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233 Cards in this Set
- Front
- Back
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The theory of endosymbiosis refers to...
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the notion that, over the course of evolution, mitochondria and chloroplasts arose from the prokaryotic cells
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The 9+2 pattern of the axoneme is nine____of tubules and two additional microtubules in the center called the____?
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outer doublets; central pair
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The main function of ribosomes is in:
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protein synthesis
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Which chemical group is at the 5' end of a single polynucleotide strand?
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Phosphate group
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The RER gets its names because its membranes are studded with...
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Ribosomes
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The pyrimidine bases are.. ...
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Cytosine, Uracil, Thymine
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Most cell membranes are composed principally of.. ..
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proteins and lipids
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Biologically, which of the following is the least important characteristic of water?
good solvent, numerous H bonds, hydrogen isotopes, polarity, or temp-stabilizing capacity? |
Water typically contains isotopes of Hydrogen bonds
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What are some characteristics of DNA?
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Complementary strands
Composed of nucleotides Antiparallel configuration Double stranded (does not contain ribose) |
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Prokaryotes have __S ribosomes with __S and__S subunits, whereas eukaryotes have__S ribosomes with__S and__S subunits.
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70, 50, 30...80, 60, 40
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The mitochondrion is where___cellular process takes place?
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Respiration
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Which part of the mitochondrial membrane contains porins?
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the outer mitochondrial membrane
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Which part of the mitochondrial membrane contains cristae?
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the inner mitochondrial membrane
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What is cristae?
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The site in the mitochondria for for electron transport and ATP Synthesis
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What is the DNA/Protein complex that contains genetic material?
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Chromatin
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What are the two types of chromatin?
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Euchromatin, the open configuration & Heterochromatin, the densely packed, transcriptionally-closed
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Transcription can occur in both the mitochondria and nucleolus?
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True, transcription can take place in both of these cellular organelles
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Where in the Mitochondria does Krebs Cycle take place; where mitochondrial DNA resides; and contains semi-fluid of the mitochondria
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The Mitochondrial Matrix
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This mitochondrial membrane is responsible for nucleotide phosphorylation?
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The Intermembrane Space
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The Powerhouse of the Cell?
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Mitochondria
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**What is the executioner of the cell; for programmed "cell death" ?
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Apoptosis
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Describe the Endosymbiotic Theory
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That both the mitochondria and chloroplast evolve from ancient bacteria
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Translation can occur in the cytoplasm and also ribosomes?
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True
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What are the sizes of prokaryotic and eukaryotic ribosomes?
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Prokaryotes are 70S with subunits of 50S and 30S, while the eukaryotes are 80S with subunits of 60S and 40S
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The SER functions to synthesize?
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Lipids
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The RER functions to synthesize?
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Proteins and also functions in protein modification
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Anterograde Transport
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Movement of material from the ER through the Golgi complex towards the plasma membrane...
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Retrograde Transport
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Movement of vessicles from the golgi cisternae back towards the ER
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Is the Endomembrane system and microubules intimately connected?
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Yes, they are...
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How are proteins modified in the RER?
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They are modified here by adding a carbohydrate chain
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What AA are used for N-linked glycosylation?
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Asparagine
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What is the terpene carrier for carbohydrates?
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Dolichol
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What is the gene affected for patients with CF?
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Delta F508 Gene
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The mutates CFTR gene would still be functional under which conditions...?
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That it could still make it to the cell surface, passing through the membrane...but this never occurs.
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If a protein is not properly folded, what is used as a marker to destroy it?
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Ubiquitin destroys them using proteosomes and their proteases
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What enzyme, found in the mitochondria, involved in phosphorylation, is found in the liver cells and involved with detoxification of drugs and meds??
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Cytochrome P450's
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What is the principle organelle involved in detoxification and drug metabolism that also conjugates noxious substances?
