1. The Cellular Level of Organization

2. Antonie van Leewenhoek - first person to see cells. Robert Hooke coined the term “cell” and illustrated what he saw.

3. Cell Theory 1.All organisms are composed of one or more cells 2.Cells are alive, and are the basic living unit of organization of all organisms 3.All cells come from other cells

6. Every cell has three main parts: 1. Plasma (cell) membrane – a boundary that separates inside of cell from external environment. 2. A set of genetic instructions In eukaryotes this is in the Nucleus; in prokaryotes there is no membrane, stays in a section of the cell is called the nucleoid. 3. A cell body - the cytoplasm

7. Cytosol – gel like substance not contained in organelles Cells are measured in micrometers or microns. Eukaryotic cells are bigger than prokaryotic cells.

8. Advantages of being made of cells: Specialization Surface area Obtaining nutrients Separating chemical processes A multicellular organism can survive the loss of single cells.

10. Cytoplasm refers to cytosol plus organelles and inclusions. cytosol - contains proteins, enzymes, nutrients, ions, and other small molecules organelles -“little organs” - highly organized structures with characteristic shapes that are specialized for specific cellular activities. inclusions - are temporary structures in the cytoplasm that contain secretions and storage products of the cell.

11. Nucleus Double membrane called the nuclear envelope Nucleoplasm Chromatin granules – unwound DNA Nucleoli – puts RNA and protein together to make ribosomes Nucleus is essential for cell survival

14. Ribosomes – made of ribosomal RNA and protein, these are the “work benches” where proteins are put together. Made up of two subunits that come together when needed. Found free in cells Also in association with endoplasmic reticulum

16. Endoplasmic reticulum (ER) Can be rough or smooth Smooth ER is the site of fatty acid, phospholipid and steroid synthesis. In certain cells also detoxifies chemicals, such as alcohol and pesticides.

18. Rough ER has ribosomes, makes proteins for export outside the cell. May add sugars to proteins and make glycoproteins.

21. Gogli complex (apparatus, body) Made of flattened sacs Process, sort and deliver proteins and lipids to the plasma membrane and forms vesicles and lysosomes. The carbohydrates of the glycoproteins may be modified to act as “shipping labels” The “UPS” of the cell

25. Lysosomes The cell’s “stomach” – vesicles that contain digestive enzymes. Fuses with vesicles containing food or microorganisms. Can be released outside the cell – “frustrated phagocytosis”

28. Mitochondria Mitochondrion – singular Two membranes – inner membrane folded. Main function is the use of oxygen to produce ATP – cellular (aerobic) respiration These are the “power plants” of the cell. Believed to once be free living organisms – have unique DNA and RNA

31. Plastids Found in plants and some protista Surrounded by a double membrane Function photosynthesis – chloroplasts –Contain chlorophyll Chromoplasts – contain red, orange or yellow pigments Amyloplasts – used to store starches

33. Cytoskeleton Made of protein tubules Gives structure and support Also acts as muscle in moving the cell and transporting materials within it. Musculoskeletal system of the cell.

37. Centrosomes and Centrioles Centrioles are 2 cylinders of tubules arranged at right angles. Form the microtubules of the mitotic spindle during cell division, and also make up a part of cilia and flagella

43. Flagella

44. Vesicles Membrane sacs that transport substances within the cell. Vesicle trafficking

45. Vacuoles Larger than vesicles Found in plant cells Can be storage areas Can contain enzymes or waste products Central vacuole helps plants maintain turgor pressure

48. Inclusions Usually contain chemical substances produced by the cell, these are temporary structures that are not surrounded by a membrane. Melanin, glycogen, triglycerides ribosomes

49. Plasma Membrane The plasma membrane does more than just separate the outside of a cell from the inside; it controls what enters and leaves the cell, and much of the activity within the cell. Most of the cell membrane is made of a phospholipid bilayer. Amphipathic molecule – phosphate heads on the outside and inside, and fatty acid tails in the middle.

51. The membrane is selectively permeable – it allows fat soluble substances to pass through (such as steroid hormones) and some other small, uncharged molecules. Cholesterol is a large molecule, and helps to stabilize the membrane in animals. Plants use phytosterol.

53. Fluid mosaic model - proteins float like icebergs in a sea of phospholipids. Proteins can be integral proteins – go all the way through the membrane, or may be peripheral proteins -bound to the inside or outside membrane.

55. Integral Proteins can be channels or transporters. Peripheral proteins can be receptors, or can be cell identity markers or recognition proteins that identify a cell as “self” (like UPC codes). These are often glycoproteins. They may also mark worn out red blood cells or cells that have been infected with a virus.

56. All cells have a plasma membrane Some cells, such as bacterial, fungal and plant cells, also have a cell wall.

57. Cell Physiology Cell membrane function: –Are selectively permeable Lipids Size Electrical charge Presence of channels and transporters

58. Movement of molecules depends on: 1. Kinetic energy Temperature 2. Concentration gradient – more of something in one area than another

59. Diffusion Passive process –Depends on concentration and kinetic energy –Does not require energy –Moves substances from an area of high concentration to an area of low concentration Down a concentration gradient

61. The most concentrated form of water is pure water. To make water less concentrated, we dissolve substances in it.

62. Tonicity Concentration of one solution relative to another Isotonic – equal concentrations Hypertonic – more concentrated Hypotonic – less concentrated

63. Tonicity – relative concentrations of solutions Isotonic – two solutions contain the same amount of substance dissolved in them- equal concentrations Hypertonic – a solution containing a greater amount of dissolved substance- more concentrated Hypotonic – a solution containing a lesser amount of dissolved substance – less concentrated

64. Osmosis The movement of water across a selectively permeable membrane, down a concentration gradient. Dialysis is the diffusion of a solute across a selectively permeable membrane.

68. Cell in an isotonic solution

69. Cell in a hypertonic solution

70. Cell in a hypotonic solution

71. Facilitated diffusion Passive process Substances can move through protein channels Substances may be shuttled across by carrier proteins Substances still move down a concentration gradient

73. Filtration Movement of water and solutes across a membrane due to physical pressure: –Gravity –Hydrostatic pressure (water pressure or blood pressure)

76. Active Transport Depends on the use of energy (ATP) Moves substances up a concentration gradient (up hill) These permease proteins are often called “pumps” –Na+ / K+ pump

79. Vesicular Transport Exocytosis – moves substances outside the cell Endocytosis – takes substances into the cell Phagocytosis – “cell eating” Pinocytosis – “cell drinking” Receptor mediated endocytosis

83. Human Immunodeficiency Virus Originally developed in apes or monkeys Probably transmitted to man in central Africa before 1931 First cases reported 1980’s in male homosexuals Transmitted by sexual intercourse, sharing needles, blood products Incidence increasing most rapidly in heterosexual females