MicroB Exam 2 (Chapter 5, 6, 8)

Describe the general purposes of cultivating viruses.

(1) to isolate and identify viruses in clinical specimens; (2) to prepare viruses for vaccines; and (3) to do detailed research on viral structure, multiplication cycles, genetics, and effects on host cells.

Glycolysis: (Starting material)

1 Glucose 2 ATP

Describe the structure of chloroplasts, and explain their importance and functions.

are remarkable organelles found in algae and plant cells that are capable of converting the energy of sunlight into chemical energy through photosynthesis.

Explain the classification scheme used for viruses.

Two special groups of viruses, termed complex viruses, are more intricate in structure than the helical, icosahedral, naked, or enveloped viruses just described. Characteristics used for placement in a particular family include type of capsid, nucleic acid strand number, presence and type of envelope, overall viral size, and area of the host cell in which the virus multiplies, and shape.

Define replication as it relates to viruses.

Viral components produced. DNAviruses-nucleus RNAviruses-cytoplasm

Describe the general structure and size range of viruses.

Viruses are ultramicroscopic (<2um) and need an electron microscope to detect them or examine their fine structure.It is important to realize that viruses bear no real resemblance to cells and that they lack any of the synthetic machinery found in even the simplest cells. The general plan of virus organization is very simple and compact. Viruses contain only those parts needed to invade and control a host cell: an external coating and a core containing one or more nucleic acid strands of either DNA or RNA.

ETC: (need oxygen?)

YES!

Kreb's Cycle: (need oxygen?)

YES!

Describe cytopathic effects of viruses and the possible results of persistent viral infections

are defined as virus-induced damage to the cell that alters its microscopic appearance. Individual cells can become disoriented, undergo gross changes in shape or size, or develop intracellular changes. It is common to note inclusion bodies, or compacted masses of viruses or damaged cell organelles, in the nucleus and cytoplasm. Examination of cells and tissues for cytopathic effects has been a traditional tool for diagnosing viral infections that is usually supplemented with more specific serological and molecular methods.

Describe envelopes and spikes, and discuss their origins.

enveloped--that is, they possess an additional covering external to the capsid called an envelope, which is a modified section of the host's cell membrane. Some proteins form a binding layer between the envelope and capsid of the virus, and glycoproteins (proteins bound to a carbohydrate) remain exposed on the outside of the envelope. These protruding molecules, called spikes or peplomers, are essential for the attachment of viruses to the next host cell.

ETC: (Location)

eukaryote: inner mitochondrial membrane prokaryote: cell (plasma) membrane

Kreb's Cycle: (Location)

eukaryote: mitochondrial matrix prokaryote: cytoplasm

Describe the basic functions of enzymes in cells.

the chemical reactions of life would never proceed without a special class of proteins called enzymes. Enzymes are a remarkable example of catalysts, chemicals that increase the rate of a chemical reaction without becoming part of the products or being consumed in the reaction.

ETC: (starting material)

10 NADH 2 FADH2 OXYGEN

Glycolysis: (Name of product)

2 NADH 4 ATP (2 net) 2 Pyruvate

Summarize the results of aerobic respiration.

2 in glycolysis; 2 in CAC; 34 in ETC and 6H20

ETC: (product)

34 net ATP (38 net for prok) 32 ATP (36 net for euk)

Kreb's Cycle: (product)

8 NADH 2 FADH 22 ATP 6 CO2

Explain the chemiosmiotic mechanism of ATP formation, its relationship to electron transport, and the final step in electron transfer.

According to a widely accepted concept called chemiosmosis, during electron transport, some of the carriers actively transport protons across the cristae membrane and into the intermembrane compartment of the mitochondrion. This process sets up a concentration gradient of hydrogen ions called the proton motive force (PMF). The PMF consists of a difference in charge between the intermembrane compartment (+) and the matrix compartment (-).

