Transcript Organic Macromolecules

Bell Ringer
• 1) How do you think bacteria can survive the
acidic conditions of the stomach and trigger a
life-threatening condition?
• 2) What type of reaction is seen below?
Turn in
• Lab Safety Sheet
• Bell Ringer Sheet
Quiz
• 15 Questions
• 15 Points
Objectives
• Use appropriate microbiology media, test
systems, and lab equipment.
• Describe the general properties and
characteristics of bacteria
– By doing this, students will be able to observe
growth characteristics of bacteria
Ubiquity of Microorganisms
• This means that microorganisms can be
found everywhere
– Soil, water, plants, animals
• Many microbes are free-living
– They don’t live on a specific host
– Most are nonpathogenic (non-disease
causing)
• Today we will culture microbes from the
environment
Ubiquity of Microorganisms
Simple streak pattern
Culturing Microbes
• Microbes need certain nutrients and growth
factors to grow and reproduce
–
–
–
–
–
–
Carbon
Nitrogen
Sulfur
Phosphorus
Trace elements
Organic growth factors
Culture Media
• Culture medium: Nutrients prepared for
microbial growth
• Sterile: No living microbes
– Autoclave at 121°C for 15 min at 15 psi
– Steam under pressure
• Inoculum: Introduction of microbes into
medium
• Culture: Microbes growing in/on culture
medium
Culture Media
• A. Chemically defined media: Exact
chemical composition is known
• B. Complex media: Extracts and digests of
yeasts, meat, or plants
– Chemical composition varies slightly from
batch to batch
– Nutrient broth
Agar
• Complex polysaccharide derived from
seaweed
• Used as solidifying agent for culture media in
Petri plates, slants, and deeps
• Generally not metabolized by microbes
• Liquefies at 100°C
• Solidifies at ~40°C
– Once solid, it will remain until heated again to
100°C
Labeling/Incubating Plates
Labeling Plate
• On back of plate with
sharpie
• Initials
• Date
• Sample
Incubation Plate
• 37⁰C
• Upside-down
• 24-48 hrs
What to Expect
• Bacteria make colonies
– Thousands of the same cells
– All cells in colony originate from single parent
• Variety of shapes, sizes, and color of various
colonies
Objectives
• By the end of the lesson, students will be able
to
– Describe basic chemistry principles including
bonding and chemical reactions.
– By understanding basic chemistry concepts,
you will be able to grasp the various
interactions between a microorganism and its
environment
Vibrio vulnificus
• How can bacteria survive the acidic
conditions of the stomach and trigger a lifethreatening condition?
• Eating raw or undercooked seafood
– Vomiting, diarrhea, abdominal pain
– Bacteria in blood (bacteremia)  drop in BP 
death 50% of the time
Water, Acids, Bases, and Salts
• Acids and Bases
– Break apart into cations and anions
– Acid – dissociates into H+ (and anions)
– pH < 7
– Inorganic – HCl, H2SO4
– Organic - Amino acids
– Base – some dissociate OH– (and cations)
– pH > 7
© 2012 Pearson Education Inc.
Figure 2.13 Acids and bases-overview
Water, Acids, Bases, and Salts
• Acids and Bases
– Buffers prevent drastic changes in pH
– proteins lose shape = loss of function
– Most microorganisms grow best between pH 6.5-8.5
© 2012 Pearson Education Inc.
Water, Acids, Bases, and Salts
• Acids and Bases
– Concentration of H+ in solution expressed by pH
scale
– Acidity increases as pH values decrease
– Each whole number decrease (pH5pH4)
indicates a 10 fold increase in acidity
– Glass of grapefruit juice (pH 3.0) has 10x more H+
ions than the same amount of tomato juice (pH 4.0)
© 2012 Pearson Education Inc.
Battery acid Extremely
Acidic
Increasing concentration
of H
Hydrochloric acid
Lemon juice
Beer, vinegar
Wine, tomatoes
Black coffee
Urine, milk
Pure water
Increasing concentration
of OH
Hydrochloric acid is how
much more acidic than
black coffee?
