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Questions and Answers
What is the shape of ribosome particles when viewed under an electron microscope?
What is the shape of ribosome particles when viewed under an electron microscope?
What is the term for collections or chains of ribosomes held together on a single mRNA molecule?
What is the term for collections or chains of ribosomes held together on a single mRNA molecule?
What is the Svedberg coefficient of the more or less spherical ribosome particle?
What is the Svedberg coefficient of the more or less spherical ribosome particle?
What are the two lower-molecular-weight components of a prokaryotic ribosome?
What are the two lower-molecular-weight components of a prokaryotic ribosome?
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What is the function of both 70S and 80S ribosomes?
What is the function of both 70S and 80S ribosomes?
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Why do eukaryotic mitochondria have 70S ribosomes?
Why do eukaryotic mitochondria have 70S ribosomes?
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What is the shape of the chromosome of E. coli?
What is the shape of the chromosome of E. coli?
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What is the process by which bacteria form two daughter cells?
What is the process by which bacteria form two daughter cells?
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What is indicated by an uppercase letter in the first position of a gene symbol?
What is indicated by an uppercase letter in the first position of a gene symbol?
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Why would an arg mutant need arginine in the minimal medium?
Why would an arg mutant need arginine in the minimal medium?
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What is the length of the E. coli chromosome in base pairs?
What is the length of the E. coli chromosome in base pairs?
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What is the duration of time required for E. coli to reproduce in a minimal glucose medium?
What is the duration of time required for E. coli to reproduce in a minimal glucose medium?
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Why would a lac mutant not grow on lactose?
Why would a lac mutant not grow on lactose?
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What is the reference point for gene positions on the E. coli chromosome?
What is the reference point for gene positions on the E. coli chromosome?
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What can E. coli use as a nitrogen source in minimal medium?
What can E. coli use as a nitrogen source in minimal medium?
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What type of medium can E. coli grow on?
What type of medium can E. coli grow on?
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What is the main difference in membrane structure between gram-positive and gram-negative cells?
What is the main difference in membrane structure between gram-positive and gram-negative cells?
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What is the purpose of the pores in the outer membrane of gram-negative cells?
What is the purpose of the pores in the outer membrane of gram-negative cells?
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What is the primary function of the capsule in bacterial cells?
What is the primary function of the capsule in bacterial cells?
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What is the composition of the capsule of Streptococcus pneumoniae type III?
What is the composition of the capsule of Streptococcus pneumoniae type III?
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What is the term for the high-molecular-weight polymers of carbohydrates that compose the capsule?
What is the term for the high-molecular-weight polymers of carbohydrates that compose the capsule?
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Which of the following bacteria produces a capsule?
Which of the following bacteria produces a capsule?
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What is the term for the material external to the cell that is composed of polysaccharides or polypeptides?
What is the term for the material external to the cell that is composed of polysaccharides or polypeptides?
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What is the function of the periplasmic space in gram-negative cells?
What is the function of the periplasmic space in gram-negative cells?
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What is the function of carbohydrate metabolism in cells?
What is the function of carbohydrate metabolism in cells?
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What is the role of cytochrome system in energy production?
What is the role of cytochrome system in energy production?
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What is the purpose of proton-translocating ATPase in energy production?
What is the purpose of proton-translocating ATPase in energy production?
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What is the byproduct of oxidative phosphorylation?
What is the byproduct of oxidative phosphorylation?
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What is the role of electron acceptors in energy production?
What is the role of electron acceptors in energy production?
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What is the process by which cells generate energy through the transfer of hydrogens?
What is the process by which cells generate energy through the transfer of hydrogens?
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What is the term for the force generated by the movement of protons across the membrane?
What is the term for the force generated by the movement of protons across the membrane?
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What is the role of phosphoenol pyruvate in energy production?
What is the role of phosphoenol pyruvate in energy production?
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What is the role of the cytochrome system in the cell?
