BIO 2060 Exam 2 Flashcards

Studies metabolism, morphology, reactions to stimuli (antibiotics, nutrients), investigations of novel proteins, etc

Physiological Studies

Testing against other microbes, hosts, etc

Genetics Studies

Testing against other microbes, hosts, etc

Microbial Interactions

• Microscopic characters, phylogenetics, etc

• Culture required for naming

Taxonomy

Can synthesize all nutrients needed for growth (with a single C source and other precursors)

Ptototroph

• Cannot synthesize all nutrients needed for growth

• Must get nutrients from environment

• Most microbes are considered this

• Can have more than 1 ________(y)

Auxotroph

Close association of two or more microbes

Symbiosis

Symbionts often rely on each other for _________

Nutirents

Malria parasite has to steal _________ from its host

Nucleosides

Arbuscular Mycorrhizal Fungia are __________ symbiotes

Mutualist

Arbuscular Mycorrhizal Fungia trade _____ from plants for nutrients thr fungus gets from the soil

Lipids

Mycobacterium leprae causes ______ in animals

Leprosy

___________ = slower growth rate as dependence of host increases

Auxotrophy

Mycobacterium leprae is a __________ pathogen

Intracellular

Helicobacter pylori is a ________, slow growing organism

Fastidious

Helicobacter pylori causes ________ in humans, and leads to ulcers and can contribute to cancer

gastritus

___% of microbes are unculturable

99

How are unculturalble microbes studied?

Microscopy/DNA based metagenomics

FISH: fluorescent in situ hybridization

Amplifies one target gene from mixed DNA, typically 16S rRNA gene for prokaryotes

Amplicon sequencing

Amplifies as much DNA as possible, can get the sequences of many genes and not just one

Metagenomics

A mixture of nutrients for growth

Medium

Agar is a ______ type of medium

Solid medium

Broth is a ______ type of medium, contains no agar

Liquid medium

A medium with an unknown chemical composition

Complex medium

precisely defined chemical composition

Defined/Synthetic Medium

Complex Recipes

Defined Recipes

Low in nutrients

Weak Medium

High in nutrients

Rich Medium

Modified from general recipes

Specialized Medium

Used to allow the growth of only certain target organisms

Selective Medium

Used to visually distinguish organisms (often closely related), often using color changes

Differential Medium

Designed to favor the growth of only certain target organisms with specific requirements (typically rare species)

Enrichment Medium

• Contains only a single organism

  • separates specific species from mixed environmental samples

  • Needed for organismal studies

  • also known as “pure culture”

Axenic Culture

Some are unicellular, others are multicellular

Fungi

• “Fuzzy”

• Irregular colonies

• Variations in form, texture, elevation, and color

Fungi and filamentous bacteria

• Smooth & gelatenous

• Compact & circular

• Variations in form, texture, elevation, and color

Bacteria and Yeasts

Bacterial growth curve

Nutrients are not replenished, waste is not removed. Mainly applies to bacteria and yeast

Closed Culture

Prokaryotes divide by _____ fission (asexual)

Binary Fission

Time cells need to adjust to medium and begin replication

Lag Phase

Lag Phase is the time needed to alter gene _______

Gene Expression

The time required to double population in the exponential phase

Generation Time

• Growth rate decreases

• Nutrients are being used up

• Accumulates waste

• May be replication rate = death rate

• Responses include flagella, anti-microbial compounds, and endospores

Stationary Phase

• Cells deplete supply of nutrients

• Synthesis of macromolecules slows

• Cells can no longer replicate

Death Phase

Number of generations/unit of time

Growth Rate

Growth Rate is ______ of the Generation Time

Inverse

The maximum population density and/or amount of cellular material produced by the culture

Growth Yield

• A continuous culture

  • Nutrients added; waste removed

  • Dilution rate must be balanced with growth rate

  • indefinite exponential phase

  • e.g. human gut

Chemostat

The cloudiness of a liquid culture

Turbidity

Sends light through a culture to measure Turbidity

Spectrophotometer

Can give a rough measure of cell density, but must have at least 10 million cells/mL for accuracy

Optical Density

• Microscope slide with a counting chamber

• Measured volume is loaded onto a grid

• Cells are counted under a light microscope

• Cheap, fast, easy

• Cant differentiate live and dead cells

Direct Counts

• First culture is diluted

• Dilutions are plated

• Colonies are Counted

• _____-_____ ___ per milliliter of initial culture is calculated

• Only counts viable (live) cells

• more time consuming

Serial Dilutions and CFU’s

Growth rate will depend of the amounts of ___(same answer)____ in the environment, AND which ___(same answer)____ species can use

Nutrients

O2 is the terminal electron acceptor in the respiratory electron transport system

Aerobic Respiration

O2 byproducts are ____ to cells! (e.g TOS or ROS)

Toxic

Can be used as a weapon against other organisms

Reactive Oxygen Species (ROS)

Fill in the blanks

1. Yes, but weak

2. No, but O2 isn’t toxic

Growth only at top where O2 is highest

Obligate Aerobic

Growth only at bottom when O2 is lowest

Obligate Anaerobic

Growth throughout the tube, densest at top

Facultative Anaerobic

Growth is evenly scattered throughout with no preference for O2 level

Aerotolerant Anaerobic

Growth in band just below surface where O2 is in low concentration

Microareophilic

Affects protein structures and proton motive force

pH

Related to water availability, cells must be able to uptake some water

Osmotic Pressure

Vapor pressure of a liquid compared to pure water

Water Activity

• Can decrease Water Activity values

• Pure water aw = 1.0

• Seawater aw = 0.98

• Honey aw = 0.6

• Most bacteria = above 0.9

• 0 - 0.6 aw = no growth

• aw 0.85 used to regulated canned goods

Solutes

Affects macrocmolecular structure, membrane fluidity, and enzyme activity

Temperature

Most human pathogens are _________

Mesophiles

Denatures proteins and nucleic acids

Heat

High temperature and pressure heating

Autoclaving

Low temperature heating

Pasteurization

Can damage cells with ice, used for preservation

Freezing

Radiation of UV 260 to 280 nm can ________ DNA

Damage

Used on living tissue

Antiseptics

Used on nonliving surfaces

Disinfectants

Metabolism

All chemical reactions in a cell

Enzymes

Metabolism depends on the ___(same answer)___present, ___(same answer)___ make up a majority of proteins in cytoplasm

Light

The energy source of Phototrophs

Oxidation of reduced chemicals (e.g. sulfite)

The Energy source of Chemotrophs

Inorganic CO2 (primary producers)

The carbon source of Autotrophs

Organic CO2 (aldehydes, AAs, lipids, alcohols)

The carbon source of Heterotrophs

Organic Molecules (e.g. glucose)

The electron source for Organotrophs

Inorganic Molecules (e.g. H2, Fe2+, ammonium NH4, nitrite NO2-, sulfur S)

The electron source for Lithotrophs

Assimilation

Incorporating nutrients into cellular parts

Mixotroph

An organism that is more than one type of “troph”

Enzymes

Catalyzes metabolism

Catabolism

Breaking down larger molecules into smaller ones, is Exergonic

Anabolism

Using smaller molecules to build up macromolecules, is Endergonic

Exergonic

Energy releasing reactions

Endergonic

Energy absorbing reactions

Active site

An enzymes __________ binds specific substrates and helps to convert them to products

Oxidation

Loss of e- or H+

Reduction

Gaining of e- or H+

Redox

The type of reaction that Oxidation and Reduction reactions are reffered to as

Activation

Enzymes lower the ______ energy