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Living things too small to be seen with the unaided eye
Who designed the nomenclature system?
What are the two names that organisms are assigned?
Genus and specific epithet, bot are underline or italicized. Genus is always capitalized
What are organisms classified into?
Bacteria, Archea, and Eukarya
Who is Robert Hooke?
He observed that cork was composed of “little boxes”; he introduced the term cell. His discovery marked the beginning of cell theory (all living things are composed of cells).
Who is the first to observe live organisms using a simple microscope?
Anton van Leeuwenhoek
What is spontaneous generation?
Some forms of life could arise spontaneously from nonliving matter
Who demonstrated that maggots appear when flies are able to lay eggs on decaying meat?
Who claimed that microorganisms could arise spontaneously from heated nutrient broth?
Who repeated Needham’s experiment and suggested that Needham’s result were due to microorganisms in the air entering his broth?
Who introduced the concept of biogenesis?
What is biogenesis?
Living cells can arise only from preexisting living cells
Who is Louis Pasteur?
He demonstrated that microorganisms are in the air everywhere and offered proof of biogenesis. He used a long-necked flasks, bent the necks into S-shape curved, which trapped any airborne microorganisms. His discoveries led to the development of aseptic techniques.
Who found that yeasts ferment sugars to alcohol and that bacteria can oxidize the alcohol to acetic acid?
What heating process is used to kill bacteria in some alcoholic beverages and milk?
Who showed a casual relationship between microorganisms and disease?
Bassi and Pasteur
Who introduce aseptic surgery?
Who proved that microorganisms cause disease?
A sequence of experimental steps for directly relating a specific microbe to a specific disease
Who demonstrated that inoculation with cowpox material provides human with immunity to smallpox?
Who introduced salvarsan? What is it used for?
Paul Ehrlich. It is used to treat syphilis
Who is Alexander Fleming?
He observed that the Penicillium fungus inhibited the growth of bacterial culture.
Antibiotic from fungus
The study of bacteria
The study of fungi, includes medical, agricultural, and ecological branches
The study of protozoa and parasitic worms
The study of immunity
The study of virus
How did the idea of spontaneous generation come about?
People came to believe that living organisms arise form nonliving matter because they would see flies coming out of manure, maggots coming out of dead animals, and microorganisms appearing in liquids after a day or two.
What are the structure of an atom?
Electrons (e-), Nucleus → protons (p+), neutron (n0)
What are protons?
The atomic number
What it the atomic weight?
The total number of protons and neutrons
An attraction between ions of opposite charge that holds them together to form a stable molecule. Weaker ionic bond are important in biochemical reactions such as antigen-antibody reactions
A bond formed by two atoms that share one or more pairs of electrons. Covalent bonds are the most common type of chemical bond in organisms and are responsible for holding together the atoms of most molecules in organisms
A relatively weak bond in which a hydrogen atom that is covalently bonded to one oxygen or nitrogen atom is attracted to another oxygen or nitrogen atom. Hydrogen bonds do not bind atoms into molecules, but rather serve as bridges between different molecules or different portions of the same molecule, for example, within proteins and nucleic acids.
A chemical reaction that absorbs more energy than it releases
A chemical reaction that releases more energy that it absorbs
- When two or more atoms, ions, or molecules combinr to form new and larger molecules
- A + B → AB
- Pathways of synthesis in living organisms are collectively called anabolic reactions, or anabolism
- The reverse of a synthesis reaction
- AB → A + B
- Decomposition reactions that occur in living organisms are collectively called catabolic reactions or catabolism
- Part synthesis and part decomposition
- AB + CD → AD + BC
- When the end product can revert to the original molecule
- A+B ⇔ AB
- Usually small, ionically bonded molecules
- Example: common acids, bases and salts
- Always contains carbon and hydrogen
- Mostly or entirely covalently bonded, and many of them are large molecules
- referems to the concentration of H+ in a solution
- pH 7 is neutral; pH value below 7 indicates acidity; pH above 7 indicates alkalinity
what are pH buffers used for
to stabilized the pH insida a cell and in culture media
How is a carbon skeleton formed?
