Question

which of the following statements is correct regarding the nucleus of eukaryotic cells?
a. it synthesizes proteins and lipids.
b. it is where ribosomes are produced.
c. it is a membrane - bound structure that houses the cells dna.
d. it provides structural support to the cell.

what is the primary difference between prokaryotic and eukaryotic cells?
a. prokaryotic cells lack a nucleus, while eukaryotic cells have a defined nucleus.
b. prokaryotic cells have more organelles than eukaryotic cells.
c. eukaryotic cells have a cell wall, while prokaryotic cells do not.
d. prokaryotic cells are larger than eukaryotic cells.

Explanation:

• For the first question:
• Option a: Protein synthesis occurs in ribosomes (on rough ER or free in cytoplasm), lipid synthesis mainly in smooth ER.
• Option b: Ribosome production (assembly) involves nucleolus (part of nucleus) but statement is too simplistic. The key defining feature of eukaryotic nucleus is housing DNA in a membrane - bound structure.
• Option c: Eukaryotic nucleus is a double - membrane - bound organelle that contains the cell's DNA.
• Option d: Structural support is provided by cytoskeleton (microfilaments, microtubules, intermediate filaments).
• For the second question:
• Option a: Prokaryotes (e.g., bacteria) lack a membrane - bound nucleus, while eukaryotes (e.g., plant and animal cells) have a defined nucleus.
• Option b: Eukaryotic cells have more organelles (mitochondria, ER, Golgi, etc.) than prokaryotic cells.
• Option c: Many prokaryotic cells (e.g., bacteria) have cell walls (peptidoglycan in bacteria), and some eukaryotic cells (plant cells - cellulose cell wall, fungi - chitin cell wall) also have cell walls.
• Option d: Eukaryotic cells are generally larger than prokaryotic cells.

Answer:

First question: C. It is a membrane - bound structure that houses the cell's DNA.
Second question: A. Prokaryotic cells lack a nucleus, while eukaryotic cells have a defined nucleus.