Catabolism in Microorganisms

Question 1

Bacterial Nutrition

What are the macronutrients covered?

Answer 1

carbon, nitrogen, phsophorous, sulfur, potassium, magnesium, calcium and sodium

Question 2

Bacterial Nutrition

What are the uses of carbon?

Answer 2

Used for proteins, carbohydrates, nucleic acids, lipids

It is 50% of the dry weight of a cell

Question 3

Bacterial Nutrition

What are the uses for nitrogen?

Answer 3

It is needed for the production of proteins (amino acids), nucleic acids (nitrogenous bases) and many polysaccharides (peptidoglycan).

It makes up 12% of the cell mass

Question 4

Bacterial Nutrition

What is the use of phosphorus?

Answer 4

It is needed for nucleic acids, phospholipids and energy conservation molecules

Question 5

Bacterial Nutrition

What is the use for sulfur?

Answer 5

It is required for some amino acids and vitamins

Question 6

Bacterial Nutrition

What is the use for potassium?

Answer 6

It is required for various enzyme substrates syntheses and activities

Question 7

Bacterial Nutrition

What is the use for magnesium?

Answer 7

It is used to stabilize negatively charged molecules like proteins, membranes and nucleic acids, Also needed for some enzyme activities.

Question 8

Bacterial Nutrition

What is the use for calcium and sodium?

Answer 8

It is not required for all cells but may be needed for cell wall stabilization and sporulation (Ca2+)

Question 9

Bacterial Nutrition

What are trace elements?

Answer 9

nutrients needed in low concentration

Question 10

Bacterial Nutrition

What is the importance of iron for cells? How do cells sequester iron?

Answer 10

It is important for enzymatic activity, DNA synthesis and other cellular functions. Cells sequester iron through siderophores which have a high affinity for iron

Question 11

Bacterial Nutrition

What organisms have adapted to use other metals as a substitute for iron?

They don’t need iron to function

Answer 11

Lactobacillus plantarum and Borrelia burgdorferi

Question 12

Bacterial Nutrition

Why is an element like Co2+ considered a micronutrient whereas an element like C is considered a macronutrient?

Answer 12

Large amounts of carbon is needed for cells to grow where cobalt is not as necessary and lower amounts are only needed.

Question 13

Bacterial Nutrition

What is the difference between defined vs complex media?

Answer 13

Defined media has extract concentration of every chemical component in that media. In addition, defined media tend to have very specific molecules while complex media don’t have extract concentration because of the type of simple ingrediaents used like yeast

Complex media will also have more sources of carbon and are less expensive and less time consuming to do.

Question 14

Bacterial Nutrition

What is the difference between selective and differential media?

these are used for enteric bacteria

Answer 14

Selective media is one thay will support the growth of what you are looking for or not supporting what you are not interested in. Differential media doesn’t prevent growth of what you are not interested, but allows you to see the distinction between the two (interested and not interested in)

differential will look what species contains or lack specific processes

Question 15

Bacterial Nutrition

What is the difference between MasConkey agar and Eosin-Methylene blue agar?

Answer 15

MacConkey agar contains bile salts and crystal violet to inhibit other bacteria; contains lactose and pH indicator to differentiate lactose fermenters.

Eosin-Methylene Blue agar contains Eosin Y (inhibits gram +) and methylene blue as well as lactose; E.coli, forms a metallic sheen due to high lactose fermentation.

MacConkey agar shows up violet while Eosin agar shows up metallic green

Question 16

Bacterial Nutrition

Why is the routine culture of Leuconostoc mesenteroides easier in a complex medium than a chemically defined medium?

Answer 16

It is less expensive, less time consuming and easier to make due to the simple ingredients.

Question 17

Bacterial Nutrition

In which medium, defined or complex, do you think Escherichia coli would grow the fastest? why?

Answer 17

It would grow faster in the complex media because it has more sources of carbon (peptide) and can use those directly rather than breaking down glucose (defined media).

Question 18

Bioenergetics

What are the roles of co-enzymes in metabolic reactions?

Answer 18

They assist enzymes in catalyzing metabolic reactions by binding to actie site of an enzyme and acceptinf or donating chemical groups like electrons or hydrogen atoms.

Question 19

Bioenergetics

How does NAD+ act/NADH act as a coenzyme?

Answer 19

NAD+/NADH act like a coenzyme by helping enzymes transfer electrons.

