Thursday, October 8, 2009

Chapter six: A tour of the cell

Q1: What's cell's component?
A1: prokaryotic: capsule, cell wall, plasma membrane, cytoplasm, DNA, ribosomes
eukaryotic: cell wall, membrane, cytoplasm, DNA, ribosome, cytoskeleton, nucleus, ER, golgi apparatus, lysosome, vacuoles and vesicles, peroxisome, mitochodria, chloroplast
Q2: what's cell's function?
A2: passing genetic information, regulation, metabolism, etc, cells are basic units of all living things.
Q3: how do people study the tiny cell?
A3: by improving and using microscope.

Five Facts:
1. to study cells, biologists use microscopes and the tools of biochemistry.
2. eukaryotic cells have internal membrane that compartmentalize
3. the endomembrane system regulates protein traffic and perfroms metabolic functions in the cell
4. the cytoskeleton is a network of fibers that organizes structures and activities in the cell
5. extracellular components and connections between cells help coordinate cellular activies.

Figure


chloroplast has bilayer, outer membrane and inner membrane. Between these two is the intermembrane space. The inner membrane is convoluted so that it has more surface. The folding of inner membrane is called cristae. Mitochondrial matrix is enclosed by the inner membrane. Free ribosomes are in the mitochondrial matrix.

Summary:
Scientists use light microscope to study most cells and bacterias and electron microscope to study bacteria, viruses, macromolecules, and atoms.Cytology is the study of cell structure. Both prokaryotic and eukaryotic have plasma membrane, cytosol, chromosomes, ribosome, ad cytoplasm. Prokaryotic cell has nucleoid instead of nucleus.
The nucleus contains most of the genes in the eukaryotic cell. Nuclear envelope encloses the nucleus, separating its contents form the cytoplasm. It is a double membrane, inner membrane supported by a protein matrix which gives the shape to the nucleus. Nucleolus storage ribosomes. chromatin form chromosomes, a complex of protein and DNA. Free ribosome in cytosol; bound ribosome in ER. Endoplasmic reticulum fold sheet or tubes of membranes. Smooth ER lacks ribosome and uses for lipid synthesis, carbohydrate storage, and detoxification of poisons. Rough ER has ribosomes, adn makes secretory proteins. Golgi apparatus package products of ER for transport. It has vesicles. Lysosome is digestive compartments. It can so phagocytosis and antophagy. Vacuoles has single membrane in plant's cell. Mitochondria are the sites if cellular respiration, the metablic process that generates ATP by extracting energy from sugarsm fats, and other fuels with help of oxygen; Chloroplasts found in plants and algae, are the sites of photosynthesis. Peroxisome use hydrogen peroxide.Cytoskeleton help cell strucure, shape, movement, and division. Three types: microtubules, microfilaments, and intermediate filaments. Cell wall supports and protects cell. it has primary and secondary walls. middle lamella connect cells. Extracellular matrix helps cells together. Intercellular junction in plant is plasmodesmata. in animals are tight junction, desmosome, and gap junction.

Key term:


  1. cell fractionation-The disruption of a cell and separation of its parts by centrifugation.

  2. scanning electron microscope (SEM)-A microscope that uses an electron beam to scan the surface of a sample to study details of its topography.

  3. transmission electron microscope (TEM)-A microscope that passes an electron beam through very thin sections and is primarily used to study the internal ultrastructure of cells.

  4. thylakoid-A flattened membranous sac inside a chloroplast. Thylakoids exist in an interconnected system in the chloroplast and contain the molecular “machinery” used to convert light energy to chemical energy.

  5. stroma-Within the chloroplast, the dense fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water.

  6. phagocytosis-A type of endocytosis in which large particulate substances are taken up by a cell. It is carried out by some protists and by certain immune cells of animals (in mammals, mainly macrophages, neutrophils, and dendritic cells).

  7. integrin-in animal cells, a transmembrane receptor protein that interconnects the extracellular matrix and the cytoskeleton.

  8. dynein-In cilia and flagella, a large contractile protein extending from one microtubule doublet to the adjacent doublet. ATP hydrolysis drives changes in dynein shape that lead to bending of cilia and flagella.

  9. collagen-A glycoprotein in the extracellular matrix of animal cells that forms strong fibers, found extensively in connective tissue and bone; the most abundant protein in the animal kingdom.

  10. basal body-A eukaryotic cell structure consisting of a 9 + 0 arrangement of microtubule triplets. The basal body may organize the microtubule assembly of a cilium or flagellum and is structurally very similar to a centriole.

Video:


http://www.youtube.com/watch?v=GW0lqf4Fqpg&feature=related


cell membrane

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