Study Questions: Chapter 28
1.) Archaea and Bacteria are the oldest, structurally simplest and most abundant forms of life. 2.) Name and describe seven ways in which prokaryotes differ substantially from eukaryotes? Unicellularity- fundamentally single-celled
Cell Size- can vary (large range changes with species)
Nucleoid- lack a membrane-bound nucleus but rather a nucleoid region Cell Division/Genetic Recombination- binary fission (does not use spindle) and do not have a sexual cycle Internal Compartmentalization- does not have internal compartments and no membrane organelles Flagella- no 9+2 structure
Metabolic Diversity- photosynthesis (oxygenic/produce oxygen and anoxygenic/nonoxygen producing) 3.) Explain 4 ways in which Archaea and Bacteria differ?
Plasma Membrane- ether bond (lipid) can also have branches (tetraethers) Cell Wall- lack peptidoglycan, has psuedomurein, does the same as peptidoglycan DNA Replication- similar to eukaryotes
Gene expression- may have two RNA polymers and different than bacteria similar to eukaryotes 4.) Name 5 key characteristics once used in classifying prokaryotes. Photosynthetic/nonphotosynthetic
Formation of spores/Division by transverse binary fission
Importance as human pathogens or not
5.) Name the domains of life.
6.) Name and describe 3 basic forms of prokaryotes.
Spirillum (long and helical-shaped)
7.) The bacterial cell wall is the single most important contributor to cell shape. 8.) Prokaryotic cell walls are constructed of many layers, which is formed from peptidoglycan polymers cross-linked by peptide side chains. 9.) Describe a Gram Stain.
Staining technique that divides bacteria into gram-negative or gram-positive based on retention of a violet dye 10.) Distinguish between gram positive and gram negative bacteria. Gram-positive- has a thicker peptidoglycan wall and stain purple Gram-negative- less peptidoglycan (no stain),red may appear (pink) 11.) Describe the additional layer found in some bacteria.
S-layer- glycoprotein layer forms a paracrystalline surface (helps with adhesion to surfaces and protection) 12.) What is the function of the capsule, flagella and pili. Capsule- enable adhesion to surfaces/ other cells and most important evading immune response Flagella- help cell move through liquid environment
Pili- more important in adhesion than movement and have a role in the exchange of genetic information 13.) Some prokaryotes are able to form endospores, developing a thick wall around their genome and a small portion of the cytoplasm when they are exposed to environmental stress. 14.) Describe the interior of bacteria.
Have 3 main components: Internal membrane- regions of plasma membrane for respiration/photosynthesis, Nucleoid region-visible region where the DNA is held, Ribosomes- that differ in RNA content 15.) Prokaryotes lack nuclei and generally do not possess linear chromosomes. 16.) DNA is localized in a nucleoid region.
17.) Prokaryotes do not reproduce sexually, but they can exchange DNA between different cells. 18.) Name and describe 3 ways bacteria exchange DNA between different cells. Conjugation- horizontal gene transfer where you have an F plasmid, donor (Fᶧ) and recipient (F¯), integration/excision Transduction- (lytic/lysogenic cycle)
Transformation- when a cell dies the remaining DNA is taken up by another live cell 19.) Define conjugation, transduction, and transformation.
Conjugation- temporary union of two unicellular organisms, during which genetic material is transferred from one cell to another Transduction- generalized (any gene can be transferred between cells lytic phage)/ specialized (few genes are transferred lysogenic life cycle) Transformation-the uptake of DNA directly from the environment 20.) DNA can be exchanged by conjugation via plasmids, by transduction...
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