A chain of carbon atoms
What are the 4 biological molecule?
Carbohydrate, lipids, proteins, and nucleic acids
- Compounds consisting of atoms of carbon, hydrogen, and oxygen. CH20
- Includes sugar and starches
- Can be classified as monosaccharide, disaccharide, and polysaccharides
- Contain from three to seven carbon atoms
- May form disaccharide and polysaccharides by dehydration synthesis
- Two molecules with the same chemical formula but different structure and properties
- Example: glucose (C6H12O6) and fructose (C6H12O6)
- A diverse group of compounds distinguished by their insolubility in water
- Simple lipids
- Consist of a molecule of glycerol and three molecules of fatty acids
- Saturated lipids
- No double bonds between carbon atoms in the fatty acids Higher melting point that unsaturated lipids
- Unsaturated lipids
- One or more double bonds
- Complex lipids consisting of glycerol, two fatty acids, and a phosphate group
- Carbon rings structures
- Amino acids are the building blocks of proteins
- Amino acids consist of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur
- Twenty amino acids occur naturally in proteins
Proteins have four levels of structure
- Primary: sequence of amino acids
- Secondary: helices or pleats
- Tertiary: overall three-dimensional structure of a polypeptide
- Quaternary: two or more polypeptide chains
What does conjugated proteins consist of?
Amino acids combined with inorganic or organic compounds
DNA, RNA- macromolecules consisting of repeating nucleotides
What is a nucleotide composed of?
Pentose, a phosphate group, and a nitrogen-containing base.
What is a nucleoside composed of?
A pentose and a nitrogen-containing base
What is DNA nucleotide consist of?
Deoxyribose (a pentose) and one of the following nitrogen-containing bases: thymine or cytosine (pyrimidine) or adenine or guanine (purines).
- Deoxyribonucleic acid
- Consist of two strands of nucleotides wound in double helix. The strands are held together by hydrogen bonds between purine and pyrimidine nucleotide: AT and GC
- Ribonucleic acid
- Consist of ribose (a pentose) and one of the following nitrogen-containing bases: cytosine, guanine, adenine, and uracil
What are the strands, composition, and function of RNA?
- Single-strands in cells and most RNA viruses
- The sugar is ribose
- Adenine, thymine, cytosine, and uracil
- Protein synthesis
What are the strands, composition, and function of DNA?
- Double-stranded in cells and most DNA viruses to form a single double helix; single-stranded in some viruses (parvoviruses)
- The sugar is Deoxyribose
- Adenine, thymine, cytosine, guanine
- Determines all hereditary traits
What happens when the bond to ATP’s terminal phosphate group is hydrolyzed?
Energy is released
What is the energy from oxidation reactions used for?
To regenerate ATP from ADP and inorganic phosphate
What are microorganism measured in?
Micrometers and nanometers
What are the physical requirement for microbial growth?
temperature, pH, and osmotic pressue
What are the chemical requirements for microbial growth?
carbon, nitrogen, sulfur, phosphorus, oxygen, trace elements, and organic growth factors
The lowest temperature at which the species will grow is called the
minimum growth temperature
________________ is the temperature at which the species grow best.
Optimum growth temperature
The highest temperature at which growth is possible is called the
maximum growth temperature
What is the pH value that most bacteria grow best?
at pH 6.5 and 7.5
All organisms require a carbon source. What does chemoheterotrophs use, what does autotrophs use?
