Biology Worksheet

Name: _______________________________________ Date: _________________ Per: _____________

Cells: The Basic Unit of Life

Directions: Define the key terms and then complete the following Section Reviews after reading through Sections 5.1 through 5.3. You will complete your answers on a separate sheet of paper and then staple this worksheet on top.

Vocabulary Words:

Cells
Cell Wall
Prokaryote
Chromosome
Cell Theory
Nucleus
Nuclear Envelope
Cytoplasm
Cell Membrane
Eukaryote
Nucleolus
Organelle

Cells: The smallest structural and functional unit of an organism.

Cell Theory: The theory that all living matter consists of cells and that cells are the structural and functional units of life.

Cell Membrane: Lies immediately against the cell wall in plant cells/ Made of protein and phospholipids/ Selectively permeable.

Cell Wall: Dead layer, large empty spaces present between cellulose fibers, freely permeable
Made of cellulose which forms very thin fibers, strong and rigid, found in plant cells, protect and support the enclosed substances (protoplasm), resist entry of excess water into the cell, give shape to the cell

Nucleus: Controls the normal activities of the cell, contains the DNA, bounded by a nuclear membrane, contains chromosomes. Each cell has fixed number of chromosomes that carry genes. Genes control cell characteristics.

Eukaryote: Contain 3 basic cell structures: Nucleus, cell membrane, cytoplasm with organelles. Usually plant an animal cells.

Prokaryote: Nucleoid region contains the DNA, Cell membrane & cell wall, Contain ribosomes (no membrane) to make proteins in their cytoplasm.

Nuclear Envelope: The double lipid bilayer membrane that surrounds the genetic material and nucleolus in eukaryote cells.

Nucleolus: Is an organelle found in cells that make ribosomes.

Chromosome: A threadlike strand of DNA. It determines the color of our hair, skin, eyes, ect…

Cytoplasm: Jelly - like substance enclosed by cell membrane. Provides a medium for chemical reactions to take place. Contains organelles to carry out specific jobs. Examples: Chloroplast & mitochondria

Organelle: (inside of a cell), Very small size, Can only be observed under a microscope, Have specific functions, Found throughout cytoplasm .

Section 5-1

1. When Hooke first used the term cell, did he intend it to apply to living material? Explain your answer. He called these chambers cells because they reminded him of the small rooms called cells in a monastery.

2. What contributions did van Leeuwenhoek, Hooke, Schleiden, Schwann, and Virchow make to the development of the cell theory? The discovered that cells were in everything and not just in that one cells Hooke discovered. They developed a cell theory that cells were in everything.

3. What role did the invention of the microscope play in the development of the cell theory? The microscope was able to magnify the cells one hundred times but he could see the cell walls that surround living cork cells.

Section 5-2

4. What are the three basic structures found in most cells? The cell membrane, or outer boundary of the cell, the nucleus, or control center, and the cytoplasm.

5. What is the function of the cell membrane? It protects the interior contents present in the cell from out into external environment.

6. Distinguish between a prokaryote and a eukaryote. Why is this distinction important to scientists?
They divide the cells into two separate categories because one of them has a nucleus and the other does not. Not all cells have a nucleus. Eukaryote cells have a nucleus while prokaryote cells do not.
Section 5-3

7. What are organelles? Give two examples of organelles. Organelles are tiny structures that perform a specialized function in the cell. Mitochondria and chloroplast are key organelles.

8. How do lysosomes function to digest particles? They break down organelles that have outlived their usefulness. They form vital functions.

9. How are mitochondria and chloroplasts similar? How are they different? They are both key organelles which is one similarity they have, a difference they have is that Mitochondria changes the chemical energy stored in food into compounds that are more convenient for the cell to use.

10. What components make up the cytoskeleton? Microtubules, Centrioles, hollow tubules.