Describe the evolutionary history of eukaryotic cells

According to the endosymbiotic theory, eukaryotic cells arose when a much larger prokaryotic cell engulfed smaller prokaryotic cells, which began to live and reproduce inside the larger cell rather than being destroyed. As the smaller cells took up permanent residence, they came to perform specialized functions for the larger cell, such as food synthesis and oxygen utilization, that enhanced the larger cell's versatility and survival. Over time the cells evolved into a single functioning entity, and the relationship became obligatory; some of the smaller cells had become organelles, the distinguishing feature of eukaryotic cells.

Kreb's Cycle: (starting material)

Acetyl CoA

Distinguish among types of capsids and nucleocapsids.

All viruses have a protein capsid, or shell, that surrounds the nucleic acid in the central core. Together, the capsid and the nucleic acid are referred to as the nucleocapsid. Viruses that consist of only a nucleocapsid are considered naked viruses. Of the 20 families of animal viruses, 13 are enveloped--that is, they possess an additional covering external to the capsid called an envelope, which is a modified section of the host's cell membrane.

Differentiate the structure and functions of flagella and cilia, and the types of cells that possess them.

Although they share the same name, the flagella of eukaryotes are much different from those of prokaryotes. The eukaryotic flagellum is thicker (by a factor of 10), has much different construction, and is covered by an extension of the cell membrane. A flagellum is a long, sheathed cylinder containing regularly spaced hollow tubules--microtubules--that extend along its entire length. Cilia (provide rapid motility) are very similar in overall architecture to flagella, but they are shorter and more numerous (some cells have several thousand). They are found only in certain protozoa and animal cells. On some cells, cilia also function as feeding and filtering surfaces.

Identify the parts of the Golgi apparatus, and explain its basic actions and uses in the cell.

At a site where it borders on the Golgi apparatus, the endoplasmic reticulum buds off tiny membrane-bound packets of protein called transport vesicles that are picked up by the forming face of the Golgi apparatus. Once in the complex itself, the proteins are further modified for transport by the addition of polysaccharides and lipids. The final action of this apparatus is to pinch off finished condensing vesicles that will be conveyed to organelles such as lysosomes or transported outside the cell as secretory vesicles.

Stage: Release (compare and contrast)

Bacteriophage: Host cell lysed Animal Viruses: Enveloped viruses bud out; nonenveloped viruses rupture plasma membrane

Stage: Synthesis (compare and contrast)

Bacteriophage: In cytoplasm Animal Viruses: In nucleus (DNA viruses) or cytoplasm (RNA viruses)

Stage: Assembly (infection) (compare and contrast)

Bacteriophage: Lysogeny Animal Viruses: Latency; slow viral infections; cancer.

Stage: Absorption (compare and contrast)

Bacteriophage: Tail fibers attach to cell wall proteins Animal Viruses: Attachment sites are plasma membrane proteins and glycoproteins

Stage: Penetration (compare and contrast)

Bacteriophage: Viral DNA injected into host cell Animal Viruses: Capsid enters by endocytosis or fusion

Describe the stages in the multiplication cycle of bacteriophages.

Bacteriophages go through stages similar to those of the animal viruses described earlier. First, they absorb to host bacteria using specific receptors on the bacterial surface. Although the entire phage cannot enter the host cell, the nucleic acid is injected through a rigid tube the phage inserts through the bacterial membrane and wall. The empty capsid remains attached to the cell surface. Entry of the nucleic acid stops host cell DNA replication and protein synthesis, and it soon prepares the cell machinery for viral replication and synthesis of viral proteins. As the host cell produces new phage parts, the parts spontaneously assemble into bacteriophages. Not all bacteriophages go immediately into a lytic cycle. Depending upon the conditions in the bacterial host, some special DNA viruses, called temperate phages, undergo adsorption and penetration into the bacterial host but are not replicated or released immediately. Instead, the viral DNA enters an inactive prophage state, during which it is usually inserted into the bacterial chromosome. This viral DNA will be retained by the bacterial cell and copied during its normal cell division so that the cell's progeny will also have the phage DNA. This condition, in which the host chromosome carries bacteriophage DNA, is termed lysogeny. Later, in a process called induction, the prophage in a lysogenic cell will be activated and progress directly into viral replication and the lytic cycle. Lysogeny is a less deadly form of infection than the full lytic cycle and is thought to be an advancement that allows the virus to spread without killing the host.

