Lab 7: Microbiology

Question 1

Prokaryotes vs eukaryotes

Answer 1

Prokarytoic cells: no nucleus or membrane-bound organelles (bacteria and cyanobacteria).
Eukaryotes: contain membrane-bound organelles. (animal, plants, fungi, protists).

Question 2

Bacteria, bacterial colony

Answer 2

• single-celled organisms.
• When exposed to nutrients like agar, forms bacterial colony: macroscopic growth of cells that all resulted from the division of a single cell. Genetically identical.

Question 3

Why is asceptic technqnique used?

Answer 3

To keep all equiment and media sterile, so that you grow only the microorganisms of interest.

Question 4

How to identify fungi and spores in agar plate

Answer 4

fuzzy solonies or strands of growth.

Question 5

Why are the bacterial colonies on “after” side of plate look to be of the same type of bacteria than on “before” side?

Answer 5

Some bacteria were washed away, but some live on the surface of the skin (seen on “before” and “after” plate).

Question 6

Control of bacterial growth is important in:

Answer 6

• Prevention of food spoilage
• Prevention of bacterial infections
• Recovery from bacterial infections

Question 7

Ways to prevent food from going bad

Answer 7

• Cooking: high temp. kills bacteria.
• Refrigeration: slows down growth of bacteria.
• Freezing: stops bacterial growth but doesn’t neccessarily kill the cells.
• High salt or high sugar content: creates a hypertonic environment, resulting in the bacteria losing water by osmosis which kills them.
• Pickling: pickling food in vinegar kills baceria by exposing them to acidic pH.

Question 8

Optimal temperature and pH for E. coli.

Answer 8

21 degrees (looks cloudy). pH 7.

Question 9

Prevention of bacerial infections

Answer 9

Soaps and detergents: mechanically remove bacteria from surfaces. Don’t usually kill bacteria.
Disinfectants: kill bacteria in the environment. Only immune compromised people need bacteria-free environment.

Question 10

Recovery from bacterial infections

Answer 10

antibiotics are used to help immune system control bacterial growth. Some bacteria become resistant to some or all currently available antibiotics.

Question 11

Zone of inhibition

Answer 11

A clear area with no bacterial growth, measures diameter, compared to Antibiotics Effectiveness Chart:
For bacteria to be susceptible to an antibiotic: the diameter must be bigger than diameter on chart.
For bacteria to be resistant: the dimater must be smaller than diameter on chart.

Question 12

Bacterial shapes

Bacterial shapes

Answer 12

Cocci: round.
Bacili: rod-shaped.
Spirila/spirochete: grows in chains or clusters, but each cell is an independant organism.

Question 13

Cyanobacteria

Answer 13

larger than other prokaryotes.
photosynthetic.

See GD

Question 14

Between euglena and paramecium, which organism is photosynthetic?

Answer 14

Eugena, it has green pigments found in chlorophyll and chloroplasts, the organelle that conducts photosynthesis..

Question 15

Protists

See euglena and paramecium

Answer 15

Informal eukaryotes that don’t fit with animal, plants, or fungi.
Vary:
* Single-celled or multicellular
* Some are photosynthetic, using light energy and CO2 to synthesize sugar.
* Some rely on consumption of other organisms for energy.
* Some are motile.

Question 16

2 ways tht euglena and paramecium are the same and different.

Answer 16

same: unicellular, have nuclei.
Different: euglena has chloroplasts and is photosynthetic. Euglena have flagella, and paramecium have cilia.

Question 17

Viruses

Answer 17

Not cells. Don’t have plasma membrane or any organelles.

Question 18

Fungi

Answer 18

Decompose deade organis material and absorb resulting chemical products as their food. Flesh is composed of hyphae. Mostly reproduce asexually by releasing spores. Includes yeast, mushrooms, lichen.

Question 19

Unicellular fungi

Answer 19

Group of organisms that includes yeast.

Question 20

Mushrooms

See GD

Answer 20

Made of hyphae.
Spores for reproduction.

Question 21

Lichen

Answer 21

Fungi and algae living in symbiotic relationship (partnership between 2 dissimlar organisms in which both partners benefit):
* Fungus absorbs water and minerls for alga and alga performs photosynthesis to provide carbohydrates for fungus.

Question 22

Cellular respiration

Answer 22

Most organisms, like yeast, convert energy stored in carbs to ATP. By products: CO2 WATER.

Question 23

Alcoholic fermentation

Answer 23

Yeast. Waste products: CO2 and ehtanol. Without using electron transport chain and produces less ATP than cellular respiration.

Question 24

What 2 variables were manipulated in the experiment?

Answer 24

Concentration of yeast and temperature.

Question 25

What temperature produced the most CO2 and why?

Answer 25

37 degrees. The tubes at 37 degrees had more concentration of yeast and were placed the optimal temperature for yeast productivity.