Microbiology 3050 The Microbial World

What is too small to be clearly seen by the unaided eye?

organisms and acellular entities

What are some exceptions to microorganisms that are smaller than 1 mm in diameter?

Mushrooms, slime mold, and thiomargarita magnifica

What are the four categories among cellular organisms?

fungi, protists, bacteria, and archaea

Example of cellular fungi

Yeast molds

Example of Cellular protist

algae protozoa slime molds

Example of cellular bacteria

Escherichia coli

Example of Cellular archaea

Methanogens

What are the four Acellular categories?

Viruses, Viroids, Satellites, and Prions

What are Viruses composed of?

protein and nucleic acid

What are Viroids composed of?

RNA

What are Satellites composed of?

Nucleic acid and often RNA

What are prions composed of?

Protein

Eukaryotic microbial cells are more complex …

morphologically compared to prokaryotes

Prokaryotic cells lack a true membrane-bound nucleus but this is not …

absolute, some prokaryotic cells do have nuclei

Eukaryotic cells have …

aa membrane bound nucleus and organelles, and are usually larger than prokaryotic cells

Prokaryotic cells have a …

cell wall, cytoplasmic membrane, nucleoid(designated area where DNA stays, not closed in), plasmids, cytoplasm, and ribosomes

Eukaryotic cells have a …

cell wall, cytoplasmic membrane, mitochondrion, nuclear membrane, nucleus, ribosomes, smooth an rough ER, cytoplasm, and golgi apparatus

All cells regardless if they are prokaryotic or eukaryotic, they have …

structure, metabolism, growth, and evolution

What is structure in the terms of all cells?

Having a cytoplasmic membrane, cytoplasm, DNA, and ribosomes

What is metabolism in the terms of all cells?

all cells use information encoded in DNA to make RNA and protein, all cells take up nutrients, transform them, conserve energy, and expel wastes (Catabolism = breaking down molecule to get energy, Anabolism = synthesizing macromolecules using energy from catabolism)

What is Growth in the terms of all microbial cells?

Making new cells / growing the population

What is Evolution in the terms of all cells?

Spontaneous mutations that result in advantageous characteristics that help microbial cells to survive which also adds to diversity

What are the properties of Some cells?

Differentiation, Communication, Motility, and Horizontal gene transfer

What is Differentiation in the terms of microbial cells?

some cells form new cell structures such as spores

What is Communication in the terms of all cells?

Cells interact with each other by chemical messengers

What is Motility in the terms of all cells?

Some cells are capable of self-propulsion using things like flagellum

What is horizontal gene transfer?

When cells share genetic information with each other, not by passing it from mother to daughter cell, instead the cell sends plasmids to others in its area, sharing its genetic information and potentially sharing advantageous genes like antibiotic resistance

Eukaryotes can range in size from …

0.8 micrometers - millions of micrometers

Most bacteria and archaea are how big?

0.2 micrometeres - 10,000 micrometers, 0.2 is the cutoff

Viruses are often how big?

0.01 micrometers - 2.3 micrometers

Why is it efficient for microbes to be smaller?

Because they have a smaller SA:V ratio, this way there is more space and area for things to enter and exit the cell

Fungi are also …

microbes, but they don’t fit the traditional characteristics of microbes

How can we tell microbes apart?

shape, size arrangement, and external features

Slime molds can be seen …

without a microscope, they can be rather large compared to other microbes, so microbes can be incredibly diverse in even size

What main group of microbes thrive in extreme environments?

Archaea

What two groups of microbes are prokaryotes?

Bacteria and Archaea, Fungi and protists are eukaryotes

Which acellular microbe group causes mad cow disease?

Prions

Archaea have a cell wall like bacteria but …

its made of a different material

True walnut means …

the cell has a nucleus meaning its a eukaryote

What do microbes need in order to grow?

They need to copy their DNA

When you take antibiotics you are selecting for …

microbes that are resistant to antibiotics, in other words you are killing those who do not have the antibiotic resistant gene, so those that have the resistant gene will live (will live = selecting for)

Size alone is not enough evidence to determine whether …

a microbe is a prokaryote