Microbiology 210 Exam 1

microbiology

a specialized study of biology that deals with the study of living things too small to be seen without magnification

microorganisms

a large, diverse group of microscopic organisms that exist as single cells or cell clusters

germs, viruses, agents

Microorganisms are commonly referred to as ________, ________, and _________.

Microbes only exist as single cells, but plant/animal cells are unable to live alone in nature and must belong to multicellular organisms.

How are microorganisms different from cells of animals and plants?

microorganisms

When looking for other planets, scientists first look for signs of _________________.

bacterial like prokaryotic organisms

The only living inhabitant of Earth for around 2 billion years

oxygenic- photosynthesis that produces oxygen

anoxygenic- photosynthesis that does not produce oxygen

Differentiate between anxoygenic and oxygenic.

biotechnology

the human manipulation of microorganisms to make products in an industrial setting

genetic engineering

manipulation of genetics of microbes, plants, and animals in order to create new products and GMOs

transferring genetic material from one organism to another to alter the DNA of an organism

Describe recombinant DNA technology.

the introduction of microbes into the environment to restore stability or to clean up toxic pollutants

ex: microbes that soak up oil spill

Describe bioremediation and give an example.

budding

process in which daughter cell grows off of mother cell

one way that yeasts reproduce

spores

cells that produce a new individual without fusing with another cell

how mold (and some yeasts) reproduce

enables the protozoa to be capable of locomotion

pseudoopodia- extensions of a cell that flow in the direction of travel, giving the organism an ameoba like structure

cilia- hair like structure that beats rhythmically to propel the protozoan through its environment

flagella- whip like structures; fewer, longer than cilia

Differentiate between pseudopodia, cilia, and flagella. Describe the role they play in the function of protozoa.

neither eukaryotic or prokaryotic

cannot live independently

simple structure- small amount of DNA/RNA wrapped in protein, may contain a lipid membrane

What structural characteristics of viruses make them unique?

living things can arise from nonliving matter

Describe the process of spontaneous generation.

Redi noticed that when decaying organisms were kept away from flies, maggots did not develop. This led him to believe the theory of spontaneous generation was false.

Describe Redi's experiments and how that affected his view on spontaneous generation.

Needham boiled/sealed beef gravy/plant matter and later noticed a cloudy substance formed. This led him to believe that a "life force" caused the spontaneous generation of this matter.

Describe Needham's experiments and observations.

Spallanzani followed a similar procedure by boiling infusions and sealing the vials, but he found that the infusions remained clear unless he broke the seal.

He concluded that Needham hadn't killed all the microbes or hadn't sealed the vials tightly; that microorganisms exist in the air and can contaminate experiments, and that spontaneous generation does not occur.

Describe Spallanzani's experiments/observations.

Pasteur boiled infusions but turned the neck of the flask into an s-shape so they were exposed to air but dust/microbes could not enter. The flasks stayed clean for 18 months until he finally exposed them to air. This disproved the theory of spontaneous generation.

Describe Pasteur's experiments and observations.

1. ask a question

2. generate a potential answer to the question (hypothesis)

3. design and conduct experiments to test the hypothesis

4. accept, reject, or modify the hypothesis

Describe the four basic steps of the scientific method.

Pasteur discovered that anaerobic bacteria produced acid in grape juice, but yeast ferments grape juice into alcohol. So he developed pasteurization (gently heating to kill bacteria then adding yeast to ferment) and began industrial microbiology (using microbes in the manufacturing process)

Describe Pasteur's role in determining the cause of fermentation and developing industrial microbiology.

1. suspected agent must be found in all cases of diseases and must be absent from healthy people

2. agent must be isolated and grown

3. agent must infect a healthy host when introduced

4. same agent must be found in experimental host

Describe Koch's Postulates.

To fulfill Koch's postulates, bacteria must be visible so it can be isolated and determined if that is the cause.

Hans Christian Gram developed the technique to leave some microbes pink and others purple to differentiate between gram negative and gram positive.

How/why was the gram stain created?

