The Big Discussion on Cells

1. The Big Discussion on Cells Did you say Cells? Yes I said Cells! YAH CELLS!!!!!!!!!!!!!

2. Living Things • All living things have a cellular organization, contain similar chemicals, use energy, grown and develop, respond to their surroundings, and reproduce. • These are the 7 major characteristics of life!

3. What is a Cell? • All organisms are made of small building blocks called cells. • A cell is the basic unit of structure and function in an organism.

4. Cell Sizes can vary • Most cells are small, about 40 human cells would fit on the dot of this letter i. • Some cells are big, the yolk of a chicken egg is a single cell. • The smallest cells are so tiny that you could fit over a million of them on the period at the end of this sentence.

5. Cell Size • Cells are made of molecules • Molecules are tiny particles of matter. • Molecules are made up of atoms. • The atom is the basic fundamental unit of matter. • Atoms are made up of protons, neutrons and electrons.

6. How Many Cells Make Up Organisms? • Organisms can be composed of only one cell or many cells. • Unicellular or single celled organisms include bacteria the most numerous organisms on Earth. • Multi-cellular organisms are composed of many cells. • You are made up of trillions of cells. • You have specialized cells in your body that perform specific functions.

7. Chemicals of Life • The most abundant chemical in cells is water. • Other chemicals are called carbohydrates and these are the energy source for the cell. • Two other chemicals are proteins and lipids which are the building materials for cells, much like wood and bricks are the building materials of houses. • Finally nucleic acids are the genetic material.

8. Cells use Energy • The cells of organisms use energy to do what living things must do, such as grow and repair injured parts. • Cells are always hard at work. • Right now your cells are busy not only with your eyes and brain but your blood cells are moving chemicals around your body. • White Blood Cells are pictured to the right!

9. How do we look at Cells? • The invention of the microscope made it possible for people to discover and learn about cells. • A microscope is an instrument that makes small objects look larger. • A light microscope that has more than one lens is called a compound microscope. • The Top 10 Microscope IMAGES!!! • Cool Microscopic Images

10. Who discovered that we have Cells? • One of the first people to observe cells was the English scientist Robert Hooke. • In 1663, Hooke observed the structure of a thin slice of cork using a compound microscope. • To Hooke the cork looked like rectangular rooms, which he called cells.

11. Who discovered that we have cells? • At about the same time that Robert Hooke made his discovery, Anton van Leeuwenhoek also began to observe tiny objects with his microscope. • Leeuwenhoek was a Dutch scientists and when he looked at water from a pond he saw tiny single celled organisms.

12. The Cell Theory • Observations from Hooke and Leeuwenhoek led to the development of the cell theory. • The cell theory states: • All living things are composed of cells. • Cells are the basic unit of structure and function in living things. • All cells are produced from other cells

13. Looking Inside Cells • Cells contain even smaller structures inside of the cell called organelles. • Organelles were called organelles because early scientists thought they looked like “inner organs” kind of like our heart, kidneys, or brain.

14. Parts of the Cell: Cell Wall • The Cell Wall is a rigid layer of nonliving material that surrounds the cells of plants and some other organisms. • Cell Walls look rectangular and shape and are only found in plant cells. • A plants cell wall helps to protect and support the cell. It provides a rigid support stand for the cell and also helps keep out some harmful substances.

15. Parts of the Cell: Cell Membrane • In plant cells the next layer inward is the cell membrane. • In animal cells the cell membrane forms the outside boundary that separates the cell from its environment. • The cell membranes main function is that it controls what substances com into and out of the cell. • For example it will let food and oxygen in but keep out harmful waste products.

16. Parts of the Cell: Nucleus • The nucleus is a large oval structure inside the cell. • The nucleus is the cell’s control center that directs all of the cells activities. • It’s really the Brain of the Cell! • The nucleus does have a nuclear membrane which is an inner protection system for the cell to protect it’s nucleus.

17. Parts of the Cell: Nucleus • Inside the nucleus you have DNA (Deoxyribonucleic acid) This is what helps cells reproduce and tells them what they should do and look like • This is why you look like a combination of your mother and father because you have DNA from both of your parents.

18. Parts of the Cell: Cytoplasm • The region between the cell membrane and the nucleus is known as cytoplasm. • This is a clear, thick, gel-like fluid. • Many of the cell’s organelles are found in the cytoplasm.

