix provides an access point for proteins like TATA box binding protein, which binds to specific ______ rich regions.
The major groove in the DNA double helix provides an access point for proteins like TATA box binding protein, which binds to specific ______ rich regions.
Match the DNA content to it's relative percentage in human nucleic acids
Match the DNA content to it's relative percentage in human nucleic acids
Which of the following is NOT a function of nucleic acids?
Which of the following is NOT a function of nucleic acids?
The central dogma of molecular biology allows for the transfer of information from RNA directly back to DNA under normal cellular conditions.
The central dogma of molecular biology allows for the transfer of information from RNA directly back to DNA under normal cellular conditions.
What is the significance of the 5' and 3' ends of a nucleic acid strand?
What is the significance of the 5' and 3' ends of a nucleic acid strand?
In eukaryotic cells, the vast majority contain ______, which also have circular DNA.
In eukaryotic cells, the vast majority contain ______, which also have circular DNA.
Match each scientist with their contribution to understanding nucleic acids.
Match each scientist with their contribution to understanding nucleic acids.
Which of the following is a characteristic feature of the DNA double helix regarding its strands?
Which of the following is a characteristic feature of the DNA double helix regarding its strands?
The minor groove of DNA is the primary site for protein binding due to its wider access.
The minor groove of DNA is the primary site for protein binding due to its wider access.
What is the role of DNA replication in the central dogma of molecular biology?
What is the role of DNA replication in the central dogma of molecular biology?
In RNA, instead of thymine, ______ base pairs with adenine.
In RNA, instead of thymine, ______ base pairs with adenine.
Match the following terms related to nucleic acids with their definitions.
Match the following terms related to nucleic acids with their definitions.
Which level of RNA structure refers to its three-dimensional arrangement, often crucial for its specific function?
Which level of RNA structure refers to its three-dimensional arrangement, often crucial for its specific function?
Non-coding RNAs have no known function and are considered 'junk' DNA.
Non-coding RNAs have no known function and are considered 'junk' DNA.
What is the difference between a nucleoside and a nucleotide?
What is the difference between a nucleoside and a nucleotide?
The distance of a complete turn of the DNA double helix is approximately ______ base pairs
The distance of a complete turn of the DNA double helix is approximately ______ base pairs
Imagine a newly discovered virus has a genome composed of RNA that, upon entering a cell, is directly translated into proteins without any DNA intermediate. Which part of the central dogma is this virus circumventing?
Imagine a newly discovered virus has a genome composed of RNA that, upon entering a cell, is directly translated into proteins without any DNA intermediate. Which part of the central dogma is this virus circumventing?
A mutation that replaces a purine with a pyrimidine is called a transition mutation.
A mutation that replaces a purine with a pyrimidine is called a transition mutation.
Flashcards
What is a nucleic acid?
What is a nucleic acid?
A linear polynucleotide consisting of a chain of nucleotides.
What is a nitrogenous base?
What is a nitrogenous base?
A nitrogen-containing molecule with either a single-ring (pyrimidine) or double-ring (purine) structure.
What is pentose?
What is pentose?
A five-carbon sugar molecule found in nucleic acids; either ribose (in RNA) or deoxyribose (in DNA).
What is phosphate in DNA?
What is phosphate in DNA?
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Which bases are purines?
Which bases are purines?
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Which bases are pyrimidines?
Which bases are pyrimidines?
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What is a phosphodiester bond?
What is a phosphodiester bond?
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DNA vs. RNA
DNA vs. RNA
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What is Complementarity?
What is Complementarity?
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How is double-helix stabilized?
How is double-helix stabilized?
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Biological role of DNA grooves
Biological role of DNA grooves
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Linear vs. Circular DNA
Linear vs. Circular DNA
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What is mRNA?
What is mRNA?
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What is tRNA?
What is tRNA?
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What is rRNA?
What is rRNA?
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What is regulatory RNA?
What is regulatory RNA?
