第二章 生命的基本单位 ---- 细胞 The basic unit of life----cell

1. 第二章 生命的基本单位----细胞The basic unit of life----cell southeast university genetic center

2. 第一节 细胞的基本特性1.1 The basic conception of cell 1.2 The size and shape of cell1.3 The prokaryotic and eukaryotic cell第二节 细胞的物质基础2.1 Inorganic substances2.2 Macromolecular components of Cells

3. 1.1 The basic conception of cell Robert Hooke observed cells of a cork tree through a primitive microscope(1665)

4. How to understand cell is the basic unit Of life structure and function?

5. A. The Cell Is The Structural Unit Of Life, All Organisms Is Made Up Of Cells.

6. B. The Cell Is The Functional Unit Of Organisms. All Metabolic Activity Is Based On Cells.

7. C. The Cell Is The Foundation Of Reproduce and The Bridge Of Inheritance.

8. D. The cell is the growing and developing basis of life

9. 1.2The size and shape of cell 细胞的大小、形态

10. Morphological Diversity

11. Rod-Shaped Bacterium, hemorrhagic E. coli (SEM x22,810)

12. 1.3 The prokaryotic and eukaryotic cell

13. Differences between Prokaryotes and Eukaryotes

15. 第二节 细胞的物质基础The material basis of cell 2.1 Inorganic substances ( 无机物） • 水(water) • 无机盐(inorganic salt)和离子(ion) • 有机小分子(small organic molecules) 1.糖(sugar) 2.脂肪酸(fatty acid) 3.氨基酸(amino acid) 4.核苷酸(nucleotide)

16. 第二节 细胞的物质基础The material basis of cell 2.2 Macromolecular components of Cells (生物大分子) • 2.2.1Carbohydrates Are Energy Sources for Cells • 2.2.2Lipids Are Components of Cell Membranes • 2.2.3Proteins Are Large Polymers of Amino Acids • 2.2.4Nucleic Acids Are the Principal Informational Molecules

17. 2.2.1 糖是细胞的能量来源Carbohydrates Are Energy Sources for Cells • Monosaccharides (single unit sugars) • Disaccharides (two unit sugars) • Oligosaccharides(3-50 unit sugars) • Polysaccharides (hundreds or thousands unit sugars)

18. 单糖　 simple sugars

19. Formation of a disaccharide by condensation and structure of two common disaccharides

20. Three important disaccharide Maltose(麦芽糖) condense by two glucose units Lactose(乳糖) condense by galactose and glucose Sucrose(蔗糖) condense by fructose and glucose

21. Polysaccharides：Images of starch (top), glycogen (middle), and cellulose (bottom)

22. Glycogen Starch Cellulose

23. 2.2.2 脂是细胞膜的主要成分Lipids Are Components of Cell Membranes Lipids have three main roles in cells: • Energy Storage Fatty Acids Are Stored In The Form Of Fats, Which Consist Of Three Fatty Acids Linked To A Glycerol Molecule. • Components Of Cell Membranes Phospholipids ; Glycolipids ; Cholesterol • Messenger Molecules Most Of Them Are Derivatives Of Cholesterol ,For Example Cortisol(甾醇） and Testosterone（睾丸激素）.

24. Phospholipid Saturated and unsaturate fatty acids steroids

25. 磷脂(Phospholipid)

26. Lipids Are Components of Cell Membranes

27. 2.2.3 蛋白质是氨基酸的聚合物Proteins Are Large Polymers of Amino Acids • Amino acids • Peptide bond and polypeptides • Protein functions

28. Structure of an amino acid Each Amino Acid Consists Of • A Carboxyl Group (COO-), • An Amino Group (NH3+) • A Hydrogen Atom • Distinctive Side Chain: unique to each type of Amino Acid

29. Amino acids

30. Formation of a peptide bond in a dipeptide

31. Four levels of protein structure

32. 蛋白质一级结构 Protein structure －primary Amino acid sequence

33. 蛋白质二级结构Protein structure －Secondary • α-helix: • right-handed • 3.6 aa per turn • hydrogen bond • N-H···O=C β -sheet:hydrogen bonding of the peptide bond N-H and C=O groups to the complementary groups of another section of the polypeptide chain.

34. Secondary structure β-pleated sheet α-helix

35. 蛋白质三级结构Protein structure －tertiary The different sections ofa-helix, b-sheet, other minor secondary structureandconnecting loopsof a polypeptide fold in three dimensions

36. 蛋白质四级结构Protein structure －quaternary Many proteins are composed oftwo or more polypeptide chains (subunits).These subunits may be identical or different. The same forces hold these subunits together. a1-yellow; b1-light blue; a2-green; b2-dark blue; heme-red

37. Quaternary structure of hemoglobin Hemoglobin (血色素四级结构)

38. The functions of protein

39. 2.2.4 核酸为主要的信息分子Nucleic Acids Are the Principal Informational Molecules • Nucleoside and nucleotide Two forms of nucleic acid • RNA( ribonucleic acid) • DNA (deoxyribonucleic acid)

40. phosphate base pentose Nucleoside and nucleotide • A mononucleotide • One Nitrogen-containing Base • One Pentose Sugar • One Phosphate Residue Derived From phosphoric acid • no phosphate group present the sugar-base combination is called nucleoside. One to Three A T G C U OH

41. Comparison of bases, nucleosides and nucleotides

42. 碱基 Nitrogenous bases Bicyclic purines: Monocyclic pyrimidine: Thymine (T) is 5-methyluracil (U)

43. 核苷 (Nucleosides) In nucleic acids, the bases are covalently attached to the 1’ position of a pentose sugar ring, to form anucleoside Glycosidic bond R Ribose or 2’-deoxyribose Adenosine, guanosine, cytidine, thymidine, uridine

44. 核苷酸(Nucleotides) A nucleotide is a nucleoside with one or more phosphate groups bound covalently to 5’-position. one to three phosphates may be attached. Phosphate diester bonds Deoxynucleotides (deoxyribose containing) Ribonucleotides (ribose containing)

45. DNA/RNA sequence: From 5’ end to 3’ end Example: 5’-TCAGGCTA-3’ = TCAGGCTA Nucleotides chain

46. DNA双螺旋(DNA double helix) Watson and Crick,1953 • Antiparellel • Base pairing: hydrogen bonding that holds two strands together • Sugar-phosphate backbones, negativelycharged:outside • bases:inside

47. Watson and Crick

48. A-T G-C 碱基通过氢键配对Base pairing via hydrogen bonds Hydrogen bonds Hydrogen bonds

49. Double helix • B form: • Right-handed • 10 base pairs/turn • 3.4 nm/turn • Diameter: 2.0nm Small groove large groove

50. A: 11 bases/turn, Right-handed,2.6nm Z: 12 bases/turn, left-handed helical, one groove