Week 3

what does lysozyme do

digestive enzyme damages peptidoglycan cell wall

what are protoplasts and spheroplasts

gram positive: protoplasts w no cell wall

gram negative: spheroplasts w some cell walls

-survive in favorable environments (e.g. urine), burst in dilute environments osmotic lysis

why doesn’t penicillin kill gram negative

-outer membrane inhibits entry of penicillin

-fewer peptide cross-bridges

-susceptible to beta lactam antibiotics that penetrate outer layer better than penicillin

what are glycoproteins or glycolipids

-proteins and lipids on surface of plasma membrane w carbohydrates attached

-protect/lubricate cell and involved in cell-to-cell interactions

what is the random motion of particles in a liquid or water

Brownian motion

facilitated diffusion

uses transport proteins, no energy

osmosis

selectively permeable, through aquaporins (protein channels), high water concentration → low water concentration

osmotic pressure

pressure needed to stop flow of water across selectively permeable membrane

-greater solute → greater osmotic pressure

what is humans isotonic rate

.85% % saline, .85 g for 100 mL water

what do hypotonic solutions do

water enters cell causing osmotic lysis, cytolysis, hemolysis

-bacteria can survive for time bc of cell wall

what happens in hyptertonic solutions

-water leaves cell

-human and bacteria cells shrink: crenation

-in bacteria: cell shrinks away from cell wall called plasmolysis : causes bacteriostasis → stops growing, not killed

what is group translocation

transporter proteins from low concentration to high concentration, change during transport to keep inside

-i.e. glycose is phosphorylated

-uses atp

roles of cytoskeleton

cell division, shape, growth, DNA movement

shape of DNA

long circle of tightly compacted double stranced DNA= bacterial chromosome

plasmid

small circles of double stranded DNA not attached to bacterial chromosome : “extrachromosomal genetic elements”

-works better in pili sex

-where bacteria stor4e genetic info to antibiotic resistance : R factors

ribosomes

two subunits, protein factories

-structurally different in prokaryotes vs. eukaryotes: streptomycin, erythromycin, and chloramphenicol inhibit prokaryotic ribosomes

what store what

metachromatic granules: phosphate/energy

polysaccharide granules: carbohydrates

lipid inclusions: fat

sulfur granules: energy

magnetosomes: iron oxide and protect cell against hydrogen peroxide

endospores

formed by gram positive bacteria (Clostridium and Bacillus) when key nutrients like carbon or nitrogen sources become scarce/unavailable

-survive for millions of years

Microbiome in Urinary System

-prevalent in urine: Lactobacillus, Corynebacterium, Streptococcus, Actinomyces, and Staphylococcus

-UTIs have higher Gardnerella and less Lactobacillus

UTI case

Lactose fermenting, gram negative rods found in cultures

Mars article

• tested Burkholderia cepacia, Klebsiella pneumonia, Pseudomonas aeruginosa, and Serratia marcescens

• these usually live harmlessly on us, but become pathogenic when stressed

what make endospores

-Clostridium bacillus are big gram positive bacteria that form endospores and cause gas gangrene.

-Bacillus anthracis causes anthrax, coal-black lesions (cutaneous anthrax from leather drums, pulmonary from inhalation, gastrointestinal from ingesting) →HIGH mortality

—biowarfare in WWII. British detonated anthrax bombs (made in Indiana) to Gruinard Island in Scotland→killed sheep, polluted land, ppl couldn’t inhabit for years

what are cilia

used for locomotion or to move materials in eukaryotes (epithelium of respiratory tract)

plasma (cytoplasmic) membrane

-external covering in eukaryote cells

-use endocytosis :

—phagocytosis: WBCs ingest and destroy microbes

—pinocytosis: extracellular fluid dissolves substance and brings into membrane

—receptor-mediated endocytosis: substance binds to receptors and triggers membrane to fold inward→how viruses enter animal cells

roll of cytoskeleton in eukaryotes

-support and movement of cells and organelles → amoeboid motion or cytoplasmic streaming

-ps enzymes that float in prokaryotes are sequestered in organelles of eukaryotes

role and placement of ribosomes

-some float free, others attached to ER

nucleus and features

-double membrane with nuclear pores to let ribosomes out and to communicate w cytoplasm

-WITHIN: nucleoli where ribosomal subunits are made!

