Micro Chapter 7 HW & Quiz

What is the correct order of the process of binary fission?

1.) a young cell 2.) chromosome is replicated 3.) protein band forms in center of cell 4.) septum formation 5.) Septum is complete and cells are divided

Nitrogen is essential for the formation of proteins, nucleic acids, and the source of cellular energy, __________.

ATP

The rate of diffusion is affected by

Temperature size of the molecules steepness of the concentration gradient

_________ is the acronym used to describe the list of essential nutrients required by alol organisms for survival.

CHONPS

Nutrient depletion and waste accumulation prevent cell growth and cells die exponentially.

Death phase

Phase during which cells are growing very quickly, at their maximum rate of cell division.

Exponential Growth Phase

Adjustment period during which cells are diving slowly while they adjust to growth conditions

Lag Phase

___________, essential for the formation of membranes, nucleic acids, and ATP, as well as sulfer, necessary for certain amino acids, must be harnessed from mineral deposits in rocks and oceans.

Phosphorus

Which enzyme is NOT involved in DNA replication? *DNA polymerase *RNA polymerase *Helicase *Gyrase

RNA polymerase

Phase during which nutrient depletion and accumulation of wastes begin to slow cell growth such that the rate of cells increase equals the rate of cell death

Stationary Growth Phase

Which type of medium is used to demonstrate oxygen requirements of microbes?

Thioglycollate

A described in "A Note About Bacterial Reproduction - and the Culture Bias," the organism Epolopisium does not divide by binary fission. Rather, each cell increases in size and divides to produce multiple daughter cells that are held within the oroginal cell well. After lysis, those daughters are released to repeatthe process. Assuming Epolopiscium could be grown in pure culture in the laboratory in broth and on solid media (it currently cannot), which method would be best for measuring the increase in biomass during growth?

Turbidity readings from a spectrophotometer, the increase in biomass will directly vary with the the turbidity of the culture.

The movement of substances from lower to higher concentration across a semipermeable membrane via a specific protein carrier and cell expenditure of energy is called

active transport

An organism that can use gaseous oxygen in metabolism and has the enzymes to process toxic oxygen products is a/an

aerobe

Microbes in a biofilm use quorum sensing to

assess the size of a particular microbial population

Most cultured bacteria tend to multiply by

binary fission

Nutrients essential for growth, reproduction, and maintenance of a bacterial cell.

carbon hydrogen oxygen nitrogen Phosphorus Sulfer

Nutrient absorption is mediated by the

cell membrane

In a close relationship, a change in one partner that results from a change in the other partner is termed

coevolution

When microbes are in a close nutritional relationship, and one benefits but the other is not harmed, it is called

commensalism

The process by which a cell uses ATP to enclose a substance in its membrane, by forming a vacuole and engulfint it, it is called

endocytosis

Both human and bacterial cells divide by mitosis

false

Cell division is triggered exclusively when cells attain a threshold mass.

false

Cells cannot begin a new round of replicxation until they have completely finished dividing.

false

DNA helicase is responsible for adding nucelotides to the growing end of the DNA

false

Environmental factors control microbial growth through their influence on enzyme activity.

false

The molecules in a solid lump of sugar do not move

false

After using the jelly on a sandwich, you close the jar and inadvertently place it on a room temperature shelf instead of in the refrigerator. When you open the jar several weeks later, you notice microbial growth of a microorganism on the surface. What type of organism is likely to grow in this environment?

fungus

An organic nutrient that cannot be synthesized by the organism and must be provided is called a/an

growth factor

You inoculate the bacterium into 3 tubes of nutrient broth medium containing salt--0.5% NaCl, 5% NaCl, and 15% NaCl. After incubation, you notice significant turbidity in the 15% NaCl medium, and modest turbidity in the 5% NaCl medium. There is no growth in the third tube. This organism would be termed ________

halophilic

Heterotrops differ from autotrophs in how they obtain their source of carbon; _________ must rely on other organism to provide them with organic molecules such as proteins and nucleic acids; whereas ________ are able to "fix" carbon from inorganic CO2, making them nutritionally independent.

heterotrophs; autotrophs

Refrigeration will ________ the doubling time of most pathogens.

increase

An important mineral ion of the cytochrome pigments of cellular respiration is

iron

The phase of the bacterial growth curve in which newly inoculated cells are adjusting to their new environment, metabolizing but not growing at an exponential rate, is the

lag phase

An important mineral ion that is a component and serves as a stabilizer of membranes and ribosome is

magnesium

Human pathogens fall into the group

mesophiles

Most of the microbiota in the human body are classified as

mesophiles

Simple diffusions is defined as the movement of ________

molecules from areas of higher concentration to areas of lower concentration

Termites are insects that require the protozoan Trichonympha in their gut to synthesize the enzyme cellulase to degrade the cellulose in wood. The protozoan uses the end products of the cellulose breakdown (glucose). This is a/an ___________ relationship.

mutualistic

The main resevoir of earth's nitrogen is in the form of ___________, which is unavailable for cellular use.

n2 gas

A few species of bacteria can carry out _________ which converts gaseous nitrogen in to a usable form. As with carbon, heterotrophs must obtain the their nitrogen from the organic molecules of other organisms.

nitrogen fixation

Regardless of an organism's ability to reside in seemingly inhospitable conditions, all cells require _________ for survival. How they obtain those nutrients varies from organism to organism, and there is no greater versatility than the ability of _________ to harness chemicals from a variety of sources.

nutrients; bacteria

An organism that cannot tolerate an oxygen environment is a/an

obligate anaerobe

Diffusion of water through a selectively permeable membrane is referred to as _________.

osmosis

The movement of molecules from an area of high concentration to an area of low concentration

osmosis

You leave your potato salad out on the table at the company picnic. When you made it, you unknowingly introduced 100 cells of Salmonella. How much time will it take for the population of Salmonella to reach at least one million if its doubling time is 20 minutes at picnic conditions?

over 4 hours

An organism that uses CO2 for its carbon needs and sunlight for its energy needs would be called a

photoautograph

What type of bacteria will grow in the refrigerator, and why is this usually not a concern?

psychrophiles; very few are pathogenic for humans

Cells must ______ their DNA prior to cell division.

replicate

The FtsZ protein is needed to form the

septum

A red blood cell placed in a hypertonic medium will

shrink

which of the following will pass through a cell membrane most easily? *small polar molecules *small nonpolar molecules *Large polar molecules *Large nonpolar molecules *Large neutral molecules

small nonpolar molecules

Calcium is required for bacteria because it

stabilizes the cell wall

The phase of the bacterial growth curve in which the rate of multiplication equals the rate of cell death is the

stationary phase

The toxic superoxide ion is converted to harmless oxygen by two enzymes,

superoxide dismutase and catalase

When sugar is mixed with water, equilibrium is reached when

the dissolved sugar molecules are evenly distributed throughout the solution

The energy source for contraction of the FtsZ ring during cell division comes from

the hydrolysis of GTP

A microorganism that has an optimum growth temperature of 37°C, But can survive short exposure to high temperatures is called a/an

thermoduric microbe

An organism with a temperature growth range of 45°C to 45°C would be called a/n

thermophile

A 5% urea solution is hypertonic to a 10% urea solution.

true

Diffusion is one of the processes whereby materials are exchanged between a cell and its environment.

true

If a cell is placed in an isotonic medium, there will be no net movement of water.

true

Osmosis is best defined as the movement of

water molecules across a membrane from an area of high water concentration to an area of lower concentration.