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Smooth ER
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What is involved in glycosylation, phosphorylation, and processing/packaging that is located near the ER, centrosome, and nucleus
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The Golgi Complex
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What are the 5 layers of the Golgi Complex?
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CGN, cis, medial, trans cisternae, TGN
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Where does most of the packaging occur in the golgi?
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TGN
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How do we move cell products from one part of the endomembrane system to the other?
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Vessicles
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Each of the 5 parts of the Golgi Complex are functionally and biochemically distinct?
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True
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Using endosomes, how do we get proteins to lysosomes?
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Tag with a mannose-6-P so they can be secreted directly via lysosomal pathways
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What is I-cell Disease
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The inability to tag a protein with mannose-6-P results in I-Cell Disease
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What are the different types of endosomes?
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Early, Late endosomes, and Lysosomes
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What do Lysosomes contain?
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A single-membrane bound organelle that contains Acid Hydrolases
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Which enzyme produces hydrogen peroxide?
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Urate Oxidase
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Which enzyme destroys H2O2?
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Catalase
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What are the three components of the cytoskeleton?
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Microtubules, Intermediate Filaments, Microfilaments
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The component of the cytoskeleton is crucial to diagnose the location of tumors; is the most stable; and can vary in tissue types
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Intermediate Filaments
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A hollow tube with a wall consisting of 13 protofilmaents and alpha and beta-tubulin
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Microtubules
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Actin that is by itself is called...
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G-Actin
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Bound Actin is called...
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F-Actin
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The dense network of microfilaments beneath the plasma membrane is called...
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the Cell Cortex
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Key Features of microvillus?
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Absorption due to actin microfilaments
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An example of actin-myosin movement?
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Skeletal Muscle Contraction
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What are mictrotubules consisting of?
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Alpha and beta tubulin
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What is the Axoneme structure?
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"9+2" pattern with 9 outer doublets of tubules and 2 additional MT in the center
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What is the role of gamma-tubulin?
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Nucleation
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The motor protein in the axoneme is called...
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Dynein
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Anything that disturbs the structure of a hemidesmosome results in...
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A Blistering Disorder
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What are the IF attached to desmosomes and hemidesmosomes?
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Tonofilaments
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Gap Junctions are...
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Cell Junctions for rapid communication
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What Junction anchors cells to the basement membrane?
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Hemidesmosomes
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What is the fn of Tight Junctions?
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Serve as Permeability Barrier and Cell Polarity
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The most abundant lipids in the plasma membrane?
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Phopholipids
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Where do you find phosphatidylserine and why?
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On the cytosolic side of the membrane because of its negative charge
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Spingolipids contain...
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Choline
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Which membrane lipid is responsible for blood types?
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Glycolipids
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What is Tay-Sachs Disease?
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The inability to break down the GM2 gangliosides
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What characteristics of Fatty Acids induce greatest membrane fluidity?
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Short C-chain, Unsaturated, Lower temperatures
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What characteristic of fatty acids induces minimal membrane fluidity?
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Longer C-Chain, Saturated, Higher temps
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Where are glycolipids found?
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On the surface of all plasma membranes
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What is the precursor steroid hormone that allows permeability?
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Cholesterol
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Localized regions of membrane lipids that are involved in cell signaling; Microdomains?
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Lipid Rafts
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Describe the outer membrane Lipid Rafts
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have elevated cholesterol and glycosphingolipds, so they tend towards lesser fluidity and thicker areas of the membrane
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Cholesterol tends to be a...
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thicker membrane
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What is a glycocalyx?
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The sugary coat outside the cell; carbohydrate-rich zone outside cell
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What is Osmosis?
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movement of water from low solute concentration to an area of high solute concentration
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Describe Hypotonic
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Solution of lower solute concentration than inside the cell; induces cell lysis
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Describe Hypertonic
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Solution of higher solute concentration than inside the cell; induced crenation
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What are the two types of carrier proteins for transport?
