Structure and Function of Cells

1. Structure and Function of Cells

2. Why are Cell So Small? • Most cells are too small to be seen without a microscope. It would take 50 human cells to cover the dot on this letter “i”. • Cells take in food and get rid of waste through their cell membrane. • If cells grew larger they would need more food and produce more waste.

3. As the cells volume increases, its surface area grows too • However the cell’s volume grows faster than the cells surface area. • If a cell gets too large , the cell’s surface area will not be large enough to take in enough nutrients or pump out enough waste. • So the area of the cell’s surface - compared with the cell’s volume– limits the cell’s size.

4. Cell Size Continued • A few cells are big. • The yolk of a chicken egg is one big cell. • The egg can be this big because it does not have to take in more nutrients.

5. Organelles • Organelles – structures within a cell that perform specific functions. • Each organelle has it’s own name. • Structure- the design or shape of an organelle. • Function – the “job” of the organelle in the cell.

6. Two Types of Cells Prokaryote • An organism that consist of a single cell that does not have a nucleus. Eukaryote • An organism made up of cells that have a nucleus enclosed in a membrane. No Nucleus Nucleus

7. Cell Wall • Cell Wall –A rigid structure that surrounds the cell membrane and provides support to the cell. • The cell wall of a plant is a ridged yet flexible structure that is made of complex sugar called cellulose. • Plants, bacteria and fungi all have cell walls.

8. Cell Membrane(Gate Keeper) • Cell membrane – protective barrier that encloses the cell. • The cell membrane contains proteins, lipids and phospholipids. • The phosphorus layer is outward facing and hydrophilic or “water loving.” • The lipids layer is inward facing and hydrophobic or “water fearing.”

9. Cytoplasm and Cytoskeleton • Cytoplasm – Clear gel like substance in a cell that cushions and protect the cell’s organelles. The fluid and most of the organelles are considered part of the cytoplasm. • Cytoskeleton – is a web of proteins in the cytoplasm.

10. Chloroplast (Solar Panels) • Chloroplast are “green" organelles that are found in all plants and some bacteria and protist such as algae. • Chloroplast are green because they contain chlorophyll. Chlorophyll is a green pigment that absorbs and traps the energy of sunlight to use in photosynthesis.

11. Chloroplast Under a Microscope http://teachertube.com/viewVideo.php?video_id=244847

12. Vacuole (Storage Tanks) • In animal and fungal cell, some vacuoles act like lysosomes because they store digestive enzymes. • In plant cells, vacuoles are large and centrally located. These large vacuoles store water and support the cell.

13. Mitochondrion(Power House/Generator) • Mitochondria – are the power source of the cell where glucose (sugar) is broken down. • When glucose is smashed inside the mitochondria, large amounts of energy in the form of ATP (adenosine triphosphate) is released.

14. Lysosome(Waste Management) • Lysosomes are organelles that contain digestive enzymes. • Lysosomes destroy worn-out organelles, gets rid of waste.

15. Nucleus(Control Center/Brain) • Nucleus- is found in eukaryotic cells: protist, fungi, plants and animals • Contains the cell’s DNA or genetic material. • Controls all cell activity. • Nucleolus – is where ribosomes are made.

16. DNA (Blueprint) • DNA- deoxyribonucleic acid • DNA is found in the nucleus • Genetic material that carries information needed to make new cells and new organism. 4 Nitrogen Bases

17. Vesicles • Vesicles are small cell organelles that are present in cells. These organelles are small, membrane enclosed sacs which store and transport substances to and from one cell to another and from one part of a cell to another. They are one of the important parts of a cell.

18. Endoplasmic Reticulum(Passageways / Delivery System) • Endoplasmic Reticulum – The ER are part of an internal delivery system made of tubes and passageways. • Substances move from the nucleus through the ER to different places in the cell. • Many chemical reactions take place in the ER where proteins, lipids, and other materials are made.

19. Smooth Endoplasmic Reticulum – is smooth not covered with ribosomes. Rough Endoplasmic Reticulum – is covered with ribosomes

20. Golgi Body(Postal Service) • Golgi Body– packages materials to be transported throughout of cell. • Lipids and proteins from the ER are delivered to the Golgi body. They are packaged in pieces of the Golgi membrane called vesiclesand are sent where they are needed in the cell.

21. Ribosomes (Protein Factories) • Ribosomes are organelles that make proteins. • Proteins are made of amino acids. • Amino Acids are 20 different organic molecules that are used to make protein.

22. Centrioles (Spindle Fiber) • Cells have two small organelles called centrioles which are a little bundle of 9 tubes. • Centrioles are seen during cell division. • During prophase, the centrioles move to opposite ends of the nucleus and a mitotic spindle of threads (spindle fiber) begins to appear. Those threads then connect to the now apparent chromosomes. During anaphase, the chromosomes are split and pulled towards each centriole.

23. Cell Song • http://www.bing.com/videos/search?q=cell+rap+song+on+youtube&mid=EEA648DCDF16FEE10F4CEEA648DCDF16FEE10F4C&view=detail&FORM=VIRE1

24. Cell Diagram- Class Assignment • Cell Diagrams • Draw separate diagrams of a plant, animal and bacteria cell. • Label each structure or part of the cell. • Write a brief description of the function of each part of the cell.