Antoni van Leeuwenhoek was the first to observe cells using a single lens microscope in the 17th century. He documented red blood cells and the circulatory system. The basic unit of structure and function of organisms is the cell. Cells come in many forms to carry out different functions in the body. The main parts of the cell are the plasma membrane, cytoplasm, and nucleus. The plasma membrane regulates what enters and leaves the cell. The cytoplasm contains organelles that carry out cellular functions. The nucleus contains genetic material that directs cell activities.

1. The Cell

2. Antoni van Leeuwenhoek (1632-1723), Dutch, maker of first single lens microscope The first to document the structure of RBC & the nature of the circulatory system protozoans & bacteria, life cycles of many species of insects. MICROMETER ( µ m) = 1/1000

3. Types of Microscopes 1. COMPOUND/LIGHT MICROSCOPE Principle: sunlight (light source) 2. ELECTRON MICROSCOPE Principle: beam of electrons a. Transmission (magnification: >/=1Mx) b. Scanning – 3D image <250,000x Magnification = extent to which an image is enlarged

6. Image under Compound microscope Scanning EM Transmission EM

7. CELL Robert Hooke (1665) = studied the cork & other plant materials  many small partitions separating cavities  cells. Basic structural and functional units of an organism Carry out all chemical activities needed to sustain life

8. Cell Diversity Cells that connect body parts Cells that cover and line body organs Cells that move organs and body parts Cell that stores nutrients Cell that fights disease Cell that gathers information and controls body functions Cells of reproduction

9. 3 Main Parts 1. PLASMA MEMBRANE 2. CYTOPLASM 3. NUCLEUS

10. 1. Plasma Membrane syn: plasmalemma, cell membrane - outer covering of the cell - surrounds each cell  separate its contents from external environment - regulates what enters & leaves the cell - allows communication

11. Plasma Membrane some, cholesterol and glycolipids LIPID BILAYER + integral and peripheral proteins SELECTIVE PERMEABILITY - water & nonpolar (lipid-soluble) molecules e.g. FA, fat-soluble vit., steroids, O2, CO2 mainly made up of phospholipids and proteins (latter, mainly glycoproteins)

12. Plasma Membrane Impermeable to: ions, glucose, a.a. transport assisted by: ion channels, transporters Integral proteins act as: receptors, enzymes, cell identity markers

13. Plasma Membrane

14. rane

15. Definition of Terms Intracellular fluid (ICF) – inside body cells i.e. fluid in cytoplasm, 2/3 of body fluid Extracellular fluid (ECF) – fluid outside body cells Interstitial fluid – the ECF between cells e.g. plasma (in blood vessels), lymph (in lymphatic vessels) ** materials dissolved in body fluids: gases, nutrients, ions, etc.

16. Definition of Terms Solute – any material dissolved in a fluid Solvent – fluid in w/c the solute is dissolved e.g. water Solution – homogenous mixture of 2 or more components (e.g. air, seawater, alcohol)

17. Definition of Terms CONCENTRATION – the amount of a solute in a solution CONCENTRATION GRADIENT – difference in concentration between 2 different areas moving down vs. moving up

18. Substances move across cellular membranes by: PASSIVE PROCESSES – substance moves down its concentration gradient using only its own energy of motion (kinetic energy) SIMPLE DIFFUSION, OSMOSIS ACTIVE PROCESSES – cellular energy (e.g. ATP) is used to push the substance through the membrane against its concentration gradient ACTIVE TRANSPORT, VESICLES

19. Passive Processes DIFFUSION – a substance moves from one place to another due to the substance's kinetic energy particles move from a region of higher to lower concentration endpoint: EQUILIBRIUM – substance is evenly distributed throughout the solution and the concentration gradient disappears may or may not involve a membrane

20. Diffusion

21. 2 Types of Diffusion 1. SIMPLE DIFFUSION lipid-soluble substances diffuse through the lipid bilayer e.g. O2, CO2, N, f.a., steroids, vit. ADEK, H2O, urea used in: exchange of gases, absorption of nutrients, release of wastes

22. Simple Diffusion

23. 2 Types of Diffusion 1. SIMPLE DIFFUSION Ion channels – allow a specific type of ion to move across the membrane through the channel's pore e.g. K, Cl, Na, Ca

25. 2 Types of Diffusion 2. FACILITATED DIFFUSION an integral membrane protein assists a specific substance across the membrane substance binds to a specific TRANSPORTER on one side of the membrane --> released on the other side after the transporter undergoes a change in shape movement along a conc. gradient, NO ATP needed e.g. glucose, fructose, galactose

