The document summarizes key aspects of cell structure and function: - The cell membrane forms a protective barrier around the cell and is selectively permeable, allowing movement of materials in and out. - Organelles such as mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, ribosomes, and the nucleus have specialized structures and functions that allow cells to carry out essential processes. - Cells obtain energy through cellular respiration in mitochondria or fermentation in the absence of oxygen. The cell cycle and processes of mitosis and meiosis allow for cell growth and division.

1. The Cell

2. THE CELL

3. Cell membrane protective covering that surrounds the cell. Maintains cell shape Selectively permeable. Ingestion by the cells (endocytosis) Excretion by the cells (exocytosis) Takes part in cell locomotion Helps in attachment of the cells Fluid in nature; not solid

4. Functions of cell membrane

5. Functions of cell membrane

6. Composition of cell membrane Phosopholipid 25% Proteins 55% Cholesterol 13% Carbohydrates 3%

8. Cell membrane structure Phospholipid bilayer: The heads of the lipids are hydrophilic (water loving) The tails are hydrophobic (water fearing).

9. Proteins: Integral; act as *channels (pores) *carriers *enzymes Peripheral; act as enzymes Cholesterol

10. Membrane CHO (Glycocalyx) Glycoproteins / Glycolipids Gives negative charge to the cell Helps in attaching cells one to another Act as receptors

11. Cytoplasm: Structure: gel-like material found inside the cell, made of water, salts, and organic materials. Function: holds the organelles, keeps them separate

12. Cell Organelles Mitochondria: “ powerhouse” of the cell Self replicative Structure: two lipid bilayer membranes outer membrane inner membrane – shelves with attached oxidative enzymes Matrix; contains necessary enzymes Function: transform the energy in food to energy the cell can use to drive chemical reactions.

13. Mitochondria

14. Formation of ATP

15. Uses of ATP

16. Cell Organelles Endoplasmic Reticulum: Structure: tubular & flat vesicular str Interconnected with one another made of lipid bilayer along with protein Endoplasmic matrix Location: located next to the nuclear membrane and connected to it Functions: Conduction Metabolism

17. Types of ER Smooth ER: does not contain ribosomes, makes lipids, transports proteins Drugs detoxification Contain enzymes for glycogen breakdown Rough ER: contains ribosomes makes proteins

18. Cell Organelles Golgi Body: Structure: 4 or more stacked layers of thin, flat enclosed vesicles Location: near the nucleus Function: packages proteins from the ER Synthesize certain CHO hyaluronic acid & chondroitin sulfate Lysosomes/ secretory vesicles distribute them around or outside of the cell. Prominent in secretory cells

19. Formation of proteins, lipids & vesicles from ER & GA

20. Cell Organelles Ribosomes: Structure: made of RNA and proteins Function: produce proteins Location: Free in cytosol attached to the endoplasmic reticulum.

21. Lysosomes Formed from Golgi apparatus Structure: lipid bilayer Sac filled with enzymes Hydrolases Compound + water Proteins………………. a.a Glycogen……………...Glucose Lipids…………………..Fatty acid & glycerol

22. Lysosomes Intracellular digestive system Damaged cellular str. Heat, cold, chemicals Autolysis Food particles phagocytic & pinocytic vesicles Bacteria Tissue regression Lack of activity in a tissue causes the lysosomes to increase their activity

23. Lysosomes Bactericidal agents Lysozymes Dissolve the bacterial cell membrane Lysoferrin Binds iron Acid Activates hydrolases & inactivates bacterial metabolism

25. Peroxysomes Formed by self replication / SER Intracellular digestive system Oxidize poisonous subs. as alcohol Enzymes: Oxidases Oxygen + Hydrogen = Hydrogen peroxide Catalases

26. Nucleus Control center of the cell Contain DNA (genes) Protein synthesis Reproduction Nuclear envelope Double layer Outer memb continuous with ER Nuclear pores Nucleoli No membrane RNA and proteins

27. Structure of nucleus

28. Cell Organelles

29. Ameboid movement

31. Ameboid movement

32. Ameboid movement Movement of entire cells in relation to its surroundings Involves pseudopodium and ATP Mechanism formation of new cell membrane & exocytosis at one end Attachment of pseudopodium to tissues Receptor proteins Absorption of the membrane & endocytosis in mid & rear portions Detachment of receptor proteins

33. Ameboid movement Cells that exhibit ameboid motion WBC Fibroblasts Embryonic cells Control of ameboid motion Chemotaxis Positive Negative

34. Genetic control of cell functions

35. DNA structure Nucleotides Phosphoric acid Sugar deoxyribose Nitrogenous bases Purine (adenine, guanine) Pyrimidines (thymine, cytosine)

36. DNA structure

37. Significance of DNA Controls formation of proteins By “Genetic code” DNA code is transferred to an RNA code (transcription)

38. Types of RNA mRNA carries the code to cytoplasm in the form of codons complementary to DNA code tRNA transports activated amino acids to ribosomes Triplets of bases on tRNA that allows it to recognize a specific codon is anticodon rRNA forms ribosomes; str. On which protein molecules are assembled

39. Transcription Temporary separation of DNA strand (RNA Polymerase enzyme) DNA code causes formation of complementary RNA codes (codons)

40. DNA code

41. Protein synthesis Code successive “triplets” of DNA bases It controls the sequence of a.a in a protein molecule to be synthesized in cell Transcription mRNA is formed containing codons which are complementary to the DNA code process of transferring the genetic code to the RNA Mutation

42. Translation Definition Formation of proteins on the ribosomes Mechanism mRNA travels thru ribosomes Ribosomes read the codons tRNA transports a.a Protein molecule is formed

46. Movement thru the Cell Membrane Remember: The cell membrane provides support and protection for the cell. The cell membrane is made of a lipid bilayer that is selectively permeable. The lipid bilayer contains hydrophilic heads and hydrophobic tails. Proteins in the bilayer help materials pass into and out of the cell.

