Rabies is from animals and virus is from internet and what not that I believe so
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.
Answer:
A promoter refers to a DNA sequence, that is, situated upstream of a gene and signals the start of transcription.
A repressor refers to a transcription factor that prevents transcription by combining with the operator site.
An insulator refers to an element that obstructs the signals between the promoters and enhancer.
A regulatory gene refers to a gene, which monitors the expression of one or more genes by preventing or encouraging transcription.
An inducer refers to a molecule that stimulates the synthesis of mRNA by disabling the protein, which inhibits the transcription.
An operator refers to a short sequence of DNA situated close to the promoter region, and is recognized by a repressor protein.
Answer:
a) facilitated diffusion requires the use of a transport protein and energy in the form of ATP
Explanation:
Diffusion is defined as the movement of substances from high to lower concentration across a potential gradient. Facilitated diffusion and simple diffusion are two different types of diffusion.
Simple diffusion does not require energy while facilitated diffusion requires energy in the form of ATP. Facilitated diffusion is a type of passive transport in which transport protein and energy is used in the form of ATP that allow the movement of substances across the cell membrane. <u>There are majorly three types of proteins involved in facilitated diffusions such as channel proteins, carrier proteins, and gated channel proteins.</u>
<u>While in simple diffusion, pumps are used to move the substance across the membrane.</u>
Hence, the correct answer is "a".