Ignaz Semmelweis

required medical students to wash their hands with clorinated lime water

Joseph Lister

began spraying wounds, incisions and dressings with phenol

Florence Nightingale

introduced cleanliness and other antiseptic techniques into nursing practice

John Snow

research into cholera epidemic highlighted a critical need to adequate sewage treatment and a clean water supply

Edward Jenner

demonstrated the protective nature of vaccinations

Paul Ehrlich

discovered that chemicals could kill microorganisms

microbial nomenclature

the process of naming microorganisms

taxonomy

the science of classifying living beings

originated over 250 years ago with the work of Carolus Linnaeus

Assigning scientific names, classifying organisms into a hierarchy of taxa, and identifying traits of organisms so they can be recognized.

Describe the primary traits of taxonomy.

genus name (capitalized) followed by species name (not capitalized)

both are italicized or underlined

How does the standardized binomial system of nomenclature assign names?

Growing, reproducing, responding, metabolizing

Describe the four major processes of living cells

a. Composition: Sticky substance surrounding the outside of the cell made of polysaccharides and/or polypeptides

b. Function: protects cells from drying out by creating a moist environment for cell to survive, can enable pathogens to survive and cause disease

c. Relevance: bacteria with capsules may be disguised from the immune system, slime layers allow bacteria to attach to surfaces with greater ease

Describe the composition, function, and relevance to human health of glycocalyces

a. Capsule: firmly attached to cell's surface, repeating units of organic chemicals (C-H) that are similar to chemicals found in the human body (can disguise foreign bacteria from the immune system), can make microbe slippery and difficult for white blood cells to phagocitize)

b. Slime layer: loosely attached to cell surface, stickiness allows prokaryotes to attch to surfaces like bioflims

Distinguish capsules from slime layers (bacteria).

a collection of microbes that adheres to a solid surface in a liquid environment

What is a biofilm?

capsule- consistent depth all the way around the bacteria

slime layer- inconsistent depth all the way around the slime layer, pieces may be floating off

Describe the differentiations between the appearances of capsule and slime layers.

a. Structure: long structures that extend through the surface and glycocalyces of bacteria, comprised of protein "flagellim", composed of filament, hook, and basal body

b. Propels the cell through its environment

Discuss the structure and function of bacterial flagella

the rotation of the flagella propels bacteria, the rotation is is powered by a flow of ions through the cytoplasmic membrane and is reversible

Describe how flagella work to propel bacteria through their environment.

a run is a counterclockwise rotation and a tumble is a clockwise rotation

Differentiate between a run and a tumble.

flagella: long structures that extend through the surface and glycocalyces of bacteria, comprised of protein "flagellium", propels the cell through its environment by rotating 360 degrees

pili: longer than fimbria but shorter than flagella, helps bacteria transfer DNA (conjugation)

fimbriae: rodlike protein extensions shorter than flagella, helps bacteria stick to one another/other surfaces, can carry enzymes that detoxify ions, can help bacteria move, can help bacteria communicate by conducting electrical signals

Compare and contrast the structures and functions of fimbriae, pili, and flagella.

Provides structure and protection, assists cells in attaching to other cells, assists cells in resisting drugs, gives bacteria shape (cocci, rods, spirilla)

Describe the function of a bacterial cell wall.

animal cells don't have cell walls, therefore antibiotics can be created to specifically target the cell walls of bacteria with no damage to animal cells

Describe the concept of selective toxicity in relation to bacterial cells vs animal cells.

teichoic acids- unique chemicals that have negative electrical charges and play a role in the passage of ions

lipoteichoic acids- teichoic acids linked to lipids that anchor peptidoglycan to the cytoplasmic membrane

What are teichoic acids/lipoteichoic acids?

mycolic acid- waxy lipid that helps organisms survive desiccation and helps cells retain moisture

acid fast stain- a special stain that detects cells with thicker layers of mycolic acid; not all gram positive cells are acid fast but all acid fast stains are gram positive

Describe the role of mycolic acid and acid fast bacteria.

