Micro Ch.3,Ch.7

What is spontaneous generation (SG)?

The ancient belief that life can arise from nonliving matter at any moment

What did Francesco Redi conclude from SG?

SG is false. Life comes from existing life

How did Francesco Redi test SG?

Set up experiment to show maggots did not spontaneously appear on meat

What did John Needham conclude?

SG is true

What was John Needham's experiment?

He boiled broth to kill microbes, but microbes later grew, so he thought a "life force" created life

What did Lazzaro Spallanzani conclude?

SG is false

How did Lazzaro Spallanzani improve Needham's experiment?

He boiled broth longer and sealed the flasks, preventing contamination

What did Louis Pasteur prove?

SG is false

What is the Swan Neck Flask Experiment?

Air could enter, but microbes were trapped in the curved neck, so sterile broth remained free of life unless contaminated.

Which experiment finally disproved spontaneous generation?

Louis Pasteur's Swan Neck Flask Experiment.

What is Modern Cell Theory?

All living organisms are composed of one or more cells

What is 1st basic tenets of Modern Cell Theory?

Cell is basic unit of structure

What is 2nd basic tenets of Modern Cell Theory?

All cells come from existing cells.

What did Robert Hooke discover?

First to describe "cells" using compound microscope and observing cork cells

What did Matthias Schleiden contribute?

He concluded that all plants are made of cells

What did Theodor Schwann contribute?

He concluded that all animals are made of cells

What did Robert Remak discover?

Cells come from other cells through cell division

What did Rudolf Virchow publish in 1855?

"All cells arise from cells" in Cellular Pathology.

What did Konstantin Mereschkowski suggest?

Suggested chloroplasts may have once lived independently outside plant cell

What did Ivan Wallin claim?

Mitochondria existed outside cells, but his results were likely due to contamination

Who strongly developed the Endosymbiotic Theory?

Lynn Margulis

What is Endosymbiotic Theory?

Mitochondria and chloroplasts were originally prokaryotic cells that established a symbiotic relationship within a eukaryotic host.

What does the Germ Theory of Disease state?

Diseases are caused by microbial infection

What did Girolamo Fracastoro propose?

Disease spreads by transferable "spores."

What did Ignaz Semmelweis discover?

‘Contaminated” doctors were spreading disease to patients, and handwashing reduced infections.

What did Ignaz Semmelweis propose?

He showed handwashing prevented disease transmission

What did John Snow discover?

Cholera outbreaks were linked to contaminated drinking water.

What disease did John Snow investigate?

Cholera

What did Louis Pasteur discover?

Microorganisms could spoil food and therefore could also cause disease in people.

What did Joseph Lister introduce?

Handwashing and the use of carbolic acid to disinfect surgical instruments and wounds.

What did Robert Koch prove?

A specific microorganism can cause a specific disease.

What are the four common components found in all cells?

1. Cytoplasm

2. Plasma (cell) membrane

3. Chromosome(s)

4. Ribosomes

What is the difference between prokaryotic and eukaryotic cells?

Prokaryotes lack a true nucleus; eukaryotes have a true nucleus.

Which domains are prokaryotic?

• Bacteria

• Archaea

Which domain is eukaryotic?

Eukarya

What are the unique structures found in prokaryotic cells?

• Nucleoid

• Inclusions

• Plasmids

• Pili

• Fimbriae

• Endospores

What is the nucleoid?

The region of a prokaryotic cell that contains DNA and DNA-associated proteins.

What is the shape of a prokaryotic chromosome?

Circular

Are prokaryotes haploid or diploid?

Haploid

What are plasmids?

Small circular, non-essential DNA molecules that can replicate independently of the chromosome.

What is the function of ribosomes?

Protein synthesis

What size are prokaryotic ribosomes?

70S

What are the two subunits of a 70S ribosome?

50S and 30S

What are inclusions?

Storage structures that store nutrients or aid in movement or specialized metabolism.

Why do bacteria store nutrients in polymerized form?

To reduce osmotic pressure inside the cell.

What is an endospore?

A dormant, highly resistant structure that protects a bacterium's genome

Why are endospores important?

They are the most resistant form of bacteria and are difficult to destroy.

What process forms an endospore?

Sporulation

What process allows an endospore to become active again?

Germination.

What are vegetative cells?

Active, growing bacterial cells under favorable conditions.

Which bacterial genera commonly form endospores?

Clostridium and Bacillus.

Which is resistant to heat and radiation?

Endospores

Which is sensitive to heat and radiation?

Vegetative cells

Which has active metabolism?

Vegetative cells

Which is dormant?

Endospores

Which contains normal water content?

Vegetative cells

Which is dehydrated?

Endospores

Which stains with a Gram stain?

Vegetative cells

Which requires a special stain?

Endospores

What is the most important function of the plasma membrane?

Selective permeability—controls what enters and leaves the cell.

What is the plasma membrane mainly made of?

A phospholipid bilayer with proteins and carbohydrates.

What type of linkage/chain is found in bacterial and eukaryotic membranes?

Ester linkages

Straight chains

What type of linkage/chain is found in archaeal membranes?

Ether linkages

Branched chains

Do archaea always have a bilayer membrane?

No. Some have a monolayer.

What is passive transport?

Movement of molecules from high to low concentration without energy (ATP). CO2

What is facilitated diffusion?

Carrier proteins move larger molecules across the membrane without ATP.

What is active transport?

Movement of molecules against their concentration gradient using ATP.

What is group translocation?

A transport process in which a molecule is chemically modified as it enters the cell, allowing movement against its concentration gradient.

Which prokaryotes can perform photosynthesis?

Cyanobacteria and photosynthetic bacteria.

Where are photosynthetic pigments located in photosynthetic bacteria?

In infoldings of the plasma membrane.

What pigments are used for photosynthesis in bacteria?

Chlorophyll or bacteriochlorophyll.

Where is the cell wall located?

Outside the plasma membrane

What differentiates Gram-positive and Gram-negative bacteria?

Differences in their cell wall structure.

What is the major component of bacterial cell walls?

Peptidoglycan

What molecules make up peptidoglycan?

Alternating chains of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM).

Coccus is

Round

Bacillus is

Rod

Vibrio is

Curved Rod

Coccobacillus is

Short Rod

Spirillum is

Spiral

Spirochete is

Long, loose helical spiral

Coccus is

Single Coccus

Diplococcus is

Pair of two cocci

-N. goborrhoeae

Tetrad is

Grouping of four cells arranged in a square

-M. luteus

Streptococcus is

Chain of cocci

-S. pyogenes

Staphylococcus is

Cluster of cocci

-S. aureus

Bacillus is

Single rod

-E. coli

Streptobacillus is

Chain of rods

-B. subtitles

What is osmosis?

The diffusion of water across a membrane in response to differences in solute concentration.

What is Isotonic solution?

No net movement of water particles.

What is hypertonic solution?

Water particles move out of the cell.

What is hypotonic solution?

Water particles move into the cell.

Which bacteria have a thick peptidoglycan layer?

Gram-positive bacteria.

Which bacteria have a thin peptidoglycan layer?

Gram-negative bacteria.

Which bacteria have an outer membrane?

Gram-negative bacteria.

Which bacteria do NOT have an outer membrane?

Gram-positive bacteria.

Which bacteria contain lipopolysaccharide (LPS)?

Gram-negative bacteria.

How are tetrapeptide chains connected in Gram-negative bacteria?

Directly cross-linked.

How are tetrapeptide chains connected in Gram-positive bacteria?

By pentaglycine cross-bridges.

What acids are found in Gram-positive cell walls?

Teichoic acids.