What is the role of the cytochrome system in the cell?
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What is the terminal electron acceptor molecule under aerobic conditions?
What is the terminal electron acceptor molecule under aerobic conditions?
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What is the molecule that serves as a terminal electron acceptor under anaerobic conditions?
What is the molecule that serves as a terminal electron acceptor under anaerobic conditions?
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What is the molecule that connects to pentose-5-P in the carbohydrate metabolism pathway?
What is the molecule that connects to pentose-5-P in the carbohydrate metabolism pathway?
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What is the molecule that is converted to glyceraldehyde-3-P in the carbohydrate metabolism pathway?
What is the molecule that is converted to glyceraldehyde-3-P in the carbohydrate metabolism pathway?
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What is the molecule that is connected to oxaloacetate in the carbohydrate metabolism pathway?
What is the molecule that is connected to oxaloacetate in the carbohydrate metabolism pathway?
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What is the molecule that is connected to sedoheptulose-7-P in the carbohydrate metabolism pathway?
What is the molecule that is connected to sedoheptulose-7-P in the carbohydrate metabolism pathway?
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What is the molecule that is connected to CO2 in the carbohydrate metabolism pathway?
What is the molecule that is connected to CO2 in the carbohydrate metabolism pathway?
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What is the molecule that is connected to glyceraldehyde-3-P in the carbohydrate metabolism pathway?
What is the molecule that is connected to glyceraldehyde-3-P in the carbohydrate metabolism pathway?
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What is the molecule that is connected to aspartate in the carbohydrate metabolism pathway?
What is the molecule that is connected to aspartate in the carbohydrate metabolism pathway?
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Study Notes
Cell Structure
- Gram-positive and gram-negative cells have different strategies for transporting materials across the membrane and into the cell.
- Gram-positive organisms have immediate access to media components through their cytoplasmic membrane.
- Gram-negative organisms have an outer membrane that must be traversed before reaching the cytoplasmic membrane, with pores formed by protein triplets that permit large molecule passage into the periplasmic space.
- Capsules are composed of polysaccharides or polymers of amino acids called polypeptides, and aid in virulence, such as the pneumococcal polysaccharide in Streptococcus pneumoniae.
Synthesis of DNA, RNA, and Protein
- Ribosomes are responsible for protein synthesis and are composed of 70S particles in prokaryotes and 80S particles in eukaryotes.
- Prokaryotic ribosomes can be separated into 50S and 30S components, while eukaryotic ribosomes are associated with the endoplasmic reticulum.
- Mitochondria display 70S ribosomes, likely due to endosymbiotic prokaryotic cells.
Chromosome Structure
- The chromosome of E. coli is a single, circular, double-stranded DNA molecule that encodes all information required for cell growth and structure.
- Gene positions can be given in base pairs starting from the gene thrL, or in minutes based on the period of time required to transfer the chromosome from one cell to another by conjugation (100-minute map with thrL at 0).
Chemical Synthesis
- E. coli can reproduce in minimal glucose medium every 40 minutes, requiring various chemical components.
- Major pathways of carbohydrate metabolism include 13 key metabolites, such as glucose, erythrose, and sedoheptulose.
- Vitamins and cofactors, such as folates, riboflavin, and coenzyme A, are essential for cell growth.
- Phospholipids, amino sugars, and phosphoenol pyruvate are also crucial components.
Energy Production
- The cytochrome system pumps H+ out of the cell, generating a proton motive force that drives ATP production.
- Under aerobic conditions, oxygen serves as the terminal electron acceptor, while under anaerobic conditions, E. coli can choose from alternate electron acceptors, such as nitrate.
- Oxidative phosphorylation occurs through the cytochrome system and ATPase, generating ATP from the proton motive force.
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Description
This quiz explores the differences in membrane transport between gram-positive and gram-negative cells, including the role of outer membranes and pores in nutrient uptake.
