Module 5 Microbial Metabolism (VIDEOS) Flashcards
refers to all of the biochemical reactions taking place in an organism.
Metabolism
2 General Categories of anabolism
Catabolism and Anabolism
builds larger organic compounds, such as carbohydrates and proteins, from simpler monomers, including glucose and amino acids.
Anabolism
hydrolyses polymers into simpler molecules, such as carbon dioxide, ammonia and water.
Catabolism
From an energy perspective, anabolic reactions form bonds which requires energy. Such energy-requiring processes are considered
endergonic reactions.
catabolic reactions break bonds, releasing energy. These processes are called
exergonic reactions.
- catalyze all chemical reactions in cells.
- are usually proteins
- increase the probability of a chemical reaction taking place, while they themselves remain unchanged
- are able to accomplish in fractions of a second, what otherwise might take hours, days or even longer to happen spontaneously under normal biological conditions.
Enzymes
4 Characteristics Common to All Enzymes:
reusable
highly specific
have an active site
required in small amounts
An enzyme molecule has an active site where it binds the substrate molecule. The substrate will then bind to the active site to form an
enzyme-substrate complex
TRUE OR FALSE
enzyme hydrolyzes a substrate, and also catalyze dehydration reactions, which would bind 2 or more molecules together forming a larger molecule.
TRUE
the 3-dimensional shape of the enzymes’ active site recognizes and holds the substrate in an enzyme-substrate complex. While in the complex, chemical bonds in the substrate are stretched or weakened by the enzyme causing the bind to break.
hydrolysis reactions of enzymes
the electron shells of the substrates in the enzyme-substrate complex are forced to overlap in the spot where a chemical bond will form. Thus, recognition of the substrate or substrates is a highly controlled, nonrandom event.
synthesis reaction of enzymes
plays a key role in metabolism, because they provide an alternate reaction pathway of less resistance. That is, with a lower activation energy barrier.
They assist in the destabilization of bonds and the formation of new ones, by separating or joining atoms in a carefully orchestrated fashion. Some enzymes are made up entirely of protein.
Enzymes
Enzymes contain small non-protein substances called ________. When a non-protein co-factor is a small organic molecule, we refer to it as a _____. They will participate in the catalytic reaction.
co-factors
co-enzyme
is a sequence of chemical reactions; each reaction catalyzed by a different enzyme in which the product of one reaction serves as a substrate for the next reaction.
a series of enzymes transforms an initial substrate into a final end product.
metabolic pathway
The pathway starts with the initial substrate and finishes with the final end product. The products of the in between stages are referred to as __________.
intermediates
the inhibitor will have a structure that is similar to the normal substrate and will compete for the enzyme’s active site.
would reduce the productivity of the metabolic pathway by slowing down or stopping the pathway altogether.
competitive inhibition
One of the most common ways of a modulating enzyme activity, is for the final end product of metabolic pathway to inhibit an enzyme in that same pathway.
If the first enzyme in the pathway is inhibited, then no product is available as input for the rest of the pathway.
feedback inhibition.
when the final end product or end molecule binds to an allosteric site, the shape of the active site changes and can no longer bind with the substrate
noncompetitive inhibition
Another way of modulating an enzyme, is by blocking its active site so that the normal substrate cannot bind
Competitive inhibition
other site where the inhibitor attaches
allosteric site
is the universal energy currency in all cells. In many metabolic reactions, energy is needed along with enzymes for reactions to occur.
are relatively unstable
ATP, adenosine triphosphate.
Breaking the so-called high-energy bond in ATP that holds the last phosphate group on the molecule, produces a more stable molecule
adenosine diphosphate or ADP
The addition of a phosphate group to another molecule
phosphorylation
ATP -> ADP (energy released)
ADP -> ATP (energy required)
all cells make ATP by harvesting energy from exergonic metabolic pathways, such as the hydrolysis of food molecules. Such a process is called
cellular respiration
- contains stored energy that can be extracted.
- is a primary source for generating ATP.
