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62 Cards in this Set
- Front
- Back
What is the main function of mitochondria?
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To convert chemical fuels into energy forms that drive cell reactions
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What are other functions of the mitochondria
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Steps in steroid synthesis
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Where is the mitochondria located?
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in all mature eukaryotic cells exc. RBC's
Found where metabolic act. is high |
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What is a porin?
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A protein that forms a freely permeable to small ions channel
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What molecule(s) is the inner membrane rich in?
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Cardiolipin, pump and transport systems
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What part of the metabolic pathway does the inner membrane participate in?
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the ETS
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Where is the ADP->ATP phosphorylating system located?
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Seen as elementary particles on stalks from the inner surface of the inner membrane?
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What is the function of cristae?
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increase surface area
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When will a cell have more cristae than another?
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When that cell has a larger energy requirement than the other.
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Cells ass. w/ steroid synthesis tend to have ________ shaped cristae?
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tubular
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The mitochondrial matrix is electron _____, whereas the innermembrane space is electron _______
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dense; lucent
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The intermembrane space is similar in concentration to the _______
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cytosol
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What enzymes are located in the innermembrane space?
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Creatine kinase, adenylate kinase, cytochrome C (ATP-using enzymes)
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What important cellular components are present in the matrix of the mitochondria
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1.Kreb's Cycle enzymes
2.B-oxidation enzymes 3.closed-circle double-stranded mitochondrial DNA 4.rRNA, tRNA, mRNA |
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Mitochondria are more numerous in cells using _______________?
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Large amounts of energy
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How does the elongation of FA's occur in the mitochondria?
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by addition of acetyl-CoA
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What are most mitochondrial proteins coded by?
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nuclear DNA, synth. in cytosol, trans. to mito. using E-req. process
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Where types of cells tend to have more mitochondria?
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1.The myofibrils of skeletal and cardiac muscle
2.Basal/lateral surfaces of cells inv. in pumping ions 3.Spermatozoa 4.Axon Terminal |
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How do mitochondria grow?
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By the addition of new materials produced in the cytoplasm to existing mito. components
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How do proteins destined for the mitochondria get there?
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A signal peptide sequence is recognized by a receptor
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Where is the receptor located?
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Outer mitochondrial membrane
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What does the receptor do to get the precursor protein inside?
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Crosses both membranes at a contact site
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What happens after crossing?
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Signal sequence is cleaved
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How do mito. proliferate?
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Organelle division (fission), not in-step with the cell cycle.
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Is the mito. capable of protein synth.
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a little
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What does mito. DNA code for?
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13 TCA Enzymes
2 rRNA's 22 tRNA's |
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What is the hypothesis of how mitochondria originated in cells?
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When the [02] increased, primitive eukaryotic cells ingulfed aerobic bacteria via endocytosis and lived in symbiosis w/the bacteria
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What three diseases are being ass. w/mitochondrial dysfunction and where is it inherited from?
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Age-related diseases
1.Alzheimer's 2.Heart Disease 3.Schizophrenia *Inherited from mother |
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What other organelle do peroxisomes usually ass. with?
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Smooth ER
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Where are large peroxisomes present?
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liver
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What type of peroxisomes are found in the rest of the body?
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micro-peroxisomes
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Do peroxisomes contain DNA or RNA?
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NO
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Where are peroxisomal enzymes produced?
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In the cytosol
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What directs peroxisomal proteins to the membrane?
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Signal sequence
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How do peroxisomes divide?
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fission
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What do perox's do to very-long chain fatty acids?
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Break down into acetyl-CoA via B-oxidation
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What inclusion is commonly found in other animals peroxisomes but not humans?
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urate oxidase
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What are the functions of perox's?
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1.Oxidze specific organic substrates
2.Segrete enzymes that use H202 3.Aids bile acid synthesis (via action of perox. enzy's) 4.B-oxidation of Very long chain FA's |
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What is the byproduct of oxidase action?
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H202
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How is H202 destroyed?
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By catalase
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What causes Zelwegger Syndrome?
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The failure of peroxisomal membrane transport proteins in bringing peroxisomal enzymes into the peroxisome.
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What are the classifications of Zelwegger's
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G1: complete loss of f(x)=death
G2: only a few peroxisomal enzymes disabled G3: only one enzyme disabled |
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What is adrenoleukodystrophy?
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The inability of peroxisomes to transport long-chain fatty acids into the cell, causes FA buildup: damages myelin, neurological damage
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What is the intracellular digestive system?
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Lysosomes and their ass. organelles
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Describe the maturation of a lysosome?
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1.Early endosomes take up material via endocytosis (sorting occurs)
2.Merge w/ late endosomes (sorting occurs) 3.Late endosome matures into lysosome |
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What is unique about the inner lysosomal membrane?
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Highly glycosylated
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Why does this occur?
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prevents hydolases inside from digesting the lysosome's membrane
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What is a residual body?
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Old lysosomes containing indigestible material
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What is the optimal pH of lysosomes?
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5
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What modifications occur to lysosomal enzymes in the Golgi
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1.Addition of mannose-6-phophate (cis-golgi network)
2.Other carb mod's 3.Sorted 4.Packaged into a vesicle |
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What purpose does the sugar groups serve on lysosomal enzymes?
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Serves as a label for routing the enz's to the lysosome
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What are the methods used by lysosomes to digest material?
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1.Endocytosis
2.Receptor-mediated endocytosis 3.Phagocytosis 4.Autophagy |
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What type of molecules enter via endocytosis?
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Fluid and small proteins
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What is clathrin-independent fluid phase pinocytosis?
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The forming of vesicles around fluid and into the lysosome
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What happens if that fluid must be digested?
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Sent to Early Endosomes
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How does receptor mediated endocytosis occur?
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By the binding of a ligand to a receptor on the lysosomal membrane.
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What does this binding cause?
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"Capping"(aggregation) of the receptor-ligand processes
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How are these aggregates now taken into the lysosomes?
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Via vesicles formed from the molecule clathrin.
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If to be digested what happens?
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The vesicle fuses with an early endosome
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Phagocytosis involves the uptake of ________
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large, solid materials (bacteria i.e.)
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What protein is used for phagocytosis?
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Actin
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What are the specific functions of lysosomes?
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1.breakdown of worn-down or excess organelles
2.Digestion of materials 3.Thyroid Hormone secretion 4.Resorption of Bone (osteoclasts) 5.Provide nutrients during starvation |