Exam 1 Q's Flashcards
- A bacterial species is defined as a group of bacteria with: a. the ability to exchange genetic material b. Greater than 50% similarity by trait comparison c. Greater than 70% similarity by DNA/DNA hybridization d. Greater than 95% similarity by 16S rRNA sequencing
c. Greater than 70% similarity by DNA/DNA hybridization
- Which of the following types of microscopy allow you to visualize bacteria without killing them? a. phase-contrast microscopy b. scanning electron microscopy c. transmission electron microscopy d. bright field light microscopy with Gram staining
a. phase-contrast microscopy
- The resolution of light microscopy is ultimately limited by: a. focal length b. lens strength c. numerical aperture d. the wavelength of visible light
d. the wavelength of visible light
- 16S rRNA is found in the: a. nucleoid b. ribosome c. periplasm d. membrane
b. ribosome
- In bacteria, there are ___________ different monomers that make up proteins. a. 4 b. 16 c. 20 d. 64
c 29
- In bacteria, there are ___________ different monomers that make up RNA. a. 4 b. 16 c. 20 d. 64
a. 4
- Which part of lipopolysaccharide contains highly negatively charged sugars? a. core b. lipid A c. O-antigen d. teichoic acid
a. core
- Which is NOT true concerning extracellular polysaccharides: a. they reduce diffusion of molecules to the plasma membrane. b. they protect bacteria from a host’s immune system. c. they help bacteria stick to surfaces. d. they are required for growth.
d. they are required for growth
- The folding of a protein into a complex and specific three dimensional shape is called the ___________ structure. a. primary b. secondary c. tertiary d. quaternary e. none of the above
C and D
- Peptidoglycan is an especially stable cell wall polymer for all of the following reasons except: a. It contains β1-4 glycoside bonds. b. It contains unusual amino acids. c. It contains peptide bonds. d. It is hydrophobic.
d. It is hydrophobic.
- An extracellular crystalline shell of protein synthesized by some bacteria is called a(n): a. teichoic acid b. slime layer c. S-layer d. capsule
c. S-layer
- Molecular chronometers must have all of the following properties for the phylogenetic analysis of organisms except: a. it has regions of low sequence similarity between some organisms b. it has regions of high sequence similarity between some organisms c. it has different functions in different organisms d. it is present in all organisms being compared
c. it has different functions in different organisms
a. Porin b. SMC c. MreB d. CreS e. Braun’s Lipoprotein 14. This protein connects the outer membrane to the peptidoglycan.
e. Braun’s Lipoprotein
a. Porin b. SMC c. MreB d. CreS e. Braun’s Lipoprotein 15. This protein makes a rod cell, rod-shaped.
c. MreB
a. Porin b. SMC c. MreB d. CreS e. Braun’s Lipoprotein 16. This protein makes the nucleoid, nucleoid-shaped.
b. SMC
a. Porin b. SMC c. MreB d. CreS e. Braun’s Lipoprotein 17. This protein increases membrane permeability.
a. Porin
a. Porin b. SMC c. MreB d. CreS e. Braun’s Lipoprotein 18. This protein directs peptidoglycan synthesis.
c, MreB
a. polysaccharide b. nucleic acid c. protein d. lipid e. structure has properties of more than one macromolecular class 19. _______________ is defined by α and β linkages.
a. polysaccharide
a. polysaccharide b. nucleic acid c. protein d. lipid e. structure has properties of more than one macromolecular class 20. _______________ is defined by the N and C termini.
c. protein
a. polysaccharide b. nucleic acid c. protein d. lipid e. structure has properties of more than one macromolecular class 21. The largest macromolecule inside the cell is made of _____
nucleic acid
a. polysaccharide b. nucleic acid c. protein d. lipid e. structure has properties of more than one macromolecular class 22. Peptidoglycan is made of _______________.
e. structure has properties of more than one macromolecular class
a. polysaccharide b. nucleic acid c. protein d. lipid e. structure has properties of more than one macromolecular class 23. A bacterial capsule is made of _______________.
d. lipid
a. polysaccharide b. nucleic acid c. protein d. lipid e. structure has properties of more than one macromolecular class
d. lipid
a. polysaccharide b. nucleic acid c. protein d. lipid e. structure has properties of more than one macromolecular class
b. nucleic acid
a. polysaccharide b. nucleic acid c. protein d. lipid e. structure has properties of more than one macromolecular class
c. protein
T/F
- Disulfide bridges are a common way to stabilize protein folding in the cytoplasm.
