MCB3020 Exam 1 USF

What is Robert Hooke known for?

He is the first person to see a cell. Also Helped construct the first microscope.

What is Antonie van Leeuwenhoek known for?

Made His own Microscope (Single-lens), Observations also published by the Royal Society.

Malpighi and Odierna

Published two volumes of microscopic observations of the human excretory system in the Royal Society

spontaneous generation

the mistaken idea that living things arise from nonliving sources

Which scientist's sought to debase spontaneous generation?

Redi and Pasteur

Francesco Redi

This scientist disproved spontaneous generation by showing that maggots do not spontaneously arise from decaying meat.

Louis Pasteur

A French chemist, this man discovered that heat could kill bacteria that otherwise spoiled liquids including milk, wine, and beer. (Swan neck experiments)

Robert Koch

Debased miasma theory of disease causation

Miasma Theory of Disease

a discredited theory in which 'bad air' was accepted as the cause of diseases.

What are the three domains?

Bacteria, Archaea, Eukarya

Traits shared by all domains of life

dsDNA, RNA pol, Protein domains, aqueous cytosol

Traits that differ between domains

Size, Metabolism, gene orientation, chromosome, multicellularity

What are the microbial eukaryotes

Protozoa, Fungi, Algae

Lynn Margulis

Developed the Endosymbiotic Theory.

Endosymbiosis

A theorized process in which early eukaryotic cells were formed from simpler prokaryotes.

Viruses

Considered by scientists to be Non-living particles

size of microbes

Can Differ in size by several orders of magnitude

What % of the ocean is chlorophyll?

60%

Bacilli

rod shaped

Cocci

spherical

Spirochetes

spiral-shaped bacteria that have flexible walls and are capable of movement

What is resolution?

The ability to clearly distinguish the individual parts of an object

light microscope (LM)

Rely on absorption of light by the target object(s)

electron microscope (EM)

Images are resolved via an electron field

Atomic Force Microscopy (AFM)

map specimen topography (3D), specimen can be alive

Gram stain

A staining method that distinguishes between two different kinds of bacterial cell walls.

Process for gram staining

1)crystal violet

2) iodine

3) ethanol

4)safranin

negative stain

colors the background, which makes capsules more visible

acid fast stain

targets mycolic acids in species of Mycobacterium

spore stain

malachite green binds to endospore coat of spore-forming bacteria

fluorescence microscopy

uses a fluorescent dye that emits fluorescence when illuminated with ultraviolet radiation

The specificity of a fluorophore is determined in part by?

Chemical affinity, labeled antibodies, DNA hybridization

Three main regions of a bacterial cell

1) envelope

2) cytoplasm

3) nucleoid

Capsule

is a layer of polysaccharide (sometimes proteins) that protects the bacterial cell. It is often associated with pathogenic bacteria because it serves as a barrier against phagocytosis by white blood cells.

What are bacteria cell walls made from

peptidoglycan

The gylcan chains consist of repeating disaccharide molecule

N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)

Archaea cell wall

composed of surface-layer (S-layer) proteins

This wall is highly permeable

Pseudomurein

a substance similar to peptidoglycan that is found in the cell wall of archaea

Algal cell walls

composed of beta(1->4) linked glucose --- referred to at cellulose

Fungal Cell walls

chitin (NAG)

teichoic acid

located on the surface of Gram (+) bacterial cell walls; covalently bound to peptidoglycan layers; help maintain structure for the peptidoglycan layer

LPS of gram negative bacteria

outward facing leaflet of the outer membrane

Mycobacterial Envelope

permeable to stains, resistant to many antibiotics, slow growth, resistant to hot immune defense

bacterial periplasm

aqueous region between outer and inner membrane

Prokaryotic membrane

consists of a phospholipid bilayer containing lipid soluble proteins

hopanoids

Structurally similar to sterols

Present in membranes of many Bacteria

(modify rigidity and fluidity)

facilitated transport

a process by which material moves down a concentration gradient (from high to low concentration) using integral membrane proteins

active transport

the movement of materials through a cell membrane using energy against a conc. gradient. Also By ATP hydrolysis

ABC transporters

carrier proteins that use energy from ATP to transport solutes

What does FtsZ (tubulin) do?

Determines cell diameter and initiates cell division

In Vivo, FtsZ forms

A dynamic Z-ring between prospective daughter cells during cytokinesis

Prokaryotic cell division

binary fission: splits in 2, exact copies, quick and efficient with few mutations, but reduces amount of genetic variation

Prokaryotic cell division results in

separate but identical daughter cells

Thylakoid

specialized intracellular membranes

Carboxyzomes

proteinaceous cellular inclusions involved in CO2 fixation

Magnetosomes

membrane-embedded crystals of magnetite used for magnetotaxis

Pili (fimbriae)

Involved in cell adherence, motility and other roles

Flagella

A long, whip-like filament that helps in cell motility. Many bacteria are flagellated, and sperm are flagellated.

flagellar motor

a molecular motor in certain cells that functions in locomotion by actively rotating a flagellum

big 6 macronutrients

Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur

(CNPHOS)

essential cations

Mg^2+

Fe^2+

K+

Ca^2+

enzyme cofactors

Mg^2+

Fe^2+

K+

Stabilization of ribosome, membranes, and nucleic acid

Mg^2+

Regulatory signaling molecule:

what is a central macronutrient to all living things

Carbon

How do heterotrophs obtain carbon?

From other organisms

How do autotrophs obtain carbon?

Co2

Energy obtained by light

phototrophy

Energy obtained by metabolism

Chemotrophy

What forms is energy commonly stored in?

1) High energy molecules(ATP)

2)electrochemical membrane potentials (PMF)

formula for exponential growth in binary fusion

2^n

where n is the # of generations

lag phase

A short period of time **prior to exponential growth of a bacterial population during which no, or very limited, cell division occurs.

log phase of growth

The second of the four phases of bacterial growth, in which cells divide at an exponential rate.

stationary phase

rate of cell growth equals rate of cell death caused by depleted nutrients and O2, excretion of organic acids and pollutants

death phase

population is decreasing at a logarithmic rate

abiotic factors

Nonliving components of environment.

ex. Temp, pH, salt, pressure

extremophiles

live in extreme environments

Psychrophiles

cold-loving microbes

(Rich in unsaturated fatty acids)

Thermophiles

heat loving (rich in saturated fatty acids)

Barophiles

can survive under extreme pressure and will rupture if exposed to normal atmospheric pressure

Most prokaryotes require water availability (aw) to be greater then?

aw>0.91

Aquaporins

channel proteins that facilitate the passage of water (protect against osmotic stress)

Halophiles

salt loving

mechanosensitive channels

pressure sensitive channels that leak solutes from the cell, lowering cytoplasmic osmolarity

Acidophiles

grow best in acidic habitats

pH homeostasis

K+/H+ (acid) or Na+/H+ (base) antiporters