KEY: Cells Unit Test
Cell membrane: The cell membrane is a semi-permeable layer that controls the movement of materials into and out of cell
Cell wall: The cell wall is the rigid outer covering that gives the plant cell its shape.
The cell wall is made of cellulose which is a fiber that gives the plants it support and structure.
Cytoplasm: The cytoplasm is the jelly-like material that cell structures float in.
Nucleus: The nucleus controls everything the cell does and contains chromosomes.
Chloroplasts: Chloroplasts are found only in plant cells and make food for the plant by the process of photosynthesis. They contain chlorophyll which gives plants their green color.
Diffusion: Diffusion is the movement of substances from an area of high concentration to an area of low concentration. It is a form of passive transport for the cell.
Osmosis: Osmosis is the diffusion of water through a selectively permeable membrane.
Concentration gradient: Concentration gradient is a change in concentration of a substance from one area to another area.
Semi permeable (selectively permeable): Semi permeable is a barrier that allows some chemicals to pass but not others.
Cell division: Cell division is a process by which cells divide to form new cells.
Mitosis: During cell division, the process in which the material from the cell nucleus divides.
Heredity: Heredity is the passing of traits from one generation to another.

In the box write the key events in each phase of cell division.
Interphase is the stage preparing for cell division during which the chromosomes makes an exact copy of itself.
Prophase
Metaphase
Anaphase
Telophase is the stage in cell division when the nucleus prepares for division by shortening and thickening the chromosomes so that they form an X.
Spindle fibers appear. is the stage at which two copies of each chromosome line up in the center of the cell. when the copies of chromosomes separate and are pulled to each side of the cell the cytoplasm pinches in at the center of the cell. There are two complete nuclei.
Cytokinesis cytoplasm divides and two new cells are formed.
Diffusion is a form of passive transport. What does that mean? Explain how it works giving a real life example.
Diffusion happens because there is a concentration gradient, areas of high and low concentration. Things will naturally move from an area of high concentration to an area of low concentration. Equilibrium tries to occur, a balance of molecules. An example is spraying perfume. If you spray perfume on yourself the concentration is high on your body. The surrounding room is lower which will cause the scent molecules to move around the room.

Explain how and why osmosis occurs in an egg placed in corn syrup? How did the water levels in the egg change? Why?
Osmosis is the movement of water across a cell membrane. The water inside the egg moved outside the egg. The concentration of water was higher in the egg which caused the movement to be outside since the concentration in the corn syrup of water was less. The egg’s water level lowered as the membrane contracted, or shrunk.
How many chromosomes does the human have? How many come from each parent?
Humans have 46 chromosomes or 23 chromosome pairs. Each parent contributes half of your chromosomes.
Describe the process of photosynthesis.
A plant cell has the ability to make its own food in a process called photosynthesis.
A plant cell has chloroplasts which are an important part of photosynthesis.
Chloroplasts contain chlorophyll which capture energy from sunlight. Then inside of the plant cell carbon dioxide and water combine using energy from sunlight in the chloroplasts
Photosynthesis has two products created by the plant cell in the chloroplast. This reaction produces a sugar which is glucose and oxygen. The plant uses the sugar as food and animals, like us, use the oxygen to breath.