False
True or False
- Serotyping is a way of classifying bacteria based on antibody reactivity.
True
True or False
- Mitochondria were once bacteria.
True
True or False
- Eukaryotes and Bacteria have been on Earth for the same amount of time.
False
True or False
- In fluorescence microscopy, the light source and detector are on the same side of the sample.
True
True or False
- In transmission electron microscopy, the electron emitter and detector are on opposite sides of the sample
True
True or False
- Detergents kill cells by disrupting the membrane.
True
Epulopiscium fishelsoni
Escherichia coli
Magnetospirillum magnetotactum
Mycobacterium tuberculosis
Mycoplasma pneumoniae
Vibrio fischeri
- Which organism of the week is unusual with respect to thearchitecture of its cell envelope
(plasma membrane and external structures)? (1 pt). How is theenvelope unusual? (2 pts)
Mycoplasma pneumoniae – no peptidoglycan, membranes contain cholesterol
Mycobacterium tuberculosis – two capsules with a waxy mycolic acid layer
Epulopiscium fishelsoni
Escherichia coli
Magnetospirillum magnetotactum
Mycobacterium tuberculosis
Mycoplasma pneumoniae
Vibrio fischeri
- Which organism of the week challenges either our definition of a bacterium or the definitionof a bacterial species (1 pt)? Why does this organism challenge the definition (2 pts)?
Escherichia coli – two members of the same species have same 16S rRNA sequence but
genome differs by 25% (2)
Epulopiscium fishelsoni – cells are not small, visible to naked eye (2). Division is not binary but division mechanism isn’t part of the bacterial definition (0).
Mycoplasma pneumoniae – all bacteria have peptidoglycan, except Mycoplasma and close relatives
Epulopiscium fishelsoni
Escherichia coli
Magnetospirillum magnetotactum
Mycobacterium tuberculosis
Mycoplasma pneumoniae
Vibrio fischeri
- Which organism of the week was thought to have organelles? (1pt) What did the internal
structures turn out to be instead? (2 pts)
Epulopiscium (1), internal daughter cells (2)
Magnetospirillum (1), membrane invaginations containing magnetite (2), storage granules (1),
magnetosomes (1), while both of the latter are correct, they were also the cause of the confusion and I’m looking for something about membrane invaginations to distinguish them from organelles.
Mycoplasma (1), attachment organelle (1), proteinaceous endoskeletal element (2).
37.Cell interior. a) What is an organelle? (2 pts)
Membrane enclosed intracellular compartment (2)
b) Why do bacteria not need organelles? (2 pts)
Small with a high surface area to volume ratio (2)
c) What is a nucleoid? (2 pts)
Region of the bacterial cell containing the compacted chromosome, not enclosed by an
additional nuclear membrane (2)
d) What is one advantage to having a nucleoid rather than a nucleus? (2 pts)
Rapid signal transduction (2)
Coupled transcription/translation (2)
Nomenclature/Taxonomy. a) Why are bacteria unable to be organized by the traditional species definition as set by Linnaeus? (2 pts)
They do not reproduce sexually (2)
b) What is numerical taxonomy? (2 pts)
Organizing by trait similarity (2)
c) What is phylogenetics? (2 pts)
Organizing by similarity of a shared polymer sequence molecular chronometer (gene/protein) (2)
d) Describe two ways in which analysis of 16s rRNA sequences changed the way biologists think about the organization of life on earth? (2 pts)
5 Kingdom tree > 3 Kingdom tree
Archaea discovered
Molecular ecology invented/microbiome
Discovery that photosynthesis is a broadly distributed trait
Proof of endosymbiotic theory of organelles
- Membranes. a) Explain the Fluid-Mosaic Model of biological membranes (2 points).
Fluid – molecules laterally diffuse rapidly in a phospholipid bilayer (1)
Mosaic – proteins embedded throughout the bilayer (1)
b) Give three types of damage that threaten the stability of biological membranes. For each type of damage, describe one specific way that bacteria defend against this damage (6 points).
Thermal - Adjust fatty acid content in phospholipids
Osmotic - Build peptidoglycan sacculus beyond membrane to contain membrane expansion
Chemical - Make outer surface highly negatively charged/charge barrier to discourage diffuse of hydrophobic molecules to membrane
