Cell Theory
What is the basic unit of structure and function in all living things?
Cells
Which organelle contains DNA and helps control the cell's activities?
Nucleus
An organism made of only one cell is called this:
Unicellular
What is the movement of particles from an area of higher concentration to lower concentration called?
Diffusion
What is the process plants use to make sugar using light energy?
Photosynthesis
According to cell theory, where do all new cells come from?
Pre-existing Cells
Which organelle releases usable energy from food during cellular respiration?
Mitochondrion
Humans, trees, and dogs are this type of organism because they are made of many cells.
Multicellular
What is the diffusion of water across a selectively permeable membrane called?
Osmosis
Which gas do plants take in from the atmosphere during photosynthesis?
Carbon Dioxide
A student discovers a new organism made of only one cell. Does it still qualify as a living thing? Explain.
Yes. Living things can consist of just one cell.
Which organelle captures light energy to make sugar during photosynthesis?
Chloroplast
True or False: A unicellular organism can carry out all the basic functions of life without help from other cells.
True
A drop of food coloring is placed in a glass of water. After several minutes, the color spreads throughout the glass. Explain why.
Particles move from high concentration to low concentration.
What are the two raw materials needed for photosynthesis?
Water, carbon dioxide
A scientist observes a cell dividing into two new cells. Which part of cell theory does this observation support?
Cells come from pre-existing cells.
A cell cannot control which substances enter or leave it. Which cell structure is most likely damaged?
Cell membrane
In multicellular organisms, different cells often have different jobs. This is called ______.
Cell specialization
A gummy bear is placed in plain water overnight and becomes much larger. What process caused this change, and which direction did the water move?
Osmosis; Water moved from outside of the better to inside of the bear.
How does energy change forms during photosynthesis?
Radiant energy from the sun is converted to chemical energy in the glucose.
A scientist discovers a microscopic organism that has cells with no nucleus. She claims it cannot be alive because it lacks a nucleus. Use cell theory to explain why that claim is incorrect.
Cell theory states that organisms are made of cells, not cells with nuclei. (Yes, there are some cells with no nuclei!)
A plant cell's chloroplasts stop working, but its mitochondria are still functioning. Explain how this affects the cell's ability to get and use energy.
The cell will make food but not be able to break it down.
Humans have mitochondria but no chloroplasts. Why?
They eat and do not make their own food through photosynthesis.
A cell is placed in very salty water. After several minutes, the cell shrinks. Explain what happened using the concepts of osmosis, water concentration, and selective permeability.
Salt was too big to move into the cell. The water concentration was higher inside the cell than outside. Water moved out of the cell through its selectively permeable membrane by osmosis, causing it to shrink.
A healthy plant is given plenty of sunlight and water and is placed in an environment with almost no carbon dioxide. Predict what will happen to its rate of photosynthesis and explain why.
Photosynthesis will decrease because carbon dioxide is required for it to occur.