1. What Are Cells?
  2. Building blocks to all living things
  3. They form tissues and organs that make up everything on earth
  4. Cells are the units of structure and function
  5. They perform every function of an organism
  6. Some Important Men of Cytology
  7. Robert Hooke
  8. Had idea that God divided living things into smaller parts (1665)
  9. Made his own microscope and studied a piece of cork
  10. Matthias Schleiden
  11. German Botanist (Botany – study of plants)
  12. 1838 wrote what was called the cell priniciple
  13. Theodore Schwann
  14. German physiologist advanced the principle in 1839
  15. The Cell Principle
  16. all living things are composed of living units called cells and cell products
  17. all cells came from preexisting cells
  18. Today this is still the universally accepted as the most fundamental law of biology
  19. Cytology
  20. The study of cells and how they work (also called molecular biology) and how they reproduce, work, and communicate with each other
  21. Learning about the variety of cells
  22. Some work by themselves – live as a single cell
  23. Cells of the human body are specialized cells
  24. each have certain tasks
  25. dependent on other cells for their existence
  26. Learning the shapes of cells
  27. Each type of cell has a special shape to help it function
  28. Learning the complexity of the cell
  29. Tiny, self-contained cities complete with power plants, chemical factories, food warehouses, and waste disposal plants
  30. Contains extensive transportation systems to import (bring in) raw materials and export products and waste
  31. All activities are over-seen by the cell’s control center
  32. Learning that this building block of all life the “cell” testify to a powerful, awesome Creator-God
  33. The Design of Cells
  34. Three main parts of every plant and animal cell
  35. Nucleus
  36. spherical body often located near center of cell
  37. contains the genetic code for the cell
  38. the master control center of the cell
  39. Cytoplasm
  40. the fluid medium for the many molecules and organelles (little organs) which are in the cell
  41. Cell Membrane
  42. outer boundary that separates cell from the environment
  43. controls what enters and leaves the cell
  44. The Nucleus
  45. Function
  46. the control center of the cell
  47. controls the life and characteristics of the organism
  48. all information encoded in the DNA (deoxyribonucleic acid)
  49. governs construction and operation of the cell
  50. contains “blueprints” used to construct cell’s machinery
  51. stores DNA
  52. stores and retrieves information (like a computer only more complex!)
  53. human DNA has 46 molecules each about 1.5 inches long.
  54. If stretched out, a human cell contains 4-6 feet of DNA yet has a diameter of only a few 1/10,000 of an inch
  55. DNA molecules are coiled on protein “spools” and “racks” that they fit into the tiny nucleus but all information can still be retrieved from them
  56. DNA and its proteins are called chromatin
  1. Other parts of the nucleus
  2. the nuclear envelope
  3. a membrane that separates the nucleus from rest of cell
  4. nuclear pores
  5. part of the envelope
  6. serve as “gates”
  7. regulate the transport of large molecules into and out of the nucleus
  8. makes up to 1/3 of membrane
  9. very selective of what it allows in – only items that are “tagged” properly
  10. nuclear matrix
  11. Coiled DNA fill most of he nucleus and it is thought to be threaded through a scaffold (matrix) made of protein and attached to nuclear envelope by thin girders
  12. Houses various enzymes and other machinery that cell uses to read and copy DNA
  13. nucleolus (nucleoli – plural)
  14. manufactures ribosomes – the protein factories for the cell
  15. after ribosomes are manufactured they are transported out of nucleus through the pores and released into cells where they manufacture proteins
  1. Cytoplasm – fluid medium of the cell
  2. Most activities of life take place in the cytoplasm and organelles
  3. Cytoplasm contains dissolved chemicals
  4. proteins, lipids, carbohydrates
  5. these are used as raw materials for manufacturing of cell parts and cell products or as items to be packaged and transported to the cell’s surface
  6. enzymes
  7. large protein molecules that carry out various chemical reactions which
  8. produces energy
  9. transform raw material into useful material
  10. breakdown old proteins to be recycled
  11. amazing work of God
  12. there are hundreds of simultaneous chemical reactions involving thousands of different kinds of compounds
  13. like hustle & bustle of a big city all wrapped up in a tiny cell to small to be seen without a microscope.
