Fermentation

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1) Aseptic technique.

Aseptic techniques are procedures that individuals in various lines of work use to insure that the materials and the area that they are working with are not contaminated with microorganisms, either from the workers themselves or from the surrounding area.

Which of the following are examples where sterile technique is important?

A surgeon performing an operation, uses aseptic technique.

A sous chef making a gravy must use aseptic technique

A microbiologist transferring a bacteria culture from one bottle to another must use aseptic technique

A father preparing formula for an infant uses sterile technique

2) Atoms and Molecules

All living organisms contain the following atoms C (carbon) N (nitrogen), O (oxygen), and H (hydrogen). These atoms and some others are combined to make the molecules that form the building blocks of life. These buildinblocks can either be constructed by cells by moving atoms from other structures to make new structures, or the entire building blocks are supplied from food.

Listed below are the four types of organic molecules that make up living organisms. Which of the listed organic molecules is matched to the correct elements that make up this molecule?

carbohydrates (an energy source) contain C,N and H

proteins contain (enzymes are proteins) C,O,H,N and some S (sulfur)

lipids contain (an energy source)C,O,H

nucleic acids (the information molecules of the cell) contain C,O,H and P

3) Nutrition and the structures of cells

A cell is the smallest unit of life. Everything that is outside of a cell is not living and is a part of the environment. Everything on the inside of the cell is a part of that living entity. The plasma membrane is the structure that defines the cell. The plasma membrane is composed of a phospholipid bylayer that surrounds the cytoplasm or liquid and soluble protein components of a cell. In order to grow and perform normal metabolic functions the cell must be able to transport substances from the outer environment to the inside of the cell. These molecules that are essential to the growth and metabolism of the cell must be able to cross the phospholipid bylayer.

 

Which of the following choices is a reasonable hypothesis as to how substances can move across the plasma membrane of a cell?

Small molecules like Oxygen and Carbon dioxide can readily diffuse through the plasma membrane

Larger molecules must first be broken down into their constituent elements of C,N,H and O on the outside of the cell, diffuse across the membrane and are then assembled on the inside

Larger molecules need to enter cells by special structures called channels, that form larger holes inside the plasma membrane so the molecules can move from the outside of the cell to the inside.

Some molecules are soluble in the plasma membrane and do not require openings to occur in the plasma membrane in order to enter a cell

 

4) Heterotrophs and Autotrophs

The suffix -trophy refers to the nutrition of an organism. Heterotrophs are organisms that use molecules made from other living organisms for their nutrition. Autotrophs are able to create their own organic molecules from such inorganic substances as Carbon dioxide. When most microorganisms grow they require some organic molecules to provide the cell with energy and the basic elements to grow and metabolize.

 

Which of the following heterotrophs and autotrophs are correctly matched to their nutrient source?

A culture of Escherichia coli growing in a media containing sugar (glucose) and some inorganic salts.

A culture of Bacillus lichiniformis growing in a media containing Yeast Extract (dead yeast cells, treated with an acid to break down the long biological polymers into their monomeric forms)

A culture of blue green algae growing in water and some inorganic salts (less than 1% dry weight)

A culture of Sacchromyces cerevisiae growing in a media containing a sugar and the amio acid phenylalanine and some inorganic salts.

5) Microorganisms eukaryotes and prokaryotes

 A microorganism is one that cannot be seen with the naked eye. It us usually smaller than 0.1milimeter and you would require some type of magnificaiton in order to see this organism. In the laboratory you would typically use a light microscope. Most quality light microscopes will allow you to observe organisms that are as small as micrometer in length.

Their are two major types of microorganisms. The prokaryotes and the eukaryotes. They differ mainly in size (eukaryotes typically are larger) genomic complexity (eukaryotes typically have more genes than prokaryotes) and the presence of internal membrane bound organelles (again, the eukaryotes have more of these internal organelles that perform specialized functions within this cell).

Which of the following organisms is correctly identified as a prokaryote or eukaryote?

Lactobacillus sanfrancisco bacterium that ferments maltose producing lactic and acetic acids that give sourdough bread its unique taste

Turbatrix aceti the vinegar eel a minute nematode worm found in acid fermenting vegetable matter

Penicillium notatum the mold that produces the antibiotic penicillin

Pseudomonas a genus of small gram negative bacteria that are an inexpensive source of some vitamins

6) Primary metabolism

More questions to come featuring the following topics.

 

7) Differences between fermentation and respiration

 

8) The growth curve and reading a graph

 

 

 

9) Strains, genus species

 

 

10) Viruses and clearing a culture

 

11) Gene induction and expression

 

12) The difference between screening and selection

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