Kim
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- Cell theory
- 1. building blocks of all life 2. all cells from division of preexisting cells 3. smallest units that perform all vital physiological functions 4. ea. cell homeostasis 5. organize & coordinate with other cells to function as a unit
- cytology
- study of cellular structure & function
- somatic cells
- most cells are somatic: diploid: 46 chromosomes
- sex cells
- haploid: 23 chromosomes
- cytoplasm vs. cytosol
- cytoplasm is everything in Cell Membrane (organelles, etc.) EXCEPT nucleus: cytosol is liquid portion of cytoplasm
- cell membrane
- outer boundary of the cell; functions: 1. isolation 2. regulate exchange 3. sensitivity 4. structural support
- cell membrane structure
- phosopholipid bilayer membrane proteins, integral vs. peripheral: most are transmembrane membrane carbohydrates or glycocalyx
- Functions of membrane protein
- 1. anchoring proteins 2. recognizer proteins 3. enzymes 4. receptor proteins 5. carrier proteins 6. channel proteins
- Membane carbohydrates: glycocalyx
- part of phosopholipid or on a protein Function: lube & protect; anchoring & locomation: specificity in binding; recognition
- Cholesterol
- provides stability for cell
- passive vs. active transport
- no energy needed vs. ATP expended
- Diffusion
- passive process: net movement of materials from high to low concentration, until gradient has been eliminated
- factors affecting diffusion
- molecule size, gradient size, distance, temperature, charge
- osmosis
- diffusion of water across sel. permeable membrane
- osmotic pressure
- pulling pressure, from high level of water to low level of water
- hydrostatic
- opposite of osmotic: pushes against fluid
- Filtration
- hydrostatic pressure forces water cross a membrane: pushes out nutrients, pulls in fluid: capillary beds, kidneys
- Carrier mediated transport
- substances that need to be carried by a protein
- 2 types of carrier mediated transport
- Facillitated Diffusion & Active Transport
- Facillitated diffusion
- molecules bind to receptor sites; shape of protein changes; homones (like insulin) may be req. to help When carriers are saturated--rate of transport cannot increase
- Active transport
- req. ATP to move ions or molecules across membrane...doesn't req. conc. gradient
- Ion pumps transport...
- ...K, Ca, Na, Mg (in countertransport)
- Transport Processes
- 1. Diffusion 2. Osmosis 3. Filtration 4. Carrier Mediated Transport 5. Vesicular Transport
- Vesicular transport
- vesicles move thing in or out via endocytosis & exocytosis: BULK transport
- 3 types of endocytosis
- 1. Receptor mediated (with ligands) 2. Pinocytosis--cell drinking 3. Phagocytosis--cell eating
- Receptor mediated
- ligands trigger receptors & when pkts are full pinches in to form coated vesicles
- Pinocytosis
- similar to Receptor mediated, but no ligands involved
- Phagocytosis
- 1.pseudopodia surround object 2. membranes fuse to form phagosome 3. fuses with lysosomes 4. digest
- Exocytosis
- reverse of endocytosis: excretion out of the cell
- Transmembrane potential
- difference in electrical charge across cell membrane: -70 millivolts in neurons; -85 mV in skeletal
- Cell life cycle
- Interphase (G1,S, G2, some G3) M phase: Mitosis (PMAT) Cytokinesis
- Stages of Mitosis
- Prophase Metaphase Anaphase Telophase (into cytokinesis)
- Prophase
- nuclear envelope disappears; chromatin coils & b/c chromosomes Centrioles move to poles; spindle apparatus forms
- Metaphase
- chromosomes line up with centromeres on the equator
- Anaphase
- centromeres break; chromosomes go to opposite ends of cell
- Telephase
- spindles disappear; centrioles go bk. towards nucleus; chromsomes uncoil; nuclear envelope reforms
- cytokinesis
- division of cytoplasm & splitting of cell along cleavage furrow
- Interphase
- G1: cells prep for division: start duplicating things S:Replication of DNA G2: Centriole replication & protein synthesis
- DNA
- provides info for the formation of structural and functional proteins and enzymes
- mRNA
- copy of a single gene goes out to a ribosome: nucleotide to amino acid to a protein
- Cytoskeleton: Structure & Function
- Structure:Microtubules; microfilaments; thick filaments; intermediate filaments Func: Maintain cell shape & assist w/intra or extra cellular movement
- Microvilli: Structure & Function
- Cellular extensions of the membrane Func: increase surface area for absorption
- Cilia: Structure & Function
- Structure: long slender extensions of cell membrane with microtubules Func: beat rhythmically to move fluids across the surface
- Centriole
- little bundles of microtubules: Func: Acts as anchor during mitosis (neurons lack tubules)
- Ribosome
- Globular protein Func: involved in translation of mRNA to produce protein: protein synthesis
- Mitochondria
- Structure: Double membrane bound organelle; smooth capsular outside/maze inside Func: produces energy in form of ATP
- Rough Endoplasmic Reticulum
- "swiss cheese" with ribosomes on outside: Func: transport & modify proteins
- Smooth Endoplasmic recticulum
- swiss cheese again: lipid synthesis
- Golgi apparatus
- stacks of flattened membranes, with hollows,like pitas (cisternae) Func: "post office" packages & delivers excretions, secretions & CM renewal vesicles
- Lysosome
- vesicles containing digestive enzymes Func: breakdown materials
- Peroxisomes
- vesicle Func: hydrogen peroxide cycle
- Nucleus
- enclosed in nuclear envelope & contains chromosomes Func: Control Center
- Nucleolus
- Dark spot in nucleus Func: production of ribosomes