bio357 unit 1 exam

Hooke

Hooke

• first to observe distinct units of living material, which he called "cells"

• created the first publication of objects seen under a microscope

• improved the design of compound microscope

van Leeuwenhoek

• first individual to observe single-celled microbes (discovered protists and bacteria)

• made single lens microscopes

• known as the "Father of Microbiology"

Pasteur

• discovered the fundamental chemical property of chirality

• discovered that fermentation was caused by living yeast (single-celled fungus)

• theory: transmission of germs causes disease

Koch

• devised the first scientific basis for determining that a specific microbe causes diseases

• used anthrax to demonstrate the "chain of infection", or transmission of disease

• determined the bacteria that causes tuberculosis

Koch's postulates

• microbe always present in diseased, absent in healthy

• microbe can be grown in pure culture with no other microbes present

• when the microbe is introduced into a healthy individual, the host shows the same disease

• same microbe re-isolated from now-sick individual

Ed Jenner

• concept and execution of 1st vaccine

• used cowpox vaccine to prevent smallpox

• known as the "Father of Immunology"

Fleming

• discovered penicillin

• discovered that microbes produce antibiotics

• discovered lysozymes

bacilli

rod-shaped

cocci/staph

sphere

spirochetes

spirals

light field

light background, dark objects

dark field

dark background, light objects

phase scope

differences in refractive index reveal shape of organelles and outline of cell; patterns of light and dark

light microscopes

maximum magnification: 1000x

fluorescence

• requires fluorophore to fluoresce

• DAPI + chlorophyll stain

TEM

• cross-section

• 20,000,000 - 50,000,000x mag.

SEM

• outside/surface of organism

• 100,000x - 3,000,000x

purpose of gram stains

• shape

• Gram + or -, which affects treatment

archaea vs. bacteria

• ether vs. ester links

• different ribosome configuration

• fatty acid monolayer in some archaea

ester links

lipid link in bacteria and eukaryotes fatty acids

ether links

lipid link in archaea fatty acids

gram positive bacteria

• thick cell wall

• ↑ peptidoglycan

• S layer

• teichoic acids

gram negative bacteria

• thin cell wall

• ↓ peptidoglycan

• outer membrane (distinct from cell membrane); contains porin; i.e. 2 membranes

cell wall

everything outside cell membrane + gives structure to cell

cell membrane

• phospholipid bilayer

• contains integral and peripheral proteins and carbohydrates

important components of cell wall

• peptidoglycan

• porous nature

• flexibility

eukaryotes vs. prokaryotes

• prokaryotes do not undergo mitosis or meiosis

• prokaryote cell wall = peptidoglycan; plants = cellulose; fungi: chitin

• structurally different ribosomes

• eukaryotes: membrane bound organelles

• prokaryotes: coupled transcription/translation

functions of the cell membrane

• permeability barrier

• structural support for protein

• detection of environmental signals

• secretion + communication

passive transport

• transport of a substance across a cell membrane by diffusion

• does not require energy

active transport

• transport of a substance across a cell membrane against the concentration gradient

• requires energy

• uses protein

proton gradient

• also called proton motive force

• changes pH in cell

• don't go through membrane easily (polar → need protein)

• move nutrients into the cell

• drive motors that rotate flagella

• drive synthesis of ATP

periplasm

fluid; space between the cell membrane + cell wall; external to the cell

capsule

external to cell wall, usually thick + gooey

glycocalyx

capsule of mycobacterium

peritrichous

flagella randomly spread around

lophotrichous

• aka amphitrichous

• tuft of flagella at one or both ends

monotrichous

single flagellum

coupled transcription/translation

• begin translation before transcription is 100% complete

• ↑ speed

antiport

the actively transported molecule moves in the direction opposite that of the driving ion

symport

the two molecules travel in the same direction

more sterols

↑ rigid cell membrane (less fluid)

less sterols

↓ rigid cell membrane (more fluid)

chemotaxis

• movement by a cell or organism in reaction to a chemical stimulus

• move towards attractants (nutrients)