- chemoheterotrophs use an organic molecule
- autotrophs use carbon dioxide
What is a culture medium?
any material prepared for the growth of bacteria in a laboratory
What is a culture?
microbes that grow and multiply in or on a culture medium
a common solidifying agent for a culture medium is called
What is a chemically defined medium?
one in which the exact chemical composition is known
what is a complex media?
one in which the exact chemical composition varies slightly from batch to batch
On the basis of preffered temperature, what are the three primary groups? (Define each)
- Psychrophiles: cold-loving microbes
- Mesophiles: moderate-temperature-loving microbes
- thermophiles: heat-loving microbes
What are the 5 groups on the basis of preferred temperature range?
What is the optimum growth of mesophiles?
- cold-loving microbes
- -8° C (minimum growth temperature)
- 15°C (optimum growth temperature)
- 19° C (maximum growth temperature)
- do not grow well at low temperature, except in comparison with other organisms
- able to degrade food
- 0° C (minimum growth temperature)
- 22°C (optimum growth temperature)
- 31°C (maximum growth temperature)
- moderate-temperature-loving microbe
- 10°C (minumum growth temperature)
- 37°C (optimum growth temperature)
- 58°C (maximum growth temperature)
- most common type of microbe
- include most of the common spoilage and disease organisms
- heat-loving microbes
- 39°C (minimum growth temperature)
- 62°C (optimum growth temperature) about the temperature of hot tap water
- 72°C (maximum growth temperature)
- 66°C (minimum growth temperature)
- 93°C (optimum growth temperature)
- 110°C (maximum growth temperature)
- most live in hot springs associated with volcanic activity
What are acidophiles?
bacteria that are remarkably tolerant of acidity
During what phase of growth there is little or no change in the number of cells but metabolic activity is high?
During what phase, the bactria mulstiply at the fastest rate possible under the conditions provided?
During what phase, there is an equilibrium between cell division and death?
During what phase, the number of deaths exceeds the number of new cells fomed?
Death phase (logarithmic decline phase)
What are/is the use of selective media, and differential media?
selective media: inhibits unwanted organisms with salts, dyes, or other chemical which allows growth of only the desired microbes
differential media are used to distinguish different organisms
What is an enrichment culture used for?
to encourage the growth of a particular microorganism in a mixed culture
How can microbes be preserved for long periods of time?
by deepfreezing or lyophilization (freezing-drying)
In a hypertonic solution what does most microbes undergo?
What can halophiles tolerate?
high salt concentrations
What is plasmolysis? How does this happen?
loss of water from a cell in a hypertonic environment.
Cellular water passes through the plasma membrane which goes into the high solute concentration. This happens when the microbial cell is in a solution whose concentration of solutes is higher than in the cell.
what are obligate halophile (extreme halophiles) ?
an organism that requires high osmotic pressures such as high concentrations of NaCl (in order for growth to occur)
What are faculative halophiles?
organisms that does not require high salt concentration but are able to grow at salt concentrations up to 2%.
a few species can tolerate even 15% salt
a complex polysacharride derived from a marine alga and used as a solidifying agent in culture media
Why is carbon needed for the chemical requirements of microbial growth?
Carbon is the structural backbone of living matter. It is needed for all the organic compounds that make up a living cell. Half the dry weight of a typical bactrial cell is carbon
Why is nitrogen, sulfur, and phosphorus needed for the chemical requirements of microbial growth?
Nitrogen makes up 14% of the dry weight of bacterial cell, and sulfur and phosphorus together constitue about another 4%
Nitrogen is primarily used to form the amino group of the amino acids of proteins.
Sulfer is used to synthesize sulfur-containing amino acids and vitamins such as thiamine and biotin. Important natural sources of sulfur: sulfate ion (SO42-), hydrogen sulfide, and the sulfur-containing amino acids
Phosphorus is essential for the synthesis of nucleic acids and the phospholipids of cell membranes. phosphate ion (PO43-)
When are organic molecules oxidized?
Where is energy generated from?
the electron transport chain
What is the final/terminal electron acceptor in aerobic respiration?
What is the terminal electron acceptor in anaerobic respiration?
sulfate, carbonate, phosphate
In cellular respiration from one molecue glucose, oxidaion produces how many molecules of the following:
- 6 molecules NADH
- 2 molecules FADH2
- 2 molecules ATP
How are electrons brought to the electron transport chain?
