Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
85 Cards in this Set
- Front
- Back
|
What structures are ONLY found in a prokaryotic cell contain? |
- Pili: attachment structures on the surface ofsome prokaryotes - Nucleoid: region where the cell’s DNA islocated (not enclosed by a membrane) - Cell wall: rigid structure outside the plasmamembrane - Capsule: jelly-like outer coating of manyprokaryotes - Flagella: locomotion organelles of somebacteria |
|
|
What structures are ONLY found in eukaryotes? |
- Lysosome: helps breaks down acid in the cellso the cell can keep making more cells (intracellular digestion) - Nucleus: the control center of cells,regulates all cell activities and contains DNA (in chromosomes) - Peroxisome: contains enzymes for degradingfatty acids and amino acids by reactions that produce H2O2 - Endoplasmic reticulum (smooth and rough):packages materials to be shipped - Golgi complex: receives, sorts, modified anddispatches proteins - Cytoskeleton: provides structural support tocell and stabilizes junctions between cells - Mitochondria:burns sugar and fat to produce energy (ATP) |
|
|
What are the substructures of a nucleus? Are they found in prokaryotes? |
· Nuclear envelope: double membranecontaining pores · Nuclear lamina: lattice-like network ofproteins that include lamins · Nucleolus: responsible for rRNA synthesisand ribosome assembly · Chromatin: nucleoprotein complex thatcontains DNA * Not found in prokaryotes |
|
|
What structures are found in BOTH prokaryotes and eukaryotes? |
- Ribosomes: organelles that synthesize proteins - Plasma membrane: membrane enclosing thecytoplasm, holds parts inside the cell and allows substances in and out of cell |
|
|
What is the function of the plasma membrane? |
- Holds parts inside the cell and allowssubstances in and out of cell · Lipid bilayer · Fluid mosaic model * Fluidity |
|
|
What enhances the fluidity of the plasma membrane? |
Ø Increased temperature Ø Increased level of Cis unsaturated fatty acids |
|
|
What decreases the fluidity of the plasma membrane? |
Ø Cholesterol Ø Long chain saturated fatty acids |
|
|
What are the different components of the plasma membrane? |
Lipids Glycolipids Glycocalyx Protein Phospholipids Cholesterol |
|
|
What lipids are found in the plasma membrane? |
· Phospholipids *Outer leaflet: phosphotidylcholine andsphingomyelin *Inner leaflet: phosphoserine andphosphoatidylethanolamine *Cholesterol: both leaflets |
|
|
What are glycolipids? Where are they found? |
· Cerebroside: contain a single sugar moiety· Other neutral glycolipids: such as RBC antigensA, B, and O · Gangliosides: contain many sugar moieties * Outer leaflet of the plasma membrane |
|
|
What is the glycocalyx? |
- 2-10% of plasmas’ weight - Hydrophilic · Protection · Cell-recognition - Glycoproteins · N-link to asparagine, O-link to serine- Glycolipids · Galactosides, cerebrosides |
|
|
What are the different types of proteins found in plasma membrane? |
- Integralmembrane proteins · Channels, pumps, carriers, receptors · Can contain attached lipid groups to increasetheir stability in the membrane - Peripheralproteins · Contribute to the cytoskeleton · Contribute to the glycocalyx - Lipid-anchored(by isoprenyl) proteins · Alkaline phosphatase · Monomeric G proteins such as Ras |
|
|
What are the different types of transportation of molecules across the plasma membrane? |
* Simple diffusion * Facilitative diffusion * Gated channels * Primary active transport * Secondary active transport * Vesicular transport |
|
|
What is simple diffusion?