Gram positive: thick layer of peptidoglycan, teichoic acids, lipoteichoic acids, mycolic acids, all acid fast bacteria are gram positive, stains purple with the gram test

Gram negative: thin layer of peptidoglycan, outer membrane bilayer (inner leaflet composed of phospholipids/proteins, outer leaflet composed of LPS, porins form channels between leaflets, periplasmic space, stains pink with the gram test

Compare and contrast the cell walls and cell envelopes of gram positive and gram negative bacteria in terms of structure and gram staining

-found only in gram negative

-outer leaflet of liopolysaccharide (LPS) and inner leaflet of phospholipids and proteins, porins form channels through leaflets so molecules can pass

- can make it harder to treat this type of bacteria

Describe the structure of the outer membrane of bacteria and its relevance to public health.

LPS (union lipid with sugar), is released when the outer membrane of a dead cell disintegrates and may trigger fever, vasodilation, inflammation, shock, blood clotting

Describe the dangers of treating gram negative bacteria due to LPS.

-gives a bacterial cell its energy

-located between the outer membrane and cytoplasmic membrane of a gram negative bacteria

-contains water, nutrients, substances, etc.

Describe the structure/function of the perplasmic space

Shaped the development of Earth's habitats, involved in the flow of energy on Earth, contribute to Earth's supply of oxygen, decompose, recycle matter, used for genetic engineering

Describe the role and impact of microbes on Earth

Humans have discovered how to utilize microorganisms for yeast, cheese production, prevent mold, prevent/treat disease, etc.

Explain how human have manipulated microorganism for their own uses over the millenia

also called a cell membrane or plasma membrane

composed of phospholipids/proteins and maybe hopanoids to create a phosopholipid bilayer

Describe the structure of a bacterial cytoplasmic membrane.

-found in bacterial cytoplasmic membranes but similar to sterol/steroid lipids found in eukaryotic membranes

-stabilizes the membrane

What is a hopanoid?

-may act as recognition proteins, enzymes, receptors, carriers, or channels

-half the membrane is composed of integral proteins

What role do proteins play in the bacterial cytoplasmic membrane?

Describes the mobility within a bacterial cytoplasmic membrane, mosaic refers to the arrangement of the membrane proteins, fluid indicates that the proteins and lipids flow laterally within a membrane

Explain the fluid mosaic model of membrane structure

Bacterial cell membranes are selectively permeable, allowing nutrients to be brought into the cell, wastes to exit the cell, passive or active movement, maintenance of a concentration gradient, and existence of an electrical gradient, produces molecules for energy storage and for harvesting light energy in photosynthetic bacteria

Describe the functions of a cytoplasmic membrane as they relate to permeability

Similarity: all require no ATP and follow the electrochemical gradient

Diffusion: movement of small chemicals only (oxygen, carbon dioxide, etc.) that require no transport proteins

Nonspecific facilitated diffusion: requires proteins (proteins allow a wide variety of molecules to pass), no large or electrically charged molecules can pass

Specific facilitated diffusion: specific integral proteins (permeases) only allow certain materials to pass through, large/electrically charged molecules cannot pass

osmosis: diffusion of water across the concentration gradient

Differentiate between the types of passive transport. (Also list similarities)

a. Isotonic: when solutions on either side of a selectively permeable membrane have the same concentration

b. Hypertonic: a solution with a higher concentration of solutes is said to be hypertonic to the other

c. Hypotonic: a solution with a lower concentration of solutes is said to be hypotonic to the other, causes cells to swell

Distinguish among isotonic, hypertonic, and hypotonic solutions

uniport- one molecule

antiport- two molecules, opposite directions

symport- two molecules, same direction

Differentiate between the types of permeases used in active transport.

A type of active transport that only occurs in some types of bacteria where the substance transported across the membrane is chemically altered and subsequently the membrane becomes impermeable to it.

Explain the process of group translocation.