In aerobic prokaryotes how many ATP molecules can be produced from complete oxidation of glucose molecule in glycolysis, the Krebs cycle, and the electron transport chain?
In (aerobic) eukaryotes how many ATP molecules can be produced from complete oxidation of glucose molecule in glycolysis, the Krebs cycle, and the electron transport chain?
What is the end-product of glycolysis?
What are the two major types of glucose catabolism? Describe each.
Cellular respiration, in which glucose is completely broken down and fermentation, in which it is partially broken down
What are enzymes?
proteins, produced by licing cells, that catalyze chemical reactions by lowering the activation energy.
What happens to enzyme at high temperature?
Enzyme undergo denaturation and lose their catalytic properties.
What happen to enzymes at low temperature?
The reaction rate decreases.
Where is most of cell's energy produced?
from the oxidation of carbohydrates
What is the most commonly used carbohydrate?
How many ATP and NADH molecules are produced from one glucose molecule?
refers to the chemical reactions that result in the breakdown of more complex organix molecules into simpler substance.
refers to chemical reactions in which simpler substance ar combined to form more complex molecules
Where is the energy for chemical reaction stored in?
What is the conversion of light energy from the sun into chemical energy? What is the chemical energy used for?
- the chemical energy is used for carbon fixation
the sum of all chemical reactions within a living organism
What are 2 reactions of metabolism?
catabolism and anabolism
What are the components of an enzyme?
cofactor (or coenzyme; if cofactor is organic) & apoenzyme.
What happens if the the cofactor is removed from a holoenzyme?
the apoenzyme will not function
What are the two most important coenzymes in cellular metabolism? What does both compound contain and its function?
- NAD+ (nicotinamide adenine dinucleotide)
- NADP+ (nicotinamide adenine dinucleotide phosphate)
both compound contain derivatives of the B vitamins niacin ( nicotinic acid). both function as electron carriers: NAD+
catabolic (energy-yielding) and NADP+
is primarily involved in anabolic reactions (energy-requiring)
What are flavin coenzymes? What does in contain and its function?
- FMN (flavin mononucleotide)
- FAD (flavin adenine dinucleotide)
- contain derivatives of the B vitamins riboflavin, function as electron carriers
What is coenzyme A (CoA)?
a coenzyme that contains a derivative of pantothenic acid, another B vitamin. CoA plays and important role in the synthesis and breakdown of fats and in a series of oxidizing reactions called the Krebs cycle.
Define the following:
- 1. any compound with which an enzyme reacts
- 2. a region on an enzyme that interacts with the substrate
- 3. a temporary union of an enzyme and its substrate
factors that influence enzyme activity
- 1. At high temperatures, enzymes undergo denaturation and lose their catalytic properties; at low temperatures, the reaction rate decreases.
- 2. The pH at which enzymatic activity is maximal is known as the optimum pH.
- 3. Within limits, enzymatic activity increases as substrate concentration increases.
- 4. Competitive inhibitors compete with the normal substrate for the active site of the enzyme. Noncompetitive inhibitors act on other parts of the apoenzyme or on the cofactor and decrease the enzyme's ability to combine with the normal substrate by altering the shape of the active site.
What is phosphorylation?
Energy released during certain metabolic reactions can be trapped to form ATP from ADP and P (a single phosphate ion). Addition of P to a molecule
List and provide examples of three types of phosphorylation reactions that generate ATP
- substrate-level phosphorylation, a high-energy P from an intermediate in catabolism is added to ADP.
- oxidative phosphorylation, energy is released as electrons are passed to a series of electron acceptors (an electron transport chain) and finally O2 or another inorganic compound.
- photophosphorylation, energy from light is trapped by chlorophyll, and electrons are passed through a series of electron acceptors. The electron transfer releases energy used for the synthesis of ATP.
what is oxidation-reduction?