Relate the main points of bioenergetics and energy strategies in microorganisms.

Bioenergetics is a study of the mechanisms of cellular energy release, including catabolic and anabolic routes. For most chemoheterotrophs, the primary catabolism of fuels (such as glucose) that release energy proceeds through a series of three coupled pathways: 1)Glycolysis: also called the Embden-Myherhof-Parnas (EMP) pathway 2)The Krebs Cycle, also known as the citric acid or tricarboxylic acid cycle TCA 3)The respiratory chain (electron transport and oxidative phosphorylation). Some anaerobic microorganisms metabolize by means of anaerobic respiration. This system may involve the same three pathways as aerobic respiration, but it does not use molecular oxygen as the final electron acceptor. Instead, it uses other oxidized ions such as NO3, SO4, or CO2 for the final electron acceptor.

Briefly describe several mechanisms in biosynthesis of macromolecules.

Biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined together to form macromolecules. Biosynthesis is usually synonymous with anabolism.

Outline the stages in cell division and mitosis.

During mitosis, however, when the duplicated chromosomes are separated equally into daughter cells, the chromosomes themselves become readily visible as discrete bodies. (G1-growth; S-DNA synthesis; G2-growth and preparation for mitosis; M-mitosis)

Describe the general life cycle and mode of reproduction in protozoans.

Ciliates participate in conjugation, a form of genetic exchange in which members of two different mating types fuse temporarily and exchange nuclei. Within the SAR, and specifically within the subgroup alveolata, lie two groups of medically important protozoa, the apicomplexans and the ciliates. The apicomplexans all share a unique structure called an apical complex that is used for penetrating host cells. Nearly all members of the group are parasitic and have complex life cycles that include multiple hosts.

Define glycolysis and explain its input and output, its basic steps, and how it is linked to the Krebs cycle and oxidative phosphorylation.

Electron carriers such as NADH produced during glycolysis and the Krebs cycle pass their electrons to the electron transport chain, which results in synthesis of a lot of ATP.

Relate the diverse sources of energy and the cellular management of energy.

Energy is defined as the capacity to do work or to cause change. In order to carry out the work of an array of metabolic processes, cells require constant input and expenditure of some form of usable energy. Cells manage energy in the form of chemical reactions that change molecules. This often involves activities such as the making or breaking of bonds and the transfer of electrons.

Describe the types of enzyme functions and methods of naming them.

Enzymes can be classified as simple or conjugated. Simple enzymes consist of protein alone, whereas conjugated enzymes contain protein and nonprotein molecules. A conjugated enzyme, sometimes referred to as a holoenzyme, is a combination of a protein, now called the apoenzyme, and one or more cofactors. Cofactors are either organic molecules, called coenzymes, or inorganic elements (metal ions) that many enzymes require to become functional. Originally, proteins were considered the only biological molecules that act as catalysts. Then biologists found a novel type of RNA they termed ribozymes.

What are the types of eukaryotic locomotor appendages.

Flagella and cilia.

Summarize key features of enzyme regulation.

Folding causes the surface of the apoenzyme to acquire three-dimensional features that create the enzymes specificity for substrates. The actual pocket where the substrate binds is called the active site, or catalytic site, and there can be from one to several such sites. Because each type of enzyme has a different primary structure (type and sequence of amino acids), this gives rise to variations in folding and unique active sites. For a reaction to take place, a temporary enzyme-substrate union must occur at the active site. There are several explanations for the way this happens. The specificity is often described as a "lock-and-key" fit in which the substrate is inserted into the active site's pocket. This is a useful analogy, but an enzyme is not a rigid lock mechanism. It is likely that the enzyme actually helps the substrate move into the active site through slight changes in its shape. This is called induced fit.

