Question

q1. explore why plant cells have a cell wall while animal cells do not have.
q2. a group of learners observed onion cells under a microscope and noted they had a rectangular shape and a given structure.
(a) what type of cell were they observing? give reasons for your answer.
(b) why is it important for plant cells to have these structures while animal cells do not?
q3. different cells perform different functions in the body.
(a) explore why red blood - cells have a biconcave shape and no nucleus.
(b) a muscle cell has more mitochondria than a skin cell. why is this an advantage for muscle cells.
(c) imagine nerve cells were shaped like red blood cells. what problems might this cause?

Explanation:

• For the question about plant cells having cell walls while animal cells don't: Plant cell walls provide structural support, protection, and help maintain cell shape and turgor pressure. Animals have other support - like skeletons and connective tissues.
• For the onion cells question: Onion cells are plant cells and have a rectangular shape due to their cell walls.
• For the importance of plant cell structures: The unique structures in plant cells like cell walls and chloroplasts (for photosynthesis) are crucial for their autotrophic lifestyle and physical support.
• For red blood cells' biconcave shape and lack of nucleus: The biconcave shape increases surface - area to volume ratio for efficient gas exchange, and lack of nucleus allows more space for hemoglobin.
• For muscle cells having more mitochondria: Muscle cells require more energy for contraction, and mitochondria are the power - houses of the cell, so more mitochondria mean more energy production.
• For nerve cells shaped like red blood cells: Nerve cells need to transmit electrical signals over long distances. A biconcave shape would not be suitable as it would disrupt the long, axon - like structure needed for signal transmission, and it would reduce the space for organelles and cytoplasm needed for maintaining the cell's function and signal - generating machinery.

Answer:

• Plant cells have cell walls for support, protection and maintaining shape. Animal cells have other support mechanisms.
• Onion cells are plant cells with rectangular shape due to cell walls.
• Plant cell structures are important for autotrophy and support.
• Red blood cells' biconcave shape aids gas exchange and lack of nucleus provides more hemoglobin space.
• Muscle cells having more mitochondria is an advantage as they need more energy for contraction.
• If nerve cells were shaped like red blood cells, it would disrupt signal transmission and reduce space for organelles and cytoplasm.