BIO 385 Chapter 1

Exam 1

Who developed a taxonomic system for naming plants and animals and grouping similar organisms together?

Carolus Linnaeus

What six categories can microorganisms be grouped into?

Fungi, protozoa, algae, bacteria, archaea, and small multicellular organisms.

Eukaryotic, obtain food from other organisms, possess cell walls, and composed of molds and yeasts.

Fungi

Multicellular, grow as long filaments; reproduce by sexual and asexual spores.

Molds

Unicellular, reproduce asexually by budding; some produce sexual spores.

Yeasts

Single celled eukaryotes. Similar to animals in nutrient needs and cellular structure. Live freely in water, some live in animal hosts. Asexual (most) and sexual reproduction. Most are capable of locomotion by pseudopodia, cilia, and flagella.

Protozoa

Cell extensions that flow in direction of travel.

Pseudopodia

Numerous, short, protrusions that propel organisms through environment.

Cilia

Extensions of a cell that are fewer, longer, and more whiplike than cilia.

Flagella

Unicellular or multicellular. Photosynthetic. Simple reproductive structures. Categorized on the basis of pigmentation, storage products, and composition of cell wall.

Algae

Unicellular and lack nuclei. Much smaller than eukaryotes. Found everywhere there is sufficient moisture; some isolated from extreme environments. Reproduce asexually (although can exchange genetic information sexually).

Bacteria and archaea

Cell walls contain peptidoglycan; some lack cell walls.

Bacteria

Cell walls composed of polymers other than peptidoglycan.

Archaea

Who proposed the idea of spontaneous generation?

Aristotle

When decaying meat was kept isolated from flies, maggots never developed. Meat exposed to flies was soon infested. As a result, scientists began to doubt Aristotle’s theory.

Redi’s experiment

Took a hay infusion broth and boiled it and then put some in a capped and uncapped jar. Both jars contained life which meant there was spontaneous generation.

Needham’s experiments

Concluded that Needham failed to heat vials sufficiently to kill all microbes or had not sealed vials tightly enough. Microorganisms exist in air and can contaminate experiments. Spontaneous generation of microorganisms does not occur.

Spallanzani’s experiments

When '“swan-necked” flasks remained upright, no microbial growth appeared. When the flask was tilted, dust from the bend in the neck seeped back into the flask and made the infusion cloudy with microbes withing a day.

Pasteur’s experiments

Suspected causative agent must be found in every case of the disease and be absent from healthy hosts. Agent must be isolated and grown outside the host. When agent is introduced to heathy, susceptible host, the host must get the disease. Same agent must be found in the diseased experimental host.

Koch’s postulates

First person to see microorganisms. Made lenses for a microscope to magnify what he was looking at enough that he could see things moving.

Antoni Van Leeuwenhoek

1. Observation

2. Questions

3. Hypothesis

4. Experiment

5. Observations (accept or reject)

Scientific method

First one to stress that we had to perform aseptic cleanliness and handwashing when moving from one patient to another in a hospital facility.

Nightingale