Chapter 3

Question 1

Metabolism

Answer 1

m—all	biochemical	reac.ons	in	a	
cell	
– Anabolic—energy	requiring	
– Catabolic—energy	releasing	
Macronutrients	
• Micronutrients

Question 2

Nitrogen

Answer 2

(13%)
• NH3 commonly used as a nitrogen source
• Some can use NO3
-
• N2—nitrogen fixers
• What cellular compounds contain nitrogen?
– Amino acids, nitrogenous bases

Question 3

Carbon

Answer 3

(50%)
• Autotrophs?
– Use CO2 as sole source of carbon, energy from
light or inorganic chemicals
• Heterotrophs?
– Requires organic carbon as sole source of carbon
• What cellular compounds contain carbon?
– Amino acids, faUy acids, organic acids, sugars,
nitrogen bases, aroma.c compounds, etc.

Question 4

Other macronutrients

Answer 4

• Phosphorous	
– nucleic	acids,	phospholipids	
• Sulfur	
– cysteine,	methionine,	vitamins	
• Potassium	
– enzyme	ac.vity	
• Magnesium	
– stabilizes	ribosomes,	membranes,	nucleic	acids,	
enzyme	ac.vity	
• Calcium	
– stabiliza.on	of	cell	walls	and	endospores

Question 5

Micronutrients

Answer 5

Iron—cellular respira.on, siderophores
• Manganese—replaces iron in some microbes
• Selenium—formate dehydrogenases (NAD+
and anaerobic metabolism, cytochromes in
electron transport chain)
• Others—cofactors for enzymes

Question 6

Culture Media

Answer 6

Nutrient	solu.ons	used	to	grow	microbes	
• Chemically	defined—known	amounts	of	
purified	chemicals	
• Complex	(undefined)—digests	of	animal	or	
plant	products,	nutrient	composi.on	is	
unknown

Question 7

Selective

Answer 7

contains	compounds	that	inhibit	the	
growth	of	some	microbes	but	not	others	
– An.bio.cs	
– Carbon	sources	
– Ex:	mannitol	salt	agar

Question 8

Differential

Answer 8

an indicator allows for
differen.a.on of microbes as they grow
– pH indicator
– Ex: mannitol salt agar

Question 9

Enriched

Answer 9

complex plus supplement, ex. blood

Question 10

Colony

Answer 10

mass of cells origina.ng from a single

cell, grows on surface of medium

Question 11

Laboratory culture: Agar

Answer 11

• Polysaccharide from red algae
• Melts at ~95°C and solidifies at ~45°C
• Solidifies culture medium

Question 12

Making a streak plate to obtain pure

cultures

Answer 12

• Isolated colonies at end of streak

- Confluent growth at beginning of streak

Question 13

Catabolic diversity

Answer 13

• Chemoorganotroph

- Anaerobic respiration

Question 14

Chemoorganotroph

Answer 14

— energy obtained by

oxida.on of organic compounds

Question 15

Anaerobic respira.on

Answer 15

electron acceptor

other than oxygen

Question 16

Chemolithotroph

Answer 16

energy obtained from
oxida.on of inorganic compounds, are also
autotrophs

Question 17

Phototrophy

Answer 17

energy obtained from light