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Discovering Cells

Discovering Cells. LIVING ORGANISMS. Plants, animals and other organisms respond to the same basic needs . Aside from a few exceptions, anything classified as living has the following characteristics:. LIVING ORGANISMS. It is made up of cells .

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Discovering Cells

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  1. Discovering Cells

  2. LIVING ORGANISMS Plants, animals and other organisms respond to the same basic needs. Aside from a few exceptions, anything classified as living has the following characteristics:

  3. LIVING ORGANISMS • It is made up of cells. • It needs water and food for energy in order to live. • It needs carbon dioxide (CO2) OR oxygen to release energy. • It grows. • It is able to reproduce (asexually or sexually). • It is able to respond to changes in its environment. • It gives off waste. • It needs a place to live.

  4. LIVING ORGANISMS ENERGY is the KEY to all of these functions. Living things consume food to get the energy they need to organize their cells, to reproduce, and to respond to changes. All living things need energy to grow and reproduce. Energy ultimately comes from the SUN!

  5. CELLS Likewise, a single cell has the same needs as an entire organism! For each cell to stay alive, it must carry out many of the same functions as the entire organism!

  6. CELLS Identical daughter cells Parent cell • It needs water and food for energy in order to live. • It needs oxygen to release energy. • It is able to reproduce (asexually: by duplicating (copying) its genetic information and then dividing This process of reproduction, called MITOSIS produces “daughter cells” that are identical copies of the parent cell!) • It is able to respond to changes in its environment. • It is gives off waste. • It needs a place to live.

  7. Cell vs Living Organism

  8. CELL THEORY Spontaneousgeneration was the idea that living things came from non-living things. This idea became a theoryand was accepted for several hundred years. In the mid- 1800’s Louis Pasteur, a French chemist, provided enough evidence to disprovethe theory of spontaneous generation. It was replaced with Biogenesis which is the theory that living things come only from other living things.

  9. The following experiments helped to prove that… LIVING THINGS COME ONLY FROM Living Things

  10. Redi’s Experiment 1. Maggots developed in the open container. 2. Maggots appeared on the netting of the covered container because the flies were still laying eggs. No maggots developed on the meat. 3. No maggots developed on or in the closed container. The flies were unable to sense the meat.

  11. Pasteur’s Experiment Dust • Broth was poured into the flask. • The broth was boiled to kill all of the microbes (bacteria). • Dust collected in the “S” of the flask BUT the flask did NOT turn cloudy. • The broth did not turn cloudy (indicating that there was bacteria present) until the flask was tipped OR until the “S” shape was removed & the broth was exposed to the dust.

  12. SEEING CELLS • Robert Hooke: • In 1665, Robert Hooke used a microscope to observe a thin slice of cork. • The cork appeared to be made up of empty little boxes or rooms. Hooke called these spaces cells.

  13. SEEING CELLS Leeuwenhoek: Around 1674, Leeuwenhoek notice single- celled organisms in a drop of lake water and scrapings from teeth & gums using a microscope that he had built. He called these moving organisms animalcules, meaning “little animals”.

  14. SEEING CELLS During the mid- 1800’s other scientists made further cell discoveries leading to the development of the CELL THEORY.

  15. SEEING CELLS Schleiden concluded that all plants are made of cells Schwann concluded that all animals are made of cells Virchow proposed that cells divide to form new cells and that all cells come from existing cells.

  16. The Cell Theory…

  17. BASIC CELL PARTS • All plant and animal cells have 3basic parts: • Cell Membrane- surrounds the cell; controls what comes in and what goes out of the cell • Nucleus-control center of the cell; controls all of the cell’s activities- the “brain” • Cytoplasm-liquid-like substance that stores wastes and allows movement of materials from one part of the cell to another part

  18. Plants have MORE… • Plants have additional organelles or tiny structures inside a cell, that animal cells do not have. • Cell Wall- supports and protects the cell • Chloroplasts- is where the plant makes its own food using the Sun’s energy

  19. BODY ORGANIZATION Cells Tissue Organ Organ System Organism… You!

  20. You try it! • How many times does a compound light microscope w/ an eyepiece lends of 10Xand an objective of 10X magnify objects? • 10X x 10X = 100X • How many times does a compound light microscope w/ an eyepiece lends of 12X and an objective of 4X magnify objects? • 12X x 4X = 48X

  21. How does material move in and out of the cell? • The Cell Membrane controls HOW materials move into or out of a cell. • Every cell (plant and animal) is surrounded by a Cell Membrane • The cell membrane is selectively permeable, which means that some substances can pass through the membrane while others CAN NOT!

  22. Transport • There are TWO process that allow materials to pass through a cell membrane 1. ACTIVE transport 2. PASSIVE transport

  23. Passive Transport • Passive Transport is the movement of dissolved materials across a cell membrane without using energy • Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration H L • Osmosis is the diffusion of H2O • Materials that move through a cell by PassiveTransport: CO2, oxygen, water

  24. Passive Transport

  25. Facilitated DIFFUSION Some molecules, like sugar, can NOT pass easily through the membrane so the proteins in the cell membrane form “channels” through which the sugars (glucose) can pass. These channels make it easier for the sugars to reach the opposite side of the cell membrane. NO ENERGY is used in facilitated diffusion so it is another form of passive transport!

  26. Active Transport • Active Transport is the movement of materials across a cell membrane using cellular energy • Energy is required for active transport because the materials are moving from an area of LOWER concentration to an area of higher concentration! L H • This requires WORK for the cell! • Using the cells energy, the proteins pick up • molecules and carry them across the membrane • Materials that move through a cell by Active Transport: • calcium, proteinsand sodium

  27. protein ATP = Energy!

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