Download Cell Biology

Cell Biology
Contents:
1. Cell structure
2. Chemical building blocks of life
3. Membranes
4. Energy and Metabolism
5. Harvesting of energy
6. DNA- genetic material
7. How cells divide
8. Sexual reproduction and meiosis
9. Mendelian genetics
10. Chromosomal basis of inheritance
11. Genes and how they work
12. Control of gene expression
13. Biotechnology and genomics
Cell Structure:
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Fundamental properties of life
o Cellular organisation
o Growth
o Ordered complexity
o Development
o Energy utilisation
o Reproduction
o Homeostasis
o Evolutionary adaptation
o Sensitivity
 Cell theory
o All orgs composed of one or more cells
o Metabolism occurs within cells
o Cells contain hereditary info
o Cell is basic unit of organisation
o Cells arise from pre-existing cells
o Hooker 1665- discovered cells
o Van Leeuwenhoek 1674- discovered animalcules (protists)
o Brown 1831- discovered nucleus
o Schleiden 1838- all plants composed of cells
o Schwann 1839- all animals and plants composed of cells
 Cell size
o Diffusion affected by conc grad, distance, temp, SA:Vol
o SA:Vol
 Limits size (otherwise would be large unicellular orgs)
 Too small (ratio), can’t keep cell alive
o pK: 1-5μm diameter
o eK: 10-100μm diameter
o cylindrical cell shape
o Human eye: frog eggs, paramecium
o Light microscope: paramecium, ova, RBC, pK, chloroplast, mitochondrion
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o Electron microscope: virus, ribosome, protein, amino acid
Prokaryotes
o Cell: lacks nucleus, lacks organelles, Bacteria and Archea
o Flagellum: made of flagellin protein, consists of hook and filament that rotates.
Protein gradient (higher conc inside ring) makes spin. Not all pK’s have flagella
Photosynthetic cyanobacterium
Plasma membrane
o Regulates uptake and release (pump) through channels/pores
o Interfaces with environment
Eukaryotes- compartmentalisation
o Animal cell
o Plant cell
 Adjacent walls, cells stuck together, no centriole
More organelles than shown in diagrams
Nucleus
o Double membrane (inner and out)
o Nuclear pores: IN- proteins, messenger molecules; OUT- RNA
o Storage of genetic material
o Regulation of development and metabolism
o Transcription of DNA sequence
o Production of RNA
o Nucleolus- synthesis of rRNA
Ribosome
o Protein synthesis
o Translation of mRNA to amino acid sequence of polypeptide
o Some attached to ER, some free
o Large and small subunit
Endoplasmic Reticulum
o Lipid synthesis
o Membrane proteins
o Rough (ribosomes attached) and smooth
o Proteins can go into rough, then move to smooth
Golgi apparatus
o Packaging
o Vesicle info
o Vesicle- membrane bond particle, packages stuff inside
o Golgi made of vesicles (released by ER)
Endomembrane system
o Protein- synthesis, transport and release
Lysosomes
o Vesicles containing digestive enzymes to break down- carbs, lipids, nucleic acids,
proteins, organelles
o Break down and recycle old/damaged organelles
o Ingest food particles
o Food vacuoles- fuse with lysosomes, e.g. paramecium
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Peroxisome
o Microbody breaks down fatty acids by oxidation
o Hydrogen peroxide
o Enzymes organised into crystalline structure
Mitochondrion
o Double membrane- endosymbiosis
o Respiration
o Sugar metabolism
o ATP generation energy
Chloroplast
o Double membrane
o Photosynthesis
o Carbon fixation
o Starch synthesis
o Fatty acid synthesis
Endosymbiosis
o Protobacterium and cyanobacterium ingested by unknown archaeon or
bacterium-argument over which was first
o Archaeon nucleus
Cytoskeleton
o Structure, support
o Size: actin intermediatemicrotubules
o Transport- moved along microtubules
Molecular motor
o Dynactin complex- connector molecule
o Dynein- ATP as energy source
o Transports vesicle
Centriole
o Organise microtubules
o Mitosis
Flagella
o 9+2 microtubule arrangement- 2 in middle, 9 pairs around outside doesn’t