Passive transport: requires no ATP, follows the electrochemical gradient, only requires integral proteins for some types of passive transport

Active transport: requires ATP and permeases for all types

Compare and contrast the passive and active processes by which materials cross a cytoplasmic membrane

a. Cytosol- liquid portion of cytoplasm, mostly water but also contains dissolved ions, carbohydrates, proteins, lipids, and wastes, contains cell's nucleoid (DNA), may contain plasmids, the site of some chemical reactions

b. Inclusions- deposits found within bacterial cytosol, storage vesicles for lipids, starch, or compounds containing nitrogen, phosphate, or sulfur

c. Ribosomes- sites of protein synthesis in the cells, thousands found in cytoplasm

d. Cytoskeleton in many cells- internal scaffolding composed of 3 or 4 types of protein fibers, plays a variety of roles such as dividing the cell in two, forming a helix down the length of the cell, determining shape of cell

e. Endospores in some cells- not reproductive structure, defensive strategy against hostile or unfavorable conditions, resistant to drying, heat, radiation, and lethal chemicals

Describe the bacterial cytoplasm and its basic contents

located in a region in the cytosol called a nucleoid, most contain a circle of double-stranded DNA as a chromosome

Describe where the DNA of bacteria is found.

an extrachromosomal piece of DNA that replicated independently of the chromosome and carries genes required for replication/cellular traits, not essential for growth/metabolism/reproduction but may provide a survival advantage

Describe the role of plasmids in bacteria.

A vegatative cell transforms into one endospore (when cell is low on nutrients) and then germinates to grow into one vegetative cell

Explain how/why some bacteria produce endospores.

1. bacteria have 70S ribosomes (30S and 50S subunits)

2. eukaryotic organisms have 80S ribosomes (40S and 60S subunits)

3. Because of the difference in sizes, antibiotics can act on 70S ribosomes without affecting 80S ribosomes

Compare the sizes of ribosomes within eukaryotes and prokaryotes and describe the medical implications of this.

a. Prokaryotes can have a cell wall and glycocalyces, eukaryotes can only have one or the other

b. Glycocalyces are never as organized in eukaryotes as in prokaryotes

c. Similar functions: anchors cells, strengthens cell surface, provides protection against dehydration, helps with cell to cell recognition/communication

Describe the structure and function of prokaryotic and eukaryotic glycocalyces

a. Eukaryotic cell walls (present in fungi. Algae, plants, and some protozoa that don't have glycocalyx) are composed of various polysaccharides, prokaryotic cell walls are composed of peptidoglycan (bacteria) or polysaccharides/proteins (archaea)

b. Similar functions: provides protection, anchors neighboring cells together, provides shape, support

Compare and contrast prokaryotic and eukaryotic cell walls and cytoplasmic membranes

a. Eukaryotic cell walls (present in fungi. Algae, plants, and some protozoa that don't have glycocalyx) are composed of various polysaccharides, prokaryotic cell walls are composed of peptidoglycan (bacteria) or polysaccharides/proteins (archaea)

b. Similar functions: provides protection, anchors neighboring cells together, provides shape, support

Compare and contrast prokaryotic and eukaryotic cell walls

a. All eukaryotic cells have cytoplasmic membranes that follow a fluid mosaic model of phospholipids and proteins (channel proteins present to anchor cells together) similar to prokaryotic cell membranes, control movement into and out with passive and active processes

b. Eukaryotic cell membranes differ due to the presence of steroid lipids to maintain fluidity, assemblages of lipids/proteins (membrane rafts), and chains of sugar molecules attached to the outer surfaces of lipids and proteins in the cytoplasmic membrane, eukaryotic cell membranes cannot perform group location, but undergo endocytosis

Compare and contrast prokaryotic and eukaryotic cytoplasmic membranes

endocytosis- type of active transport unique to eukaryotes, involves the physical manipulation of the cytoplasmic membrane

exocytosis- enables substances to be transported out of the cell

phagocytosis- endocytosis with solids

pinocytosis- endocytosis with liquids

Describe endocytosis vs exocytosis and differentiate between phagocytosis and pinocytosis.

contains flagella, cilia, nonmembranous organelles (ribosomes, cytoskeleton, centrioles and centrosome- play a role in mitosis) and membranous organelles (nucleus, ER, golgi, lysosomes, peroxisomes, vacuoles, vesicles, mitochondria, chloroplasts)