  14. Organelles (little organs) float in cytoplasm
  15. skeleton of cells
  16. cytoskeleton
  17. cellular framework
  18. keeps cell from being squashed or distorted by the slightest pressure
  19. contains smaller filaments that act like cables, girders and winches
  20. can change the shape of the cell so that it can move and function through the body – called “creeping cells”
  21. God designed intricate internal skeleton
  22. Microtubules
  23. Hollow, rod-like girders composed of a protein called tubulin
  24. Primary composition of the cytoskeleton
  25. They are important part of certain organelles like cilia and flagella
  26. The highway of the cell
  27. things made in one part of cell are transported to another through these microtubules
  28. protein is packaged in a special container called a vesicle
  29. a special motor protein takes the vesicle through microtubule to where it belongs
  30. scientists have seen things transported in both directions at one time like a two-lane highway
  31. can be moved or destroyed and rebuilt to change the cells appearance
  32. shifted by tiny musclelike proteins which act like winches and cables
  33. Mitochondria (mitochondrion) – power plants of the cell
  34. “burns” carbohydratesand fats and uses the energy to produce ATP (adenosine triphospate)
  35. large, sausage-shaped structure
  36. has an outer and inner membrane
  37. smooth outer membrane has portholes which allow molecules to pass through
  38. inner membrane – highly folded for more surface area for power generators
  39. contains transport proteins, ion pumps, and large ATP generators
  40. 80% of membrane is protein
  41. most mammal cells contain between 1000-2000 mitochondria
  42. the more active the cell the more mitochondia
  43. heart cell – many
  44. fat cell – few
  45. can also export some byproducts of power generation and also producing heat to maintain operating temperature
  46. Chloroplasts in plant cells
  47. Do the same work as the mitochondrion
  48. Produce energy for plant through photosynthesis
  49. Ribosomes – protein factories
  50. Proteins are very important molecules within the cell – they are necessary for most every function
  51. Proteins are manufactured by ribosomes
  52. Powered by ATP (produced by the mitochondria) they assemble amino acids into complex proteins
  53. They follow the “blueprints” from the cell’s nucleus
  54. A single cell may have tens of thousands of ribosomes
  55. Composed of two halves that fit together like a clam shell
  56. The process
  57. A “blueprint” molecule is fed through the center of the ribosome like a typewriter ribbon
  58. The ribosome assembles amino acids into a protein chain
  59. When complete ribosome opens, releases the protein and grabs another protein “blueprint”
  60. They are the smallest and most numerous of organelles
  61. Very complex - each one consists of more than 360,000 atoms
  62. Endoplasmic Recticulum – multi-purpose network
  63. Dense network of membranes (reticulum come from Latin meaning “small net”)
  64. Called “ER”
  65. Attaches to the outside of the cell’s nucleus and extends through the cell
  66. Its purpose
  67. Like an industrial complex
  68. Ribosomes move to ER when they need to make a protein for export to another cell or for one of the cell’s membranes
  69. It also breaks down toxins and wastes
  70. Manufactures fat molecules
  71. Two types
  72. Rough –
  73. closest to nucleus
  74. contains many ribosomes so it has a rough appearance
  75. Smooth –
  76. further from the nucleus
  77. contains fewer ribosomes
  78. mostly contains enzymes for recycling and for fat production
  79. Golgi Complex – shipping center of the cell
  80. Structure
  81. Is a stack of flattened, membrane enclosed compartments – looks like a stack of hollow pancakes
  82. Held together by the cytoskeleton of cell
  83. Purpose
  84. Receive proteins from the rough ER and prepare them for transport
  85. They package and ship to the final destination
  86. some go to various parts of the cell
  87. some go to cell membrane
  88. some released from cell like digestive enzymes, blood proteins, glandular secretions
  89. Shipping process
  90. Proteins made in the rough ER are tagged with “shipping tags” which tell where they are to go
  91. It sorts the proteins according to their tags
  92. Proteins going to the same place are loaded into a container called a vesicle attached to a microtubule
  93. A motor protein whisks the vesicle to final destination where it is unloaded to do their jobs
  94. Lysosomes – recycling centers
  95. Special vesicle whose wall contains ion pumps that make the interior very acidic
  96. Proteins that are labeled for recycling are dumped into the lysosome and broken down by the acid and special enzymes
  97. Can also be used to attack bacteria that invade body
  98. Vacuoles – storage containers
  99. Found in plants and animals
  100. Plant vacuoles
  101. They don’t take in their food, they make it and need large storing areas
  102. In some plants like the onion 90% of the cell’s interior can be a vacuole
  103. Animal vacuoles
  104. More numerous but much smaller
  105. Cell membrane – the covering of the cell
  106. Importance
  107. separates from the outside environment
  108. also known as the plasma membrane
  109. controls what enters and leaves the cell
  110. shows God’s masterful design
  111. without this perfect design the cell would suffer instant death
  112. Structure
  113. thin, flexible barrier
  114. made of phospholipids – special lipid molecules with a small amount of cholesterol to maintain flexibility
  115. it is self-sealing and self-repairing
  116. can be squashed and deformed and not break
  117. cell membranes within the cell are all about the same os the outside membrane
  118. Support and reinforcement
  119. membrane skeleton – a network of fibers that support the cell membrane
  120. made from strong, cable-like proteins called spectrin
  121. act like steelbelts of a car tire allowing the cell to move without ripping or tearing but still allowing it to be flexible
  122. many of the spectrin fibers are attached to special winch like proteins called actin which allow the cell to constrict the membrane by tightening certain fibers
  123. Machinery
  124. there are proteins and other molecules embedded in the membrane
