Question

question #4: which claim best explains why only one generation of genetically modified keratinocytes must be genetically altered and transplanted into an individual to continue producing appropriate amounts of keratin? the lab - grown keratinocytes will undergo meiosis and pass the keratin dna to future generations of skin cells. the modified cells will undergo mitosis and pass the functioning keratin gene on to future generations of skin cells. only the modified skin cells will be able to undergo mitosis, causing all body cells of the individual to produce appropriate levels of keratin. when the cells undergo meiosis, the dna will be modified in future generations of skin cells to include only the genes for appropriate levels of keratin production.

Explanation:

To solve this, we analyze each option:

• Option 1: Lab - grown keratinocytes (skin cells) are somatic cells. Somatic cells undergo mitosis, not meiosis. So this option is incorrect as it claims meiosis.
• Option 2: Modified skin cells (somatic cells) divide by mitosis. When they divide, the modified genetic material (for keratin production) is passed on to the daughter cells. So future generations of skin cells (produced by mitosis of the modified cells) will have the functioning keratin gene, allowing appropriate keratin production for that individual. This makes sense.
• Option 3: Skin cells are somatic cells and their modifications are not passed on to all body cells. Also, the claim that only modified skin cells can undergo mitosis is false as all somatic cells can undergo mitosis.
• Option 4: Skin cells are somatic cells and do not undergo meiosis. Meiosis is for gamete production. So this option is incorrect.

Answer:

The modified cells will undergo mitosis and pass the functioning keratin gene on to future generations of skin cells.