|
- Simplediffusion: movement down a concentration gradient · Limited to small size and lipid solubility * Gases * Small uncharged polar molecules (Water, ethanol,short-chain FA) *Lipophilic molecules (Steroids) |
|
|
What is facilitative diffusion? |
- movement down a concentration gradients with aidof transport proteins, no ATP required · Charged molecules require a carrier protein tocross membrane · Ion channels: open in response to specificsignals * Uniport carrier proteins * Cotransport carrier protiens |
|
|
What are uniport carries proteins? |
*Specific for substrate and inhibitors *Saturation kinetics *Regulated physiologically |
|
|
What are cotransport carrier proteins? |
*Symporters *Antiporters |
|
|
What is the mechanism of CFTR? |
· Cysticfibrosis transmembrane conductance regulator (CFTR): ligand-gated channelcontrolled by phosphorylation - Two intracellular binding domains control opening of the channel, anadenine nucleotide-binding domain ( ABD ) and a regulatory protein ( R ) 1. Phosphorylation of the regulatory subunit byprotein kinase A (PKA) causes a conformational change that allows ATP to bindto the ABD (adenine nucleotide-binding domain). 2. Hydrolysis of bound ATP opens the channel sothat chloride ions can diffuse through. |
|
|
What is primary active transport? |
movement against a concentration gradient usingATP energy |
|
|
What are examples of primary active transport? |
· Na+/K+-ATPase pump (3Na out for every 2K in) · Ca2+-ATPase pump |
|
|
What are the Na+/K+-ATPase pump inhibited by? Enhanced by? |
Inhibited by: Ø β-Blockers,succinylcholine Ø Cardiotonic steroids, digitalis, and ouabain;lack of oxygen (hypoxia) Enhanced by: Ø Albuterol, insulin |
|
|
What is the Ca2+-ATPase pump? |
*Maintain low cytosolic Ca2+concentration *Plasma membrane Ca2+-ATPase in mostcells *Muscle Ca2+-ATPase |
|
|
What is secondary active transport? |
- movement against a concentration gradient usingsecond molecule & ATP |
|
|
What are examples of secondary active transport? |
· Na+-linked symporters *SGLUT1 symporter Ø for Na+/glucose Ø in kidney and intestine · Na+-linked Ca2+ antiporter *Maintain low cytosolic Ca2+ *inhibited by digitalis |
|
|
What is the concentration of Na+ inside the cell? What is the concentration of glucose in the cells? |
* Na+ is low in the cell *Glucose is high in the cell |
|
|
What is vesicular transport? |
· Endocytosis(transport into the cell) *Movement of macromolecules from outside the cellto the inside of the cell by the active invagination of the plasma membrane(i.e. cholera toxin) Ø Phagocytosis: when cells eats something Ø Pinocytosis: when cell drinks something· Exocytosis(transport out of the cell) *Macromolecules are packed in secretory vesiclesand then extruded from the cell · Protocytosis (endocytosis that occurs viacavaolae) |
|
|
What is cystic fibrosis? |
Cl--ATPase pump, CFTR gene transporter defect |
|
|
What is cystinuria? |
- Impaired reabsorption of dibasic amino acids · Cystinuria is an autosomal-recessive defect inreabsorptive transport of cystine and the dibasic amino acids ornithine,arginine, and lysine from the luminal fluid of the renal proximal tubule andsmall intestine. The only phenotypic manifestation of cystinuria is cystineurolithiasis, which often recurs throughout an affected individual’s lifetime.Surgical intervention is necessary, but the cornerstones of treatment aredietary and medical prevention of recurrent stone formation |
|
|
What is Hartnup's disease? |
- Impaired absorption of tryptophan · Diarrhea, dermatitis, dementia |
|
|
What is Familia hypercholesterolemia? |
- Lack of functional receptors for LDL, transporter defect, genetic |
|
|
What is the function of lysosomes? |
- Lysosome: helps break down acid in the cell sothe cell can keep making more cells · Contain enzymes for intracellular digestion· 60 forms of acid hydrolases |
|
|