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Uniport, Cotransport
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Carrier protein for single solute transport & example
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Uniport; Glutpermeases as an example
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What are two types of Cotransport?
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Symport transports in the same direction, and Antiport tranports in the oppositde direction. Exa re Cl-Bicarb exchangers
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What are the 3 types of ion channels?
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Voltage-gated, Ligand-gated, Mechanosensitive
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An example of indirect active transport is?
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Na-Glucose Symporter where the cell creates the gradient
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Describe direct AT and give example
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Energy in the form of ATP is spent in the process, an example is Na/K pump
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GTPases are inactive (turned off) when bound to?
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GDP
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GTPases are active (turned on) when bound to?
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GTP
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What is Ras?
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A monomeric GTPase
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What inactivates Ras?
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GAP (GTPase Activating Proteins)
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What activates Ras?
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SOS is a GEF (Guanine Exchange Factor) that turns on Ras
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What can activate the Ras pathway?
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Tyrosine Kinase growth factor
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What is SOS?
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SOS is a Guanine-nucleotide exchange factor, associated with GRB2
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What are the four types of transport ATPases?
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P-type, F-type, V-type, ABC-type
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What type of transport ATPases are responsible for maintaining an ion gradient across the membrane like the Na/K pump and proton pump in the stomach
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P-type ATPases
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What type of transport ATPases found in bacteria, chloroplasts, and in mitochondria ATP synthases?
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F-type ATPases
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What type of transport ATPases pump protons into organellse and structurally related to F-type ATPases?
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V-type ATPases
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Large superfamily, handles a wide variety of solutes (ions, sugars, AA, peptides, polysaccharides)?
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ABC-type ATPases
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What are examples of ABC-type transporters?
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CFTR, chloroquine transporter, multidrug resistant proteins
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What is the nucleolus Organizer Region?
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a stretch of DNA carrying multiple copies of rRNA genes
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What contains the nucleolus organizer region (NOR)?
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The Nucleoli
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rRNA genes reside on which acrocentric chromosomes?
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13, 14, 15, 21, 22
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What bond holds the nucleotides together?
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Phosphodiester bonds
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The double helix DNA strands are held together by?
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Hydrogen Bonds
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Nucleosomes are made of ?
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Histones (H2A, H2B, H3, H4); also has 146 bp of DNA wrapped around histone octamer
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DNA that is scattered across the genome?
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Interspersed DNA
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Where do you find repetitive DNA?
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Centromeres and Telomeres
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Multiple copies of DNA arranged next to each other in a row?
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Tandemly repeated DNA
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Abnormal recombination between different copied of the repeats can lead to...
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Deletion or rearrangement of the gene
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Sequences that have 300bp, have been implicated as the cause of mutations in hereditary diseases by retrotransposition?
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Alu and L1
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The histones that binds to linker DNA
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H1
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DNA wrapped in nucleosomes can form, slightly thicker fibers and require... ..?
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30nm- chromatin fiber, requires H1
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30nm chromatin is aka...?
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Solenoid
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Trancriptionally Active genes are located in...also are acylated histones... ..
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Euchromatin
**acetlyation is associated with increased transcription |
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Highly-folded chromatin that is usually transciprtionally inactive, methylated DNA is often associated with it.. ..
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Heterochromatin
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What is epigenetic?
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Any factor that can affect gene function without change in the genotype
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What is a Barr Body?
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The inactive X chromosome in female cells
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Place on chromosome that contains the DNA sequence for a particular gene?
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Gene Locus
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What are the stages of the cell cycle?
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G1, "G0", S, G2, M phases
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Stage of cell cycle that no DNA synthesis occurs?
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G1
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If GF's are not available during G1, what happens to the cells?
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Cells enter a quiescent stage, G0
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What stage of the cell cycle does DNA synthesis occur, where DNA is doubled?
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S phase
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What holds the sister chromatids together?
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Centromeres
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What is a kinetochore?