27. Passive Processes 2. OSMOSIS = net movement of water through a selectively permeable membrane - water moves from an area of higher water to an area of lower water concentration - or, from an area of lower solute concentration to an area of higher solute concentration OSMOTIC PRESSURE – depends on the concentration of its solute particles - the higher the solute conc., the higher the osmotic pressure

28. Osmosis

29. EFFECT of OSMOSIS in CELLS ISOTONIC = any solution in w/c cells maintain their normal shape and volume, concentrations of solutes are same on both sides = tissue fluids, blood plasma, 0.9% NSS, 5% dextrose (glucose) HYPOTONIC = lower concentration of solutes (higher conc. of H2O) than the cytosol inside the cell = cell swells --> ruptures HYPERTONIC = higher concentration of solutes (lower conc. of water) than the cytosol inside the cell = cell shrinks

30. Effects of Osmosis

31. Passive Processes 3. FILTRATION = process by w/c H2O and solutes are forced through a membrane (or capillary wall) by fluid or hydrostatic pressure (pressure gradient) e.g. filtering capacity of the kidney (e.g. in urine formation)

32. Active Processes 1. ACTIVE TRANSPORT - cellular energy is used to transport substances across the membrane against a concentration gradient (from an area of low to an area of high concentration), needs ATP - splitting of ATP changes the shape of a transporter protein (PUMP) --> moves a substance across the membrane against its conc. gradient - Na, K, H, Ca, I, Cl

33. Active Transport

34. Active Processes 2. TRANSPORT IN VESICLES - VESICLE – small round sac formed by budding off from an existing membrane - transport substances, take in and release substances - requires energy (ATP)

35. 2 Types of Transport in Vesicles 1. ENDOCYTOSIS – materials move into a cell in a vesicle formed from the plasma membrane - substances are surrounded by a piece of the plasma membrane w/c buds off inside the cell to form a vesicle containing the ingested substances.

36. 1. PHAGOCYTOSIS – large solid particles (e.g. bacteria, viruses, aged or dead cells), are taken in by the cell - fuses w/ a lysosome --> break down of material - e.g. WBCs, macrophages 2 Types of Endocytosis

37. 2. BULK-PHASE ENDOCYTOSIS (PINOCYTOSIS) – cells take up tiny droplets of ECF - fuses with a lysosome --> enzymatic breakdown of engulfed solutes 2 Types of Endocytosis

38. 2 Types of Transport in Vesicles 2. EXOCYTOSIS – results in secretion (release of materials from a cell) a. SECRETORY CELLS – release digestive enzymes, hormones, mucus, etc. b. NERVE CELLS – during release of neurotransmitters * membrane-enclosed secretory vesicles form inside the cell, fuse w/ the cell membrane, and release contents into the ECF

39. Exocytosis

40. Table. 3.2

41. Specializations of the Plasma Membrane Microvilli Membrane junctions

42. Membrane Junctions 1. TIGHT JUNCTIONS = formed from fusion of adjacent cell membrane --> impermeable or leak-proof sheets = keep digestive juices & harmful substances from damaging the organs or getting into the bloodstream 2. DESMOSOMES = anchoring junctions (button-like thickenings), prevent cells under mechanical stress from being pulled apart e.g. skin 3. GAP JUNCTIONS = allows communication e.g. heart, nervous system

43. 2. Cytoplasm consists of all cellular contents bet. the cell membrane and nucleus Includes: CYTOSOL (ICF) – fluid portion of the cytoplasm, 55% of total cell volume, 75-90% H2O, site of chemical reactions ORGANELLES – specialized structures inside cells w/ specific functions

44. 1. Cytoskeleton network of 3 different types of protein filaments 1. MICROFILAMENTS – thinnest, concentrated at the periphery --> strength and shape - provides mechanical support and generates movement - anchor cytoskeleton to integral proteins - support for microvilli - intercellular attachment

45. 1. Cytoskeleton 2. INTERMEDIATE FILAMENTS – found in parts of cells subject to tension (stretching), hold organelles in place, intercellular attachment 3. MICROTUBULES – long, hollow tubes, determines cell shape, movement of organelles w/in the cell, migration of chromosomes during cell division, movement of cilia and flagella

47. found near the nucleus Includes: 1. Centrioles (paired) – composed of microtubules 2. Pericentriolar material – composed of tubulins, organizing centers for growth of the mitotic spindle (role in cell division) 2 . Centrosome

48. 3. Cilia and Flagella CILIA – short, hairlike projections extending from the surface of the cell propel fluids across surfaces of cells FLAGELLA - move an entire cell

49. 4. Ribosomes Tiny, round, dark bodies Actual site of protein production high rRNA content Free ribosomes attached to RER

