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D-microbiology > week 4-microbial nutrition and growth > Flashcards

week 4-microbial nutrition and growth Flashcards

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Biology 101 flashcards
1
Q

Define microbial growth

A

Increase in number of cells(through reproduction)

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2
Q

Why do organisms require nutrients? Where do human pathogens get nutrients from?

A

So they can metabolize, so they can reproduce and grow

They get nutrients from humans

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3
Q

Name the 4 most common nutrients needed by microbes

A

Carbon
Hydrogen
Oxygen
Nitrogen

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4
Q

Why is it important that microorganisms have a carbon source?

A

essential for catabolizing to generate ATP

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5
Q

What are the main possible carbon sources
for a microorganism?

A

Carbs, amino acids, fats,(organic).
co2(inorganic)

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6
Q

Why do cells require water? Can they survive without water?

A

Need water so metabolic reactions can occur in the cell

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7
Q

Why is oxygen deadly for obligate anaerobes?

A

Lacks protective enzymes necessary that would break down the toxic oxygen forms

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8
Q

Why is hydrogen essential for life

A

helps form bonds

in water

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9
Q

How can obligate aerobe protect itself from toxic o2
why can’t anaerobe protect itself

A

aer- makes enzymes to break down toxic 02

an-does not make the enzymes required to fight toxic forms of 02

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10
Q

Why is nitrogen important for a microbe?

A

Found in all amino acids
part of nitrogenous bases (DNA RNA)

D-ATCG
R-AUCG

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11
Q

Why is phosphorous important for microbes?

A

P- important for backbone of DNA + RNA
also P in ATP

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12
Q

optimal

A

best case scenario for a microorganism
optimal temp, ph etc.., there will always be an optimal range for the organism

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13
Q

Briefly describe the different types of physical growth factors that can affect a microorganism -Temp

A

increasing temp from optimal-denatures proteins(loses function)/liquify cell membrane

too low from optimal-membrane becomes rigid and fragile-slow down metabolism

each organism can survive over a specific temperature range-minimum temp and max temp

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14
Q

Briefly describe the different types of physical growth factors that can affect a microorganism -PH

A

Changes in ph away from optimal ph can denature proteins

normally a very shallow range of ph

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15
Q

Briefly describe the different types of physical growth factors that can affect a microorganism -Hydrostatic pressure

A

Water exerts pressure in proportion to its depth.

Their membranes and enzymes depend on this pressure to maintain their three- dimensional, functional shape.

like human in deep sea- too high of pressure and 3d shape will change

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16
Q

Hypotonic solution-osmotic pressure

A

less salt in water then cell

water will be drawn into cell-causing it to burst

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17
Q

Hypertonic solution-osmotic pressure

A

Very salty solution-more salt then water

Water will be drawn out of cell, causing cell to shrink

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18
Q

Isotonic solution-osmotic pressure

A

level of salt in cell and salt in water are same

There is NO movement of water(no osmosis)

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19
Q

Briefly describe the different types of physical growth factors that can affect a microorganism -osmotic pressure

A

More solutes = higher osmotic pressure.

Osmosis is the movement of water—water follows salt (water moves toward the area with higher solute concentration).

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20
Q

Psychrophiles

A

low temp

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21
Q

mesophiles

A

body temp

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22
Q

thermophiles

A

higher temps

23
Q

barophiles

A

extreme pressure

24
Q

Neutrophiles

A

neutral ph

25
Q

acidophiles

A

low ph

26
Q

Alkaliphiles

A

(high pH).

27
Q

Halophiles

A

-prefer salt

28
Q

What is a “fastidious” organism?

A

Organisms requiring a large number of growth factors and that are difficult to grow in the lab

29
Q

What is a “culture media” and what is its purpose?

A

a collection of nutrients used to cultivate (grow) microorganisms outside of the body or its natural environment-usually done on a plate

30
Q

What does the term “culture” refer to in microbiology?

A

refers to act of growing microorganisms or the microorganisms that are being grown

31
Q

What does a PURE culture contain?

A

one Single species in a streak plate

32
Q

What is a “colony”?

A

an group of cells arising from single parent cell

Colonies arise from a single cell of one species

33
Q

What are some characteristics of colonies?

A

What are some characteristics of colonies?
Shape, margin, elevation, size, texture, appearance, pigmentation, optical property

34
Q

“defined” medium

A

exact chemical composition is known-used to grow a specific microorganism-grows one type of microorganism

35
Q

“complex” medium

A

(i.e. nutrient broth, nutrient agar, nutrient slants): contain variety of nutrients that can support growth of greater number of microbes
Also used to grow microbes whose exact nutritional needs are unknown

36
Q

Define “differential media”?

A

ingredients that show a visible change on the colonies or the media itself

-each individual change indicates a specific characteristic

37
Q

Define “selective media”?

A

contain substances that promote growth of one type of microbe or inhibit growth of unwanted microbes

38
Q

How can viruses be grown in the lab?

A

culturing

39
Q

What method do most bacteria use to reproduce?

A

Binary fission-cells grow twice the normal size and then divides in half

40
Q

What is the purpose of the “streak plate method” of growing microbes?

A

Thin out sample,
goal is to end up with isolated colonies, individual cells that have grown into individual colonies

41
Q

Briefly describe the 4 phases of microbial growth (lag, log

A

lag-Cells adjusting to new environment, do not reproduce

log-exponential growth, bacteria synthesize necessary chemicals for conducting metabolism

42
Q

Briefly describe the 4 phases of microbial growth stationary, decline)

A

stationary- number of cells dying equal the number of cells produced

decline-cells die at a faster rate then reproduction

43
Q

facultative anaerobe

A

most versatile, can switch between using oxygen and not using oxygen

44
Q

Aerobe

A

Use oxygen for cellular respiration

45
Q

Anaerobe

A

do not use oxygen for cellular respiration

46
Q

Microaerophile

A

requires very low levels of oxygen for aerobic respiration

47
Q

obligate aerobe

A

Will die without oxygen

48
Q

obligate anaerobe

A

Die in presence of oxygen

49
Q

aerotolerant anaerobe

A

do not use oxygen, but will not die from low levels of oxygen

50
Q

MacConkey:

A

-Selective for Gram Negative Bacteria,
-Inhibits Gram Positive Bacteria.
-Differential for Fermentation of lactose (colonies bright/dark pink)
-Non lactose fermentation (very light/ clear)

51
Q

Emb

A

-Selective for Gram negative bacteria,
-Inhibits gram positive bacteria.
-Differential for Fermentation of lactose (colonies are dark purple/ metallic green)
-Non lactose fermentation (very clear/light)

52
Q

Msa

A

-Selective for Staphylococcus, micrococcus.
-Inhibits any other microorganism.
-Differential for Non pathogenic ( no change)
Pathogen present (becomes yellow)

53
Q

Blood agar

A

full of Blood
anything can grow
differntial for No hemolysis (agar stays red around colonies - no breakdown of RBC’s)

Incomplete Hemolysis (partial breakdown of RBC’s, greenish /brownish color)

Complete Hemolysis (complete breakdown of RBC’s. Agar becomes colorless

D-microbiology (13 decks)

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