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Where MT attach in the M phase
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What is the direction of DNA synthesis?
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5' --> 3'
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What is the direction to read the DNA template?
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3' --> 5'
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Unwinding the DNA helix requires?
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Helicase, topoisomerases, and Single stranded binding proteins
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What controls supercoiling?
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Topoisomerases
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What unwinds DNA
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Helicase
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What do SSBs do?
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To maintain DNA in the open configuration
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A type-II topoisomerase used by bacteria?
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DNA Gyrase
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What initiates DNA replication?
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Primase, an RNA polymerase
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Okazaki fragments are joined by?
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DNA ligase
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What are the stages or subdivisions in mitosis?
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Porphase, prometaphase, metaphase, anaphase, telophase (PPMAT)
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Stage of mitosis where the nuclear membrane breaks down
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Prometaphase
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What stage where sister chromatids separate and move towards opposite poles?
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Anaphase
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Formation of mitotic spindle
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Prophase
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Describe Cytokinesis
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Division of the cytoplasm, formation of 2 cells from 1
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What drives process of Cytokinesis?
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Contractile ring
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What is the function of Meiosis I?
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Separation of the homologs
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What is the function of Meiosis II?
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Separation of sister chromatids
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Stage of Meiosis I where genetic recombination occurs and synaptonemal complex forms
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Prophase I
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Chromosomes held together in metaphase I where homologs are still crossing over?
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Chiasmata
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What are the two major rest points in female cells?
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Diplotene (in prophase I) and metaphase II
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What are the subdivisions of prophase I in meiosis I?
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leptotene, zygotene, pachytene, diplotene, diakinesis
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How are cells held together in the zygotene?
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Synaptonemal complex
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What subdivision of meiosis I is the stage of max condensation?
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Diakinesis
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What is nondisjunction?
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Failure of two members of a homologous chromosome pair to separate during anaphase
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Of the following lipids, which is found in approximately equal amounts in both the outer and inner portions of the lipid bilayer?
A) phophatidyl ethanolamine B) phosphatidyl choline C) phosphatidyl serine D) cholesterol E) all of the above |
Cholesterol
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Charlie, an Angus bull, is heterozygous (Bb) for coat color, where B = black and b = brown. Charlie therefore has a black coat. Black is Charlie's
A) homozygous state. B) gene conversion. C) genotype. D) phenotype. E) heterozygous state. |
Phenotype
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In eukaryotes, enzyme responsible for transcribing most protein-coding genes is
A) RNA polymerase III B) RNA polymerase II C) RNA polymerase I D) All three types of RNA polymerase can transcribe protein-coding genes |
RNA Polymerase II
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In eukaryotes, the "start" codon also specifies the amino acid,
A) phenylalanine B) glycine C) valine D) aspartate E) methionine |
Methionine
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Which amino acid residue is the site of N-linked glycosylation?
A) Asparagine B) Arginine C) Threonine D) Serine E) Both threonine and serine |
Asparagine
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The regions of DNA in a eukaryotic gene that encode a polypeptide product are called:
A) enhancers B) ribosomes C) leader sequences D) promoters E) exons |
Exons
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Which of the following is not part of a human chromosome in any phase?
A) histone B) centriole C) euchromatin D) nucleosome E) centromere |
Centriole
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The nuclear membrane functions as a
A) means of sequestering many of the mRNA processing activities from the cytosol. B) selective barrier, allowing certain substances in or out. C) means of separating nuclear and cytoplasmic constituents. D) means of localization of the chromosomes within the cell. E) all of the above |
All of the above
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The stage of meiosis where cells become haploid.
A) anaphase I B) prophase I C) prophase II D) anaphase II |
Anaphase I
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The appropriate folding of a newly translated product is essential, and continual misfolding often leads to disease, especially in vertebrates. This misfolding, particularly in the situation of prion diseases, may be due to
A) chaperone activity. B) errors facilitated by the enzyme foldase. C) errors perpetuated during self-assembly. D) insertion of inappropriate amino acids during translation. E) rearrangements by translocase. |
Chaperone Activity
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Which of the folowing terms describes the role of the glucocorticoid receptor?
