Question
How is DNA used to identify different organisms? One by counting the number of chromosomes in each cell two by comparing the d n a sequence to a known sequence in a database three by observing how d n a appears under a microscope four by measuring the physical size of d.N a molecules
Answers
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GPT-4o mini
DNA is primarily used to identify different organisms through:
**2. Comparing the DNA sequence to a known sequence in a database.**
This method involves sequencing the DNA from an organism and then comparing it to existing sequences in biological databases, such as GenBank or the European Nucleotide Archive. By identifying similarities or differences in the DNA sequences, researchers can determine the species or closely related species of the organism in question.
The other options you provided are less effective for identifying organisms:
1. **Counting the number of chromosomes in each cell** can provide some information, especially in plants and some animals, but it is not as precise or informative as DNA sequencing for species identification.
3. **Observing how DNA appears under a microscope** is not a standard method used for identification since DNA is typically too small to be observed directly at the level of individual molecules without special staining techniques.
4. **Measuring the physical size of DNA molecules** does not provide specific information about the identity of an organism, as variations in size can occur across different species and do not correlate neatly with distinct identities.
Therefore, comparing DNA sequences is the most accurate and widely used method for identifying different organisms.
**2. Comparing the DNA sequence to a known sequence in a database.**
This method involves sequencing the DNA from an organism and then comparing it to existing sequences in biological databases, such as GenBank or the European Nucleotide Archive. By identifying similarities or differences in the DNA sequences, researchers can determine the species or closely related species of the organism in question.
The other options you provided are less effective for identifying organisms:
1. **Counting the number of chromosomes in each cell** can provide some information, especially in plants and some animals, but it is not as precise or informative as DNA sequencing for species identification.
3. **Observing how DNA appears under a microscope** is not a standard method used for identification since DNA is typically too small to be observed directly at the level of individual molecules without special staining techniques.
4. **Measuring the physical size of DNA molecules** does not provide specific information about the identity of an organism, as variations in size can occur across different species and do not correlate neatly with distinct identities.
Therefore, comparing DNA sequences is the most accurate and widely used method for identifying different organisms.
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