Discuss the structure, basic formation, and roles of ATP in cells.

For energy to be biologically useful, it must ultimately be captured through phosphorylation, a process that adds an organic phosphate to adenosine diphosphate, converting it to ATP.

Discuss the importance of fungi in ecology, agriculture, commerce, and medicine.

Fungi synthesize antibiotics which inhibit bacterial growth. Fungi decompose organic matter and return the nutrients to the soil. Fungi can be pathogenic to field crops and can rot food during transport. Fungi form associations with plant roots to help them take up water and nutrients.

Describe the main catabolic pathways and their locations in aerobic respiration.

Glycolysis (cytoplasm): a series of reactions that and extract energy from glucose by splitting it into two three-carbon molecules called pyruvates. Krebs Cycle (mitochondrial matrix):A central metabolic pathway for generating building blocks for the cell. Respiratory Chain (mitochondrial cristae): electron transport and oxidative phosphorylation.

Describe the plan of a basic eukaryotic cell and organelles, and indicate the structures all cells possess and those found only in some groups.

In general, eukaryotic microbial cells have a cytoplasmic membrane, nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, vacuoles, cytoskeleton, and glycocalyx. A cell wall, locomotor appendages, and chloroplasts are found only in some groups.

Identify several pathways where molecules can be redirected or converted into useful cell products.

In the event of an inadequate glucose supply, pyruvate serves as the starting point in glucose synthesis from various metabolic intermediates, a process called gluconeogenesis. amination - the addition of an amino group to a carbon skeleton. Amino acids and carbohydrates can be interchanged through transamination as well

Explain what is meant by the term protist, and outline the types of organisms belonging to this designation.

In the past, any simple eukaryotic cell that lacked multicellular structure or cell specializing had been placed into the Kingdom Protista--the protists generally as an algae (photosynthesis) or protozoan (nonphotosynthetic). Although exceptions had always risen with this classification scheme--notably multicellular algae and the photosynthesis protozoans--most eukaryotic microbes had been readily accommodated in the Kingdom Protista as traditionally presented.

Describe the virus-host relationship.

Invasion begins when the virus encounters a susceptible host cell and absorbs specifically to receptor sites on the cell membrane. The membrane receptors that viruses attach to are usually glycoproteins the cell requires for its normal function. The mode of attachment varies between the two general types of viruses. In enveloped forms such as influenza virus and HIV, glycoprotein spikes bind to the cell membrane receptors. Viruses with naked nucleocaspids use surface receptors on their capsids to adhere to cell membrane receptors. Because a virus can invade its host cell only through making an exact fit with a specific host molecule, the range of hosts it can infect in a natural setting is limited. This limitation, known as the host range, can vary from one virus to another. It also explains why viruses usually have tissue specificities called tropisms for certain cells in the body.

Explain what is meant by lysogeny, prophage, lysogenic induction, and lysogenic conversion.

Lysogeny: condition in which the host chromosome carries bacteriophage DNA. Prophage: inactive state. Induction: the prophage in a lysogenic cell will be activated and progress directly into viral replication and the lytic cycle. Conversion: When a bacterium acquires genes from its temperate phage.

Describe the structure of a mitochondrion, and explain its importance and functions.

Mitochondria (energy) and cristae (folds) matrix (fluid filling cristae)

Define the glycocalyx for eukaryotic cells and list its basic functions.

Most eukaryotic microbes have a glycocalyx, an outermost boundary that comes into direct contact with the environment. This structure is usually composed of polysaccharides and appears as a network of fibers, a slime layer, or a capsule much like the glycocalyx of prokaryotes. From its position as the exposed cell layer, the glycocalyx serves a variety of functions. Most prominently, it promotes adherence to environmental surfaces and the development of biofilms and mats. It also serves important receptor and communication functions and offers some protection against environmental changes.

Glycolysis: (Need oxygen?)

NO

Outline the general reactions of photosynthesis and the importance it holds for the energetics of life.

