1. Cells and macromolecules
Section A
Cells and macromolecules
Protein
DNA

2. A1 Cellular classification
A2 Subcellular organelles
A3 Macromolecules
A4 Large macromolecular Assemblies

3. A1 Cellular classification
A1-1 Eubacteria
A1-2 Archaea
A1-3 Eukaryotes
A1-4 Cellular differentiation

4. Prokaryotes
原核细胞
Eukaryotes
真核细胞
Eubacteria 真细菌
Archaea 古细菌

5. A1-1 Eubacteria
The Eubacteria are one of two subdivisions of the prokaryotes.

6. A1-1 Eubacteria
Cell wall: to prevent cell lysis in environments of low osmolarity
Plasma membrane: lipid bilayer and embedded proteins for small molecule exchange
Genetic materials: nucleiod (single and circular chromosome), plasmid
Ribosmes: protein synthesis machinery
Pili: to allow the cell to attach to other cells and surfaces
Flagella: whose rotating motion allows the cell to swim

7. A1-1 Eubacteria Escherichia. coli Mycoplasma genitalium
E.coli has a genome size of 4600 kb, which is sufficient genetic information for about proteins.
Mycoplasma genitalium
It has only 580 kb of DNA and encodes just 470 proteins.

8. A1-2 Archaea The second subdivision of the prokaryotes
Structurally, they are similar to eubacteria
The display some unusual biochemical

9. A1-3 Eukaryotes
Eukaryotes are defined by their possession of membrane-enclosed organelles with specialized metabolic function.
Eukaryotic cells tend to be larger than prokaryotes.
Eukaryotes are classified taxonomically into four kingdoms: animals, plants, fungi and protists.

10. A1-3 Eukaryotes Organelles Cytoskeleton Genetic system
Controls the shape and movement of the cell
Organizes some metabolic functions
Genetic system

11. 1-10 mm, no distinct subcellular organelles, pili, flagella 10-100 mm,
Prokaryotes
Eukaryotes
Eubacteria
Archaea
Structural features
1-10 mm, no distinct subcellular organelles, pili, flagella
mm,
Organelles
Biochemistry
rRNA molecules are different among these kingdoms
Ester linkage
Ether linkage
Energy production, metabolism
Replication, transcription and translation
Differentiation
Formation of spores
Embryonic cell differentiation

12. Phylogenetic tree determined by rRNA sequence comparisons

13. A1-4 Cellular differentiation
Definition: The daughter cells change their patterns of gene expression to become functionally different from the parent cell after cell division.
The main molecular reason: change of the genes being transcribed, but not that of the DNA content.
Regulated by developmental control genes, mutations in these genes result in abnormal body plans.

14. A1-4 Cellular differentiation
Spore formation among prokaryotes and lower eukaryotes

15. A1-4 Cellular differentiation
Embryonic cell differentiate into highly specialized cells among higher eukaryotes.
tadpole

16. A2 Subcellular organelles
A2-1 Nuclei
A2-2 Mitochondria and chloroplasts
A2-3 Endoplasmic reticulum
A2-4 Microbodies
A2-5 Organelle isolation

17. RNA transcription & processing
A2-1 Nuclei
Nuclei: The membrance-bound nucleus contains the bulk of the cellular DNA in multiple chromosomes.
DNA replication
RNA transcription & processing
Ribosome assembly

18. A2-2 Mitochondria
Oxidation of nutrients to genetate energy in the form of adenosine 5’-triphosphate(ATP).
Main function: cellular respiration/ATP production via oxidative phosphorylation

19. A2-2 Chloroplasts
The chloroplasts of plants are the site of photosynthesis, the light-dependent assimilation of CO2 and water to form carbohydrates and oxygen.

20. A2-3 Endoplasmic reticulum
The endoplasmic reticulum is an extensive membrane system within the cytoplasm and is continuous with the nuclear envelope.
Two forms are visible in most cells.
Smooth endoplasmic reticulum
Rough endoplasmic reticulum

21. A2-3 Endoplasmic reticulum
The rough endoplasmic reticulum is so-called because of the presence of many ribosomes. These ribosomes specifically synthesize proteins intended for secretion by the cell or those destined for the plasma membrane or certain organelles.