change/move
o Cilia made of same material as flagella, just shorter
Extracellular matrix
o Animals
o Fibrous proteins
Cell junctions
o Tight and anchoring- bind cells together
o Binds actin in one cell to actin in other cell
o Tight junction- actin
o Anchoring junction- intermediate filaments
o Communicating junction- chemicals to communicate between cells, chemical and
electrical gap junctions
Plant cell walls
o Middle lamella
o Peptin- glue
o Plasmodesmata- connecting junctions
 Central tubule connects cells
Chemical building blocks of life:
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Fundamental properties of life- ordered complexity, molecules, structurefunction
Chemistry dictates biology
o Orgs  cells molecules atoms subatomic particlesprotons, neutrons,
electrons
o Molecules determine size, structure and function
o Understand how molecules interact understand how cells function
Chemical bonds
o Atoms form bonds
 Share electrons- stable structures
 Attraction of opposites- electrical charges
o Oxidation and reduction
 LEO- Loss of Electrons = Oxidation
 GER- Gain of Electrons = Reduction
o Valence electrons (electrons going to be shared or lost- outer shell),
electronegativity, octet (rule of 8), inert gases
o Ionic, covalent, polar covalent, hydrogen bonds
o Van der Waals forces- tiny force, not as strong as hydrogen, very close together,
make big molecules stable
o Hydrophobic interactions- parts of molecules stay away from water/hydrogen
bonding
Water
o Covalent bonds, electronegativity, partial charges, polar molecule hydrogen
bonds
o Aqueous environment for metabolism- 70% of cell
Carbon
o Framework of biological molecules
o Bonded to C, H, O, P, S
o Up to 4 covalent bonds
o Hydrocarbons- C + H, nonpolar
o Biological molecules
 Hydroxyl, carboxyl, carbonyl, amino, sulfhydryl, phosphate, methyl
 Functional groups add chemical properties
o Atoms in body: H-63%, O-25%, C-9%, N-1.5%
o Molecules by mass in cells- 65% water, 18% proteins, 12% lipids
Isomers
o Compounds with same molecular formula, but rearrange parts
o Structural isomers- different C skeleton
o Stereoisomers- same C skeleton
 Differ in how groups attached
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Enantiomers- mirror image, chiralD (right) sugars, L (left) amino acids
 Affects refraction when light shone through crystal
Macromolecules
o Cellular structurepolymer monomer (complexsimple)
o Carb- starch grains in chloroplaststarchmonosaccharide
o Nucleic acid- chromosome DNA Strand nucleotide
o Protein- intermediate filamentpolypeptide amino acid
o Lipid- fat droplets in celltriglyceride fatty acid
Synthesis and degradation
o Dehydration= condensation
 Formation of large molecules by removal of water
 Monomers are joined to form polymers
 Take 2 H and O out of molecules to take out water
o Hydrolysis
 Breakdown of large molecules by addition of water
 Polymers are broken down to monomers
Carbs:
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Carbon: hydrogen: oxygen 1:2:1
Empirical formula: (CH2O)n
C—H: covalent bonds
o Carbs- energy storage
o Sugars, starch, glucose
Monosaccharides- sugars
o Simplest carbs
o 3 carbon sugars- glyceraldehyde
o 5 carbon sugars- ribose, deoxyribose
o 6 carbon sugars- glucose (C6H1206)  forms ring inside aqueous cell (drawn as
ring as opposed to linear molecule)
 Fructose- structural isomer
 Galactose- stereoisomer
o Enzymes distinguish- structural isomers, stereoisomers
Disaccharides
o 2 monosaccharides linked- dehydration synthesis
o Sugar transport or energy storage- sucrose, maltose, lactose
Polysaccharides
o Long chains of monosaccharides- dehydration synthesis
o Energy storage: starch plants, glycogen animals
o Structural support: cellulose plants, chitin arthropods, fungi
Nucleic acids:
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Polymer- nucleic acids
Monomers- nucleotides
o Sugar + phosphate + nitrogenous base
o Sugar: DNAdeoxyribose, RNA ribose