Describe the cytoplasm of eukaryotes.

a. Prokaryotes- cytosol, inclusions, ribosomes, cytoskeleton, endospores

b. Eukaryotes- cilia, ribosomes, cytoskeleton, centrioles/centrosome, nucleus, ER, golgi body, lysosomes, peroxisomes, vacuoles, vesicles

c. Both contain flagella, but flagella structures differ

d. Overall, eukaryotes have membrane bound organelles and a more complex structure

Compare and contrast the cytoplasm of prokaryotes and eukaryotes

a. Eukaryotic flagella are found inside the cell (prokaryotic extends past the glycocolyx)

b. Eukaryotic composed of tublin rather than flagellin

c. Eukaryotic may have a single or multiple flagella

d. Eukaryotic cells don't rotate like prokaryotic flagella do and don't move in runs or tumbles, but push or pull cell through medium

e. Both move in response to stimuli

Compare and contrast the structure and function of prokaryotic and eukaryotic flagella

found only in eukaryotic cells, motile, short, hairlike structures surrounded by cytoplasmic membrane, beating propels unicellular eukaryotes through their environment and moves substances past the surface of multicellular eukaryotes

Describe the function of cilia.

protein producing organelles that may be found attached to the ER of be free within the cytosol, size 80S (60S and 40S subunits) larger than prokaryotes, nonmembranous organelles

Explain the role of ribosomes in eukaryotes.

centrioles- involved in organization of the mitotic spindle and completing the cell cycle

centrosome function unknown, nonmembranous organelles

What are centrioles and centrosome?

a. internal scaffolding of fibers and tubules

b. anchors organelles, controls movement of organelles (even during endocytosis), produces the basic shape of the cell, nonmembranous organelle

Describe the structure and function of the cytoskeleton.

organelle containing most of the cells DNA, cell can have one or multiple (or lose their nuclei), contains a nucleoplasm, nucleoli chromatin, surrounded by a nuclear envelope.

Describe the structure of the nucleus in eukaryotic cells.

nucleoplasm- liquid portion

nucleoli- site of RNA synthesis

chromatin- masses of DNA associated with histones

nuclear envelope- double membrane of two phospholipid layers, contains nuclear pores to control import/export of cell

List and explain each of the structures found within a nucleus.

netlike arrangement of hollow tubules that are continuous with the outer membrane of the nuclear envelope, functions as a transport system, can be smooth or rough

Describe the structure and function of endoplasmic reticulum within a eukaryotic cell.

flattened hollow sacs with a phospholipid bilayer surrounding it, processing/packaging center for large molecules leaving cell, packages secretions in vesicles prior to exocytosis, not in all eukaryotic cells

Explain the structure and function of the Golgi body

both are membranous sacs that store and transfer chemicals within a eukaryotic cell

Compare the functions of vacuoles and vesicles.

lysosomes- only found in animal cells, contain catabolic enzymes that destruct old, diseased cells and digests nutrients that have been phagocytized

peroxisomes- derived from ER, contains catalase and oxidase to degrade poisonous metabolic wastes, found in all types of eukaryotic cells but prominent in the kidneys and liver cells of mammals

Compare and contrast the function of lysosomes and peroxisomes.

found in most eukaryotic cells (cell can have 1000 or more), "powerhouses of the cell", has two membranes composed of a phospholipid bilayer, produces most of the ATP in an organism, contains 70S ribosomes and a circular molecule of DNA similar to prokaryotes

Describe the function of the mitochondria in eukaryotic organisms.

light-harvesting, only found in photosynthetic eukaryotes, pigments produce ATP and sugar from light and carbon dioxide, similar to prokaryotes because of the two phospholipid bilayer membranes, DNA, and 70S ribosomes

Describe the function of chloroplasts.

a. The similarities between prokaryotes and the mitochondria/chloroplasts have led to the theory that eukaryotes formed when a larger anaerobic prokaryote unified with a smaller aerobic prokaryote, the smaller became an internal parasite and eventually lost the ability to live independently (though still retained DNA, ribosomes, etc.)

