Week 2: The Cell Flashcards
What are the 4 components in the cell theory
- cells are the building blocks of all organisms
-all cells come from the division of prexisiting cells - cells are the smallest unists that perform all vital physiological functions
- each cell maintains homeostasis at the cellular level
What are the 5 functions of the plasma membrane
- physical isolation : barrier
- regulation of exchange with the environment: ions and nutrient enter, wastes elimianted/cellular prods released
- sensitivity to environment: extracellular fluid composition and chem signals
- structural support: anchor cells+tissues
Describe the strucuture of the plasma membrane
- a phospholipid bilayer
- hydrophillic heads face outwards toward water envionrments
- hydrophobic fatty acid tails- inside membrane
- barrier to ions and water soluble compounds
8 types of membrane proteins
- integral(inside)
- peripheral(inside/or outer)
- achoring(stabilizers-inside/out of structures)
- recognition(identifiers-label own cells and outside cells)
- enzymes(catalyze reaactions)
- receptor(bind and respond to ligands(ions/hormones)
- carrier(transport specific solutes thru)
- channels(regulate water flow+solutes passing thru membrane, open or close to regulate passage of subtances)
3 types of membrane carbohydrates
- proteogylycans, glycoproteins,glycolipids
- extend outside of membrane
- form sticky sugar coat(glycocalyx)
4 Functions of glycocalyx
- lubrication+protextion
-anchoring+locomotion)
-specifity in binding to receptors - recognition(immune response)
Describe the structure of cytoplasm
- contains all material inside the cell+cytosol(intracellular fluid)
- nutrients,ions,proteins,waste products (dissolved)
- high protein and potassium lvls
- low carbs,lipid.amino acid, Na+ lvl
Describe the two types of organelles, and 7,5 examples
- nonmembranous
-> no membrane - direct contact w cytosol
- cytoskeleton, centroiles,ribosomes,proteasomes,microvilli,cilia,flagella
-membranous
->isolated from cytosol by plasma membrane
->endoplasmic reticulum, golgi apparatus, lyosoymes, peroxisomes, mitochondria
What are Cytoskeletons
structural proteins for shape and strength
- micro fillaments, intermediate fillmaents, microtublets
What are microfillaments
- thin filaments made of protein actin
- provide mechanical strength
- interact w proteins to adjust consistency of cytosol
- and w thick myosin filaments for muscle contraction
What are intermediate filllaments
- mid sized between microfillaments and microtubules
- durable
- strengthen the cell+maintain shape
- stabilize organelles position
- stabilize cell position
What are microtubules
- large hollow tubes of tubulin proteins
- attach to centrosome
- strengthen cell+Anchor organelles
- change cell shape
- move organelles w help of motor proteins
- form spindle apparatus to distribute chromosomes
- form centrioles and cilia of organelles
What are microvilli
- increase surface area for absorption
- attach to cytoskeleton
What are centrioles
- form spindle apparatus during cell divison
- surrounded by centrosomes - cytoplasm nes to nucleus
What is cillia
- extensions of plasma membrane
- move fluids across cell surface
- primary cillium=nonmotile-
-> senses environmental stimuli - moitle cilia cells line respiratory+reproductive tracts
->microtubulus in cilia anchored to a basal body - flagellum is tail-like extension of cell membrane
Structure and function of ribosomes
- organlles that synthesize proteins
- composed of small+large ribosomal subunits
->contain rRNa - free ribsome in cytoplasm=manafacture proteins->enter cytosol
- fixed ribsomes attach to ER-manafacture proteins->enter ER for packaging
Function of proteasomes
- contain enzymes (proteases)
- dissassemble damaged proteins for recylcing
2 types of endoplasmic reticulum, and 4 functions
- contains storage chambers = cisternae
- smooth+rough(SER+RER)
- synthesis of proteins,carbs,lipids
- storage of synthesised molecules and materials
- transport of materials within the er
- detoxification of drugs or toxins
What is smooth ER and 4 functions
- no ribosomes attached
- synthesizes
-> phospholipids+cholestorol(for membranes)
->steriod hormones(for reproductive systems)
->glycerides(storage in liver+fat cells)
->glycogen(storage in mucscle_liver cells)
what is rough ER and 3 functions
- surface covered w ribosomes
- active in protein nd glycoprotein synthesis
- folds proteins in secondary+teritary strcutures
- encloses products in transport vesicles for delivery to golgi apparitus
what are golgi apparitus and 4 functions
- where vesicles enter forming face, exit maturing face
- modifies and packages secretions(hormones,enzymes)for release from cell
- adds or removes carbs to or from proteins
- renews or modifies plasma membrane
- packages special enzymes w vesicles for use in cytoplasm
what are lysosymes and 2 types
- enzyme containg vesciles produced by golgi apparatus
- desotry bacteria,break down molecules, recyle damages organelles
- primary lysosymes
->contain inactive enzymes
-secondary lysosymes
->formed when primary lys fuse w damages organelles+enzymes r activated
What is autolysis
- self destruction of damaged or inactive cells
- lysosyme membrane breaks down
- digestive enzymes released
- cell destroyed
- cellular materials digested
What are peroxisomes+ 3 function
-small,enzyme containing vesicles
- produced by division of of existing perixosomes
- break down organic compounds such as fatty acids
- produce the free radical hydrogen peroxide
- catalase converts hydrogen peroxide to oxygen and water
What is the mitochondria and function
-smooth outer membrane
-inner membrane has numerous folds(Cristae)
