Ch. 7 Study Guide Flashcards by Bethany Au

Water makes up __% of a typical bacterial cell and __% of a typical human cell

70% of bacterial cell
___% of human cell

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Proteins make up __% of a bacterial cell?

97% (organic compounds-mostly proteins)

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Nucleic Acids (DNA/RNA) make up __% of a bacterial cell?

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Carbohydrates make up __% of a bacterial cell?

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Lipids make up __% of a bacterial cell?

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Inorganic compounds make up __% of a bacterial cell?

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Is there a significant difference between the chemical compositions of a bacterial and a human cell?

Not a huge difference

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An _______ is an organism that uses inorganic CO2 as its carbon source and convert it into organic compounds

Autotroph

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Is an autotroph nutritionally dependent on other living things? Why?

No- doesn’t use carbon from other organisms-uses inorganic carbon

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A _________ is an organism that must obtain its carbon from an organic form

Heterotroph

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Are heterotrophs nutritionally dependent on other living things?

Yes

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What is the difference between organic and inorganic carbon?

Carbon Dioxide is inorganic

Carbonate is organic

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Define Fastidious

Requiring strict nutritional environmental conditions for growth

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Macroelements vs. Microelements

Macroelements: required in large quantities, such as phosphate

Microelements: Trace: required in small quantities, such as zinc

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Name 3 examples of growth factors needed by some organisms

Animo acid
Nitrogenous base
vitamin

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Define a growth factor

An essential nutrient that cannot be synthesized by an organism and must be provided by the diet to facilitate growth

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Why is it difficult for bacteria to uptake iron?

Ferric iron is very insoluble

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What do bacteria need iron for?

respiratory protein structure: cytochromes

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How do bacteria uptake iron?

They secrete siderophores, which complexes with ferric iron and is transported into the cell

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How are chemoheterotrophs classified according to their methods for obtaining organic carbon? List all 3

Saprobes: metabolize the organic matter of dead organisms
Symbiotic Microbes: Obtain organic matter from living organisms
Photoheterotrophs: obtain carbon from organic carbon or sunlight

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Describe a chemoautotroph

An organism that relies on inorganic chemicals for energy and carbon dioxide for carbon

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Methanogenesis is a process carried out by what domain of life?

Methanogens- produce methane gas- ARCHAEA

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Are all enzymes located inside of a cell?

No- some are membranous or exoenzymes

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What is a parasite?

An organism that lives within/on a host, receiving nutrients/protection. The host receives some degree of harm

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What is an ectoparasite?

Parasites that live ON the body

What is an endoparasite?

Parasites that living within the organs and tissues

What is an intracellular parasite?

A parasite that lives within cells- the most extreme type

Define osmosis

Diffusion of water through a semipermeable membrane

Define diffusion

passive transport from a low-high gradient

What types of lipids are typically found in bacterial membranes?

Phospholipids

Define passive diffusion and give an example

Substances move down their gradient without using energy: osmosis

Define facilitated diffusion

Passive transport that requires a carrier but doesn't use energy: aquaporins

Define active transport and give an example

Requires energy, carrier proteins, and don't rely on a gradient: carrier-mediated active transport

Define group translocation and give an example

A transported molecule is chemically altered: glucose/fructose

Define Halophiles

Needs or tolerates high salt concentrations

Define Osmotolerant

don't require high solute concentrations

Define acidophiles

grow at extreme acid pH

Define neutrophiles

majority of microorganisms grow at pH 6-8

Define alkalinophiles

grow at extremely alkaline pH

Define Psychrophiles

optimum T below 15 C

Define psychotrolerant

Capable of living in extremely cold conditions

Define Mesophiles

optimum T 20-40 C most human pathogens

Define thermophiles

optimum T greater than 45 C

Define hyperthermophiles

Thrive at 80 C or higher

Define obligate Aerobe

NEEDS oxygen to grow

Define facultative anaerobe

uses oxygen but can grow without it more growth at top of deep

Define aerotolerant

indifferent to oxygen even distribution

Define anaerobic

does not use oxygen

Define microaerophiles

require only a small amount of oxygen

Define barophiles

Thrive under extremely high hydrostatic pressure

What enzymes are used to protect against toxic O2 products?

Catalase Superoxide dismutase

O2 is reduced by an electron and becomes a ________

superoxide radical O2-

What other forms of reactive oxygen species do microbes need to protect against?

hydrogen peroxide hydroxyl radical

What is considered the most dangerous ROS? (Reactive Oxygen Species)

superoxide ion O2-

AEROBES: do they use O2? Can they detoxify it? What enzymes?

Yes Yes catalase/superoxide dismutase

MICROAEROPHILES: do they use O2? Can they detoxify it?

Yes- small amounts Yes- small amounts

AEROTOLERANTS: Do they use O2? Can they detoxify?

No Yes

FACULTATIVE: do they use O2? Can they detoxify?

Yes, but don't require it Yes

ANAEROBES: do they use O2? Can they detoxify?

No No

Define and contrast Sessile and Planktonic

Sessile: fixed/attached, unable to move Planktonic: float around on bodies of water until they stick to something and form a biofilm

Define symbiosis

two organisms living in a close partnership mutualism commensalism parasitism

Define symbiont

Each member in a symbiotic relationship

Define holobiont

A collection of different species/organisms, including the host

Define obligate mutualism

2 organisms rely on one another to survive

Define non-obligate mutualism

Both benefit, but can live without eahcother

Define commensalism

One member benefits, the other is unaffected

Define predation

One member preys on the other

Define syntrophy (cross-feeding)

Shared habitat, members feed off others' released substances

Define amensalism

One member produces antibiotics to harm another member- competition

Give an example of mutualism

Termites and their gut microbes that digest dietary cellulose

Give an example of cooperation (non-obligate mutualism)

Plant cells and the fungi that grow within, protecting the plant from drought and insects

Give an example of parasitism

Plasmodium parasitizing red blood cells and causing malaria

Give an example of amensalism

Ants that spread antibiotic microbes through fungi food to protect it from parasites

Give an example of syntrophy (cross-feeding)

nutrient/bioelement recycling in biofilms

What is quorum sensing?

Cell communication to know when a biofilm reaches a Quorum (sufficient # of bacteria) uses inducer molecules

Provide an example of a cellular process regulated by quorum sensing

Gene expression

Ch. 7 Study Guide Flashcards

(76 cards)