19. Parts of the Cell: Mitochondria • Inside the cytoplasm you can find rod shaped structures called mitochondria. • Mitochondria are called the powerhouses of the cell because they produce most of the energy the cell needs to carry out its functions. • Muscle cells rely heavily on mitochondria.

20. Parts of the Cell: Endoplasmic Reticulum • The endoplasmic reticulum (ER) looks like a giant maze of passageways. • The endoplasmic reticulum is responsible for moving proteins and other materials from one part of the cell to another.

21. Parts of Cells: Ribosomes • Attached to the outer surface of the endoplasmic reticulum are small grain-like bodies called ribosomes. • Ribosomes function as factories that produce proteins for the cell. • From the ribosomes and endoplasmic reticulum the proteins are transported to the golgi apparatus.

22. Parts of the Cell: Golgi Bodies • Within the endoplasmic reticulum you will find a flattened collection of sacs and tubes. These are called Golgi Bodies. • The Golgi Bodies are like the cells mailroom. They receive proteins , package them, and distribute them to different parts of the cell.

23. Parts of the Cell: Chloroplasts • Only plant cells and other protist type cells have chloroplasts. • The chloroplasts help capture energy from sunlight and use it to produce food for the cell. • The chloroplasts give plants their green color. • They are responsible for photosynthesis.

24. Parts of the Cell: Vacuoles • Throughout the cell you can find large water-filled sacs floating in the cytoplasm. • These sacs are called vacuoles. Vacuoles store food and other materials needed by the cell. • All plant cells have a large central vacuole.

25. Parts of the Cell: Lysosomes • Lysosomes are small round structures that contain chemicals that break down large food particles smaller ones. • Lysosomes also break down old cell parts and release the substances so they can be used again

26. Parts of the Cell: Cillia and Flagella • Cillia are hair like structures that are found on bacteria and some protist cells. They are like a bunch of tiny ores that are used for movement • Flagella is a whip like structure that some bacteria and protists cells have. When they whip their tail they propel themselves through the water.

27. Bacterial Cells • Bacterial cells are smaller than plant or animal cells. • Bacterial cells do have a cell wall and membrane but they do not have a nucleus. • Organisms whose cells lack a nucleus are called prokaryotic or the organsimsprokaryotes.

28. Animal or Plant Cells • Animal and Plant cells both have a nucleus so we call their cells eukaryotic or the organisms eukaryotes.

29. Bacteria vs. Plant vs. Animal Cell

30. How are Plant Cells and Animal Cells Different? • Plant Cells are rectangular in shape due to their Cell Walls. • Plant cells have chloroplasts which perform photosynthesis. • Plant cells have a large central vacuole. This helps regulate how much water the plants lets in or keeps out. It regulates osmosis!

31. Draw an Animal Cell

32. Draw a Plant Cell

33. Draw a Bacteria Cell

34. The Importance of Cells • Think about every time you need energy to move your cells have to actively be working so that you can move. • Think about every time you breathe in your individual cells have to take in oxygen and use it to make energy. • All of our energy needs are met by small tiny parts of our body that we barely even think of.

35. Transport within Cells • Diffusion is the movement of molecules from a high concentration to low concentration. • Diffusion does not require energy use. It’s kind of like riding your bicycle down hill. You still get somewhere and you still move but you don’t have to use the pedals. • Diffusion is a type of passive transport. • Sometimes protein channels can help in moving materials into the cells. They are embedded in the cell membrane.

36. Transport within Cells • Active transport is the movement of materials through a cell membrane using energy. • By doing so cells have move molecules into the cell that they need but this requires energy because there is not a concentration difference. • This type of transport is kind of like riding a bicycle up hill you get to your destination but it requires energy to do so.

37. Osmosis and Diffusion • Remember that diffusion is when you have particles move from high concentration to low concentration. • Remember that osmosis is when you have water move from high to low concentrations. • This is important when plants regulate their water supplies. • Red Blood Cells can burst if they don’t use osmosis correctly.

38. What causes Diffusion? • Molecules are always moving. As they move, the molecules bump into one another. The more molecules there are in an area, the more collisions there will be. • Collisions cause molecules to push away from one another. • Over time, the molecules of a substance will continue to spread out.