Microbio exam 2

What site on an enzyme is where the substrate binds?

Active site

What organic molecule binds to enzymes?

Coenzymes

What is a catabolic pathway?

Chemical reactions that break down complex molecules into simple molecules, releasing ATP.

Is nitrogen fixed to ammonia by cyanobacteria?

Yes, cyanobacteria can turn nitrogen into ammonia.

What are light reactions of photosynthesis?

Energy from sunlight is transferred into NADPH and ATP.

Can E. coli ferment lactose?

Yes.

Can Microbacterium degrade cholesterol?

Yes, certain species are capable.

Is oxygen necessary for the electron transport chain?

Yes, oxygen is necessary.

In batch culture, how does the log phase of the bacterial growth curve appear?

Linear on a plotted semi-log scale.

How would you describe the enzyme of extreme alkaphiles?

The pH is extremely high, ranging from pH 8 to pH 10.5.

What is the correct order of the phases of the growth phase?

Lag phase, log (exponential) phase, stationary phase, and death (decline) phase.

How would you describe the cell membrane of microbes that thrive at low temperatures?

Has a high portion of unsaturated fatty acids.

What is the difference between differential and selective media?

Differential media contains specific ingredients to distinguish species; selective media inhibits growth of certain microbes.

Which organisms survive better in dry environments, fungi or bacteria?

Fungi are better equipped to survive in dry environments.

Do halo bacteria grow in low or high salt concentration?

High salt concentration.

Which halo-tolerant microbes can cause food poisoning?

Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes.

Who identified nucleotide bases in DNA and RNA?

Albrecht Kossel.

Where did Mendel publish his work?

Mendel published his work in the "Proceedings of the Natural History Society of Brünn" in 1866, detailing his experiments with pea plants and the principles of inheritance.

Who worked on chromosomal inheritance?

Walter Sutton and Theodor Boveri.

Who worked on the one gene or one enzyme theory hypothesis?

George Beadle and Edward Tatum.

Who provided evidence that DNA is the genetic material rather than protein?

Alfred Hershey and Martha Chase.

Who first demonstrated horizontal transmission of information?

Frederick Griffith.

What rules relate adenine and guanine to the other two nucleotide bases?

Chargaff’s Rules state that adenine pairs with thymine and guanine with cytosine.

Who suggested that the DNA molecule has three strands?

James Watson and Francis Crick.

What is located at the end of a 5' end DNA strand?

A phosphate group.

What are stop codons also known as?

Termination codons or nonsense codons.

What amino acid is attached to tRNA?

Aminoacyl-tRNA synthetase enzyme.

Where is uracil found?

RNA.

What is another name for a template strand?

Antisense strand.

What occurs during transcription that involves RNA polymerase?

RNA polymerase binds to the promoter region.

Do prokaryotes have a single origin of replication?

Yes, prokaryotes only have one origin of replication in their DNA.

Do eukaryotes have multiple origins of replication?

Yes, eukaryotes may have multiple origins of replication on each chromosome.

What are common milk-borne pathogens?

Bacteria, protozoa, and viruses; e.g., Listeria, E. coli, salmonella (bacteria) and Cowpox, Hep A (viruses).

Does commercial sterilization kill microbes?

Yes, sterilization kills microbes.

Can pasteurized foods spoil?

Yes, milk can spoil.

What do autoclaves use to sterilize materials?

Pressurized steam.

Does sonication cause cavitation in cells?

Yes, cavitation will result from sonication.

What do HEPA filters filter?

Airborne particles, mostly microbes, to control microbial growth.

Are X-rays and gamma rays ionizing radiation, and do they cause thymine dimers?

Yes, they are ionizing radiation but do not directly cause thymine dimers; thymine dimers are caused by UV rays.

Are soaps without added ingredients bactericidal?

No, they are not bactericidal.

What method of biomedical control does not rely on nature in proteins?

Lyophilization.

Where are phenolic compounds found in nature?

In vascular plants.

What is a fomite?

An inanimate object that can be contaminated with infectious microorganisms and serve as a vehicle for transmitting disease to a new host.

At which biosafety level are HEPA filters required?

Biosafety level 2 and up.

What is aseptic technique?

A technique that prevents the spread of infection by avoiding contamination.

Why are extracellular polymeric substances important?

They act as a protective matrix providing adhesion, stability, nutrient exchange, and protection from pH changes, desiccation, and antimicrobial agents.

What media is commonly used to determine the oxygen requirement of bacterial species?

Thioglycolate broth.

How would a microaerophile grow in a thioglycolate tube?

Just below the surface of the tube.

What microbes live in a salt lake?

Halophiles.

What microbes can survive in the ocean?

Thermophiles and Barophiles.

Where in the DNA structure do DNA binding proteins bind?

The major groove.

What is a phenotype?

An observable trait determined by the appearance of an organism.

What is the lag phase in bacterial growth?

The lag phase is the initial period where there is no growth of bacterial cells.

What is the log phase in bacterial growth?

A period of rapid growth of bacterial cells.

What occurs during the stationary phase?

The number of cell deaths and growth are equal, resulting in a constant population size.

What happens during the death or decline phase?

The death rate surpasses the growth rate.

What do thermophiles and mesophiles describe?

Thermophiles live in extreme heat, from 50 to 80 degrees Celsius; mesophiles can withstand 20 to 45 degrees Celsius, including most human pathogens.

What are the categories of anaerobes?

Obligate anaerobes (need no oxygen), facultative anaerobes (can use oxygen), aerotolerant anaerobes (don't need oxygen but can survive in it), and microaerophiles (need a small amount of oxygen).