Answer:
two objects with the same electric charge rub together
Explanation:
Watson and Crick determined base pairing by using Chargaff's rule to fit the bases together.
<h2>Further Explanation
</h2>
- Watson and Crick discovered that the DNA strands exists as a double helix, which appears like a twisted ladder.
- In doing so, Watson and Crick used the Chargaff’s rule to confirm the base pairing in the double stranded DNA, so as to fit the complementary bases together.
<h3>Structure of DNA</h3>
- DNA is a nucleic acid that carries genetic material in all living organisms. DNA is a double stranded nucleic acid whose building blocks are known as nucleotides.
- Each nucleotide contains a sugar, a phosphate group and a nitrogenous base. The four nucleotide bases found in the DNA are Adenine, Cytosine, Thymine and Guanine.
- The strands of DNA are attached to each other as a result of base pairing that occurs through hydrogen bonding as explained by Chargaff’s rule.
<h3>Chargaff’s rule.
</h3>
- Chargaff’s rule describes the base pairing in a DNA molecule, such that the base Guanine pairs with the base Cytosine in the complementary strand, while the base Adenine pairs with Thymine.
- This means the number of thymine bases in a DNA molecule will be equal to the number of Adenine bases, while Guanine bases will be equal to Cytosine bases.
- The result is a ratio of 1:1 between pyrimidines and purines in a molecule of DNA.
- Chargaff's rule of base pairing provided Watson and Crick with a prove that their model was correct, since it agreed with Chargaff's as far as the percentages of A,T,G, and C in DNA are concerned.
- According to Watson and Crick model, the hydrogen bonds could only form between adenine and thymine, and between cytosine and guanine to create an almost perfect fit.
Keywords; Watson and crick model, Chargaff’s rule, DNA, and base pairing.
<h2>Learn more about;
</h2>
- DNA and its structure; brainly.com/question/6460381
- Watson and crick model; brainly.com/question/1462835
Level; High school
Subject; Biology
Topic; Nucleic acids
Sub-topic: DNA structure and base pairing.
1. True.
2. Given: Mass = 30 Kg
Acceleration = 2.0m/s2
Force= mass x acceleration
Force= 30Kg x 2.0 m/s2
Force= 120 N
3. Given : Mass = 30 Kg
Force= 180 N
Force = Mass x Acceleration
Acceleration = Force / Mass
= 180 N / 30 Kg
Acceleration = 6.0 m/s2
Use the quadratic formula
Answer is B.
