Chapter 7 and 8: Microbial Metabolism and Genetics- Part 1 Flashcards
Glycolysis…
Oxidizes glucose to pyruvate
Pentose phosphate pathway
Less commonly used than glycolysis, initiates the oxidation of glucose
TCA Cycle
Incorporates an acetyl group and releases CO2
In prokaryotes, the membrane (where respiration occurs?) is the..
Cytoplasmic membrane surrounding the cell
IN eukaryotes, the membrane (where respiration occurs?) is the…
Inner membrane of the mitochondrion
The eukaryotic and prokaryotic systems of respiration are..
Nearly identical
In respiration, a ________ _________ ________ is used to consume donated electrons
Terminal electron acceptor
What is commonly used as the acceptor by aerobic microorganisms?
Oxygen!
Fermentation is used by..
Organisms that cannot perform respiration to consume electrons
- Oxygen not available
- Obligate anaerobes
Fermentation products are particularly useful for identifying ______ bacteria
Enteric (bacteria of the intestines
E coli is a…
Facultative anaerobe
An obligate anaerobe can either undergo ______ or _____ ______
Fermentation
Anaerobic photosynthesis
Does the ETC or fermentation produce more energy?
ETC
Saccaromyces is…
Yeast
produces ethyl alcohol
Central dogma of molecular biology
DNA –> RNA–> Protein
(via transcription then translation)
&DNA replication to create duplicate of original molecule
Differences between Eukaryotic and Prokaryotic Gene expression: Prokaryotic mRNA
mRNA is not processed
Differences between Eukaryotic and Prokaryotic Gene expression: Eukaryotic mRNA
A cap is added to the 5’ end of mRNA and a poly A tail is added to the 3’ end
Exons are..
Expressed and made into proteins
Introns are…
Removed by chopping them out
Differences between Eukaryotic and Prokaryotic Gene expression: Prokaryotic introns
mRNA does not contain introns
Differences between Eukaryotic and Prokaryotic Gene expression: Eukaryotic introns
mRNA contains introns, which are removed by splicing
Differences between Eukaryotic and Prokaryotic Gene expression: Prokaryotic translation
Translation of mRNA begins as it is being transcribed
Differences between Eukaryotic and Prokaryotic Gene expression: Eukaryotic translation
The mRNA transcript is transported out of the nucleus so that it can be translated in the cytoplasm
Monocistronic
One RNA molecule is for 1 protein
Polycistronic
One RNA could make multiple proteins
Differences between Eukaryotic and Prokaryotic Gene expression: Prokaryotic (polycistronic vs monocistronic)
mRNA is often polycistronic; translation usually begins at the first AUG that follows a ribosome binding site
Differences between Eukaryotic and Prokaryotic Gene expression: Eukaryotic (polycistronic vs. monocistronic)
mRNA is monocistronic; translation begins at the first AUG
In general, would the process of protein synthesis (transcription followed by translation) be faster for prokaryotes or eukaryotes?
Prokaryotes
(Do not have to remove introns, one RNA for multiple proteins, mRNA not processed and does not have to travel out of the nucleus)
Prokaryotic Gene Regulation: Some genes are _________ expressed
Constitutively
Two step process of prokaryotic gene regulation
Have to remove repressor and add activator
Prokaryotic gene regulation: repressors
Bind to the DNA between the promoter and transcriptional start site, thus block RNA polymerase
Prokaryotic gene regulation: activators
Interact with the promoter region to facilitate RNA pol binding
The lac operon is a…
Sensing pathway for lactose
What stimulates the expression of genes that metabolize lactose?
The presence of lactose and absence of glucose in culture media
lac Operon process Step #1
As glucose levels drop, cAMP increases
After cAMP increases, what happens in the presence of lactose?
cAMP binds to catabolite activating protein (CAP), allowing it to bind to the promoter
After CAP binds to the promoter…
Allolactase, an isomer of lactose, binds to the lac represser, preventing it from binding to the DNA
After allolactase binds, what happens?
RNA polymerase binds to the DNA and begins mRNA synthesis
Why doesn’t lactose metabolism occur in the presence of glucose?
Because cAMP would not be present which prevents binding to activator site
What is the purpose of allolactase?
To remove the repressor
The lactose operon contains how many genes?
Three
What does permeate do?
Affects permeability, helps bring lactose inside of cell
