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BIO 205 MICROBIOLOGY EXAM 2025 QUESTIONS AND ANSWERS GRADED A+ RIO SALADO COLLEGE Define Pathogenic. disease producing Types of microbes 1.Bacteria 2.Archea 3.Fungi 4.Protozoa 5.Algae 6.Viruses 7. Parasites Bacteria single celled, genetic material not enclose in membrane, some can complete photosynthesis, some can swim using flagella
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Define Pathogenic.
disease producing
Types of microbes
1.Bacteria
2.Archea
3.Fungi
4.Protozoa
5.Algae
6.Viruses
Bacteria
single celled, genetic material not enclose in membrane, some can complete photosynthesis, some can swim using flagella
Bacteria are enclose in:
Cell walls made of peptoglycan
Bacterial Cells are called?
Prokaryotes
Bacterial Cell Shapes (3)
Prokaryotes include both:
Bacteria and archeas
Bacterial reproduction
Binary Fission: divide into two equal cells
Fungi
eukaryotic, unicellular/multicellular, cell walls composed of chitin, can reproduce sexually/asexually, feed on organic material from their environment
Unicellular form of fungi:
yeasts (oval microbes, larger than bacteria)
Most popular fungi
molds (form visible masses called mycelia)
Protozoa
unicellular, eukaryotic microbes, various shapes, live as free entities or as parasites.
How do protozoa move and reproduce:
pseudopods, flagella, or cilia. Can reproduce asexually and sexually.
Algae
photosynthetic eukaryotes, various shapes, reproduce sexually and asexually. Need light, water and carbon dioxide for food production and growth. Play important role in balance of nature
Algae cell wall:
composed of cellulose
Algae found in:
fresh/salt water, soil and associated with plants
Viruses
very small (only be seen with electron microscope), acellular,
Virus Structure
contains a core made of one type of nucleic acid (DNA or RNA). core is surrounded by protein coat. Sometimes coat is encased by an additional lipid membrane
Fermentation
souring and spoilage are caused by microbes in the air called bacteria
Pasteurization
Pasteurs solution to keep wine and beer from spoiling. Heat the liquid enough to kill most of the bacteria.
Germ theory of disease
the idea that microbes might cause disease
Vaccination
Edward jenner took scrapings from a cow pox blister and then scratched the arm of healthy 8yo with the scrapings. A few days later the 8yo became slightly ill but never contracted small pox.
immunity
protection from a disease by vaccination
Why does vaccination work?
after it is grown in laboratories for long periods of time it can lose its virulence
antibiotics
chemicals produced naturally by bacteria and fungi to act agains other microbes
Chemistry
science if the interaction between atoms and molecules
Structure of atoms
smallest units of chemical elements, consist of nucleus (which contains protons) and electrons which move around the nucleus
Atomic number:
total number of protons in the nucleus
Atomic weight
total number of protons AND neutrons
atoms share pairs of electrons. stronger than ionic bonds and more common
Hydrogen bonds
when a hydrogen bond exists when a hydrogen atom covalently bonded to 1 oxygen or nitrogen atom is attracted to another O or N atom. weak links
Chemical reactions
making or breaking of chemical bonds. are reversible
Endergonic reaction
require energy
exergonic reaction
release energy
Synthesis reaction
atom, ions or molecules are combined to form a larger molecule
Decomposition reaction
larger molecule is broken down into component molecules, atoms or ions
Exchange reaction
2 molecules are decomposed and their subunits are used to synthesize 2 new molecules
Organic compounds
always contain carbon and hydrogen, mostly or entirely covalently bonded, many are large molecule. Carbs, Lipids, Proteins, Nucleic acid, ATP
Inorganic Compound
usually small, ionically bonded. Ex: water, common acids, bases and salts.
water
most abundant substance in cells, excellent solvent bc polar, good temp buffer, a reactant in many decomposition reactions of digestion
Lipids
distinguishes by their insolubility in water.
Saturated lipid
contains no double bonds between carbon in the fatty acids have higher melting points
unsaturated lipid
has 1 or more double bond. have lower melting points
Phosolipids
consist glycerol, 2 fatty acids and a phosphate group
amino acids
building blocks of proteins. consist of carbon, hydrogen, oxygen, nitrogen and sometimes sulfer
how many amino acid occur naturally in proteins?
Nucleic Acids
DNA, RNA. are macromolecules consisting of repeating nucleotides
Nucleotide
composed of a pentose, phosphate group, and nitrogen containing base
Necleoside
composed of a pentose and a nitrogen containing base
Adenosine Triphosphate
ATP. stores chemical energy for cellular activities.
How is energy released?
When the bond to ATPs terminal phosphate group is hydrolyzed
fluorescence microscopy
specimens are first stained with fluorochromes and viewed through a compound microscope using a uv light. seen as bright object with dark background
Electron microscopy
uses beam of electrons instead of light. electromagnets instead of glass lens control the focus, illumination and magnification. three dimensional views and thin sections can be seen.
Simple stain
aqueous or alcohol solution of single basic dye. used to make cellular shapes and arrangements visible
Differential Stains
(gram stain or acid fast stain) differentiate bacteria according to their reactions to the stains
Gram stain procedure
uses a purple stain (crystal violet), iodine as a mordant, alcohol as a decolorizer and a red counterstain. GP bacteria will retain the purple stain and GN bacteria do not and appear pink from counterstain
Special Stains
Negative is used to make microbial capsules visible
Acid fast stain
acid fast microbes will appear red bc they retain the carbolfuchsin after the acid alcohol decolorization. non acid fast microbes take up the methylene blue counterstain and appear blue
Negative stain
used to make microbial capsule visible
Endospore and flagella stain
stains that color only certain parts of bacteria
Prokaryotic vs Eukaryotic
Prokaryotic lack membrane enclosed organelles (eukaryotic doesn't) Peptoglycan is found in prokaryotic cell walls but not in eukaryotic
Frimbriae and Pili (p)
short thin appendages. Frimbriae help cell adhere to surfaces. Pili join cells for the transfer of DNA from one cell to another
Gram positive cell walls (p)
consist of many layers of peptoglycan
gram negative bacteria (p)
have a lipolysaccharide-lipoprotein-phosoplipid outer membrane surrounding a thin peptoglycan layer
Endosymbiotic theory
eukaryotic cells evolved from symbiotic prokaryotes living inside other prokaryotic cells
Cytoplasm (P)
fluid component inside the plasma membrane. mostly water
ribosomes (p)
consist of rRNA and protein. protein synthesis occurs here but can be inhibited by certain anitbiotics
endospores (p)
resting structures formed by some bacteria. allow survival during adverse environmental conditions
Process of endospore formation
called sporulation.
Eukaryotic plasma membrane
also phosolipid bilayer, contain carbs attached to proteins and sterols (not found in prokaryotic cells
Flagella and cilia (E)
flagella are few and long in relation to cell size. cilia are numerous and short. used for motility. Cilia can move substances along the surface
cytoplasm (E)