What are the two forms of lysosomes and their functions? |
*Primarylysosomes: budding from the trans side of the Golgi complex *Secondarylysosomes: fusion of the primary lysosome with the substrate to be degraded |
|
|
What are some lysosomal storage diseases? |
*I-celldisease (mucolipidosis II): a disorder of protein targeting where Lysosomalproteins are not sorted *Tay-Sachs:accumulation of partially digested gangliosides in lysosomes * Pompe: accumulation of glycogen particles inlysosomes |
|
|
What are the reactions that occur in the lysome? |
Most lysosomal enzymes are hydrolases, whichcleave peptide, ester, and glycosidic bonds by adding the components of wateracross the bond. These enzymes are active at the acidic pH of the lysosome andinactive if accidentally released into the cytosol |
|
|
What are the components of the mitochondria? |
*Outer membrane *Inner membrane *Intermembrane compartment *Matrix |
|
|
What is the outer membrane of the mitochondria? |
– Containsporin and highly permeable |
|
|
What is the inner membrane of the mitochondria? |
– Impermeableto most small ions and molecules – Cristaecontain the enzymes for electron transport and oxidation phosphorylation(produces ATP) |
|
|
What is the intermembrane compartment of the mitochondria? |
– Containscreatine phosphokinase and adenylate kinase (add phos groups) |
|
|
What is the matrix of the mitochondria? |
– Enclosedby the inner membrane – Dehydrogenases(add water) – ProduceNADH and FADH2 for energy generation via electron transport chain – Adouble-stranded circular DNA genome – RNA,protein, and ribosomes – Intramitochondrialgranules: calcium andmagnesium |
|
|
What are the major steps in the energy extraction process of the mitochondria? |
1. Import and export of materials (such as fat and sugar derivatives)to and from the mitochondria 2. Breakdown of fattyacids through β-oxidation andthe removal of electrons in the citric acid cycle (TCA) 3. Passage ofelectrons through the major complexes of the respiratory chain (aka electrontransport chain) 4. Manufacture of ATPby ATP-synthase |
|
|
Energy shortage in the tissues can cause what? What is this caused by? |
*muscle weakness, fatigue and problems in the heart,kidneys, eyes and endocrine system. * Mitochondrial diseases that affect one or more steps in the energy making process |
|
|
What is a peroxisome? |
Contains enzymes for degrading fatty acids &amino acids by reaction that produce H2O2 |
|
|
What is the structure and function of a peroxisome? |
• Containenzymes that transfer hydrogen atoms from organic substrates to oxygen to formhydrogen peroxide • Catalasedegrades hydrogen peroxide to water and oxygen • Synthesizeand degradation of hydrogen peroxide • Beta-oxidationof very long chain fatty acids • Phospholipidexchange • Bileacid synthesis |
|
|
What is PBD? |
• Peroxisomebiogenesis disorders (PBD): fail to oxidize very long chain fatty acids andaccumulate bile acid precursors |
|
|
What is Zellweger Syndrome? |
PBD – Zellwegersyndrome (cerebrohepatorenal) • Decreasedperoxisome in liver, brain and kidney • Increasediron and copper • Damagedvision, enlarged liver |
|
|
What is neonatal adrenoleukodystrophy? |
PBD – Neonataladrenoleukodystrophy (ALD) • Progressivebrain damage • Damagedadrenal gland |
|
|
What is infantile refsum disease? |
PBD • Malformationof myelin sheath around nerve cells • Neurologicdamage: cerebellar degeneration, peripheral neuropathy |
|
|
What is the nucleus and its functions? |
* Nucleus: the control of cells, regulates all cell activitiesand contains DNA (in chromosomes) • Functionsof nucleus – DNAreplication – Replicationrepair – Transcription – Processingof pre-cursor RNA molecules |
|
|
What is the nuclear envelope? |
– Doublemembrane containing pores – 90nmin diameter – Theouter nuclear membrane is continuous with the endoplasmic reticulum |
|
|
What is the nuclear lamina? |