Glucose
if cells consume oxygen in making ATP, the process is called
aerobic respiration
In other instances, cells can make almost equally substantial amounts of ATP without using oxygen in a process called ___________.
another organic molecule replaces oxygen
anaerobic respiration
Another form of anaerobic metabolism is _________.
fermentation
Aerobic cellular respiration occurs in _____. The process is represented by the following chemical equation: glucose and oxygen along with ADP are used to produce carbon dioxide, water and ATP.
obligate aerobes
Aerobic cellular respiration can be conveniently divided into 3 stages:
glycolysis, the citric acid cycle, and oxidative phosphorylation
is the first stage of energy extraction. Glycolysis is a metabolic pathway yielding ATP and NADH
Glycolysis
In glycolysis, the splitting of glucose occurs in the ______of the microorganism and involves a metabolic pathway that converts the initial 6-carbon substrate, glucose, into 2 3-carbon molecules called ______.
cytosol;
pyruvate
is a series of chemical reactions that are referred to as a cycle, because the end product formed is used as a substrate to initiate the entire pathway.
citric acid cycle or Kreb’s cycle,
is the process by which most of the ATP molecules form. Oxidative phosphorylation refers to a sequence of reactions in which 2 events happen: electrons transport and ATP synthesis.
Oxidative phosphorylation
The actual mechanism for ATP synthesis comes from the pumping of proteins through a process
chemiosmosis
Proteins are broken down into individual amino acids. Enzymes then convert many amino acids to pathway components by removing the amino group and substituting a carbonyl group. This process is called ______ which is ________.
deamination; protein metabolism
Fats are extremely valuable energy sources because their chemical bonds contain enormous amounts of chemical energy. Although proteins are generally not considered energy sources, cells use them for energy when and fats are in short supply
Fat metabolism
create ATP in the absence of oxygen. In environments that are anoxic and without an alternative electron acceptor, much of the organic material will be catabolized through fermentation.
is the enzymatic process for producing ATP using endogenous organic compounds as both electron donors and acceptors. Exogenous electron acceptors include oxygen, nitrate, sulfate and carbonate.
Fermentation
Photosynthesis can be separated into (2)
light dependent and light-independent reactions.
In the first part of photosynthesis, light energy is converted into or fixed as chemical energy in the form of ATP and NADPH. Thus, the process is referred to as the______________ because light energy is needed for the process.
energy-fixing reactions or light-dependent reactions
ight energy is absorbed by a green pigment called
chlorophyll A
Chlorophylls and accessory pigments make up light receiving formation of ATP in a process called _____________.
photophosphorylation
In the second stage of photosynthesis, another cycle metabolic pathway forms carbohydrates. This process is known as the __________, because carbon in carbon dioxide is trapped or fixed into carbohydrates and other organic molecules.
carbon-fixing reactions or light-independent reactions or Calvin cycle
In addition to cyanobacteria, a few other groups of bacteria also can trap energy by photosynthesis. 2 such groups are the ___________ and _________, so named because of the colors imparted to them by their pigments. These bacterial organisms have chlorophyll-like pigments known as _________to distinguish them from other chlorophylls.
green bacteria and purple bacteria; bacteriochlorophylls
In the energy fixing reactions, the organisms do not use water as a source of hydrogen ions and electrons. Consequently, no oxygen is liberated and the process, therefore, is called ________________.
an-oxygenic photosynthesis.
Microorganisms must meet certain nutritional requirements for growth. Besides water, which is an absolute necessity, they need nutrients that can serve as energy sources and raw materials for the synthesis of cell components. These generally include proteins for structural compounds and enzymes, carbohydrates for energy, and a series of vitamins minerals and inorganic salts.
Patterns of metabolism
2 different patterns exist for satisfying an organism’s metabolic needs. These patterns are _________and ________.
are primarily based on the source of carbon used for making cellular components.
autotrophy heterotrophy
Organisms that synthesize their own foods from simple carbon sources, such as carbon dioxide, are referred to as _________
autotrophs
Those that use light as energy sources, such as cyanobacteria, are called _________.
photoautotrophs
Microorganisms including the cyanobacteria and algae can carry out photosynthesis using water and producing oxygen gas in a process called _______________, while other bacterial species carry out _____________ using hydrogen sulfide rather than water and produce sulfur granules rather than oxygen gas.
oxygenic photosynthesis
an-oxygenic photosynthesis
Another group of autotrophs do not use light as an energy source. Instead, they use inorganic compounds and are referred to as .
chemoautotrophs
2 types of heterotrophs
photoheterotrophs and Chemoheterotrophic
use light as their energy source and preformed organic compounds such as fatty acids and alcohols as their sources of carbon. Photoheterotrophs include certain green non-sulfur and purple non-sulfur bacteria.
photoheterotrophs
_____________ microorganisms are those that feed exclusively one dead organic matter commonly called _______
Chemoheterotrophic; saprobes
In contrast, chemoheterotrophs that feed on living organic matter such as human tissue, are commonly known as ____________
parasites
