DNA structure Flashcards
What are the four nitrogenous bases found in DNA?
Adenine, Thymine, Cytosine, and Guanine.
Which nitrogenous base pairs with Adenine in DNA?
Thymine.
True or False: Cytosine pairs with Uracil in DNA.
False.
Fill in the blank: In DNA, Guanine pairs with ______.
Cytosine.
Who is known for Chargaff’s rules?
Erwin Chargaff.
What does Chargaff’s first rule state?
The amount of Adenine equals the amount of Thymine, and the amount of Cytosine equals the amount of Guanine.
Multiple Choice: Which of the following is NOT a nitrogenous base in DNA? A) Adenine B) Uracil C) Thymine D) Cytosine
B) Uracil.
What type of bond connects nitrogenous bases in DNA?
Hydrogen bonds.
True or False: DNA is a double helix structure.
True.
What is the role of nitrogenous bases in DNA?
They encode genetic information.
Fill in the blank: The complementary base pairing in DNA involves ______ with ______.
Adenine with Thymine and Guanine with Cytosine.
Short Answer: What is the significance of Chargaff’s rules in molecular biology?
They helped establish the base pairing rules which are fundamental for DNA structure and replication.
Multiple Choice: Which nitrogenous base is found in RNA but not in DNA? A) Adenine B) Thymine C) Uracil D) Cytosine
C) Uracil.
What two components make up the backbone of a DNA molecule?
Sugar and phosphate.
True or False: Erwin Chargaff discovered the structure of DNA.
False.
Fill in the blank: Chargaff’s second rule states that the amount of ______ is not necessarily equal to the amount of ______.
Adenine; Cytosine.
Short Answer: What is the significance of the double helix structure of DNA?
It allows for the compact storage of genetic information and facilitates replication.
What are purines and pyrimidines in the context of DNA?
Purines are Adenine and Guanine; Pyrimidines are Cytosine and Thymine.
Multiple Choice: Which of the following bases is a pyrimidine? A) Adenine B) Guanine C) Cytosine D) Both B and C
C) Cytosine.
What is the primary function of DNA?
To store and transmit genetic information.
True or False: The sequence of nitrogenous bases in DNA determines the sequence of amino acids in proteins.
True.
Fill in the blank: The Watson-Crick model of DNA was based on Chargaff’s ______.
Rules.
Short Answer: How did Chargaff’s observations contribute to the discovery of the DNA structure?
They provided critical evidence for the complementary base pairing that underlies the double helix structure.
What is the difference between ribonucleic acid (RNA) and deoxyribonucleic acid (DNA)?
RNA contains ribose sugar and uracil instead of thymine, while DNA contains deoxyribose sugar and thymine.
Multiple Choice: Which base is paired with Cytosine in DNA? A) Adenine B) Thymine C) Guanine D) Uracil
C) Guanine.
Who is Rosalind Franklin?
Rosalind Franklin was a British chemist and X-ray crystallographer whose work was crucial in understanding the molecular structures of DNA.
True or False: Rosalind Franklin’s X-ray diffraction images were key to discovering the double helix structure of DNA.
True
Fill in the blank: Rosalind Franklin’s famous photograph of DNA is known as Photo _____.
51
What technique did Rosalind Franklin use to analyze the structure of DNA?
X-ray crystallography
Multiple Choice: Which of the following contributions is Rosalind Franklin most known for? A) Discovering penicillin B) Developing the polio vaccine C) X-ray diffraction images of DNA D) The theory of relativity
C) X-ray diffraction images of DNA
Chargraff’s Rules
A=T, C = G %
James Watson and Frances Crick
No actual DNA experiments, realized DNA Structure was a helix from Franklin’s photographs and created metal model and won Nobel prize 1962
What are the four nucleotide bases in DNA?
Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
True or False: In DNA, adenine pairs with cytosine.
False. Adenine pairs with thymine.
Fill in the blank: The base pairing rule states that ______ pairs with thymine and ______ pairs with guanine.
adenine; cytosine
Which of the following pairs are complementary in DNA? A) A-T, B) C-G, C) A-C, D) Both A and B.
D) Both A and B.
What type of bond holds the complementary base pairs together in DNA?
Hydrogen bonds.
