Life Science Chapt3
- 1. Life Science Chapter 3 Spring 06’
- 2. Cells are the building blocks of life All living things begin life as a single cell Those cells reproduce and become organisms containing trillions of cells Think of your body as a brick wall-each brick is a cell with a job to do
- 3. Discovery of the cell 1665 Robert Hooke placed a piece of dead corkwood under a microscope. He noticed many different tiny openings in the cork. They looked like rooms-he called them cells. What he saw was dead. Scientists can now look at living cells and see the organelles inside doing their jobs
- 4. Cell Theory 1800’s Scientists had developed more powerful microscopes. They could see some structures inside the cell. They also could see some of the activities going on with those structures Cell Theory says: All living things are made of one or more cells Cells carry out all life functions New cells only come from other living cells
- 5. Cell Parts Cell membrane- a thin flexible covering that controls what goes in and what goes out of the cell. Cytoplasm- a clear jellylike substance within the cell. Activities between the different structures is regulated by the cytoplasm. The structures are called organelles
- 6. Organelles Nucleus - surrounded by the nuclear membrane the nucleus is the control center for the cell. Genes store information and are found in the nucleus. Mitochondria- the “powerhouse” of the cell. Bean shaped structure that controls the “power” in the cell. They breakdown molecules of food and release the energy.
- 8. Organelles Vacuole - The storeroom of the cell. Food and water are stored here as well as waste Ribosome - Small structures that make protein for the cell
- 9. Organelles Endoplasmic Reticulum, ER- Network of tubes inside the cell that works as a highway moving molecules from place to place Golgi Bodies- flattened, folded sacs that package and move materials (the Fed-Ex of celldom) through the cell.
- 10. Organelles Lysosome - round packets that contain chemicals to break down molecules in the cell. They also breakdown the dead parts of the cell.
- 11. Plant cells are different from animal cells Plant cells have chloroplasts which are structures that help plants make food using light (photosynthesis) Plant cells also have a cell wall which is rigid and helps the plant stand up. Plant cells have fewer vacuoles than animal cells. The one or two vacuoles are larger due to the water needs of the plant.
- 13. More building Tissues Organs Organ Systems Cells
- 14. Tissue -groups of cells that work together to do a certain job Muscle tissue Covering tissue-skin Connective tissue-bone Nerve tissue 4 Types of tissue
- 15. Groups of tissue then work together to do certain jobs. These groups of tissue are called organs. Your heart is an organ that has several different types of tissue. Muscle tissue make your heart pump, nerve tissue tells it when to pump, and connective tissue holds it all together.
- 16. Plants have organs too. Plants have cells and tissue just like animals. Plants also have organs. Plant organs would include- Flowers Leaves Stems Roots
- 17. Cell Reproduction Cells reproduce by dividing the nucleus and forming two new cells. This process is called mitosis. The new cells are called daughter cells. Daughter cells have the same traits as the parent cell.
- 18. Cell reproduction Before mitosis the chemical in the nucleus makes a replica of itself. The chemical then forms strands called chromosomes. Chromosomes are thick strands of nuclear material that passes on traits from the parent cell to the daughter cells during mitosis.
- 19. Stages of Mitosis Prophase -The nuclear membrane disappears, the chromosomes can be seen under a microscope Metaphase - The chromosomes line up in the center of the cell
- 20. Stages of Mitosis Anaphase- The chromosomes split and separate. Each set goes to an end of the cell Telophase – The middle of the cell begins to pinch apart. A nuclear membrane forms around each set of chromosomes. In plant cells a new cell wall also forms.
- 22. Review Cells are the basic building blocks of life. Some parts of the cell include the cell membrane, the nucleus, cytoplasm, mitochondria, vacuoles, ribosome, endoplasmic reticulum, Golgi bodies, and Lysosome. Cells can reproduce by dividing in two. This process is called mitosis.
- 23. Review Plant cells differ from animal cells in three important ways-plant cells have chloroplasts. Plant cells have a cell wall. Plant cells have fewer but larger vacuoles A group of cells that work together to do a certain job is called a tissue. A group of tissues that work together to do a certain job is called an organ.
- 24. Review Meiosis is a type of cellular reproduction that produces sex cells