Seawater
Baking soda
Milk of magnesia
Household ammonia
Household bleach
Oven cleanerExtremely
Basic
Sodium hydroxide
a) 100x
b) 1,000x
c) 10,000x
d) 100,000x
Water, Acids, Bases, and Salts
• pH tolerance
– Most microorganisms grow best between pH 6.58.5
– There are some exceptions
– Fungi generally like more acidic environments
– Special media used to culture fungus
– Propionibacterium acnes tolerates acidic conditions
– Able to grow on the skin (pH= 4.0)
– Helicobacter pylori can tolerate pH as low as 1.5
– Grows in stomach and produces ulcers
© 2012 Pearson Education Inc.
pH Indicators Used in Culture Media
• Color change indicates pH
• A pH indicator is incorporated into the media
– Sugar fermentation = acidic pH
– Protein degradation = basic pH
• A = acid (yellow)
• G = gas (bubbles)
• K = alkaline (red)
Water, Acids, Bases, and Salts
• Raw Oysters and Antacids: A Deadly Mix?
– P. 39
– Vibrio vulnificus- present in marine environments
– Invades human body by eating seafood or through
open wounds
© 2012 Pearson Education Inc.
Raw Oysters and Antacids: A Deadly Mix?
• On a separate sheet of paper, answer
the following questions in complete
sentences
– 1) Why are patients who take antacids at
greater risk for infections with V. vulnificus?
– 2) Will antacids raise or lower the pH of the
stomach? Explain
– 3) Other than not taking antacids, what can
people do to reduce the risk of infection?
Bell Ringer
• On a blank piece of paper, make a Think-PairShare sheet
– You need the following 3 columns
– What I thought, What my partner thought, What
we will share
• How do antacid tablets work to relieve
indigestion and/or a sour stomach?
– Use the terms acid, base, and pH in your
answer
Objective
• Use appropriate microbiology media, test
systems, and lab equipment.
• Describe the general properties and
characteristics of bacteria
– By doing this, students will be able to observe
growth characteristics of bacteria
Lab Report
• Observe and record the colony morphology of
your samples
• Observe and record 2 other samples from
different students
– Fill in the chart
• Answer the questions
Example
• Yellow, circular, entire, raised
Example
• White, Irregular, Undulate, Flat
Bell Ringer
• After swabbing the floor and culturing the
plate for 48hrs at 37 C, you notice that there
isn’t any growth. Explain why this may have
occurred.
Objectives
• By the end of the lesson, students will be able
to
– Describe basic chemistry principles including
describing different organic molecules
– By understanding basic chemistry concepts,
you will be able to grasp the various
interactions between a microorganism and its
environment
Organic Macromolecules
• Contain carbon and hydrogen atoms
– Macromolecules – large molecules used by all
organisms
– Lipids
– Carbohydrates
– Proteins
– Nucleic acids
– Monomers – basic building blocks of
macromolecules
© 2012 Pearson Education Inc.
Organic Macromolecules
• Functional Groups – specific chemical
arrangement of atoms
– NH2 amino functional group
– Found in amino acids
– OH hydroxyl functional group
– Found in alcohols
– R (residue) stands for atoms in a compound that
change from one molecule to another
© 2012 Pearson Education Inc.
Organic Macromolecules
• Lipids
– Hydrophobic
– Afraid of, or insoluble in water
• Four groups
– Fats
– Phospholipids
– Waxes
– Steroids
© 2012 Pearson Education Inc.
Organic Macromolecules
• Fats
–Energy stored in covalent bonds
© 2012 Pearson Education Inc.
Organic Macromolecules
• Phospholipids
–The fatty acid tail is nonpolar
–Phospholipid head is polar
–Forms phospholipid bilayer
© 2012 Pearson Education Inc.