On land, green plants are the primary photosynthesizers; and in aquatic ecosystems, where 80% to 90% of all photosynthesis occurs, this role is filled by algae, cyanobacteria, and green sulfur, purple sulfur, and purple nonsulfur bacteria. Photosynthesis occurs in two phases: the light-dependent reactions, which proceed only in the presence of light waves, and the light-independent reactions, which can operate without direct exposure to light, but are still reliant on the energy molecules made in the light-dependent reactions. Solar energy is delivered in discrete energy packets called photons (also called quanta) that travels as waves. The activity that has the greatest impact on photosynthesis is the absorbance of light by photosynthetic pigments. These chlorophylls, which are green; carotenoids, which are yellow, orange, or red; and phycobilins, which are red or blue-green. These light-dependent reactions are responsible for photophosphorylation, the channeling of energy extracted from light to make high-energy bonds of ATP. The systems that carry the photosynthetic pigments are also the sites for the light-dependent reactions. They occur in the thylakoid membranes of compartments called grana in chloroplasts and in thylakoid layers of the cell membranes of cyanobacteria. These systems exist as two different complexes called photosystem 1 (PS700) and photosystem 2 (PS680).

Describe three ways in which animal viruses enter into a host cell.

Once attached to a host cell, animal viruses may enter in a variety of ways: by endocytosis, where the membrane folds in; by making channels in the host membrane (through which DNA or RNA can be injected); or, for enveloped viruses, by fusing with the membrane and releasing the capsid inside of the cell.

Explain two ways in which animal virus are released by a host cell.

To complete the cycle, assembled viruses leave their host cell in one of two ways. Nonenveloped and complex viruses that reach maturation in the cell nucleus or cytoplasm are released through cell lysis or rupturing. Enveloped viruses are liberated by budding or exocytosis from the membranes of the cytoplasm, nucleus, endoplasmic reticulum, or vesicles.

Describe the structure of the two types of endoplasmic reticulum and their functions.

Originating from, and continuous with, the outer membrane of the nuclear envelope, the ER serves as a passageway for materials between the nucleus and cytoplasm. It also provides significant compartmentalization for numerous cell activities. The two types of endoplasmic reticulum are the rough endoplasmic reticulum (RER) and the smooth endoplasmic reticulum (SER). These two ER networks are similar in origin and are directly connected to each other, but they differ in some aspects of structure and function.

Indicate how viruses were discovered and characterized.

Pasteur postulated that rabies was caused by a virus (1884).

Discuss the importance of prions and viroids and the diseases they cause.

Prions are a group of noncellular infectious agents that are not viruses and really belong in a category all by themselves. The term prion is derived from the words proteinaceous infectious particle to suggest its primary structure: a naked protein molecule. They are the only biologically active agent that lacks any sort of nucleic acid (DNA or RNA) and were unknown until the early 1980s. The diseases associated with prions are known as transmissible spongiform encephalopathies (TSEs). This description recognizes that the diseases are spread from host to host by direct contact, contaminated food, or other means. Plants are also parasitized by viruslike agents called viroids that differ from ordinary viruses by being very small (about one-tenth the size of an average virus) and being composed of only naked strands of RNA, lacking a capsid or any other types of coating.

Summarize the main characteristics of protozoan form, nutrition, and locomotion.

Protozoa lack a cell wall. Except for one group, protozoa are motile by means of pseudopods ("false foot"), flagella, or cilia. A few species have both pseudopods (also called pseudopodia) and flagella. Some unusual protozoa move by a gliding or twisting movement that does not appear to involve any of these locomotor structures. Pseudopods are blunt and branched, or long and pointed, depending on the particular species. The flowing action of the pseudopods results in amoeboid motion, and pseudopods also serve as feeding structures in many amoebas. In most ciliates, the cilia are distributed over the surface of the cell in characteristic patterns. Because of the tremendous variety in ciliary arrangements and functions, ciliates are among the most diverse cells in the biological world. In certain protozoa, cilia line the oral groove and function in feeding; in others, they fuse together to form stiff props that serve as primitive rows of walking legs.