50. 5. Endoplasmic Reticulum (ER) network of folded membranes 2 Types Rough ER – extends from the nuclear envelope, studded w/ ribosomes, synthesis of secretory proteins and membrane molecules Smooth ER – extends from the RER --> network of membranous tubules, lacks ribosomes, f.a. & steroids (e.g. estrogen, testosterone) are produced, detoxification (e.g. alc, pesticides, carcinogens)

51. 5. Endoplasmic Reticulum (ER)

52. 6. Golgi Complex Stack of flattened membranous sacs Modify and package proteins secretory vesicles carries proteins and phospholipids to become part of cell membrane incorporated in lysosomes

54. 7. Lysosomes membrane-encosed vesicles, >/= 60 digestive enzymes digestion, recycling autophagy, autolysis

56. 8. Peroxisomes Sacs containing oxidase enzymes Use oxygen to detoxify harmful or poisonous substances (e.g. alcohol, formaldehyde) Disarm “free radicals” FR -> H2O2->H2O liver and kidney cells

57. 9. Proteasomes continuous destruction of unneeded , damaged or faulty proteins contain proteases

58. 10. Mitochondria powerhouse of the cell (site of ATP production) increased in: muscles, liver, kidneys

59. 3. Nucleus most prominent feature of a cell NUCLEAR ENVELOPE – separates the nucleus from the cytoplasm NUCLEAR PORES – control movement of substances NUCLEOLI – sites of assembly of ribosomes

60. 3. Nucleus GENES – hereditary units direct cellular activities arranged along chromosomes 46 chromosomes (23/parent) in a nondividing cell, chromosomes appear as diffuse granular mass --> CHROMATIN GENOME – total genetic information carried in a cell or organism

64. Protein Synthesis DNA found in genes gives instructions for making proteins 1. Transcription – DNA is copied --> RNA 2. Translation – information in RNA (attached to a ribosome) is translated into a sequence of a.a. --> protein molecule

65. Transcription occurs in the nucleus genetic info in DNA base triplets is copied into complementary sequence of CODONS in a strand of RNA (helped by RNA polymerase) PROMOTER – sequence of nucleotides in DNA where RNA polymerase attaches to TERMINATOR – sequence of nucleotides in DNA where transcription ends

66. 3 Kinds of RNA 1. Messenger RNA (mRNA ) – directs synthesis of a protein 2. Ribosomal RNA (rRNA) – joins w/ ribosomal proteins to make ribosomes 3. Transfer RNA (tRNA) – binds to an a.a. and holds it in place on a ribosome until it becomes part of a protein during translation

67. Base pairing

68. Translation mRNA attaches to ribosomes and directs protein synthesis by converting sequence of nucleotides (CODON) into a specific sequence of a.a. --> PROTEIN tRNA contains the triplet of nucleotides called ANTICODON Protein synthesis ends when ribosome reaches a STOP CODON 15 a.a./second

70. Somatic Cell Division process by which damaged, diseased or worn out cells are replaced process by which cells reproduce themselves

71. 2 Types of Cell Division 1. REPRODUCTIVE CELL DIVISION (MEIOSIS) - the process that produces gametes (sperm & oocytes) 2. SOMATIC CELL DIVISION - division of all body cells (except gametes) --> two identical cells

72. Prerequisite of somatic cell division: DNA Replication DNA – building blocks “nucleotides” Deoxyribose sugar Phosphate group Nitrogen-containing base

73. duplication of the DNA sequences that make up the genes and chromosomes --> daughter cells w/ same genes and same number of chromosomes Prerequisite of somatic cell division: DNA Replication

74. DNA Replication

75. Cell Cycle sequence of changes that a cell undergoes from the time it forms until it duplicates its contents and divides into two cells 2 MAJOR PERIODS 1. INTERPHASE – cell is not dividing 2. MITOTIC PHASE – cell is dividing

76. DNA replication occurs manufactures organelles and cytosolic components increased metabolic activity cell is growing Interphase

77. Mitotic Phase consists of: MITOSIS – nuclear division CYTOKINESIS – cytoplasmic division into 2 cells

78. PROPHASE = chromatin coil and shorten  chromosomes, bar-like bodies Chromosome = 2 strands of chromatids , held together by a buttonlike body, centromere Mitosis

79. Mitosis STAGES : METAPHASE – chromosomes cluster and align at the center (metaphase plate)

80. Mitosis STAGES: ANAPHASE – movement of chromosomes toward opposite ends of the cell

81. Mitosis STAGES: TELOPHASE – chromosomes uncoil and become chromatin again, nuclear envelope forms around each chromatin mass

82. Cytokinesis division of a cell's cytoplasm and organelles formation of cleavage furrow that extends around the center of the cell endpoint: 2 new and separate cells

84. END QUIZ NEXT MEETING!