• move away from repellents (poison)

minimal defined media

know exactly what's in the media, contains only nutrients essential for growth of certain microbe

complex media

nutrient rich media with poorly defined components

differential media

can distinguish between various bacteria on the basis of metabolic differences

selective media

allows growth of certain species/strains of organisms but not others

autotrophy

make the 4 macromolecules

heterotrophy

needs pre-formed 4-macros

photoautotrophy

use light energy → make macros

chemoautotroph

uses inorganic compounds as e- donors (ex. hydrogen, iron, etc.)

chemoheterotroph

• aka chemoorganotroph

• uses organic compounds as e- donors

photoheterotrophy

light energy makes organic compounds donate e-

assimilation

• nitrogen → ammonium

• nitrogen fixers: huge energy sink; do not get energy from this

• make nitrogen part of oneself

dissimilation

• phase of nitrogen cycle where energy is being made

• ammonium → nitrate → nitrite

coupled transport

• antiport and symport

• doesn't need to use ATP directly

• can move molecules against conc. gradient not via active transport

• use free energy released as ion moves down its concentration gradient to drive the transport of a second molecule against its concentration gradient

endocytosis

uptake particles

pinocytosis

uptake of a solution (dissolved substances)

exocytosis

• out of cell

• excrete waste, enzymes, etc.

viable

• alive -metabolically active

• can divide if environment conditions are favorable

lag phase

• not dividing

• acclimating to new environment, getting ready to divide

log phase

doubling

stationary phase

rate of death = rate of division (cells dying @ same rate they're dividing)

death phase

dying faster than dividing

batch (closed system)

limited resources (ex. test tube, flask)

chemostat (open system)

keep providing nutrients and removing waste

biofilm

• a community of microbes growing on a solid surface

• can be pure culture or mix

• quorum sensing: cell to cell communication

heterocyst

specialized cell that does nitrogen fixation

cyanobacteria

• prokaryotic

• can do both nitrogen fixation and photosynthesis

psychrophile

< 15°C

mesophile

15-45°C

thermophile

50-80°C

hyperthermophile

80°C

barotolerant

10-495 ATM (can survive at 495, not growing)

barophile

growing >380 ATM

normal salt

0.1-1M NaCl (0.2%-5%)

halophile

2M NaCl (10-20%)

acidophile

< pH 5

neutrophile

pH 5-8

alkaliphile

pH 9

strict aerobe

• must use oxygen in respiration and deal with ROS (free radicals)

• allowing formation of H+ gradient → allow formation of ATP

facultative anaerobes

either ferment (does not use oxygen) or use oxygen (respiration)

aerotolerant anaerobes

• ferment only

• don't use oxygen but can deal with ROS

microaerophile

• only deal with low levels of oxygen

• minimal anti-ROS

strict anaerobe

killed by oxygen/ROS (environment with oxygen)

superoxide dismutase

enzyme that catalyzes the conversion of superoxide (radical) into hydrogen peroxide

catalase

enzyme that converts hydrogen peroxide into water and oxygen

peroxidase

enzyme that converts hydrogen peroxide into water and NAD⁺

oligotrophy

low/limited nutrients

eutrophic

high nutrient levels (from agriculture and sewage) → algae blooms → oxygen depletion

sterilization

• kills everything, remove life

• very difficult and expensive

disinfection

• kills disease-causing organisms

• used on inanimate objects (ex. toilet, door handle)

• bleach, ethanol

antisepsis (antiseptic)

• kills pathogens on living tissue

• hydrogen peroxide

• iodine

sanitation

• reduces disease population below safe levels

• cost effective

cidal

kill

static

stop growth

autoclave

• sterilization

• 120°C, 15 psi, 20 minutes

• wet heat (???)

dry heat

• cooking in oven

• sanitation, not sterilized

pasteurization

• 63°C for 30 mins

• 72°C for 15 sec

• reduce disease-causing microbes

filter sterilization

• used on things that are heat sensitive (autoclave will denature proteins, enzymes, etc.)

• holes let liquid through but too small for microbes to get through