Bio 202

Exam 2

What are biopolymers

Biological molecules and bacterial foods

Mass spectrum

Instrument that creates profile for microbes

Organic compounds

Carbohydrates, proteins, lipids, nucleic acids

Function of a cell depends on

Composition, chemical bonds, structure (shape, polarity, charge, size)

Polymerization

Small molecules of monomers synthesize to create polymers

Starch is made up of

Glucose

Proteins are made up of

Amino acids

Triglycerides are made up of

Fatty acids

DNA is made up of

Nucleotides

Carbohydrate basic formula

(CH2O)n

Carbohydrates are made of

Energy + energy storage + materials

Proteins are chains of … joined by … their function is determined by …

Amino acids … peptide bonds … their 3-dimensional shape

1 degree structure

Amino acid sequence

2 degree structure

Alpa helices and beta sheets

3 degree structure

3D shape and how the protein folds together

4 degree structure

Two proteins joined together

What are sterols

Cholesterol, hopanoids, ergosterol

What do sterols do

Help stabilize membranes (eukaryotes, bacteria, mycoplasma)

Fatty acid basic formula

CH3 - (CH2)n - COOH

Triglyceride

Glycerol and 3 fatty acids

Phospholipids

Glycerol + 2 fatty acids + phosphate

Isoprenols

Waxes, pigments, fragrances

Nucleotides

5 - carbon sugar, phosphate, nitrogenous base

Purpose of metabolism

Growth, maintenance, make more cells

Catabolism

Breakdown and release of energy

Anabolism

Build up reactions, require energy

Phototrophs

Use light as their source of energy

What two ways to cells handle energy

Chemical bond energy (ATP) and reducing power (NADH and FADH)

Chemical energy

Electron containing inorganic compounds strip inorganic chemicals of their electrons and use them for energy

Energy is used for what types of work

Transport, mechanical, chemical

Reducing power consists of

Reduction and oxidation

Reduction

Gaining electrons and hydrogen / Losing oxygen

Oxidation

Losing electrons and hydrogen / Gaining oxygen

When food is burned (oxidized) what happens?

Bonds are broken and ATP is made, electrons and H+ ions are freed

During energy capture, when cells trap electrons and hydrogen what happens?

Coenzymes are then used to serve as electron acceptors and to make ATP in the ETC

What is not used up in reactions?

Coenzymes and cofactors

Enzymes are affected by

pH and temperature

Metabolic reactions require

Enzymes

Hydrolysis

Chemical breakdown of a compound due to water

Glycolysis (central metabolism)

Breakdown of glucose by enzymes which releases energy and pyruvate

Glycolysis occurs in the

Cytoplasm

What is the net gain of glycolysis?

2 ATP + 2 NADH

Ribose

5C sugar needed for DNA

Erythrose

4C sugar needed for 3 amino acids

Enter Doudoroff pathway

Less efficient, creates half the ATP

Krebs cycle is most common to

Aerobic and anaerobic organisms

Krebs cycle intermediates

Citrate, alpha ketoglutarate, succinate, malare, fumarate, oxaloacteate

Electron transport chain purpose

Convert reducing power to ATP

ETC location

Plasma membrane, mitochondrial membrane

ETC is a series of …

Proteins in membranes

ETC is what type of reaction

Redox

How many ATP per FADH2 and NADH (ETC)

2 and 3

Glycolysis energy yield

2 ATP + 2 NADH

Krebs cycle energy yield

2 ATP + 8 NADH + 2 FADH2

Tributary pathways

Fats and proteins are converted to simpler forms suitable for glycolysis/Krebs

Deamination

Release of ammonia (catabolism)

Fermentation

Metabolism without need for an external electron acceptor

Anaerobic respiration

Bacteria and archaea .. used in Krebs cycle and ETC (different electron acceptors instead of O2)

Ecological impact of anaerobic respiration

Denitrification of soil, methane production, sulfur cycling

Fermentation is a low energy alternative to what

Respiration

Biochemistry of fermentation

Starts with glycolysis, produces pyruvate, NADH, and ATP

Lactic acid fermentation

C3H4O3 → C3H6O3

Alcoholic fermentation

C3H4O3 → C2H6O + CO2

Propionic acid fermentation

C3O3H4 → C3O3H6

What can be fermented?

Sugars, amino acid

Chemolithotrophy

Use ETC for oxidization, electrons are used to create NADH or ATP, O2 as an electron acceptor

Photosynthesis light reactions

Light energy is converted to ATP, NADPH, NADH (need ETC)

Photosynthesis dark reactions

ATAP, NADPH, NADH are used in biosynthesis

ETC cyclic phosphorylation

Generates ATP only

Noncyclic phosphorylation

ATP and NADPH are generated

Nutrient uptake and growth leads to

Increased size

Cell division leads to

Increased cell number

What is binary fission

Growth in size and the pinch of a cell, splits into two

Solid medium

Agar-based, all cells identical and allows for separation of mixed cultures

Liquid medium

Planktonic growth in labs, aquatic environments, and industry

Biofilms

Bacterial growth on surfaces, have increased antibiotic resistance and their a source of persistent infections

Biofilm development

Attachment and genetic reprograming - loss of flagella and synthesis of EPS

Microbial growth curve: Lag phase

Synthesis of necessary components

Microbial growth curve: Exponential phase

Uniform, rapidly dividing

Microbial growth curve: Stationary phase

Nutrient depletion and/or waste accumulation

Microbial growth curve: Death phase

Death phase

Population size calculation

N\[(t) cells after incubation\] = # of cells at the start X 2^#number of generations

Generation time

The time it takes for a population to double in number

Direct count

Dilute, fix, and stain cells, then count individually

Coulter counter

Measures electrical current/resistance, does not distinguish live/dead cells

Viable plate method (indirect counting)

Count colony, only living and viable cells

Most probable number

Based on # of cloudy broths, useful for water testing, counts only living cells

Turbidity

Estimates cell density, beam of light passes through using a spectrophotometer

If a pH is too low/high, proteins…

Denature

One pH level equates to

10 x more acidic or basic

How does temperature effect microbial growth

Too hot - proteins fall apart / enzymes and chem reactions work faster at higher temperatures

Obligate anaerobe

Need oxygen to survive

Facultative anaerobe

Switch from anaerobic to fermentation if needed

Aerotolerant anaerobe

Tolerate oxygen (fermentation)

Strict anaerobe

Killed by oxygen

Microaerophile

Need O2 in small amounts

Barophiles

Require high pressure

Barotolerance

Can withstand high pressure

UV radiation

Damage DNA, does not penetrate far

Ionizing radiation

Sterilizing agents