Explain what is meant by oxidation-reduction
a coupled reaction in which one substance is oxidized and one is reduced
- 1. Oxidation is the removal of one or more electrons from a substrate. Protons (H+) are often removed with the electrons.
- 2. Reduction of a substrate refers to its gain of one or more electrons.
- 3. Each time a substrate is oxidized, another is simultaneously reduced.
- 4. NAD+ is the oxidized form; NADH is the reduced form.
- 5. Glucose is a reduced molecule; energy is released during a cell's oxidation of glucose.
Describe the mechanism of enzymatic activity
When an enzyme and substrate combine, the substrate is transformed, and the enzyme is recovered. Enzymes are characterized by specificity, which is a function of their active sites.
fill the active site of an enzyme and compete with the normal substrate for the active site. this is possible because its shape and chemical structure are similar to those of the normal substrate
do not compete with the substrate for the enzyme's active site; instead, they interact with another part of the enzyme
inhibition of an enzyme in a particular pathway by the accumulation of the end-product of the pathway; also called end-product inhibition
stops the cell form making more of a substance than it needs and thereby wasting chemical resources
acts on the first enzyme in a metabolic pathway
the sum of all chemical reactins within a living organism
what are the two classes of chemical reaction
- release energy- catabolism
- require energy- anabolism
Describe/Define catabolism. Give example
Catabolism is the breakdown of complex organic compounds into simpler ones
are called catabolic or degradative reactions
hydrolytic reactions (use water in which chemical bonds are broken)
exergonic (produce more energy than the consume)
example: cells break down sugars into CO2 and H2O
Anabolism is the building of complex organic molecule from simpler ones
are called anabolic or biosynthetic reaction
involves dehydration synthesis reactions (release H20)
endergonic (consumes more energy than they produce)
example: formation of proteins from amino acids, nucleic acids from nucleotides, polysaccharides from simple sugars
Why is catabolic reaction important for anabolic reaction to occur?
Catabolic reactions provide the building blocks for anabolic reactions and furnish the energy needed to drive anabolic reactions.
How is energy-requiring and energy-releasing reaction made possible in the 2 types of chemical reactions?
through the molecule ATP (adenosine triphosphate)
ATP __(1)___ energy derived from __(2)___ reactions and __(3)___ it later to drive _(4)____ reactions and perform other cellular work.
- 1. stores
- 2. catabolic
- 3. releases
- 4. anabolic
ATP molecule consist of:
- 3 phosphate group
When the terminal phosphate group splits from ATP what is formed?
ADP (adenosine diphosphate)
The principal properties of a group of proteins involved in almost all biologically important chemical reaction is/are:
When does chemical reaction occur?
when chemical bonds are formed or broken
What must happen for reactions to take place?
atoms, ions, or molecules must collide
Define collision theory
explains how chemical reactions occur and how certain factors addect the rates of those reactions
What is the basis of collision theory?
all atoms, ions, and molecules are continuously moving and are thus continuously colliding with one another
What factors determine whether a collision will cause a chemical reaction?
the velocities of the colliding particles, their energy, and their specific chemical configurations
The collision energy required for a chemical reaction is its _____, which is the amount of energy needed to disrupt the stable electronic configuration of any speific molecule so that the electrons can be rearranged.
The _____ is the frequency of collisions containing sufficient energy to bring about a reaction- depends on the number of reactant molecules at or above the activatin energy level.
What is one way to increase the reaction rate of a substance?
raise its temperature
What are catalysts?
substances that can speed up a chemical reaction without being permanently altered themselves
In living cells, what serves as biological catalysts?
Identify the role of ATP as an intermediate between catabolism and anabolism.
catabolism is energy forming (ADP+P --> ATP) so in catabolism ATP is the product. anabolism: is energy storing (ATP --> ADP +P) in anabolism ATP starts the reaction. SO: ADP + P --> <-- ATP