exam 1 Flashcards
true membrane-bound nucleus
bacteria - no
archaea - no
eukaryotes - yes
DNA complex with histones
bacteria - no
archaea - some
eukaryotes - yes
chromosomes
bacteria - one circular, single origin
archaea - one circular, multiple origins
eukaryotes - more than one
Plasmids
bacteria - very common
archaea - very common
eukaryotes - rare
Introns in genes
bacteria - rare
archaea - rare
eukaryotes - yes
nucleolus
bacteria - no
archaea - no
eukaryotes - yes
mitochondria, chloroplasts, ER, Golgi, and lysosomes
bacteria - no
archaea - no
eukaryotes - yes
plasma membrane
bacteria - ester link, hopanoids, some sterols
archaea - glycerol and diglycerol tetraethers
eukaryotes - ester-linka and sterols
flagella
bacteria - single type
archaea - more than one type
eukaryotes - 9+2 pattern, 20 microtubules
peptidoglycan in cell walls
bacteria - yes
archaea - no
eukaryotes - no
ribosomes size and structure
bacteria - 70s; 3 rRNAs; 55ribosomal proteins
archaea - 70s; most have 3 rRNA - 68 ribosomal proteins
eukaryotes - 80s; 4rRNAs - 80 ribosomal proteins
cytoskeleton
bacteria - rudimentary
archaea - rudimentary
eukaryotes - yes
gas vesicles
bacteria - yes
archaea - yes
eukaryotes - no
study of disease in humans and animals is the field of :
1) medical
2) immunology
3) biotech
1) medical
epidemiologists working in the field of ____microbiology monitor the prevalence of disease in populations:
1) medical
2) public health
3) ecology
2) public health
scientists study how the immune system protects the body in the field of __:
1) medical
2) public health
3) immunology
3) immunology
in the field of __ , however, a variety of approaches are used to describe microbial diversity in terms of relationships between organisms and their governments:
1) molecular
2) microbial ecology
3) virology
2) microbial ecology
merging both medical and microbial ecology, the field of ___microbiology concerns the role of microbes in crop production and as pesticides :
1) food and dairy
2) agricultural
3) industrial
2) agricultural
another area that parallels agricultural microbiology is the study of microbial spoilage, which is part of the field of ____ micro:
1) industrial
2) public health
3) food and dairy
3) food and dairy
Researchers in the field of ___ microbiology develop ways to exploit the metabolic abilities of microbes to generate valuable products:
1) Industrial
2) public health
3) food and dairy
1) industrial
Bacteria and archaea are typically fixed to slides by _____ while eukaryotes with subcellular structure, such as protists, are typically fixed by ______.
heat ; chemicals
The initial statement of the _______ hypothesis proposed that over time a bacterial endosymbiont of an ancestral cell in the eukaryotic lineage lost its ability to live independently.
Endosymbiotic
The endosymbiont then became either a _______, if the intracellular bacterium used aerobic respiration, or a ________, if the endosymbiont was a photosynthetic bacterium.
mitochondrion ; chloroplast
Recently the endosymbiotic hypothesis for mitochondria has been modified by the ______ hypothesis. This asserts that the endosymbiont was an anaerobic bacterium that produced hydrogen and carbon dioxide as end products of its metabolism.
hydrogen
Over time, the host became dependent on the hydrogen produced by the endosymbiont. Ultimately the endosymbiont evolved into one of two organelles. If the endosymbiont developed the capacity to perform _______ respiration, it evolved into a mitochondrion.
aerobic
However, if the endosymbiont did not develop this capacity, it evolved into a __________ - an organelle found in some extant protists that produce ATP by a process called ___________.
hydrogenosome ; fermentation
Which domain describes an organism that lacks linear chromosomes BUT has peptidoglycan cell walls?
Bacteria
In endospore formation, when DNA condenses and aligns itself in the center of the cell, the cell is called a __________.
mother cell
The “cis” side of the Golgi complex refers to which side of the Golgi?
The side of the Golgi facing the ER.
The proper sequence of reagents in the Gram stain procedure is:
crystal violet, iodine, ethanol, safranin
In the gram-positive bacterial cell wall, the tetrapeptides that extend from the peptidoglycan layers are linked by _________.
peptide interbridges
What domain produces hams and cannulae?
Archaea
What domain has a cell envelope that often contains an S layer?
Archaea
The domain that has chromosomes associated with histones.
Archaea
The domain that has membrane lipids containing isoprenic hydrocarbons.
Archaea
The domain with membranes that can be monolayers or bilayers.
Archaea
The domain with flagellar rotation powered by proton motive force.
Bacteria
The domain that has lipids with fatty acids attached to glycerol by water bonds.
Bacteria
The domain that contains hollow flagella.
Bacteria
The domain with cell envelopes with peptidoglycan.
Bacteria
What microscope would be the best to use to constituents within a cell?
Transmission electron microscope
What is a component of the outer membrane in Gram-negative bacteria that results in septic shock upon entering the bloodstream?
Lipopolysaccharide
An archaeologist in a nutrient-poor environment is most likely to use _______ for nutrient uptake.
ABC transport
An organism characterized by having cells containing DNA in a membrane-bound organelle.
Eukaryote
An organism characterized by having a cell lacking a membrane-bound nucleus.
Prokaryote
An infectious agent consisting of only protein.
Prion
An infectious agent consisting of only RNA.
Viroid
An infectious agent made up of protein, nucleic acids and sometimes a lipid membrane.