A) TATA box B) Cis element C) Promoter D) Transcription factor E) Enhancer |
Transcription Factor
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DNA replication is
A) conservative. B) irregular. C) semi-conservative. D) spontaneous E) dispersive. |
Semi-Conservative
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Which of the following are termination codons?
A) UUU, UAA & UAG B) UUU, UAG, UGA & UAA C) UGA, UAA & UAG D) AUG & UAA E) AUG, UAA, UGA & UAG |
UGA, UAA, UAG
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The site of RNA polymerase binding to the DNA template is called
A) Carboxyl end B) Domain C) Promoter D) Enhancer E) Leader sequences |
Promoter
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DNA replication
A) is not edited once polymerization has occurred. B) is conservative. C) is partially regulated by promoter/terminator sites. D) proceeds by making two continuous strands. E) requires a type of RNA polymerase |
Requires a type of RNA Polymerase
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The alternative forms of a gene that can be expressed are known as
A) loci B) alleles C) spores D) haplotypes E) genes |
Alleles
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Which of the following is the correct order of the levels of DNA packaging in eukaryotic chromosomes?
A) nucleosome → looped domains → chromatin fiber → heterochromatin B) chromatin fiber → nucleosome → looped domains → heterochromatin C) heterochromatin → nucleosome → chromatin fiber → looped domains D) chromatin fiber → heterochromatin → nucleosome → looped domains E) nucleosome → chromatin fiber → looped domains → heterochromatin |
Nucleosome-->chromatin fiber-->looped domains-->heterochromatin
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A patient has been diagnosed with having a cancerous tumor. It has been discovered that a malfunction is occurring in his cell signaling pathway. Which of the following mutations would likely contribute to tumor formations?
A) GTP staying bound to RAS B) PIP 3 becoming dephosphorylated C) AKT being degenerated D) GDP staying bound to RAF |
GTP staying bound to Ras
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DNA polymerase uses a nucleoside triphosphate, bearing phosphates on the 5' carbon to form a phosphodiester linkage to the free 3' hydroxyl group on the end of the DNA strand it is synthesizing.
A) True B) False |
True
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Which of the following is NOT a function of membranes?
A) regulation of transport B) information storage C) cell-cell communication D) compartmentalization E) delineation |
Information Storage
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The major lipids found in membranes are
A) cholesterol and sphingomyelin B) phospholipids, glycolipids, and cholesterol C) triacylglycerols and cholesterol D) phospholipids and free fatty acids E) cholesterol, inositol, and glycolipids |
Phospholipids, glycolipids, cholesterol
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Which of the following molecules would NOT readily cross an intact cell membrane by simple diffusion?
A) oxygen B) glucose C) fatty acids D) water E) ethanol |
Glucose
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An example of a purine is
A) uracil. B) cytosine. C) guanine. D) acridine. E) thymine. |
Guanine
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What protein will cause the activation of RAS?
A) SOS B) GRB2 C) RAF D) RAS Kinase E) MAPKK |
SOS
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With regard to the semipermeable nature of the plasma membrane, which of the following would readily cross without the aid of a transport protein?
A) glucose B) calcium ions C) amino acids D) water E) DNA |
water
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The phases of meiosis that most resemble those of mitosis are
A) meiosis I, except for the pairing of homologs. B) meiosis II, except for the pairing of homologs. C) the meiosis I phases. D) the meiosis II phases. E) both A and B |
Meiosis II Phase
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With respect to the outer and inner faces of the lipid bilayer of the cell membrane, the composition of lipids is
A) asymmetrical. B) not identical, but symmetrical. C) highly random and varies throughout the cell. D) a mirror image. E) identical. |
Asymmetrical
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The phase of the cell cycle associated with the doubling of the amount of DNA in the cell is
A) M. B) G1. C) S. D) G0. E) G2. |
S
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Based on your knowledge of the chemistry of the cell membrane, which of the following compounds would you couple with a new drug in order to achieve better uptake by cells?