Organic Macromolecules
• Waxes
– Contain one long-chain fatty acid
– Insoluble in water
– Mycobacterium tuberculosis is surrounded by a
waxy wall
– Resistant to drying
© 2012 Pearson Education Inc.
Organic Macromolecules
• Steroids
– Four rings fused
– Hormones
– Chemical messengers
– Part of phospholipid
membrane
– Keeps membrane fluid
and flexible at low
temperatures
© 2012 Pearson Education Inc.
Organic Macromolecules
• Carbohydrates
– Composed of carbon, hydrogen, and oxygen
– Functions
– Long and short energy reserve
– Make up DNA and RNA
– Form cell wall
– Cell to cell communication
© 2012 Pearson Education Inc.
Organic Macromolecules
• 1) Monosaccharides
– Simplest sugars
– Deoxyribose
– Glucose
• 2) Disaccharides
– Two monosaccharides linked together
– sucrose (table sugar)
© 2012 Pearson Education Inc.
Figure 2.18 Monosaccharides-overview
Organic Macromolecules
• 3) Polysaccharide
– More than two monosaccharides
– Cellular structure or store energy
– Peptidoglycan – long polymer composing
bacterial cell walls
– Cellulose – cell walls of plants
– Glycogen – energy storage in animal cells
© 2012 Pearson Education Inc.
Figure 2.20 Polysaccharides-overview
Organic Macromolecules
• Proteins
– Mostly composed of C, H, O, N, S
– Functions
– Structure
– Enzymatic catalysis
– Regulation
– Transportation
– Defense and offense
© 2012 Pearson Education Inc.
Organic Macromolecules
• Amino Acids
–
–
–
–
Monomers
21 amino acids
Side groups differ (R) among A.A
Peptide bond links amino acids via dehydration
reaction
© 2012 Pearson Education Inc.
Figure 2.21 Amino acids-overview
Figure 2.23 Linkage of amino acids by peptide bonds
Dehydration
synthesis
Carboxyl Amino
group group
Amino acid 1
Amino acid 2
Peptide bond
Dipeptide
Organic Macromolecules
• Protein Structure
– Structure = function
– 1) Primary structure
– Amino acid sequence
– Combination unique to each protein
– A single change in ONE amino acid can disrupt
function
– 136th amino acid valine replaced with alanine
causes formation of prions
– Proteins spread, causing mad cow disease
© 2012 Pearson Education Inc.
Organic Macromolecules
• Protein Structure
– 2) Secondary structure
– Polypeptide chain folds into α-helices and β-pleated
sheets
– Held together by ionic bonds, hydrogen bonds, and
hydrophobic and hydrophilic forces
– 3) Tertiary structure
– folds into 3D shapes
– Disulfide bridges are formed to hold the shape
together
– 4) Quaternary structure
– Two or more tertiary structures coming together
© 2012 Pearson Education Inc.
Figure 2.24 Levels of protein structure-overview
Organic Macromolecules
• Protein Structure
–Physical and chemical factors cause loss of
shape = loss of function
– pH changes, extreme hearting, changes in salt
concentrations
– Denaturation – disruption in the 3D structure of
proteins
– temporary or permanent
© 2012 Pearson Education Inc.
Organic Macromolecules
• Nucleic Acids
– DNA and RNA: the genetic material of
organisms
– RNA also acts as enzyme, binds amino
acids, and helps form polypeptides
© 2012 Pearson Education Inc.
Organic Macromolecules
• Nucleic Acids
– Nucleotides are monomers that make up nucleic
acids
– Composed of three parts
– Phosphate
– Pentose sugar
– Nitrogenous bases (A,T,C,G)
© 2012 Pearson Education Inc.
Figure 2.25 Nucleotides-overview
Figure 2.26 General nucleic acid structure-overview
Organic Macromolecules
• Nucleic Acids
– Nucleic acid function
– DNA is genetic material of all organisms and
of many viruses
– Cells replicate and pass on DNA to their
descendants
– RNA helps synthesize proteins
© 2012 Pearson Education Inc.