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53 Cards in this Set
- Front
- Back
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What is the shape of archaeal DNA? (Eg. linear, circular) How is it packaged? |
Circular, and is wrapped around histones. Also happens in Eukarya. |
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What is the difference between Bacteria and Archaea in regards to their lipids? |
Bacteria lipids are bound by ester linkages, whereas archaeal lipids have ether linkages. |
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Although archaeal organisms do not have peptidoglycan walls, many have a cell wall made of what material? |
Pseudomurein |
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How does peptidoglycan and pseudomurein differ? |
Pseudomurein's backbone is composed of alternating molecules of NAG and NAT, and connected by beta-1,3 glycosidic linkages, rather than beta-1,4 linkages in peptidoglycan. |
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What are thermophiles, halophiles, barophiles and acidophiles?
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Heat-loving, salt-loving, pressure-loving, and acid-loving |
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What is some special adaptations that allows extremophiles to withstand conditions of extreme heat? |
The microbes have a lipid monolayer plasma membrane, thermostable proteins, molecular chaperones (refold denatured proteins). |
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What is a difference between the plasma membranes of Bacteria and Archaea? |
Archaea has a unique bilayer construction; the location of their phosphate groups are different, and they have phytanyl side chains instead of fatty acids (in bacteria). |
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what is more stable? A bilayer or a monolayer? Why? |
Monolayer - There's phosphoglycerol molecules on both ends and are covalently linked. |
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What is a cannulae? |
Hollow glycoprotein tubes that link together to form a complex network. |
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How do flagellas differ between Bacteria and Archaea? |
Bacteria flagellas grow from the tip, whereas Archaea flagellas grow from the base. |
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What are some protein adaptations for Archaea to make them more stable? |
More alpha-helical regions, more salt bridges/side chain interactions, more arginine/tyrosine, less cysteine/serine, strong chaperone protein complexes, reverse DNA gyrase enzyme to increase supercoiling (prevents from denaturing). |
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Which 2 nitrogenous bases form 3 hydrogen bonds? |
Guanine and cytosine
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Most halophiles are phototrophic. What does that mean? |
They possess no chlorophyll pigments. They generate a PMF using a molecule called bacteriorhodopsin. |
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What is a methanogen? And where are they located? |
Organisms who produce methane by reducing CO2 with H2. They live in strictly anoxic conditions. |
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what are some examples of a methanogen hfacabitat? |
Marshes, swamps, the human gut, animal digestive tracts, hydrothermal vents |
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What is the shape of Eukaryal DNA (Eg. linear? Circular?) |
Linear |
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In Eukaryotes, where does transcription occur? What about translation? |
Transcription occurs in the nucleus, whereas translation occurs in the cytoplasm. |
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What does the ER/Golgi Apparatus do? |
Proteins are often extensively modified in these structures prior to reaching their destinations. |
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What does the mitochondria do? |
Cell metabolism, produce ATP (chemiosmosis), cellular respiration. |
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What does the chloroplast do? |
Cell metabolism, produce ATP (chemiosmosis), fix carbon into organic compounds. |
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How are cellulose and chitin molecules linked? |
Beta-1,4 glycosidic bonds between sugars. |
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What are the three major pieces of the cytoskeleton? |
1) Microtubules 2) Microfilaments |
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What is the purpose of microtubules? |
Intracellular transport, separation of chromosomes in mitosis and meiosis, cell movement. |
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What is the purpose of microfilaments? |
Maintain cell shape, create division furrow in cytokinesis, cell movement. |
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What is the purpose of intermediate filaments? |
Nuclear structure, cell-cell interactions |
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What is the difference between the flagellas of Bacteria and Eukarya? |
1) Bacteria are non-flexible, eukarya are. 2) Bacteria flagellas extend from the cell membrane, eukarya flagellas are covered by the cell membrane. 3) Bacteria flagella is composed of flagellin subunits, whereas eukarya is composed of a 9+2 array. |
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What is the model organism for Fungi? What makes it a good model organism? |
Saccharomyces cerevisae. Yeast. Easy to study eukaryotic structure/gene expression. |
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What is the model organism for protozoa? |
Giardia lamblia. |
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What is the model organism for slime moulds? What makes them a good model organism? |
Dictyostelium discoideum. Good to study ecology, cell motility, and cell-cell communication. |
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What is the model organism for algae? What makes it a good model organism? |
Chlamydomonas. Good for studying eukaryal flagella biogenesis/function. |
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What is an ascus? |
Saccharomyces in its diploid form. |
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What is some evidence for endosymbiotic theory? |
1) Mitochondria/chloroplasts resemble bacteria in shape and size 2) They have double membranes 3) "Cell" division with FtsZ 4) Each has its own DNA 5) Circular chromosomes |
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Why are viruses not technically considered alive? |
Because they can not metabolize or replicate independently. |
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What is a bacteriophage? |
Viruses that infect bacteria. The most abundant viruses on Earth. |
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what is a capsid? |
A protein structure around the genome that is composed of many capsomere proteins. |
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What is the shape of viral DNA? (Eg. Linear? Circular?) |
Both linear and circular. |
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What are the two types of symmetry found in viruses? |
Helical and icosahedral. Most bacteriophages have an icosahedral "head" and a helical "tail". |
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Where do enveloped viruses get their lipid bilayer (plasma membrane)? |
The membrane of the host cell, or can be derived from the golgi, ER, or nucleus. |
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how do most viruses enter a host cell? |
They possess an attachment protein that binds to a receptor protein on the surface of the host. |
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Describe the process of viral replication: |
1) Adhere - stick to a host cell 2) Enter 3) Uncoat - release genome 4) Synthesis - express and replicate genome 5) Assembly - create and replicate genome 6) Exit - new particles leave cell |
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How does HIV enter the host cell? |
It attaches to CD4 receptors on T cells |
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How do bacteriophages enter the cell? |
They use their tail to penetrate the host cell's plasma membrane and inject their genomes. |
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What is the Coevolution Hypothesis? |
Viruses orginated about the same time as other microbes and have been coevolving with them. |
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What is the Regressive Hypothesis? |
Viruses are previously alive organisms that have evolutionarily regressed into host-dependent particles. |
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What is the Progressive Hypothesis? |
Viruses originated from genetic material that gained the ability to replicate and be transmitted semi-autonomously. |
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What are the 2 ways that viruses enter animal cells? |
Endocytosis and membrane fusion |
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How do viruses enter plant cells? |
Depends on damage to plant tissues to open a spot in the cell wall Eg. Wind/rain/fire/human-induced |
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What is the lytic cycle? |
The phage enters, replicates and lyses the host cell. |
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What is the lysogenic cycle? |
The phage integrates their genome into the host cell genome, becoming a "prophage". Replicates until stress. |
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Is HIV lytic or lysogenic? |
Lysogenic |
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How can viruses be identified? |
Electron microscopy and nucleic acid analyses. |
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What are viroids? |
Naked RNA genome. Most likely to be replicated by host enzymes. Only observed to cause disease in plants. |
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What are prions? |
Do not possess any sort of genome yet they are still able to replicate and infect host cells. They are responsible for transmissible spongiform encephalopathies, such as Mad Cow disease. |
