Plant vs. Animal Cells
Which structure is present in plant cells but absent in animal cells: cell wall, nucleus, or cell membrane?
Cell wall.
Which organelle controls the activities of the cell?
Nucleus.
What is the movement of particles from a region of higher concentration to a region of lower concentration called?
Diffusion.
Which structure controls what enters and leaves both plant and animal cells?
Cell membrane.
Name two structures commonly found in plant cells but not in animal cells.
Cell wall and chloroplasts.
Which organelle is the site of aerobic respiration?
Mitochondrion.
What is the movement of water molecules through a partially permeable membrane from a dilute solution to a more concentrated solution called?
Osmosis.
Oxygen moves from the air spaces in the lungs into the blood, where its concentration is lower. Which process is responsible?
Diffusion.
Both plant and animal cells contain a nucleus. What is its main function?
It contains genetic material (DNA) and controls cell activities.
Which organelle absorbs light energy for photosynthesis?
Chloroplast.
Which transport process requires energy to move substances against their concentration gradient?
Active transport.
A plant cell is placed in pure water and becomes firm. Explain why it becomes firm.
Water enters the cell by osmosis. The vacuole expands, and the cell contents press against the cell wall, making the cell turgid.
A cell contains a cell wall, chloroplasts, and a large permanent vacuole. Identify the cell type and explain your answer.
A plant cell, because it has all three characteristic structures.
Explain why muscle cells contain many mitochondria.
Muscle cells require large amounts of energy for contraction. Mitochondria release energy through aerobic respiration.
A plant cell is placed in a concentrated sugar solution and loses water. Explain why this happens.
Water moves out of the cell by osmosis through the partially permeable cell membrane into the solution with a lower water potential.
A student observes a cell with a nucleus, cytoplasm, cell membrane, and cell wall. What additional structures could help identify it as a plant cell?
Chloroplasts or a large permanent vacuole. Not all plant cells contain chloroplasts.
A cell has a nucleus, cytoplasm, mitochondria, and a cell membrane, but no cell wall or chloroplasts. Explain why it is most likely an animal cell.
These structures are found in animal cells, while the absence of a cell wall and chloroplasts supports the identification as an animal cell.
A cell produces large amounts of protein. Which organelle is directly responsible for protein synthesis, and which organelle helps transport proteins through the cell?
Ribosomes carry out protein synthesis. The endoplasmic reticulum helps transport proteins through the cell.
Root hair cells absorb mineral ions from the soil even when the concentration of these ions is lower in the soil than inside the cells. Identify the process and explain why energy is required.
Active transport. Energy is required because mineral ions move against their concentration gradient.
Compare active transport and osmosis in terms of the substances moved, direction of movement, and energy requirement.
Active transport: moves substances such as mineral ions against their concentration gradient and requires energy. Osmosis: moves water through a partially permeable membrane down its water potential gradient and does not directly require cellular energy.