A) polar amino acids B) lipids C) several mannose-6-phosphate monomers D) any hydrophilic substance E) carbohydrates |
Lipids
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Where would you expect to find an organism possessing a cell membrane with the following composition: large proportions of cholesterol and a predominance of unsaturated fatty acids?
A) upper levels of an aquatic environment B) frozen wastelands C) tropical regions D) temperate regions E) equatorial regions |
Frozen Wastelands
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Of the subphases of prophase I of meiosis, the phase at which mammalian egg cells are arrested for years during oogenesis is
A) diakinesis. B) diplotene. C) pachytene. D) leptotene. E) zygotene. |
Diplotene
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Transcription is similar to DNA replication in that
A) an RNA transcript is synthesized discontinuously and the pieces then joined together. B) nucleotide polymerization occurs only in the 5..-to-3.. direction. C) the newly synthesized RNA remains paired to the template DNA. D) it uses the same enzyme as that used to synthesize RNA primers during DNA replication. |
Nucleotide Polymerization occurs only in the 5'-->3' direction
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Which lipids can be found in a plasma membrane?
A) phospholipids. B) sphingolipids. C) cholesterol. D) both B and C E) choices A, B, and C |
choices A, B, C
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The proteins which complex with DNA producing the "beads on a string" or nucleosomes are called:
A) histones B) proteases C) kinases D) spindle fibers |
Histones
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Which component of transcribed RNA in eukaryotes is present in the initial transcript but is removed before translation occurs:
A) 3' Poly A tail B) codons coding for the protein to be produced C) Ribosome binding site D) Intron E) 5' cap |
Intron
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A sample of cells is placed in a salt solution. The cells shrink and the membrane is distorted. Relative to the cell, the solution is probably:
A) isotonic B) hypotonic C) hypertonic D) osmotic |
Hypertonic
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Release factors of translation recognize the codon
A) AUG. B) GGA. C) UGA. D) GUA. E) UUU. |
UGA
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Which of the following can be classified as a glycolipid?
A) sphingomyelin B) cerebroside (galactocerebroside) C) phosphatidylcholine D) phosphatidylserine E) cholesterol |
Cerebroside (galactocerebroside)
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Which enzyme is responsible for amino acid acitivation and the joining an amino acid to a tRNA?
A) IF2 B) Peptidyl transferase C) N-formylmethionase D) Amino hydroxylase E) Aminoacyl-tRNA synthetase |
Aminoacyl-tRNA synthetase
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Which of the following regions of a gene tells RNA polymerase where to start
transcribing DNA into RNA? A) 5' capping signal B) promoter C) coding region D) terminator E) enhancer |
Promoter
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How thick is a DNA solenoid?
A) 30 mm B) 10 nm C) 700 nm D) 30 nm E) None of the above |
30nm
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What is another common name for lipid rafts?
A) Microdomains B) Lipofuscins C) Glycosphingoids D) Clatherins E) Residual bodies |
Microdomains
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Transcription of 18S, 28S and 5.8S ribosomal RNAs is primarily the function of
A) RNA polymerase I. B) RNA polymerase III. C) primase. D) mitochondrial RNA polymerase. E) RNA polymerase II. |
RNA Polymerase I
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Which of the following statements about RNA processing is true?