22. A2-3 Endoplasmic reticulum
The Smooth endoplasmic reticulum carries many membrane-bound enzymes, including those involved in the biosynthesis of certain lipids and the oxidation and detoxificatin of foreign compounds such as drugs.

23. A2-4 Microbodies
Lysosomes: Contain a variety of digestive enzymes capable of degrading proteins, nucleic acids, lipids and carbohydrates.
Peroxisomes: Confine highly reactive free radicals and hydrogen peroxide.
Glyoxysomes: Carry out the reactions of the glyoxylate cycle.

24. A2-5 Organelle isolation
Equilibrium centrifugation
Rate zonal centrifugation
Differential centrifugation
To call the parameter which characterizes the movement of the particle at the centrifugal force place.

25. A3 Macromolecules
A3-1 Macromolecules
A3-2 Complex macromolecules

26. A3-1 Macromolecules Proteins
Proteins are polymers of amino acids linked together by peptide bonds.

27. A3-1 Macromolecules Nucleic acids
Nucleic acids are polymers of nucleotides.

28. A3-1 Macromolecules
Polysaccharides are polymers of simple sugars covalently linked by glycosidic bonds.

29. A3-1 Macromolecules Lipids
individual lipids are not strictly macromolecules, large lipid molecules are built up from small monomeric units and involved in many macromolecule assembly

30. A3-2 Complex macromolecules
Many macromolecules contain covalent or noncovalent associations of more than one of the major classes of large biomolecules, which can greatly increase the functionality or structural capabilities of the complex.

31. A3-2 Complex macromolecules
Nucleoproteins
Associations of nucleic acid and protein
telomerase / ribonuclease P
Glycoproteins
Contain both protein and carbohydraty components
They are important components of cell membranes and mediate cell-cell recognition.
Proteoglycans / Mucoproteins
Large complexes of protein and mucopolysaccharide Found in bacterial cell walls and in the extracellular space in connective tissue

32. A3-2 Complex macromolecules
Lipid-linked proteins
Have a covalently attached lipid componemt. This groups serve to anchor the proteins in membranes through hydrophobic interactions with the membrance lipids and also promote protein-protein association.
Glycolipids
Covalently linked lipid and carbohydrate include cerebrosides and gangliosides. Abundant in the membrans of brain and nerve cells
Lipoproteins
The lipids and proteins are linked noncovalently
Lipid transport

33. A4 Large macromolecular Assemblies
A4-1 Protein complexes
A4-2 Nucleoprotein
A4-3 Membranes
A4-4 Noncovalent interactions

34. A4-1 Protein complexes
The eukaryotic cytoskeleton consists of various protein complexes: Microtubules
Microfilaments
Intermediate filaments

35. A4-2 Nulceoprotein
Nucleoproteins comprise both nucleic acid and protein.
Ribosomes are the large cytoplasmic ribonucleoprotein.

36. A4-2 Nulceoprotein Chromatin: deoxyribonucleoprotein consisting
of DNA and histones to form a repeating unit called nucleosome
Viruses:protein capsid + RNA or DNA
Telomerase: replicating the ends of eukaryotic chromosomes. RNA acts as the replication template, and protein catalyzes the reaction

37. A4-3 Membranes
peripheral transmembrane protein integral transmembrane protein transmembrane protein

38. A4-4 Noncovalent interactions
Charge –charge
Charge –charge interactions operate between ionizable groups of opposite charge at physiological pH.
Charge –dipole/ dipole -dipole Charge –dipole form when either or both of the participants is a dipole due to the asymmetric distribution of charge in the molecule.
Dispersion force/ hydrophobic interaction
Transient dipoles arising from the motion of their electrons.

39. A4-4 Noncovalent interactions
(偶极)
(uncharged molecules)

40. A4-4 Noncovalent interactions
Van der waals forces
Noncovalent associations between electrically neutral molecules.
Hydrogen bonds
Form between a covalently bonded hydrogen atom on a donor group and a pair of nonbonding electrons on an acceptor group.