Final answer:
DNA mutations can occur as induced mutations through exposure to environmental mutagens like UV rays and chemicals, or as spontaneous mutations resulting from errors in DNA replication or natural chemical changes. These mutations can impact the organism by altering the nucleotide sequence and the resulting proteins.
Step-by-step explanation:
When Can Mutations in DNA Molecules Occur?
Mutations in DNA can occur due to various factors and are classified as either induced mutations or spontaneous mutations. Induced mutations happen as a result of exposure to environmental agents, such as UV rays, x-rays, chemicals, and other mutagens. On the other hand, spontaneous mutations arise without any external environmental factors and are the outcome of natural reactions within the body, including errors during DNA replication or naturally occurring chemical changes in the DNA, such as tautomerism, depurination, or deamination.
Mutations can significantly impact an organism because they cause changes in the nucleotide sequence of the DNA. This can lead to alterations in proteins, potentially affecting the phenotype. Various processes, such as cell division (mitosis and meiosis), DNA damage, and repair mechanisms, are involved in the occurrence of mutations. While some mutations may be harmless, others can result in diseases or genetic disorders.