A) Capping on the 3' end of the RNA is important for RNA stability B) RNA splicing removes exons from the RNA transcript C) The poly-A tail is added to the 3' end of RNA by a special polymerase called poly-A polymerase D) RNA splicing occurs in the cytoplasm once the transcript is bound to a ribosome |
The poly-A tail is added to the 3' end of RNA by a special polymerase called poly-A-polymerase
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Cholesterol
A) destabilizes the cell membrane. B) intercalates between the fatty acid chain within the bilayer. C) increases permeability for small cations. D) is found in abundance in prokaryotic cell membranes. E) all of the above |
intercalates btwn the FA chain within the bilayer
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By convention, the sequence of bases in a nucleic acid is usually expressed in the _________ direction.
A) 3' to 5' B) 5' to 3' C) 1' to 3' D) clockwise E) 3' to 1' |
5'-->3' direction
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Which structure includes all of the others?
A) genes B) chromosomes C) nucleolus D) nucleus |
Nucleus
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The main function of ribosomes is in:
A) DNA replication B) Protein synthesis C) Transcription D) Respiration |
Protein Synthesis
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Which chemical group is at the 5' end of a single polynucleotide strand?
A) Diester group B) Purine base C) Phosphate group D) Nitrogen group E) Hydroxyl group |
Phosphate Group
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Most cell membranes are composed principally of
A) DNA and ATP B) chitin and starch C) proteins and lipids D) nucleotides and amino acids |
Proteins & Lipids
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Which of the following is NOT a characteristic of DNA?
A) complementary B) composed of nucleotides C) antiparallel D) double-stranded E) contains ribose |
contains ribose
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A protein is destined to be secreted from a cell. In which organelles would you expect to find the protein after it is produced in the rough endoplasmic reticulum?
A) endosome B) secretory vesicle C) Golgi apparatus D) lysosome E) nucleus |
golgi apparatus
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The microtubule-organizing center (MTOC)
A) acts as an anchor for both ends of the microtubule. B) is called a centrosome during interphase. C) is associated with two centrioles in plant cells. D) is positioned near the cell membrane. E) serves as a site for microtubule and microfilament assembly. |
is called a centrosome during interphase
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Intermediate filaments are
A) composed of actin B) composed of globular proteins only. C) different in different cell types. D) smaller than actin filaments. E) composed of tubulin. |
different in different cell types
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In a nucleic acid, the bases are always attached to the _______________ carbon of the sugar.
A) 2' B) 5' C) 4' D) 1' E) 3' |
1'
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The smooth endoplasmic reticulum functions in synthesis of
A) polysaccharides. B) lipids. C) proteins. D) DNA. E) all of the above |
Lipids
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The __________ is a complex network of interconnected filaments and tubules that extends throughout the cytosol, from nucleus to the inner surface of plasma membrane.
A) desmin sheath B) cytoskeleton C) microfilament array D) microtubule apparatus E) cell scaffold |
Cytoskeleton
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In nucleic acids, the free hydroxyl group is attached to the _______________ carbon of the sugar.
A) 2' B) 5' C) 3' D) 4' E) 1' |
3'
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Why do polar substances such as sodium chloride (NaCl) dissolve so readily in water?
A) The sodium ions repel the partial negative end of the water dipole. B) NaCl is a very dry powder, and the water is able to soak into the salt. C) The nonpolar ends of the water molecules are able to surround the charged salt ions. D) Spheres of hydration form between the water and the ions. |
Spheres of Hydration form between the water and the ions
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Which organelle has only a single membrane around it?
A) mitochondrion B) ribosome C) nucleolus D) nucleus E) peroxisome |
Peroxisome
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F-actin filaments
A) are oriented similar to DNA, with strands helical and antiparallel to one another. B) are composed of G-actin dimers. C) are composed of polymerized G-actin monomers wound around each other in a helix. D) are composed of four linear strands. E) polymerize at the same rate in both directions from both ends of the filament. |
composed of polymerized G-actin monomers wound around each other in a helix
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Pericentriolar material is composed of numerous rings of __________ in combination with a protein known as __________ within the centrosome.
