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Unit 4

Unit 4. Cells and their Structure. Levels of Organization. Diversity of Cellular Life. Cell Specialization – when a group of cells work together to perform a specific job. The Cell Theory is a theory that describes the properties of a cell. All living things are composed of cells

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Unit 4

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  1. Unit 4 Cells and their Structure

  2. Levels of Organization

  3. Diversity of Cellular Life

  4. Cell Specialization – when a group of cells work together to perform a specific job

  5. The Cell Theory is a theory that describes the properties of a cell. • All living things are composed of cells • Basic units of structure and function in living things • Cells are produced from existing cells

  6. Categories of CellsType 1 Prokaryotes • Unicellular – one cell • No Nucleus – DNA free floating • Example – Bacteria • Used in technique called Recombinant DNA

  7. Shapes of Prokaryotes • Cocci = spherical (round) • Bacillus = (rod shaped) • Spirilla = helical (spiral)

  8. Types of Bacteria Example The Good • E. Coli are found in the intestines of humans and aid in digestion. • Streptomyces is used in making antibiotics. • Rhizobium are helpful bacteria found in the soil. They convert nitrogen in the soil.

  9. Types of Bacteria Example The Bad • E. Coli can also be harmful if food or water is contaminated with it and then eaten. • Salmonella is very dangerous and lives in the intestinal tracts of humans. It is spread via feces. Foods like poultry and eggs can be contaminated with salmonella and cause severe diarrhea.

  10. These are prokaryote E. coli bacteria on the head of a steel pin.

  11. Recombinant DNA

  12. What the heck is Recombinant DNA? A series of procedures that are used to join together (recombine) DNA segments. A recombinant DNA molecule is constructed from segments of two or more different DNA molecules. Under certain conditions, a recombinant DNA molecule can enter a cell and replicate there, either on its own or after it has been integrated into a chromosome. For example: Insulin + Bacterial DNA Antifreeze from fish + tomato DNA Growth Hormone + Bacterial DNA Human + (other) Human DNA

  13. Why Make Recombinant DNA? Recombinant DNA Technology May Allow Us To: • Cure or treat disease • Genetically modify our foods to increase flavor, yield, nutritional value or shelf-life • Better understand human genetics • Clone cells or organs

  14. Why use Prokaryotes-Bacteria? • They’re relatively simpleorganisms. • They reproduce very quickly and asexually (this means that the “daughter” cells will contain the exact same DNA as the “parent” cell). • It’s pretty easy to get DNA back into the bacteriaafter you’ve changed it.

  15. Recombinant DNA The foreign DNA is first joined to a small circular DNA molecule found in bacteria known as a plasmid

  16. Restriction enzymes • A restriction enzyme (RE) is a specialized proteinthat cuts DNA in a very specific place. • Molecular scissors

  17. Step to Recombinant DNA

  18. Steps to Recombinant DNA Step 1: • Isolate (find) the human gene responsible for producing insulin and decide where you want to put it. • In this case, we decide to put our human DNA into the plasmid of E. coli, a very common bacterium.

  19. Step 2: • Get the bacterial (plasmid) DNA out of the E. coli. We do this by basically exploding them. Step 3: • Cut your human DNA and bacterial DNA with the same restrictionenzyme

  20. Step 4: • Mix the cut human DNA, which contains the insulin gene, with the cut bacterial DNA. • They’ll stick together because they were cut with the same restriction enzyme.

  21. Step 5: Get your new recombinant plasmid back into the bacteria. This is easy because bacteria will take in DNA that’s floating around near them. We call this “transformation”.

  22. Voila!! Now your Prokaryote-Ecoli will use its new DNA to make human insulin! Because they reproduce so quickly, you’ll soon have thousands, millions, or billions of human insulin making machines. By filtering out the bacteria after they’ve made insulin, you’ve got clean human insulin that can be packaged and given to diabetic patients.

  23. Categories of Cells Type 2 Eukaryotes • Unicellular or Multicellular • Has a Nucleus • Example – Plant, Animal, fungi

  24. How are Eukaryotes Different from Prokaryotes Eukaryotes have a nucleus that contains DNA and Prokaryotes do not

  25. Types of Eukaryotic Cells in the Human Body

  26. Two Types of Eukaryotes – Animal and Plant Cell Let’s take a good look at these eukaryotes!

  27. Cell Structures in common

  28. Only Plant cell Structure • choroplast • Cell wall

  29. Only Animal cell Structure • Centriole-involved in cell division • Lysosome- uses enzymes for digestion and waste removal (food particles, worn out organelles, viruses and bacteria centriole

  30. Nucleus • Controls most of cells processes • Contains genetic information-DNA • Chromosomes inside nucleus are the threadlike structures containing genetic information

  31. N Nucleolus • Found inside nucleus • Produces ribosomes

  32. Nuclear Envelope (membrane) • Surrounds genetic material

  33. Ribosomes • Makes proteins for cell • Instructions come from the nucleus

  34. Endoplasmic Reticulum • Synthesizing, packaging and transporting of proteins • Two types – rough ER and smooth ER • Network of membranes

  35. Golgi Apparatus • Packaging system • Takes small molecules and makes larger ones then stores them

  36. Vacuoles • Storage areas for water, salt, proteins, carbohydrates • Large structures in plants

  37. Mitochondria • Synthesis and release of energy • Powerhouse of cell

  38. Cell Membrane • Regulates what enters and exits the cell • Provides protection and support • Semi-permeable – allows small substances through and keeps larger substances out • Made of lipids and proteins

  39. Cell Membrane

  40. Cell Wall (Plant Only) • Provides support, protection and structure for plant cell

  41. Chloroplast (Plant Only) • Site of photosynthesis

  42. Cytoplasm • Jelly-like substance that holds organelles

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