Open Ended - Exam 1

What is a microscope? Why is this tool so important in microbiology?

A microscope is a tool used to view organelles or elements that are not visible from the eye which includes microbes. This tool is important to microbiology because microbiology is the study of microbes and microorganisms.

What is a pathogen? What is an opportunistic pathogen? What is a commensal?

A pathogen is a microbe that can cause disease. An opportunistic pathogenic is a microbe that if given the opportunity it may causes disease. A commensal is

What is a prokaryotic cell? What is a eukaryotic cell? What is a virus?

A prokaryotic cell is single-celled a cell without a membrane bound nucleus or organelles. Eukaryotic cells are cells with a distinct nucleus and organelles. Virus is acellular, meaning they are not cells or living things. They consist of DNA and RNA and are surrounded by a protein coat lipid membrane.

Why is a virus a "non-living" entity?

A virus is a "non-living" entity because without a host cell, viruses are not able to grow on their own.

What features do all lipids share?

All lipids are hydrophobic along with fats.

List four functions for proteins.

Defense, movement, structural, transport

Give an example of dehydration reaction. Give an example of hydrolysis reaction. How are these reactions related?

Dehydration reaction is joining 2 amino acids together with the loss of water. Hydrolysis is splitting part of the amino acids. Dehydration reaction is the reverse of hydrolysis reaction.

What is differential media? What is selective media?

Differential media is used to differentiate closely related groups of organisms by using certain ingredients to produce growth, which will not cause the organisms to not appear to alike, allowing differentiation. Selective media is used to allow growth of one organism by adding ingredients to boost its growth while allow other organisms to grow around it.

What is endospore-forming cell?

Endospore-forming cells are cells that go into hibernation; they are resting cells.

Suggest some ways that one would go about determining if mitochondria and chloroplasts originated from prokaryotic cells.

Every cell needs energy in some way, either if it's from the sun or the nutrients around it. Because mitochondria makes food for energy for the cell and chloroplast receives energy from the sun, these two organelles makes the most sense with being originated in prokaryotic cells because without energy the cell would be dead. Also, food is essential to the life of a cell as well.

What are the steps involved in viral replication?

Lytic cycle: 1. Attachment - bind to host cell 2. Penetration - penetrates host cell, injects DNA 3. Biosynthesis - direct synthesis of viral components by host cell 4. Maturation - viral components are assembled 5. Release - host cell lyses and new virions are released

What is microbiology?

Microbiology is the study of microorganisms and microbes.

Name the subunits of proteins, polysaccharides, and nucleic acids.

Proteins - Amino Acids Polysaccharides - Monosaccharaides (Sugars) Nucleic Acids - Nucleotides

Why is resolving power important in microscopy?

Resolving power is important in microscopy because it allows for a more detailed view of any organism that is looked at under a microscope.

What are the major components of a virus?

The major components of a virus are DNA, mRNA and Proteins.

What are the major divisions of microbiology?

The major divisions of microbiology are mycology, bacteriology, phycology, protozoology, virology and parasitology.

Why is structure important for the function of a protein?

The structure of a protein tells what job the protein might have. If the protein isn't structured correctly it may not do the right task.

What are the two major groups of lipids? Give an example of each group.

Triglycerides - saturated and unsaturated fats Steroids - cholesterol

Since viruses lack metabolic enzymes, how can they synthesize necessary components?

Viruses are able to synthesize components by using their DNA and RNA and the DNA of living cells produce all of the components needed to get their job done.

Name several general characteristics that can be used to define prokaryotes

• DNA has 1 chromosome • 1 circular chromosome • No histones • No membrane bound organelles • MUCH smaller than eukaryotes • Divides by binary fission • No organized nucleus

What is unique about prokaryotic DNA?

Prokaryotic DNA has 1 circular chromosome with a circular shape unlike eukaryotes.

What is an electron microscope? What are some differences as compared to a light-microscope?

An electron microscope is one that using electrons for visibility instead of visible light rays. Compared to light-microscopes, electron microscopes do not allow one to view live specimen, electron microscopes can magnify a specimen more than light-microscopes and electron microscopes have high resolving power unlike light-microscopes.

What is a gram-stain? Describe what happens at each step in the gram stain.

Gram-stain is a method used to classify distinctive bacterial species. The steps of gram stain are as follows: 1. Place the organism onto the slide by smearing it. 2. Heat fix the slide so that the organism adheres to the slide. 3. Flood the smear with crystal violet and allow for 60 secs so that the dye can adhere to organism. 4. Tilt slide and rinse with tap water to clear of dye. 5. Flood smear with Gram's iodine and let it stand for 60 seconds. 6. Rinse. 7. Decolorize the slide using acetone by dropping acetone onto the slide, while tilted, until acetone runs down the slide clearly. 8. Rinse with tap water. 9. Counterstain slide with safranin for 45 seconds. 10. Rinse with tap water. 11. Blot slide dry and view slide with oil immersion.

Differentiate between pili and fimbrae.

Pili allows for congregation and bacterial sex while fimbrae allows for attachment and specific attraction. Pili are involved in mobility and fimbrae interacts with proteins on the surface on the interacting cell. Fimbrae are hairlike appendages.

What is plasmid DNA?

Plasmid DNA is a small DNA inside of a cell that is separated from a chromosomal DNA. It can replicate independently.

What are the four levels of protein structure, and what is the distinguishing feature of each?

Primary - amino acid sequence Secondary - alpha helices and beta pleated sheets Tertiary - protein folding to create a 3 dimensional shape Quaternary - polypeptide chains form a single protein

Construct a chart that reviews that major similarities and differences between prokaryotic and eukaryotic cells.

Prokaryotic Cells Unicellular No membrane bound organelles Circular DNA No organized nucleus Eukaryotic Cells Multicellular Membrane bound organelles Non-Circular DNA Nucleus

What are the five "I"'s in microbiology?

The 5 I's in microbiology are inoculation, incubation, isolation, inspection and identification.

What is the cell envelope? What is the difference between a gram (+) and gram (-)?

The cell envelope is a membrane structure that protects the cells from its environment. The difference between gram positive and gram negative is that gram-positive has a thick peptidoglycan layer while gram-negative has a thin layer and other membrane.

What is the difference between a naked and enveloped virus?

The difference between a naked and enveloped virus is how they enter and exit a cell. Naked viruses enter a cell by engulfing it and they exit through Lysis. Enveloped celled enter a cell through membranes and they exit by budding.

What is the importance of the streak-plate method? Draw out an example of how you would streak out a plate.

The importance of the streak-plate method is to be sure of visibility of the side and good isolation method for obtaining samples of organisms without acquiring many cells at one time while sampling. *I understand how to streak a plate but I will attach a picture to be certain of my answer