Microbiology: Module 9

denatured which can irreversibly destroy function

At higher temperatures, enzymes are

Heterotroph

An organism that obtains carbon from pre-formed organic molecules is called

Entner-Doudoroff pathway

Name one alternative pathway to glycolysis

False

Anaerobic respiration is a synonym for fermentation

NAD+

the oxidized form of nicotinamide adenine dinucleotide

Ribosomal RNA

the primary molecule used by Woese to place organism into domains

Photoheterotroph

an organism type that gets its carbon from pre-formed organic molecules and its energy from light

an explanation that is well-supported by evidence

In science, a “theory” is:

Proteobacteria

What group on Tree of life does the molecular evidence show as the ancestors of mitochondria?

b

Which of the following pathway is used in some bacteria which do not have glycolysis:

a. Embden-Meyerhof

b. Entner-Doudoroff

c. Pentose phosphate

glucose catabolism

What do anabolic processes require?

• ATP

• NADPH (reducing power)

Pentose Phosphate Pathway

• An alternative pathway to glycolysis that produces NADPH and 5-carbon sugars (ribose) for biosynthesis

• Occurs simultaneously with glycolysis.

• Found in Bacillus subtilis and Escherichia coli.

Entner-Doudoroff Pathway

An alternative glucose catabolism pathway used by some bacteria instead of glycolysis or the pentose phosphate pathway.

• Produces 2 NADPH per glucose.

• Produces 1 ATP per glucose.

• Found in Pseudomonas, Rhizobium, and Agrobacterium.

Absence of Oxygen

When oxygen is unavailable, cells must recycle NADH back to NAD⁺ so glycolysis can continue.

Anaerobic Respiration

A type of respiration that uses an electron acceptor other than oxygen.

Anaerobic Respiration

• Different bacteria use different acceptors including:

 Nitrate (Pseudomonas)

 Sulfate (Desulfovibrio)

 Others

• Use only part of the Krebs cycle

• Less ATP generated than in aerobic respiration

Fermentation

• Electron acceptor is an organic molecule

• No additional ATP made from pyruvate

fermentation

A process that regenerates NAD⁺ by transferring electrons from NADH to an organic molecule.

Lactic Acid Fermentation

Glucose → Glycolysis → Pyruvate → Lactate

Ethanol Fermentation

Glucose → Glycolysis → Pyruvate → Acetaldehyde → Ethanol

Phototroph

An organism that gets its energy from light.

Chemotroph

An organism that gets its energy from chemicals

Autotroph

An organism that uses carbon dioxide (CO₂) as its carbon source

Heterotroph

An organism that obtains carbon from preformed organic molecules.

Photoautotroph

Uses light for energy and CO₂ for carbon

Chemoautotroph

Uses chemicals for energy and CO₂ for carbon.

Chemolithoautotroph

Uses inorganic chemicals for energy and CO₂ for carbon.

Chemoorganoautotroph

Uses organic chemicals for energy and CO₂ for carbon.

Photoheterotroph

Uses light for energy and organic molecules for carbon.

Chemoheterotroph

Uses organic chemicals for energy and organic molecules for carbon

• Archaea

• Bacteria

• Eukarya

What are the three domains of life?

By comparing rRNA sequences.

How were the three domains determined?

16S rRNA

Prokaryotes (Bacteria & Archaea)

18S rRNA

Eukaryotes

molecular clock

Biological molecule sequences (such as rRNA) that change over time and are used to estimate evolutionary relationships.

Endosymbiotic Theory

an explanation for the origin of some organelles

Chromosome: Linear

Ribosomes: 80S

First amino acid: Met

Cell division: Mitosis

Cell type comparison for eukaryotes

Chromosome: circular

Ribosomes: 70S

First amino acid: fMet

Cell division: Binary fission

Cell type comparison for Bacteria, Mitochondria, and Chloroplasts

Glycolysis

The breakdown of glucose to produce ATP and pyruvate.

rRNA sequence similarities between bacteria and mitochondria/chloroplasts

Strongest molecular evidence for endosymbiosis?

Glycolysis

• Found in cytoplasm of cells in all domains

• Central to the biochemistry of cells

• Does not require oxygen

• Intermediates serve as precursors for other molecules in the cell

Anoxygenic (Cyclic) Photosynthesis

Photosynthesis that does not produce oxygen.

• Found in several groups of bacteria, including some cyanobacteria

Oxygenic Photosynthesis

Photosynthesis that produces oxygen.

• Cyanobacteria

Endosymbiotic Event

Cyanobacteria became chloroplasts after entering ancestral eukaryotic cells.

Prokaryotes

existed about 3.5 billion years ago.

Eukaryotes

evolved about 1.4 billion years ago.

Eukaryotes

evolved from a prokaryotic ancestor.