Lecture 15

Question 1

Why do cells need iron

Answer 1

-Electron transport chain
-helps transfer electrons since they can bind to iron

Question 2

TonB

Answer 2

Found in outer membrane, transports iron & other trace elements

Question 3

How do bacteria acquire iron?

Answer 3

Siderophores

Question 4

What are siderophores

Answer 4

proteins used to get iron

Question 5

Lipocalin 2

Answer 5

When gut is inflamed, lipocalin 2 will inhibit enterobactin

Question 6

Why is iron a limiting agent

Answer 6

Iron is a limiting agent in bacteria cells because it is an essential nutrient for their growth and survival, but it is often scarce in the environment and tightly regulated by the host, making it challenging for bacteria to acquire sufficient iron for their needs.

Question 7

How does E.coli Nissle outcompete Salmonella?

Answer 7

E.coli Nissle outcompetes Salmonella by using a similar mechanism to acquire iron that is not inhibited by lipocalin 2
-uses salmochelin as well but has other siderophores that Salmonella does not

Question 8

How does fermentation relate to glycolysis

Answer 8

Fermentation maintains NAD+ level for glycolysis

Question 9

True or false: Fermentation relies on respiration

Answer 9

False
-Fermentation has nothing to do with respiration, only makes NAD+ for glycolysis

Question 10

Homolactic fermentation

Answer 10

Leads to production of ONE fermentation product which is LACTATE
-also makes NAD+
-yogurt

Question 11

Heterolactic fermentation

Answer 11

Leads to production of MORE products
-Lactate, ethanol, and CO2
-also makes NAD+
-sauerkraut, silage, kefir, kimchi

Question 12

What products do homolactic fermentation make

Answer 12

Lactate

Question 13

What products do heterolactic fermentation make?

Answer 13

Lactate, ethanol, and CO2

Question 14

How can lactic acid cause cavities?

Answer 14

A biofilm will form on teeth
-inside biofilm there is intracellular polysaccharide (glycogen) that is not actively diving so it goes through glycolysis
-streptococcus mútanos goes through fermentation
-Lactic acid fermentation can cause an acidic environment in the mouth which will demineralize the teeth and cause cavities

Question 15

Does fermentation require oxygen?

Answer 15

Fermentation does not require oxygen but can also do fermentation if oxygen is present

Question 16

True or false: All microbes utilize glycolysis

Answer 16

False
-Some microbes use the Entner-Doudoroff pathway instead pf glycolysis

Question 17

What is the Entner-Doudoroff pathway?

Answer 17

Combines the pentose phosphate and glycolic pathway
-Makes 1 ATP instead of 2 like glycolysis
-Makes NADPH and NADH

Question 18

What is the Pasteur effect?

Answer 18

-Oxygen inhibits fermentation
-With oxygen: bacteria consumes less glucose
-Without oxygen: consumes more glucose

Question 19

Why is industrial alcohol production kept in anaerobic conditions?

Answer 19

-Anaerobic conditions forces the facultative anaerobes to choose the fermentation pathway instead of aerobic respiration
-With O2 no alcohol is made
-Without consumes more glucose, sugars are converted into ethanol and CO2

Question 20

True or false: with oxygen facultative anaerobes consume more glucose

Answer 20

False
In aerobic (w/ oxygen) condition facultativos anaerobes will consume LESS glucose

Question 21

True or false: without O2 facultative anaerobes consume more glucose

Answer 21

True
In anaerobic conditions that facultative anaerobes consume MORE glucose