Chapter 3: The Cell

What is spontaneous generation? (1600-1800)

the idea that microorganisms arise from non-living things

Who used meat and maggots do disprove spontaneous generation?

Francesco Redi (1668)

Who used broth in a flask to disprove spontaneous generation?

Lazaro Spallanzani (1768)

Who was Louis Pasteur?

• a teacher, painter, and then a chemist

• changed science by being the first to observe microorganisms causing disease

What does the Germ Theory of Disease state?

It states that some diseases are caused by microorganisms

Who was able to prove the germ theory?

Robert Koch

What is the first principle of koch’s theory

1. specific causative agent must be found in every case of the disease

What is the second principle of koch’s theory?

The disease organism must be isolated in pure culture

What was the third principle of koch’s theory

Inoculation of a sample of the culture into a healthy, susceptible animal must reproduce the same disease

What was the fourth principle of koch’s theory?

the disease organism must be recovered from the inoculated animal

What did Koch identify?

• Mycobacterium tuberculosis/TB

• Vibrio Cholerae/ Cholera

Who was ridiculed for trying to introduce hand-washing before treatment of patients?

Ignaz Semmelweis

Who developed the idea that bandages and other insturments should be sterile before being used again?

Joseph Lister (1865)

Who made up the two core principles of modern cell theory?

R. Remak and R. Virchow

What are the two core principles of modern cell theory?

1. microorganisms (germs) cause diseases

2. specific germs cause specific diseases

How did those two principles change medicine?

It changed medicine by showing that diseases are not caused by bad air, curses, or spontaneous generation but by identifiable, preventable microorganisms

What does “omnis cellula a cellula” mean?

all cells arise from cells

Why are bacteria arranged a certain way?

They are arranged a certain way to reproduce

How do bacteria reproduce?

Via binary fission but do not separate

1st step of endospores

DNA replicates

2nd step of endospores

membranes form around the DNA

3rd step of endospores

Foreshore forms additional membranes

4th step of endospores

protective cortex forms around the spore

5th step of endospores

Protein coat forms around the cortex

6th step of endospores

endospores is released

What is an isotonic solution?

no net movement of water

What is a hypertonic solution?

water particles move out of cell

What is a hypertonic solution?

Water moves into the cell

What do only acid-fast bacteria have?

mycolic acid

Where is the outer membrane typically found?

in gram-negative bacteria

What is gram-negative outer membrane made of?

lipopolysaccharides (LPS)

What does LPS function as?

an endotoxin

What does each LPS contain?

a core polysaccharide, and an O-side chain

What can parts of O side chain called antigens be used to detect?

serological or immunological tests to identify specific pathogenic strains like escherichia coli

When are endotoxins released from gram-negative bacteria?

when bacteria are dying (or killed), antibiotics can cause worsening of symptoms

Is LPS used to identify gram-negative bacteria?

Yes

How can you control bacteria damage?

• Destory cell wall, and bacteria will die

• Penicillin blocks peptidoglycan synthesis

• enzyme lysosomes digest peptidoglycan

What is chemotaxis?

when cells move guided by chemicals

• - high to low

• + low to high

What is phototaxis?

when cells move guided by light

• - high to low

• + low to high

What is 1 flagella called?

Monotrichous

What are two flagella called?

Amphitrichous

What are bunch of flagella called?

Lophotrichous

What are around/all throughout flagella called?

Peritrichous

What do axial filaments help bacteria do?

help bacteria move

What do pili allow for?

anchoring to surface

What do fimbriae allow for

attachment to a surface

• contribute to pathogenicity