Virus
What microscope is used to examine both stained or unstained specimens?
bright-field microscope
It is called a bright-field microscope because it forms a ______ image against a _______ background.
dark ; brighter
What is mounted within or beneath the stage of the bright-field microscope and focuses a cone of light on the slide?
condenser
A microscope that retains proper focus when the objectives are changed.
par focal
Light from the illuminated specimen is focused by the ______, creating an enlarged image with the microscope. The ______ further magnifies this primary image.
objective lens ; ocular lens
The total magnification is calculated by multiplying the _____ and _____ magnifications together.
objective ; eyepiece
The ability of a lens to separate or distinguish between small objects that are close together.
resolution
Name the three types of light microscopes that create detailed, clear images of living specimens.
- ) dark-field microscopes
- ) phase-contrast microscopes
- ) differential interference contrast microscopes
Microscopy in which the specimen is brightly illuminated while the background is dark.
dark-field microscopy
The minimal distance becomes smaller as the ______ of light used decreases and as the numerical aperture increases.
wavelength
What will increase numerical aperture and resolution when using a microscope?
immersion oil
Using dark-field microscopy, a hollow cone of light is focused on the specimen to that unreflected and unrefracted rays do not enter the ________ lens.
objective
What two microscopes create images by detecting the differences in refractive indices and thickness?
- ) differential interference contrast microscope
2. ) phase-contrast microscope
A fluorescent dye.
fluorochrome
Green fluorescent gene encodes a ______ that naturally fluoresces green when exposed to light of a certain wavelength.
protein
What type of light source is used by a confocal microscope?
laser
What is obtained using a lens with the largest possible numerical aperture and light of the shortest wavelength?
the best resolution
When preparing a specimen for microscopy, what two things generally occur during the fixation step?
- ) cells are attached to the slide
2. ) cells are killed
A light microscope in which monochromatic laser derived light scans across the specimen at a specific level. Stray light from above and below the plane of focus is blocked out to give an image with excellent contrast and resolution.
confocal microscope
The only light used to create an image by what microscope is from the plane of focus, and a much sharper image is formed.
confocal microscope
Fixation technique that inactivates proteins, and destroys proteins of sub cellular structures.
heat fixation
Fixation technique that inactivates proteins, but protects fine cellular substructure.
chemical fixation
A chemical group with double bonds that absorbs visible light and gives a dye its color.
chromophore group
A staining procedure in which a dye is used to make the background dark while the specimen is unstained.
negative staining
What unique biomolecule is found in acid-fast bacterial cell walls that prevents dyes from binding readily to these cells?
mycolic acid
A substance that helps fix dye on or in a cell.
mordant
An extremely heat and chemical-resistant dormant, thick-walled spore that develops within some members of the bacterial phylum Firmicutes.
endospore
Capsules are networks composed mostly of ______ that surround many bacteria.
polysaccharide
Methylene blue, crystal violet and safranin are examples of which type of dye?
basic
Most membrane-associated lipids are _______: they are structurally symmetrical with polar and nonpolar ends.
amphipathic
A polar substance that has a strong affinity for water (or is readily soluble in water).
hydrophilic
A non polar substance lacking affinity for water (or which is not readily soluble in water).
hydrophobic
Are loosely connected to the membrane and can be easily removed. They are soluble in aqueous solutions and make up about 20-30% of total membrane protein.
peripheral membrane proteins
Are not easily extracted from membranes and are insoluble in aqueous solutions when freed of lipids. They are amphipathic.
integral membrane proteins
Hydrophobic regions are buried in the lipid while the hydrophilic portions project form the membrane surface.
amphipathic
2 functions for integral membrane proteins.
- ) transport proteins
2. ) energy-conserving processes
Lipids found in bacterial membranes that are similar in structure and function to the steroids found in eukaryotic membranes.
hopanoids
What are the three types of growth factors?
- ) amino acids
- ) purines and pyrimidines
- ) vitamins
Compounds that must be acquired from the environment for cell survival.
growth factors
The unaided energy-free movement of molecules across a membrane.
passive diffusion
The use of ATP to power the movement of substance across a membrane is commonly referred to as ________ transport.
primary active transport
Transport of molecules across the membrane using an additional solute.
secondary active transport
What term is used to describe the plasma membrane and all layers external to it?
call envelope
Describes the chemical modification of a molecule as it is transported into a bacterial cell.
group translocation
Elements such as carbon, oxygen, hydrogen, nitrogen, sulfur, and phosphorus are considered what?
macronutrients
The “energy free” movement of molecules across a membrane with the aid of a transporting protein is called what?
facilitated diffusion
What is the layer of lipid macromolecules that surround the cell’s cytoplasm?
plasma membrane
Complex of sugars and amino acids that forms a mesh like structure.
peptidoglycan
Peptidoglycan is composed of what two things?
- ) sugars
2. ) amino acids
What is the role of teichoic acids?
give added strength to then cell wall
Teichoic acids are common among gram (+ or -?) bacteria.
gram +
Lipopolysaccharieds are found in gram (+ or -?) bacteria?
gram -
What is well known to protect gram-negative bacteria from environmental toxic substances?
LPS
The LPS component responsible for stimulating an antibody response in gram-negative bacterial infections is the what?
O antigen
Which organism group has cell walls composed of peptidoglycan?
bacteria
A regularly structured layer composed of protein or glycoprotein the tiles on the surface of many bacteria and archaea.
S-layer
Who established the 3 domains
Carl Woese