47. Movement thru the Cell Membrane: Diffusion Diffusion is the process of cells moving from areas of high concentration to areas of low concentration. Remember the scent diffusion lab from 7 th grade? Occurs because molecules are constantly moving. This random movement causes the molecules to become evenly spread out.

48. Movement thru the Cell Membrane: Diffusion Molecules diffuse (move from high to low concentration) until the molecules are evenly spread out. This is called equilibrium. Diffusion doesn’t stop at equilibrium, the molecules just move in equal numbers. If one molecule enters an area, another molecule leaves.

49. Movement thru the Cell Membrane: Diffusion Cells use diffusion to get substances into and out of the cell. Example: During photosynthesis, oxygen is produced inside the cell. When this happens the concentration of oxygen becomes higher inside the cell than outside and oxygen diffuses out of the cell.

50. Movement thru the Cell Membrane: Osmosis Osmosis is the diffusion of water through a membrane. Water moves into an area with low concentrations and out of areas with high concentrations. Both diffusion and osmosis are forms of passive transport (they require no energy)

51. Movement thru the Cell Membrane: Active Transport materials move from low concentration to high concentration. requires energy! Active transport Endocytosis: moving a particle into the cell Phagocytosis Pinocytosis Exocytosis: moving a particle from inside the cell to outside.

52. Mec hanism of pinocytosis

53. Movement thru the Cell Membrane: Active Transport Endocytosis Exocytosis

54. Cell Growth and Division Multicellular organisms grow because cell division increases the number of cells in them. Cells become specialized during the development of an organism. Cells that are damaged or worn out are replaced by cell division.

55. Cell Growth and Division: The Cell Cycle Interphase: The part of the cell cycle when the cell is not dividing. This is the longest phase in the cell cycle. Cells grow and go about their daily routines in this part of the cycle. DNA (genetic material) replicates.

56. Cell Growth and Division: The Cell Cycle Mitosis: the part of the cell cycle where the nucleus divides. Occurs in non-reproductive cells and produces exact copies of the parent cell. Prophase: The chromosomes condense Metaphase: The chromosomes line up in the middle of the cell. Anaphase: The chromosomes separate and are pulled to either end of the cell. Telophase: The new nuclear membrane forms. Cytokinesis: The cell splits in half.

57. Cell Growth and Division: The Cell Cycle

58. Cell Growth and Division: The Cell Cycle Meiosis: The cell division that takes place within reproductive cells. Produces cells that only have one pair of chromosomes. Meiosis produces egg and sperm cells. Before meiosis begins, the chromosomes from the parent cell are copied.

59. Cell Growth and Division: The Cell Cycle Meiosis I: Pairs of chromosomes separate Prophase I: Chromosomes pair up Metaphase I: The chromosome pairs line up in the middle of the cell. Anaphase I: Chromosome pairs are pulled apart to opposite ends of the cell Telophase I: A new cell membrane forms around the chromosomes. Cytokinesis: The cell splits into two daughter cells

60. Cell Growth and Division: The Cell Cycle Meiosis II: Chromosomes separate Prophase II: In each daughter cell, there are two copies of a chromosome. Metaphase II: Each chromosome in each daughter cell lines up in the middle of the cell. Anaphase II: Each chromosome in each daughter cell is pulled apart to opposite ends of the cells. Telophase II: A new cell membrane forms, splitting each daughter cell into two new cells. Cytokinesis: The cells divide into four new cells.

62. Cells and Energy: Respiration Most chemical reactions that take place in cells require an energy source. Mitochondria in both plant and animal cells release this energy through respiration. Respiration is the process by which oxygen (O 2 ) is combined with food (sugar) to release energy. Before respiration can occur in the mitochondria, sugar in the cytoplasm is broken down. This releases a small amount of energy.

63. Cells and Energy: Respiration If oxygen is not present in the environment, anaerobic respiration takes place. Fermentation : the process of cells releasing energy without oxygen. There are two types of fermentation: Alcoholic fermentation Lactic Acid fermentation

64. Cells and Energy: Respiration If oxygen is present in the environment, aerobic respiration can occur. After sugar in the cytoplasm is broken down, the smaller pieces travel to the mitochondria and are broken down even more. This produces energy, called ATP (adenosine triphosphate). Oxygen also enters the mitochondria and combines hydrogen to produce water. Glucose + Oxygen  Energy + Water + CO 2

65. Cells and Energy: Photosynthesis Plant cells gain energy through the process of photosynthesis . Photosynthesis takes place in chloroplasts. Chloroplasts contain chlorophyll, the green pigment that captures sunlight for the plant. Carbon dioxide (CO 2 ) and water enter the chloroplasts while the chlorophyll captures sunlight. The energy from the sunlight changes the CO2 and water into oxygen and sugar. CO 2 + Water + Energy  Oxygen + Sugar