Zamora Test 3 PP

Study Material from Power Point

Carbon Skeleton

__ comes froms Krebs cycle or glycolysis

Dehydrogenase

Removes or adds Ammonia

Snythetase

Adds ammonia

Transaminase

Transfers Ammonia

Snythase

Transfers ammonia

Fatty acids

Biosynthesis of __ makes 2 carbon atoms at a time

Acyl carrier protein (ACP) & NADPH

Biosynthesis of fatty acids requires __&__.

Phosphogluconate pathway, Pentose Phosphate pathway, hexose monophosphate shunt

Synthesis of pentose sugar

CTP and TMP

Products of Pyrimidine biosynthesis

UMP intermediate

What kind of intermediate is in pyrimidine biosynthesis

Orotic acid

Precursor in pyrimidine biosynthesis

Activated ribose

__ is added to the pyrimidine ring after its fully synthesized.

Purine Biosynthesis

Starts from amino acids, CO2 and formyl groups

Formyl groups

__ added with the help of folic acid in purine biosynthesis

Inosinic acid (IMP)

Intermediate of the purine biosynthesis

AMP and GMP

What is formed from the IMP (in purine biosynthesis)

Methotrexate, aminopterin

__ inhibits tetrahydrofolate to TMP

6-mercaptopurine

__ inhibits conversion of IMP to AMP

5 fluoropyrimidine

__ blocks conversion on UMP to TMP

Sulfonamides

__ block folic acid synthesis in nucleeotide synthesis

Nutrients

Supply of monomers (or precursors of) required by cells for growth

Macronutrients

Nutrients required in large amounnts

Micronutrients

Nutrients required in trace amount

Carbon

Required by all cells & major element in all classes of macromolecules

Organic carbon

Heterotrophs use __?

Carbon dioxide (CO2)

Autotrophs use __?

Nitrogen

Key element in proteins, nucleic acids, and many more cell constituents

Phosphorus (P)

Synthesis of nucleic acids and phospholipds

Sulfur (S)

__-containing amino acids (cysteine and methionine)

Sulfur

What macronutrient is in vitamins such as thiamine, biotin, lipoic acid and coenzyme A

Potassium (K)

Required by enzymes for activity

Magnesium (Mg)

Stabilizes ribosomes, membranes, and nucleic acids (also required for many enzymes)

Calcium (Ca)

Helps stabilize cell walls in microbes and plays a key role in heat stability of endospores

Sodium (Na)

Required by some microbes (e.g., Marine Microbes)

Carbon, Nitrogen, Phosphorus, Sulfur, Potassium, Magnesium, Calcium, Sodium

Macronutrients

Iron (Fe)

Key component of cytochromes and FeS proteins involved in electron transport

Growth Factors

Organic compounds required in small amounts by certain organisms

Vitamins, amino acids, purines, and pyrimidines

Examples of growth factors

Vitamins

Most commonly required growth factor (most function as coenzymes)

Culture media

Nutrient solutions used to grow microbes in laboratory

Defined media and Complex media

Two broad classes of media used in microbiology

Defined media

Precise chemical composition is known

Complex media

Composed of digests of chemically undefined substances (e.g.,yeast and meat extracts)

Semisolid or solid

__ media contains agar or gelatin

Enriched media

__contains complex media plus additional nutrients

Differential media

__ allows multiple types of bacteria to grow but display visible differences in how they grow (e.g. Spirit blue agar, Starch agar, Skim milk agar)

Selective media

__ inhibits the growth of bacteria (Asparagine agar, Phenylethyl alcohol agar)

Salmonella Shigella agar, MacConkey Agar, Mannitol Salts Agar

Examples of selective and differential agar

Culture

ability to grow microbes

Pure culture

Contains only one type of microbe

Contaminants

Unwanted organisms in a culture

Streak plate

streaking pattern on agar

Spread plate

drop of liquid on agar spread with a sterile glass rod

Pour plate

Mix bacteria with melted agar that is cooled to 42 degrees C

Subculture

A __ places the same bacteria on a new media (risk of mutation)

slows down

Refrigeration __ growth of bacteria (1-2 months)

Binary fission

Bacteria divide into 2 cells by __

Number and size

Bacteria can grow (increase) in __

Doubling time

Amount of time required for population to double

Generation time

Amount of time required for a complete division cycle

Turbidity

The greater the __, the larger the population size

Turbid

A clear nutrient solution becomes __ or cloudy as microbes grow in it.

Microscopically

Direct cell count is measured __

Coulter counter

__ electronically scans a fluid as it passes through a tiny pipette

Flow cytometer

__ works similarly to a coulter counter, but can measure cell size and differentiate between live and dead cells.

Spectrophotometer

Turbidity is measured with a __ and is referred to as optical density (OD)

Direct count

__ is a particle count done through microscopic examination

Coulter counter

__ uses electricity to count cells but cannot distinguish live from dead cells

Flow cytometer

__ uses fluorescent dyes and lasers to count cells and can distinguish live from dead cells

Heat sensitive

In a pour plate __ organisms die

Most Probable number method

Statistical method for measuring bacteria in liquid

Bacteria can NOT grow on agar

The most probable number method is used when __.

Batch culture

a closed-system microbial culture of fixed volume

Lag phase, Exponential phase, Stationary phase, Death phase

The four phases of typical GROWTH CURVE for population of cells grown in a closed system

antimicrobial agents and heat

Microbes in exponential growth phase are more vulnerable to __

Actively growing cells

__ cells are more vulnerable to conditions that disrupt cell metabolism and binary fission

Early and middle stages

A person actively shedding bacteria in the __ of infection is more likely to spread it than a person in the later stages.

Continuous culture

An open-system microbial culture of fixed volume

Chemostat

Most common type of continuous culture device

Rate and population density

Both __ of culture can be controlled independently and simultaneously

Dilution rate

Rate at which fresh medium is pumped in and spent medium is pumped out

Cardinal temperatures

The range of temperatures for the growth of a given microbial species

Minimum temperature

The lowest temperature that permits a microbes continued growth and metabolism: below this temperature its activities are limited.

Maximum temperature

The highest temperature at which growth and metabolism can proceed before proteins and denatured.

Optimum temperature

An intermediate between the minimum and the maximum that promotes thee fastest rate of growth metabolism

Temperature requirements

membrane fatty acid composition and protein composition differ with__.

Stenothermal

Grows in a narrow temperature range

Eurythermal

Grows in a wide temperature range

Water

Organisms have to extract __ from environment

Xeromyces sp.

Example of Osmotolerant

Saccharomyces sp.

Example of Osmophilic

Staphylococcus aureus

Example of Halotolerant

Vibrio sp., Halobacterium sp.

Example of Halophillic

pH= -log [H+]

Formula for pH

Optimum

Each organism has a pH __.

Acidophiles

Organisms that like low pH

Thiobacillus sp.

Example of acidophile

Alkaliphiles

Organisms that like a high pH.

Natronomonas

Example of Alkaliphiles

Aerobic

Requires oxygen