- cristae surround fluid contents
- take chemical energy from food (glucose)-> produce energy molecule ATP
4 processes that produce mitochondrial energy
- Glycolysis: glucose to pyruvic acid(in cytosol
-> mitochondria absorb pyruvate molecules - ctric acid(krebs) cycle: occurs in mitochondrial matrix
->breaks down pyruvate - electron transport chain:inner mitochondrial membrane
- aerobic metabolism(cell rep): mitochondria use oxygen to break down food and prod ATP
-> prod 95% of atp needed to keep cell alive
->glucose+oxygen+ADP->co2+h20+atp
Describe structure and function of the nucleus
- largest organele
- cells control centre
- nuclear envelope=double membrane around the nucleus
- perinculear space=between 2 layers of nuclear envelope
- nuclear pores= communication passages in nuclear envelope
Describe the 3 structures inside nucleus and their fucntions
- nuclear matrix in nucleoplasm: support fillaments
- nuceoli: nuclear organelles
-> synthesize rRNA+ assemble subunits - > made of rna enzymes histones
- nucleosome: DNA coiled around histones
->loosely coiled into chromatin in nondividing cells
->tighlt coiled chromosomes form before divison
What information is stored in the nucleus
- genetic code
->chemical language of dna instructions
->sequence of bases (A,G,T,C)
-> triplet code:3 bases, 1amino acid - gene
-> DNA instructions for one protein
->functional unit of heredity
Define permeability
- determines what moves in or out of a cell
- allows nothing in/our=impermeable
- allows anything to pass =freely permeable
- restricts movement =selectively permeable(plasma membrane; restricts based on size,e charge, shape,lipid solubility)
Transport processes through plasma membrane
- passive processes(no energy)
-active processes(energy) - diffusion+osmosis(passive)
- carrier mediated transport(passive or active)
- vasiuclar transport(Active)
What is diffusion
- movement of a substance from area of higher concentration to area of lower concentration
- ions and molecules are constantly in motion
->molecules in solution move randomly
->random motion causes mixing
What is concentration gradient
-diff betnween high and low concentrations of a substance
What are the 5 factors influencing diffusion
- distance the particle has to move
- ion and molecule size
->smaller=faster diffusion - temperature
->more heart=fast diffusion
-concentration gradient
->steeper grad=faster diffusion
-electrical forces=opposites attract, like repel - presence of channel proteins
2 types of diffuson and molecules/susbtances involved
-simple diffusion
->lipid soluble compounds(alcohol, steroids,fattyacids)
->dissolved gasses(o2,co2)
->water molecules
-channel mediated diffusion
->water soluble compounds and ions
->affected by size, charge, interaction w channel walls
Describe the process of osmosis
- is diffsion of water across a selectively permeable membrane
- water molecules diffuse across a membrane toward solution w more solutes
- occurs more rapidly than slute diffusion
->as water can pass thru a membrane thru abundant water channels(aquaporins
->aquaporins>solute channels
What is osmotic pressure
- force with which pure water moves into a solution as a result of solute concentration
-hydrostatic pressure is pressure needed to block osmosis
What is tonicity and 3 types
- describes how a solution affects a cell
- isotonic solution-> does not cause osmotic flow
-hypotonic solution->lower solute concentration than the cell
-hypertonic solution->higher solute concentration than the cell
Cells in 3 diff types on tonicity solutions
- in a isotonic solution
->stays the same size and solution
-cell In hypotonic solution
->gains water+may rupture(hemolysis)
-cell in hypertonic solution
->loses water and shrinks(creation)
What is carrier mediated transport
- proteins tranport ions or organic substances across plasma membrane
- rate depend on availability of transport proteins +substrates
-cofactors such as hormones affect activity of carriers
What is symport
cotransport
two substances move in same direction at same time
what is antiport
-countertransport
one substnace moves in while one moves out
Describe facillitated diffusion
- passive
- movement of molecules across a membrane by carrier protein
- molecules too large too fit thru channel proteins(glucose,amino acids)
- molecule binds to specific receptor site on carrier protein
- protein shape changed,molecule difuses thru
Describe primary active transport
- carrier proteins pumping substances against a conc grad using atp
- sodium potassium echange pump
->one atp powers the movement of 4 na+ ions and two k+ ion in
What is vesicular transport and the 4 types
- materials move in or out of cell in vesicles
- endocytosis:importation of extracellular materials packaged in vesicles, requires atp
->receptor mediated endocytosis
->pinocytosis
->phagocytosis
What is receptor mediated endocytosis
receptors(glycoproteins) bind target molecules(ligands)
-receptors and their ligands migrate to clathrin-coated pits of plasma membrane to enter cell
-some receptors are associated with membrane lipids and small indentations called caveolae
what is pinocytosis
endosomes “drink” extracellular fluid
what is phagocytosis
- cytoplasmic extensions called pseudopodia (pseudo- = false, podon = foot)
- large objects are engulfed in phagosomes
what is exocytosis
granules or droplets are released from the cell as a vesicle fuses to plasma membrane
what is membrane potential
- when positive and negative charges are separated, a potential difference is created
-unequal charge across the plasma membrane is membrane potential
-resting membrane potential ranges −10 mv to −100 mv, depending on cell type