  125. some act as ion pumps allow the cell to pump in or out of cell atoms of sodium, potassium, calcium, and hydrogen to preserve correct balance
  126. some act as portals, allowing certain molecules in and out of cell
  127. some act as sensors to inform the cell of the environment around it – they alert the cell to hormonal changes which signal a special task
  128. some act as guards, identifying things that want in to make sure they are acceptable
  129. Plant cell walls
  130. outside the cell membrane of a plant a rigid, box-like structure is manufactured called a cell wall
  131. this stiffens the plant and allow it to stand upright without a skeleton
  132. also protects from bacteria tat tries to invade plants
  133. composed of millions of cellulose threads
  134. in trees and other very stiff plants produce another material called lignin
  1. The Life and Work of a Cell
  2. Maintaining Life
  3. Designed to do work – some very specialized
  4. skin cells – protect what lies beneath
  5. gland cells – secrete substances that aid in many functions
  6. nerve cells – carry electrochemical impulses to help body to move and react
  7. muscle cells – contract using special protein molecules
  8. liver cells – act as giant chemical factories
  9. all cells need to do certain daily functions to survive
  10. process of maintaining a stable internal environment is called homeostasis
  11. God has designed them so well that some can last well over a century (100 years)
  12. taking in food to power its systems
  13. takes in food from outside the cell or releases some of its stored food sources
  14. brings it in and processes into energy
  15. disposal of wastes
  16. breaks down the foods and what the cell can not use is waste
  17. the cell will excrete (get rid of) any waste products
  18. pumping ions in and out to balance osmotic pressure and pH
  19. osmotic pressure
  20. water diffuses in and out of cells depending upon the concentration of dissolved salts in the cell’s cytoplasm and in the environment
  21. red blood cell placed in pure water, water will diffuse into cell until it bursts
  22. if placed in a tube of concentrated salts, the water will leave cell until it shrink and dies
  23. cells of the body constantly regulate their internal osmotic pressure
  24. proper pH
  25. measures the concentration of acids and bases in and around the cell
  26. by using their ion pumps the cell can adjust their internal pH or adjust the outside pH
  27. replacing and refurbishing worn-out factories, power plants, and other machinery
  28. much energy is put into maintaining and repairing the cell
  29. machinery wears out with use
  30. constantly takes out of circulation old proteins and replaces then with newly manufactured proteins
  31. the old ones are taken to the recycling plant (lysosomes) were they are broken down into simple amino acids and rebuilt
  32. proteins are generally recycled every 7-10 days as preventative maintenance
  33. the cell also has repair centers to repair slightly damaged proteins without rebuilding them
  34. some proteins are constantly reading the cell’s DNA code in order to prevent or correct any damage caused by heat, ultraviolet light, or radiation
  35. cytoskeleton must be rearranged to meet cell’s needs
  36. poisons must be deactivated
  37. Energy requirements of the cell
  38. Cells either make their own food using energy from the sun (as in plants) or acquire it from other sources (like the animal kingdom)
  39. A cell’s energy has to gotten from its environment because according to the laws of physics energy can not created or destroyed only transferred or transformed
  40. Primary task of the cell to is to obtain energy to do its work
  41. Photosynthesis and cellular respiration
  42. storing energy
  43. photosynthesis – means “putting together with light”
  44. it is the basis for sustaining life on earth
  45. transforming solar energy into chemical energy of sugar molecules
  46. it forms glucose – basic energy food of the cell made from carbon dioxide and water
  47. action takes place in the chloroplasts which are organelles in green plants
  48. releasing energy – cellular respiration
  49. is the breakdown of chemical substances such as glucose within a cell for the purpose of releasing energy
  50. this energy is used to synthesize adenosine triphosphate (ATP)
  51. nearly all life processes are powered by ATP
  52. the cell takes carbohydrates (glucose), fats and proteins (if it is short of other food)
  53. respiration allows these foods to be broken down to release their energy for functions of life and they release carbon dioxide and water as waste products
  54. all cells work the same way – the pattern of the Master Creator
  55. opposite processes
  56. photosynthesis – water molecules (H2O) are split into hydrogen and oxygen and the hydrogen combine with carbon to form glucose
  57. respiration – hydrogen is split from glucose molecule and united with oxygen to form water and what is left is carbon dioxide (CO2)
  58. Active transport of cells
  59. Some things can diffuse through the cell membrane
  60. For other things to pass through membrane, the cell must expend energy – this is active transport
  61. endocytosis
  62. taking in of a large molecule
  63. can be done one of two ways
  64. phagocytosis – “cell eating” – the membrane works to surround the molecule and then engulfs it
  65. example – white blood cells – engulf and eat bacteria that invades the body and cells
  66. pinocytosis – “cell drinking” – intake of liquids – a small opening allows a small amount of fluid in and then pinches off to trap some liquid in the cell
  67. exocytosis
  68. the removal of waste products
  69. secretion filled vesicles move to the surface and then open releasing their contents to the outside
  70. Cell movement
  71. Some cells need to move around to accomplish their job
  72. Some cells need to produce a moving current to move fluids throughout the body
  73. Types of movement apparatus
  74. flagella
  75. a large, moveable whiplike tail that extends from the cell
  76. cilia
  77. move by hair-like projections that extend from the cell membrane
  78. how they move
  79. molecular machines made of microtubules and motor proteins encased in a flexible membrane
  80. this movement is almost like rowing a boat
  81. some bacteria can swim nearly 50 times its body length in 1 second (equal