b. Evidence: presence of DNA, 70S ribosomes, two bilipid membranes in chloroplasts/ribosomes,

c. Theory does not explain double membrane of nuclear envelope of who organelles protein comes from nuclear DNA and cytoplasmic ribosomes

Describe and list evidence for the endosymbiotic theory

a. Metabolism- collection of controlled biochemical reactions that take place within cells of an organism, requires energy from light or catabolism of nutrients, ultimate function of metabolism is reproduction

b. Anabolism- synthesizing large molecules from smaller ones, constructs larger building blocks from precursor metabolites/energy/enzymes

c. Catabolism- breaks larger molecules into smaller ones to form precursor metabolites

Distinguish between metabolism, anabolism, and catabolism

a. Both reactions occur simultaneously and work to transfer electrons from a donor to an acceptor using electron carrier molecules

b. An oxidation reaction occurs by an atom losing a simple electron, losing a hydrogen atom, or gaining an oxygen atom

c. A reduction reaction occurs by gaining a simple electron or an electron that's part of a hydrogen atom (composed of one proton and one electron)

Contrast oxidation and reduction reactions

the free energy released when electrons move from donor to acceptor, used to synthesize ATP during aerobic respiration, used to reduce metabolic intermediates and generate ATP

Describe reducing power.

a. Cellular respiration- results in breakdown of glucose to carbon dioxide and water, after glycolysis continues to Kreb cycle and electron transport chain to produce a large amount of ATP, can be anaerobic or aerobic

b. Fermentation- results in organic waste products, after glycolysis converts pyruvic acid into other organic compounds, produces much less ATP

c. Both- begin with glycolysis (catabolizes a single glucose into two molecules of pyruvic acid and a small amount of ATP

Compare and contrast cellular respiration and fermentation

3 products of catabolism in cellular respiration

a. Precursor metabolites- numerous small molecules produced as a result of catabolism (large to small molecules), catabolic pathways produce ATP and provide building blocks for anabolic pathways

b. Reducing power- free energy released when electrons move from donor to acceptor, during aerobic respiration, this energy is used to synthesize ATP

c. ATP- used to power cellular reactions, generated from respiration/fermentation

Distinguish between precursor metabolites, reducing power, and ATP, including why each is important for a cell

a. The potential energy generated from the proton gradient is used to phosphorylate ADP into ATP

b. The proton gradient is created by the oxidation of carriers in an electron transport chain

Describe the role of a proton gradient in oxidative phosphorylation

a. Aerobic respiration- oxygen is the final electron acceptor

b. Anaerobic respiration- inorganic chemicals other than oxygen are the final electron acceptor (ex: sulfate, nitrate, sulfur)

c. Fermentation- organic molecule from within the cell (ex: pyruvate, acetaldehyde)

Discuss the final electron acceptors in aerobic respiration, anaerobic respiration, and fermentation

a. Some cells cannot oxidize glucose due to a lack of final electron acceptors, lack of oxygen, etc

b. Cells must provide an alternative source of NAD+ (typically yielded by electron transport chain) to power glycolysis and Krebs cycle

Describe why an organism uses fermentation to break down carbohydrates

-cells acquire nutrients and energy (from light or catabolism)

-energy is stored in ATP

- cells catabolize to form precursor metabolites

-precursor metabolites, energy, and enzymes are used in anabolic reactions to construct building blocks

-building blocks anabolically linked together in polymerization reactions

-cells assemble macromolecules into cellular structures

-once cells have doubled in size, they reproduce

ultimate goal of metabolism: enable the organism to reproduce

Summarize the eight elementary statements regarding metabolic processes.

oxidized: NAD+, NADP+, FAD

reduced: NADH, NADPH, FADH2

Identify examples of oxidized and reduced molecules.

energy that organisms release from nutrients is stored in phosphate bonds of ATP

the process of phosphorylation is how the inorganic phosphate is added to a substrate to convert ADP to ATP

Describe the role of phosphate bonds and explain what phosphorylation is.