– alatticelike network of proteins that include lamins – Laminsattach chromatin to the inner membrane of the nuclear envelope |
|
|
What is the nucleolus? |
• responsiblefor rRNA synthesis and ribosome assembly • threezones of nucleolus: – Granularzone: at the periphery, contain ribosomal precursor particles – Fibrillarcore: contain DNA that is not being transcribed. – Fibrillarregion: centrally located, contains ribonuclear protein fibrils. |
|
|
What is chromatin? |
– Nucleoproteincomplex that contains DNA plus histones and other proteins |
|
|
What is the endoplasmic reticulum? |
Endoplasmic reticulum (smooth and rough): packages materialsto be shipped |
|
|
What is the smooth endoplasmic reticulum (SER)? |
· Lack ribosomes · Synthesizes phospholipids, triglycerides, &sterols (steroid alcohols) · Detoxification via hydroxylation and conjugationreactions · Glycogen degradation and gluconeogenesis · Lipolysis and lipoprotein particles assembly· Contains the cytochrome P450 oxidativeenzymes involved in metabolism of drugs & toxic chemicals |
|
|
What is the rough endoplasmic reticulum (RER)? |
· Continuous with the outer nuclear membrane · Studded with ribosomes on the cytoplasmic side · Synthesizes proteins destined for the Golgicomplex, lysosome, the plasma membrane and secretion from the cell · Synthesized proteins undergo posttranslationalmodifications (such as initiation of N-linked glycosylation or addition of GPIanchors |
|
|
What is the golgi complex? |
Golgi complex: receives, sorts, modifies and dispatchesproteins • Twodistinct faces: – Thecis face is associated with the RER – Thetrans face is oriented toward the plasma membrane |
|
|
What is the function of the golgi complex? |
• Posttranslationalmodification and sorting of newly synthesized proteins and lipids • Transportsthese proteins to the lysosome, secretory vesicles or the plasma membrane |
|
|
What is I-cell disease? |
Disease associated with golgi complex – (mucolipidosisII): • Phosphorylationof mannose in glycoproteins targets proteins to lysosomes, catalyzed byN-acetylglucosamine-phosphotransferase and N-acetylglucosaminidases • Deficiencyof N-acetylglucosamine-phosphotransferase results in enzymes (hydrolases)sending enzymes to the wrong destination and accumulation of undegradedglycoconjugates in lysosomes • Skeletalabnormalities, coarse features, restricted joint movements, and psychomotorretardation |
|
|
What is hyperproinsulinemia? |
Defect associated with golgi complex • Elevatedlevels of proinsulin in serum resulting from failure of a peptidase to cleaveproinsulin to insulin and C-peptide in Golgi complex • similarto noninsulin-dependent diabetes |
|
|
What is the endomembrane system? |
Endomembrane System: composed of the differentmembranes that are suspended in the cytoplasm within a eukaryotic cell |
|
|
What are the organelles and relationships among them in the endomembrane system? |
1. Nuclear envelope isconnected to RER, which is also continuous with the SER 2.Membranes and proteins produced by the ER flow in the form of transportvesicles to the Golgi3.Golgi pinches off transport vesicles that give rise to lysosomes and vacuoles 4.Lysosome available for fusion with another vesicle for digestion 5. Transportvesicle carries proteins to plasma membrane for secretion 6. Plasma membrane expands by fusion of vesicles; proteinsare secreted from cell |
|
|
What is the cytoskeleton and what are is parts? |
*Cytoskeleton:provides structural support to cell and stabilizes junctions between cells *Microtubules *Microfilaments *Intermediate Filaments |
|
|
What are microtubules? |
· Polymers of tubulin *alpha-tubulin *beta-tubulin |
|
|
What are the functions of microtubules? |
*Chromosome movement during meiosis and mitosis *Form spindles *Intracellular vesicle and organelle transport–Kinesin and dynein *Ciliary and flagellar movement |
|
|