A) gamma tubulin; pericentrin B) alpha tubulin; cilium C) pericentrin; tubulin GTP D) beta tubulin; tubulin GTP E) alpha tubulin; gamma tubulin |
Gamma-tubulin; pericentrin
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Why is a selectively permeable membrane so important to living things?
A) It allows cells to attach to adjacent tissues. B) Proteins will avoid a selectively permeable membrane. C) It provides a good barrier between the inside and outside of the cell. D) The membrane may absorb many times its weight in cholesterol. E) all of the above |
Provides a good barrier between the inside and outside of a cell
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Which statement best describes the function of the Golgi apparatus?
A) Production of energy during photosynthesis B) Synthesis and assembly of membrane and secreted proteins C) Digestion of extracellular material D) Specific transport and signaling systems E) Processing of membrane and secreted proteins, including glycosylation |
Processing of membrane and secreted proteins, including glycosylation
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The methanobacteria, halobacteria, and sulfobacteria are included in which bacterial group?
A) cyanobacteria B) archaebacteria C) blue-green algae D) eubacteria E) all of the above |
Archaebacteria
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Which of the following is a disaccharide?
A) glucose B) lactose C) fructose D) N-Acetlyglucosamine E) galactose |
Lactose
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In relaxed muscle, calcium is found in high concentration in the
A) myofibril. B) sarcolemma. C) sacroplasmic reticulum. D) T tubules. E) neuromuscular junction. |
Sarcoplasmic Reticulum
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The inside of the bilayer is
A) hydrozine B) hydrophallic C) hydrophobic D) hydrophilic |
Hydrophobic
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Which type of bond links glucose units together in glycogen?
A) β(5'->3') B) β(6->4) C) α(1->4) D) β(1->4) E) α(5'->3') |
alpha (1-4)
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Which of the following is an eukaryotic characteristic?
A) cell fission B) membrane-bound nucleus C) little processing of RNA D) 70S ribosomes |
membrane-bound nucleus
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Communication between animal cells is facilitated by
A) plasmodesmata. B) gap junctions. C) adhesive junctions. D) tight junctions. E) both B and C. |
Gap Junctions
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What is at the 2' position of a RNA nucleotide?
A) phosphate group B) methyl group C) a hydrogen molecule D) hydroxyl group E) a nitrogenous base |
Hydroxyl group
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In some diseases like cystic fibrosis, a cell membrane receptor fails to function. In the majority of cases, the problem comes from a change in the receptor so that it cannot reach the cell surface. The site in the cell where membrane proteins are synthesized and assembled builds up with the abnormal protein. This site would likely be the:
A) peroxisome B) nucleus C) mitochondria D) lysosome E) endoplasmic reticulum |
ER
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Which of the following processes would be most likely to occur in the Golgi apparatus?
A) glycosylation of proteins B) detoxification of drugs C) synthesis of steroids D) synthesis of DNA E) production and packaging of lipids |
glycosylation of proteins
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What does the BCL2 Protein do?
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Controls Apoptosis in the mitochondria, like Cytochromes C does
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What is the function of Colchicine?
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degrades MT infrastructure
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Taxol is used for...
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a great breast cancer drug
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Statins...
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prevent cholesterol formation
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Clathrin coat for Lysosomes functions as...
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a protein coat spontaneously forming a cage around the vessicles...
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What is the process that occurs at the 5 position of cytosine and often correlates with gene inactivation?
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Methylation
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What modification of histones is characteristic of actively transcribed chromatin and can weaken the binding of histones to DNA or alter their interactions with other proteins?
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Acetylation
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There is sometimes reverse transcriptase activity in Euakryotes even if the cells are not infected with a virus...this activity can be attributed to
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the presence of retrotransposons
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Where is the cellular location of the glucocorticoid receptor?
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Cytosol
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Most common proto-oncogenes mutated in cancer is Ras, which regulatory protein would be up-regulated if Ras was constitutively active in a tumor cell?
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Raf
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