-DNA is in form of chromatin and condenses into chromosomes

roles of rough and smooth ER

-rough : ribosomes

-smooth: synthesizes phospholipids →cell membrane!, fats, and steroids

-inactivates and detoxifies drugs/alcohol (more prolific smooth ER→ higher tolerance)

Golgi complex

packages proteins like enzymes (brought by transport vesicles) into storage vesicles called lysosomes (digest old cells)

-WBCs have large numbers of lysosomes

vacuoles

membrane bound bags filled w water, enzymes, ions (created by golgi or endocytosis)

mitochondria

-double membrane

-inner folds called cristae , where chemical reactions w enzymes occur

-center is called matrix where metabolic steps create ATP

-have their OWN ribosomes like prokaryotic/bacterial ribosomes

(can reproduce via binary fission, used to be free living)

how can mitochondria be damaged

antibiotics like chloramphenicol can inhibit synthesis of ribosomes→ stem cells in bone marrow die→ lose blood cells, platelets→ aplastic anemia/ pancytopenia → tx: bone marrow transplant

anabolic vs catabolic reactions

anabolic: combine substances, requires energy

catabolic: break down substances, release energy

how is energy created

there is stored energy in the BONDS of phosphates. When ATP breaks off into ADP, it releases energy. ATP is constantly being synthesized and broken down.

-60% released as heat, 40% momentarily saved in ATP

dental plaque

microbial metabolism allows microorganisms to grow and create dental plaque → dental caries (cavities)

enzymes

-proteins that act as chemical catalysts

-lower activation energy by:

—3 D shape

—arrange substrates

—collision theory: energy transferred in collision breaks or forms new bonds

-ex. : beta-lactamase: targets beta lactam ring in penicillin/cephalosporin

how are some antibiotics penicillin resistant

they make the enzyme beta lactamase that targets the beta lactam ring in penicillin and other beta lactam drugs

what are the parts of an enzyme

-enzymes have apoenzyme (protein) and cofactor (non protein)

-cofactors can be:

-metal ion (like calcium, iron, zinc, mg)

-coenzymes (organic molecules)

—apoenzyme + cofactor = holoenzyme

what are examples of coenzymes

-nicotinamide adenine dinucleotide ← from niacin

-flavin adenine dinucleotide←from riboflavin

-(both NAD and FAD are hydrogen ion carriers)

-Coenzyme A (CoA) from pantothenic acid

sequence of enzyme

substrate contacts active site by brownian motion → temporary enzyme-substrate complex forms→ substrate transformed→ product released→repeat w same enzyme

What are competitive inhibitors

-aka competitive analog

-bacteriostatic effect by taking place of substrates

-ex: sulfa drugs inhibit para-aminobenzoic acid (PABA)

—para-aminobenzoic acid makes folic acid→necessary for bacteria’s DNA (human cells have different ways to make folic acid)

-ps PABA supplements or sunscreen reverse effects of sulfanilamide

-CANNOT be used on immunocompromised patients (bc its bacteriostatic not bacteriolytic) and WBCs won’t eat em up

-sulfa drugs like trimethoprim-sulfamethoxazole cause allergic reactions like Erythema multiforme → Stevens Johnson

Noncompetitive inhibitors

-act on enzyme: allosteric inhibition: alter shape

-ex: nerve gases )Soman-GD, Sarin-BG, VX) →irreversible

-Act on metal ions (cofactors)

-ex: cyanide binds to iron in iron containing enzymes, fluoride binds to calcium

-ex: sodium citrate binds to calcium, which is a cofactor for blood clotting enzymes (helps in blood bank bags; when put in humans the sodium citrate is metabolized by citric acid cycle)

Feedback inhibition

-final product of enzyme assembly line acts as starting enzyme inhibitor: reversible allosteric noncompetitive enzymatic inhibition

oxidation and reduction

oxidation is addition of oxygen or removal of electron (hydrogen)

reduction is loss of oxygen or addition of electron (hydrogen ion)

cellular respiration

cellular respiration and fermentation allow energy to be produced from glucose

-uses long chains of oxidation-reduction reactions (compared to producing electrical power by using energy from a flowing stream)

Glycolysis

-start w 1 glucose, 6 carbon, 12 hydrogen, 6 oxygen

-end w 2 atp, 2 pyruvic acid (3 carbon each), and two NADH (to transport 2 hydrogen ions)

-this is anaerobic , and produces NO CO2

guessing game kid article

-ear infection→ couldn’t prescribe amoxicillin (beta lactam) bc of diarrhea

-gave trimethoprim-sulfamethoxazole

-red spots, fluid-filled vesicles, target lesions →erythema multiforme (allergic reaction to sulfa drugs)

—can lead to Stevens Johnson →blindness, death, skin falling off→ try to keep fluid in balance and avoid shock, take vital signs