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Study Notes
- Molecular biology had a milestone in 1953.
- The central dogma of molecular biology published August 8, 1970, deals with the detailed residue-by-residue transfer of sequential information.
- The central dogma of molecular biology states that information cannot be transferred from protein to protein or nucleic acid.
Flow of Information
- DNA undergoes replication and transcription.
- RNA undergoes reverse transcription and translation.
- Protein synthesis by ribosome complexes is achieved through mRNA.
- Protein's can't transfer nucleic acid.
Nucleic Acids - Composition
- Nucleic acid is a linear polynucleotide.
- It consists of phosphate, pentose, and a nitrogenous base.
- Nucleoside is a nitrogenous base + pentose.
- Nucleotide is a nucleoside + phosphate.
Nitrogenous Base
- Classified as purines or pyrimidines
- Purines include adenine (A) and guanine (G).
- Pyrimidines include uracil (U), thymine (T), and cytosine (C).
Sugar- Pentose
- Includes ribose and deoxyribose.
Acid Residue - Phosphate
- Phosphoric acids are an important component.
Nomenclature
- Adenosine monophosphate (AMP).
- Adenosine diphosphate (ADP).
- Adenosine triphosphate (ATP).
Nucleic Acids
- Nucleic acids consists of a polynucleotide
- Polynucleotides have a 5' end and a 3' end.
- Phosphodiester bonds connect the nucleotides.
DNA vs RNA
DNA
- Bases: adenine (A), guanine (G), cytosine (C), and thymine (T).
- Pentose: deoxyribose.
- Includes phosphate.
- Double-stranded structure.
RNA
- Bases: adenine (A), guanine (G), cytosine (C), and uracil (U).
- Pentose: ribose.
- Includes phosphate.
- Single-stranded structure.
DNA Structure
- The double-helix structure exhibits complementarity.
- The total amount of adenine (A) equals thymine (T); cytosine (C) equals guanine (G).
- DNA double helix is stabilized by hydrogen bonds between bases.
- Stacking of the aromatic rings of the bases stabilizes the helix
- Aromatic rings on one strand stack atop each other, with a 36° twist per base pair.
- Double-helix strands are antiparallel, running 5' to 3' and 3' to 5'.
- Double-helix grooves facilitate biological roles.
- The major groove binds specific proteins like TATA box binding protein.
- These proteins bind to A and T rich regions and unwind and bend DNA, aiding in transcription.
Linear vs Circular DNA
- Linear DNA is found in eukaryotes and arranged in multiple linear molecules called chromosomes.
- Circular DNA is found in prokaryotes and some viruses.
- Eukaryotic cells contain mitochondria with circular DNA.
RNA Structure
- Includes primary structure, secondary structure and tertiary structure
- Contains single-stranded, double-stranded, and loop structures.
- Able to form tertiary structures.
- Structure depends on function.
- Structurally more varied than DNA.
Biological Functions
DNA
- Storage of information.
RNA
- Realization of information.
- Some viruses also store information in RNA
mRNA
- Messenger RNA.
- Synthesized during transcription.
- Delivers copied information to cytoplasm.
- Serves as a matrix in protein synthesis.
tRNA
- Transfer RNA.
- Binds activated amino acids.
- Delivers them to ribosomes for protein synthesis.
- At least 20 types exist, tied to the number of coded amino acids.
- Eukaryotic cells have isoacceptor tRNA.
- Regulates the speed and intensity of protein synthesis.
rRNA
- Ribosomal RNA.
- Part of the ribosomal complex.
- Catalyzes the formation of peptide bonds in the large subunit.
- Controls precise binding of mRNA in the small subunit.
Regulatory RNA's
- Noncoding RNA molecules playing roles in epigenetic regulation.
- Influences differentiation and development.
- Small nuclear RNA (snRNA).
- Micro RNA (miRNA).
- Small Interfering RNA (siRNA).
- Long non-coding RNA (lncRNA).
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