Describe the main events in the light-dependent reactions and the products that result.

Solar energy is delivered in discrete energy packets called photons (also called quanta) that travels as waves. The activity that has the greatest impact on photosynthesis is the absorbance of light by photosynthetic pigments. These chlorophylls, which are green; carotenoids, which are yellow, orange, or red; and phycobilins, which are red or blue-green. These light-dependent reactions are responsible for photophosphorylation, the channeling of energy extracted from light to make high-energy bonds of ATP.

Outline the prominent characteristics of enzymes.

Speed up reaction and lower energy of activation. At the molecular level, an enzyme promotes a reaction by serving as a physical site upon which the reactant molecules, called substrates, can be positioned for various interactions. Although an enzyme binds to the substrate and participates directly in changes to the substrate, it does not become a part of the products, it is not used up by the reaction, and it can function over and over again.

Compare the methods and uses of cell culture, bird embryos, and live animals in growing viruses.

Systems of cultivation with broader applications were developed, including in vitro cell (or tissue) culture methods and in vivo inoculation of laboratory-bred animals and embryonic bird tissues. Live animals: It is an intact and self-supporting unit, complete with its own sterile environment and nourishment. Furthermore, it furnishes several embryonic tissues that readily support viral multiplication. Every year, hundreds of millions of chicken embryos are inoculated to prepare influenza vaccines.

Explain how fungi are identified.

The Kingdom Fungi is filled with organisms of great variety and complexity that have survived on earth for approximately 650 million years. About 100,000 species are known, although experts estimate a count much higher than this--perhaps as high as 1.5 million. For practical purposes, mycologists divide the fungi into two groups: the macroscopic fungi (mushrooms, puffballs, gill fungi) and the microscopic fungi (molds, yeasts). Although the majority of fungi are either unicellular or colonial, a few complex forms such as mushrooms and puffballs are considered multicellular.

Explain the basic steps in the Krebs cycle, its input and output, and how it is linked to oxidative phosphorylation

The Krebs cycle is the second of three stages of cellular respiration, in which glucose, fatty acids and certain amino acids, the so-called fuel molecules, are oxidized. The oxidation of these molecules is primarily used to transform the energy contained in these molecules into ATP.

Discuss the major characteristics of algae, and explain how they are classified.

The algae are a group of photosynthetic organisms most readily recognized by their larger members, such as seaweeds and kelps. In addition to being beautifully colored and diverse in appearance, they vary in length from a few micrometers to 100 meters long. Algae occur in unicellular, colonial, and filamentous forms, and the larger forms can possess tissues and simple organs. An algal cell exhibits most of the organelles. The most noticeable of these are the chloroplasts, which contain, in addition to the green pigment chlorophyll, a number of other pigments that create the yellow, red, and brown coloration of some groups.

Indicate the basic structure of the cytoskeleton, and explain its main features and functions.

The cytoplasm is transversed by a flexible framework of molecules called the cytoskeleton. This framework has several functions, including anchoring organelles, moving RNA and vesicles, and permitting shape changes and movement in some cells. The three main types of cytoskeletal elements are actin filaments, intermediate filaments, and microtubules. Actin filaments are long, thin protein strands about 8nm in diameter. Found throughout the cell but especially just inside the cell membrane, actin filaments are responsible for cellular movements such as contraction, pinching during cell division, and formation of cellular extensions. Microtubules are long, hollow tubes about 25 nm in diameter, composed of protein subunits of tubulin. Microtubules maintain the shape of eukaryotic cells when they don't have cell walls, and serve to transport substances from one part of the cell to another. Intermediate filaments, as their name suggests, are intermediate in size between the other two elements, appearing as ropelike structures about 10 nm in diameter. Their main role is the structural reinforcement of the cell and of organelles, for instance, supporting ribosomes and mitochondria.

Relate the stages in the multiplication cycle of animal viruses, and summarize what is happening in each stage.