NAD+ - enzyme 1 reacts with substrate (electron donor) and oxidized form of coenzyme; in this process NAD+ gains in an electron, becomig NADH and the substrate is oxidized

NADH - enzyme 2 reacts with substrate (electron acceptor) and reduced form of coenzyme; in this process NADH loses an electron and the substrate is reduced

Reminder that oxidized is loss of electrons and reduction is gain of electron

Question 20

Bioenergetics

What is free energy?

Answer 20

Free energy (G) is the nergy released from a reaction that can be used to do work.

Question 21

Bioenergetics

How do you calculate the change in free energy? What does the sign of the result mean?

Answer 21

Change in free energy (G0’) is the products minus the reactants.
If result is negative, then the reaction releases energy and is exergonic.
If the result if positive, the reaction requires energy and is endergonic.

Question 22

Bioenergetics

What is Gf0? How is the free energy of formation (Gf0) is calculated?

Answer 22

Gf0 is the energy required for the formation of a compound from its elemets.

Formula: delta G0 = Gf0 (products) - Gf0 (reactants)

Question 23

Bioenergetic

What is the difference delta G0’ and delta G

Answer 23

Delta G0’ is the change in free energy under standard conditions.
Delta G0 is the change in free energy under actual conditions in nature

Question 24

Bioenergetic

What are catabolic and anabolic reactions? Which are exergonic and endergonic?

Answer 24

Catabolic - breaking down some compound which releases energy; exergonic (-)

Anabolic - building up compound and require energy; endergonic (+)

Question 25

# Bioenergetic Why wouldn't hydrogen and oxygen in a tube form water?

Answer 25

Because there is no activation energy activation energy - the energy required to bring all molecules in a chemical reaction into the reactive state

Question 26

# Bioenergetic What are enzymes?

Answer 26

They are catalytic proteins that speed up the rate of biochemical reactions by lowering the activation energy without changing the bioenergetics of the reaction. They are also highly specific to their substrate.

Question 27

# Bioenergetics What is a prosthetic group?

Answer 27

non-peptide enzyme-associated molecule that is tightly bound as part of the enzyme complex

Question 28

# Bioenergetic What is a coenzyme?

Answer 28

non-peptide enzyme-associated that is loosly bound to the enzyme complex and may be associated with several different enzymes

Question 29

# bioenergetics Where on an enzyme does the substrate bind?

Answer 29

active site

Question 30

# bioenergetics What are oxidation-reduction (redox) reactions?

Answer 30

They are reactions involving the transfer of electrons from electron donor to electron acceptor.

Question 31

# Bioenergetics What does it mean to be oxidized or reduced? Which is is the e- donor and acceptor?

Answer 31

Oxidized - loss of electrons; donor Reduction - gain of electrons; acceptor

Question 32

# Bioenergetics In the reaction H2 + 1/2 O2 --> H2O what is the electron donor and what is the electron acceptor? why?

Answer 32

Hydrogen is the electron donor because it has a lower electronegativity meaning it has a weaker tendency to attract electrons, therefore it would rather give them away. Oxygen is the electron acceptor because it has a higher electronegativity due to it's almost full outer shell (6 out of 8 electrons), so it wants more electrons.

Question 33

# Bioenergetic What is reduction potential?

Answer 33

It is the tendnecy of a compound to accept or release electrons expressed quantitatively. A high reduction potential means it wants to gain electrons while a low reduction potential means it want electrons as much (or event will donate them).

Question 34

# Bioenergetics - storage What happens when energy is released in redox reactions?

Answer 34

The energy is conserved int he formation fo certain compounds that contain energy-rich phosphate or sulfure bonds. The most common of these commpounds is adenosine triphosphate (ATP)

Question 35

# Bioenergetics What is long-term storage link to?

Answer 35

It is linked to the formation of polymers, which can be consumed to yield ATP

Question 36

# Bioenergetics What are examples of long-term energy storage molecules in bacteria?

Answer 36

- glycogen (polysaccharides) - poly-hydroxyalkanoates (poly-B-hydroxybutrate) - element sulfur polymers - inorganic molecules used by sulfure chemolithotrophs

Question 37

# Bioenergetics What are some compounds used in energy conservation?

Answer 37

* ATP * phosphoenylpyruvate * acetyl-coaA * glucose-6-phosphate * acetyl phosphate ## Footnote Think about what processes these are found