How can microtubules undergo rapid assembly and disassembly? |
*Accomplished by microtubule organizing centersand two accessory proteins: tau protein and microtubule-associated protein *Blocked or reversed by calcium |
|
|
What is Chediak-Higashi syndrome? |
*defect in microtuble polymerization Ø delayed fusion of phagosomes with lysosomes inleukocytes, thus preventing phagocytosis of bacteria Ø increased fusion of melanosomes in melanocytes,leading to albinism Ø granular defects in natural killer cells andplatelets |
|
|
What are microfilaments and their functions? |
· Composed of actin *Each actin filament (F-actin) contains twostrands of actin helix *Each actin helix contains 13.5 molecules ofglobular actin (G-actin) · Local movement · Sliding filament movement vInteraction between actin and myosin |
|
|
What are intermediate filaments and their function? |
· Intermediate in thickness between microtubulesand microfilaments · Function primarily in structural roles · Contain several types of tissue-specificproteins *Cytokeratins: epithelia tissue *Desmin: smooth muscle, Z disk of skeletal andcardiac muscle *Vimentin: cells of mesenchymal origin(endothelial cells, fibroblasts, chondroblasts, vascular smooth muscle) *Neurofilaments: neurons *Glial fibrillary acidic protein (GFA): astrocytes |
|
|
What is the diameter (nm) of microfilaments, intermediate filaments, and microtubules? |
6nm, 10nm, and 23nm respectively. |
|
|
What is cholera and how does it enter the cell? |
*A bacterial disease usually spread throughcontaminated water *GM1 ganglioside receptor on the intestinal cell, triggering endocytosis of the toxin |
|
|
What does cholera cause and how? |
• Choleratoxin increases the efflux of sodium and chloride ions from his intestinalmucosal cells into the intestinal lumen • Causes severe diarrhea and dehydration• Requires immediate treatment because the disease can cause death within hours even inpreviously healthy people • Still present in Asia, the Middle East, Latin America, India and sub-Saharan Africa • Last major outbreak in USA occurred in 1911 |
|
|
What are the treatments of cholera? |
• Cholerais easily treated • Option1: oral rehydration solution (ORS) containing Na+, K+and glucose • Option2: a diet of rice (which contains glucose and amino acids) • Option3: Tetracyclines rapidly stop the shedding of vibrios (Gram-negativebacteria possessing a curved rod shape) *Tetracycline resistance has appeared duringepidemics. • Option4: Fluoroquinolones |
|
|
0.1A = ? nm 1A = ? nm = ? m 10A= ? nm |
* 0.01nm *0.1nm, 10^-10m *1nm |
|
|
What are symporters? |
––both go through at the same time in and out |
|
|
What are antiporters? |
–onegoes in then one goes out not at the same time |
|
|
What are the micro-molecules formed from the degradation of the following macromolecules: proteins, poly/oligosaccharides, DNA/RNA, triglycerols, phosphoacylglycerols. Where does this occur? |
*Amino Acids *Monosaccharides *Nucleosides and Inorganic phosphate *Fatty acids and glycerol *Inorganic phosphate and head molecules *Occurs in the lysosome |
|
|
How many chromosomes are in the human DNA? |
46 or 2 pairs of 23 |
|
|
Can translation occur on SER? |
No |
|
|
Can translation occur on RER? |
Yes |
|
|
What basic structure do microfilaments have? |
double helix |
|
|
What basic structure do intermediate filaments have? |
two anti-parallel helices/dimers, forming tetramers |
|
|
What basic structure do microtubules have? |
protofilaments, in turn consisting of tubular subunits |
|
|
What is the basic subunit of microfilaments? |
actin |
|
|
What are some examples of basic subunits of intermediate filaments? |
*vimentin (mesenchyme) *glial fibrillary acidic protein (glial cells) *neuro-filament proteins (neuronal processes) *keratins (epithelial cells) *nuclear lamina |
|
|
What are the basic subunits of microtubules? |
alpha and beta tubulin |