The general phases in the life cycle of animal viruses are absorption (binding of virus to a specific host cell), penetration (genome enters host cell), synthesis (viral components are released), assembly (new viral particles are constructed), and release (assembled viruses are released by budding (exocytosis) or cell lysis) from the host cell. Viruses vary in the exact mechanisms of these processes but we will use a simple animal virus to illustrate the major events.

Describe the main events in the light-independent reactions and the products that result.

The light-independent reactions of the Calvin cycle can be organized into three basic stages: fixation, reduction, and regeneration. (reactions in which ATP and NADPH from the light-dependent reactions are used to produce high-energy sugars.)

Characterize the cell wall and membrane of eukaryotic cells.

The nature of the layer beneath the glycocalyx varies among the several eukaryotic groups. Fungi and most algae have a thick, rigid cell wall surrounding a cell membrane. Protozoa, a few algae, and all animal cells lack a cell wall and are encased primarily by a cell membrane.

Discuss the medical impact and importance of viruses.

The nature of viruses has at times been a major impediment to effective therapy. Because viruses are not bacteria, antibiotics aimed at bacterial infections do not work for viruses. Although more antiviral drugs are being developed, most of them block virus replication by targeting the function of host cells. This can cause severe side effects.

Describe the structure of the nucleus and its outstanding features.

The nucleus is a large compact body that is the most prominent organelle of eukaryotic cells. It is separated from the cell cytoplasm by an external boundary called a nuclear envelope or membrane. The main body of the nucleus consists of a matrix called the nucleoplasm and a granular mass, the nucleolus. The nucleolus is the site of ribosomal RNA synthesis and a collection area for ribosomal subunits.

Describe some of the process of fermentation and the products that result.

The pathways of acidic fermentation are extremely varied. When glucose is fermented to a mixture of lactic acid, acetic acid, and carbon dioxide, as is the case with Leuconostoc and other species of Lactobacillus, the process is termed heterolactic fermentation. Mixed acid fermentation produces a combination of acetic, lactic, succinic, and formic acids, and it lowers the pH of a medium to about 4.0.

What is involved in amphibolism.

The property of a system to integrate catabolic and anabolic pathways to improve cell efficiency.

Discuss the importance of the helminth parasites.

These worms and larvae live in the small bowel and are referred to as intestinal parasites

Describe the unique characteristics of viruses.

They are a type of obligate intracellular parasite that cannot multiply unless it invades a specific host cell and instructs its genetic and metabolic machinery to make and release quantities of new viruses.

Describe several ways that algae are important microorganisms.

They are photosynthetic. Plankton are responsible for photosynthesis in marine environments.

in vitro

cell or tissue culture methods

Glycolysis: (location)

cytoplasm

in vivo

inoculation of laboratory bred animals and embryonic bird tissues.

Explain what is meant by the term fermentation and how fermentation is used by natural biological systems and biotechnology.

is a process that involves (1) the incomplete oxidation of glucose or other carbohydrates in the absence of oxygen; (2) the oxidation of NADH to NAD+, which is essential to the continuation of the glycolytic pathway; (3) the use of organic compounds as the terminal electron acceptors; and (4) the release of a small amount of ATP. Fermentation products can be grouped into two general categories: alcoholic fermentation products and acidic fermentation products. Alcoholic fermentation occurs in yeast or bacterial species that have metabolic pathways for converting pyruvic acid to ethanol.

Define metabolism and differentiate its two types.

pertains to all chemical workings of cells. It is a shorthand term for encapsulating almost any activity or behavior of an organism, from the general to the specific, including growth, synthesis, transport, digestion, energy release and consumption, and movement. Although metabolism entails thousands of different reactions, most of them can be placed into one of two general categories. In the case of catabolism, larger molecules are degraded or broken down into smaller molecules, usually with the release of energy. In the case of anabolism, also called biosynthesis, larger molecules are built from smaller ones, which results in the formation of cell structures. It is usually driven by energy derived from catabolism.