The Cell and Cell Theory

1. The Cell and Cell Theory

2. What is Biology? • Bio = “Life” • Ology = “the study of” • Create a list in you notes titled: • Etymology • Etymology = “study of word origins” • Etymology website: Etymonline

3. How do we know what is life/living? • Characteristics of life/living things: • Brainstorm and create a list of things that all living things have in common.

4. Characteristics of life/living things: • 1. Made of cells • 2. Reproduce • 3. Grow and develop • 4. Make or use “food” energy • 5. Sense and react to their environment • 6. Based on a universal genetic code DNA or RNA • 7. Maintain stable internal environment (a.k.a. homeostasis) • 8. As a group. Change over time (a.k.a. adapt/evolve) • *When considering these, be careful not to be too anthropocentric in your thinking.

5. Parts of the Cell Plant and animal cells have many membrane bound organelles that help these cells perform all of the necessary jobs.

6. Cell organelle assignment:( See pg 174-) • Fill in the chart for each organelle and/or cell structure: • 1) Cell membrane 2) Cytoplasm 3) Nucleus • 4) Chromosomes 5) Nucleolous 6) Ribosomes • 7) Endoplasmic reticulum 8) Mitochondria • 9) Golgi bodies 10) Lysosomes 11) Centrioles • 12) Vacuoles 13) Cell wall 14) Chloroplasts • 15) Cytoskeleton

8. Endosymbiotic theory: • See pgs 180 and 427-428. • Summarize what the theory says and provide a sketch to illustrate. Be sure to include the evidence for this theory.

9. Endosymbiotic Theory (a.k.a. Endosymbiont Hypothesis): • -Chloroplasts and mitochondria were once free-living, primitive organisms with an “early/primitive nucleus”(Prokaryotic). • -Also around at this time were cells with a “true nucleus” (Eukaryotic). • -The prokaryotic organisms were “taken in” by the more advanced cell(s). • -Inside the new cell, the prokaryotes became incorporated into the functioning of the eukaryotes, allowing it/them to complete the following processes: • a) photosynthesis, (due to the chloroplasts) • b) cellular respiration, a.k.a. “breathing to produce energy” (via mitochondria)

10. -The newly incorporated organisms were now acting as organelles (mini-organs) for a host cell. • -Cells which took in both types became plants and plant-like protists; those taking in only mitochondria became animals, fungi, and non plant-like protists. • -Both types of cells/organisms now living together in a symbiotic relationship.

11. Endosymbiotic Theory (a.k.a. Endosymbiont Hypothesis): • Evidence for this idea: • Both Mitochondria and chloroplasts have: • Plasma membranes (a.k.a. cell membranes) very similar to those of free living prokaryotes today. • Their own DNA, and that DNA is similar to bacterial DNA (bacteria are prokaryotes). • Their own ribosomes and those ribosomes are similar to those of bacteria. • Divide and reproduce similar to the way that bacteria do (by binary fission). • There are more pieces of evidence but it gets much more detailed and specific. Is this enough to convince you?

12. Types of Cells: • Prokaryotic Cells: Lack a nuclear membrane • Ex: Bacteria and Blue-Green Algae • Eukaryotic Cells: Have a true nuclear membrane Ex: Plant, animal cells

13. The development of cell theory (pg 170): • Aristotle (334 BCE): Living things could spontaneously generate from non living or dead things. (a.k.a. abiogenesis) (Ex: maggots and mushrooms grow on rotting organisms, frogs fall with rain) Janssen (1590): Eyeglass maker, created first microscopes.

14. Robert Hooke (1665): Discovered and named cells by looking at cork under microscope. • Anton van Leeuwenhoek (1674): Discovered tiny organisms in pond water.

15. The development of cell theory: • Schleiden and Schwann (1838-39): Using microscopes, declared all plants and all animals to be made of cells. • Virchow (1858): Stated that all cells come from pre-existing cells. • Louis Pasteur (1864): Uses experiments similar to Redi and Spallanzani to disprove spontaneous generation once and for all. (pgs 11 and 12)

16. The Cell theory: • 1. All living things are made of cells. • 2. Cells are the basic unit of life. • 3. All cells come from existing cells.

17. Cell Boundaries and Transport (182-189): • 1. What are the functions of the cell membrane? • 2. What do we call the double layered sheet that forms the core of nearly all cell membranes? • 3. What is the difference in function of the proteins and the carbohydrates attached to a cell membrane? • 4. In what organisms are cell walls found? • 5. What are plant cell walls mostly made of? • 6. What do we mean the ‘concentration of a solution’? • 7. What is diffusion? • 8. What does it mean when we say that a system has reached equilibrium? • 9. What does it mean when we say that biological membranes are selectively permeable? • 10. What is osmosis?

18. 11. Looking at figure 7-15 on page 185, answer the following questions? • a) In the beaker on the left, which solution is hypertonic and which is hypotonic? (left solution vs right solution). • b) In this model, to which material is the membrane permeable, water or sugar? • c) Draw a third beaker which would show two solutions (left and right) which are isotonic. • 12. What happens in the process of facilitated diffusion? • 13. What is the role of protein channels in the cell membrane? • 14. What is active transport? • 15. What is the difference between active transport and facilitated diffusion? • 16. Describe each of the following forms of active transport: • a) endocytosis, b) phagocytosis, c) pinocytosis, d) exocytosis

19. The cell membrane: -gatekeeper -controls movement of materials in and out of the cell.

20. The cytoplasm: -jelly-like -supports organelles -where nutrients are absorbed, transported and processed and wastes are stored before disposal

21. The nucleus: -control center for cell functions -storage center for the instructions of life (DNA).

22. Chromosomes: -thread-like structures that carry the genetic information. -DNA/genes (found in the nucleus)

23. The nucleolus: -darker area found inside the nucleus -involved with the synthesis of proteins

24. Ribosomes: -build proteins essential for cell growth and reproduction -the proteins make up all cell structures

25. The endoplasmic reticulum: -canals that transport materials to different parts of the cell.

26. Mitochondria: -where cellular respiration takes place and energy is provided to the organism.

27. Golgi bodies: -package and store proteins Lysosomes: - contain enzymes which help break down food and digest waste and worn out cell parts.

28. Centrioles: -needed for cell division in animal cells

29. Vacuoles: -fluid-filled storehouses that contain water, food, wastes, and other materials.

30. Cell wall: -provides protection and support for the plant cell. Chloroplasts: -production and storage of food in plant cells. -Contain chlorophyll, specialize in photosynthesis.

31. Cytoskeleton – a network of protein filaments that give a cell its shape Microtubules and microfilaments make up the cytoskeleton

32. Flagella are thread-like fibers (tails) that propel certain cells (ex. sperm) Microfilaments are pipe-like structures that help provide shape and movement for the cells. They are like the rebar that are placed on a garage floor before pouring cement Microtubules are tiny threadlike fibers that transport materials throughout the cytoplasm.

33. Each chromosome contains many different genes. Genes are units of genetic information that determine the specific characteristics of an individual.

34. Types of endoplasmic reticulums • Rough Endoplasmic Reticulum (RER) – has many ribosomes attached to the canals. These ribosomes synthesize proteins. RER is predominant in cells that specialize in secreting proteins • Smooth Endoplasmic Reticulum (SER) – is free of ribosomes and is found in the areas in which fats or lipids are synthesized.