Podcast
Questions and Answers
What type of bond is formed between the phosphate group and the sugar in a nucleotide?
What type of bond is formed between the phosphate group and the sugar in a nucleotide?
- Phosphodiester bond (correct)
- Peptide bond
- Hydrogen bond
- Ionic bond
Which two bases belong to the purine category in DNA?
Which two bases belong to the purine category in DNA?
- Adenine and Cytosine
- Guanine and Uracil
- Adenine and Guanine (correct)
- Thymine and Cytosine
Which component of a nucleotide is NEVER found in proteins?
Which component of a nucleotide is NEVER found in proteins?
- Amino acid
- Nitrogenous base
- Phosphate group (correct)
- Sugar
What characterizes the ribose sugar found in nucleic acids?
What characterizes the ribose sugar found in nucleic acids?
What is a significant difference between DNA and RNA regarding nitrogenous bases?
What is a significant difference between DNA and RNA regarding nitrogenous bases?
Which components make up a nucleotide?
Which components make up a nucleotide?
Which of the following nitrogenous bases is found only in RNA?
Which of the following nitrogenous bases is found only in RNA?
What distinguishes DNA from RNA at the molecular level?
What distinguishes DNA from RNA at the molecular level?
What is a nucleoside composed of?
What is a nucleoside composed of?
Which of the following statements is true regarding the bases in nucleic acids?
Which of the following statements is true regarding the bases in nucleic acids?
What does Chargaff’s rule state about the relationship between adenine and thymine in DNA?
What does Chargaff’s rule state about the relationship between adenine and thymine in DNA?
What was one of the main conclusions from Chargaff's research on DNA?
What was one of the main conclusions from Chargaff's research on DNA?
How did X-ray diffraction contribute to our understanding of DNA structure?
How did X-ray diffraction contribute to our understanding of DNA structure?
What did Rosalind Franklin achieve in the study of DNA using X-ray diffraction?
What did Rosalind Franklin achieve in the study of DNA using X-ray diffraction?
Which statement is true regarding the relationship between guanine and cytosine in DNA?
Which statement is true regarding the relationship between guanine and cytosine in DNA?
What shape of molecule did the X-ray diffraction patterns suggest DNA had?
What shape of molecule did the X-ray diffraction patterns suggest DNA had?
What does Chargaff's second rule indicate?
What does Chargaff's second rule indicate?
What did Watson and Crick contribute to the understanding of DNA?
What did Watson and Crick contribute to the understanding of DNA?
What did the X-ray diffraction reveal about the dimensions of the DNA helix?
What did the X-ray diffraction reveal about the dimensions of the DNA helix?
What is indicated by Chargaff's first rule?
What is indicated by Chargaff's first rule?
Both DNA and RNA contain the nitrogenous base U.
Both DNA and RNA contain the nitrogenous base U.
A nucleotide consists of a nitrogenous base, a ribose sugar, and a phosphate group.
A nucleotide consists of a nitrogenous base, a ribose sugar, and a phosphate group.
The absence of a hydroxyl group at the C-2' position is a characteristic that distinguishes DNA from RNA.
The absence of a hydroxyl group at the C-2' position is a characteristic that distinguishes DNA from RNA.
The purines found in nucleic acids are adenine, guanine, cytosine, and thymine.
The purines found in nucleic acids are adenine, guanine, cytosine, and thymine.
A nucleoside is formed when a nitrogenous base is bonded to a pentose sugar.
A nucleoside is formed when a nitrogenous base is bonded to a pentose sugar.
DNA is primarily composed of four different types of nucleotides.
DNA is primarily composed of four different types of nucleotides.
In nucleic acids, ribose sugar is a six-membered ring structure.
In nucleic acids, ribose sugar is a six-membered ring structure.
Sulfur is a component found in all amino acids but not in DNA.
Sulfur is a component found in all amino acids but not in DNA.
Phosphodiester bonds connect the nitrogenous bases with the sugar in a nucleotide.
Phosphodiester bonds connect the nitrogenous bases with the sugar in a nucleotide.
RNA contains thymine in place of uracil.
RNA contains thymine in place of uracil.
Study Notes
Nucleic Acids: Building Blocks
- DNA & RNA are built from nucleotides
- Nucleotides have three components:
- Nitrogenous base: Adenine (A), Guanine (G), Cytosine (C), Thymine (T) (in DNA), Uracil (U) (in RNA).
- Pentose sugar: Ribose (in RNA), Deoxyribose (in DNA).
- Phosphate group
- Two types of nitrogenous bases:
- Purines: Double-ringed structures, including Adenine (A) and Guanine (G)
- Pyrimidines: Single-ringed structures, including Cytosine (C), Thymine (T), and Uracil (U).
DNA Structure
- DNA is made of four nucleotides: A, T, C, and G
- RNA contains uracil (U) instead of thymine (T)
- DNA is a double helix:
- Two strands wrap around a central axis.
- Strands are antiparallel: One strand runs 5' to 3', the other 3' to 5'.
- Phosphodiester backbone: Repeating sugar-phosphate units linked by phosphodiester bonds.
- Nitrogenous bases: Extend towards the interior of the helix, forming base pairs.
Base Complementarity
- Adenine (A) forms two hydrogen bonds with Thymine (T).
- Guanine (G) forms three hydrogen bonds with Cytosine (C).
- This pairing is called complementarity.
- The diameter of the double helix is constant due to pairing a purine with a pyrimidine.
Chargaff's Rules
- The amount of adenine (A) in DNA always equals the amount of thymine (T).
- The amount of guanine (G) always equals the amount of cytosine (C).
- A = T and G = C
- The ratio of G-C to A-T varies among different species.
Watson-Crick Model
- Two antiparallel polynucleotide chains coiled around a central axis.
- Bases of each chain are perpendicular to the axis.
- Complementary base-pairing holds strands together.
- Each turn of the helix is 3.4 nm long, containing 10 base pairs.
- Major and minor grooves alternate along the length of the molecule.
- Diameter of the double helix is 2 nm.
RNA Structure
- Similar to DNA, but with key differences:
- Ribose replaces deoxyribose.
- Uracil replaces thymine.
- Most RNA is single-stranded.
- Three classes of RNA involved in gene expression:
- Ribosomal RNA (rRNA)
- Messenger RNA (mRNA)
- Transfer RNA (tRNA)
- Uracil pairs with adenine during transcription and RNA base pairing.
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Description
This quiz covers the building blocks of nucleic acids, focusing on the structure of DNA and RNA. Learn about nucleotides, nitrogenous bases, and the unique features of double-stranded DNA, including its antiparallel strands and phosphodiester backbone.
