BISC 261 ; Exam 1

define the term microbiology.

a branch of science that involves organisms and acellular entities too small to be seen by the unaided eye

what do microbes play an essential role in recycling? what are some examples of this?

essential elements, the carbon & phosphorus cycles

where can microbes be found?

everywhere

how do microbes benefit society? what do they provide us with?

bread, yogurt, beer

approximately what percent of microbes cause disease in people, plants, and/or animals?

6%

how can the members of the microbial universe be described?

as organisms and acellular entities too small to be seen by the unaided eye

what do microbes lack?

differentiated tissues

what are 4 examples of cellular microbes?

fungi, protists, bacteria, archaea

what are 4 examples of acellular microbes?

viruses, viroids, satellites, prions

what are the 2 types of microbial cells?

prokaryotic and eukaryotic

how can prokaryotic cells be described?

cells with contents not divided by membranes into compartments; lack a nucleus

how can eukaryotic cells be described?

cells with a nucleus and membrane-bound organelles that separate some materials and processes

what are the three domains commonly used in the microbial universe?

bacteria, archaea, and eukarya

what do bacteria and archaea usually lack?

a nucleus

is Domain Bacteria or Domain Archaea more closely related to Domain Eukarya?

Domain Archaea

how are organisms classified into the 3 domain system?

using the comparison of ribosomal RNA (rRNA)

true or false: ALL life has ribosomes.

true

what is the difference between bacterial cell walls and archaean cell walls?

bacteria have cell walls of peptidoglycan, archaea do not

what is the difference between bacterial and archaean lipids?

bacterial lipids are similar to eukaryotes, while archaea have unique membrane lipids

what is the difference between the habitats bacteria and archaea live in?

bacteria are ubiquitous and only some are in extreme environments, whereas many archaea are in extreme environments

what is a special/interesting place bacteria can be found living in?

the human body

true or false: some archaea have unusual metabolic characteristics

true

are protists generally smaller or larger than bacteria and archaea?

larger

what are 2 examples of protists?

algae and protista

what are the 2 major groups of fungi?

yeasts and molds

are yeasts unicellular or multicellular?

unicellular

are molds unicellular or multicellular?

multicellular

what can molds also be known as?

mushrooms

what do viruses require to replicate?

a host cell

what can viruses cause?

a range of diseases and some cancers

what are prions?

infectious proteins

what kinds of diseases can prions cause?

mad cow disease, scrapie (brain/neurological disease)

what are 3 defining qualities of life?

cells and organization, energy use and metabolism, reproduction

what hypothesis attempts to explain the earliest pre-cells?

the RNA world hypothesis

what were the earliest molecules?

RNA

what are ribozymes?

RNA molecules that form peptide bonds and perform cellular work and replication

what were the earliest “cells”?

RNA surrounded by liposomes

what is a liposome?

a spherical sac of phospholipid molecules

what is the RNA world hypothesis in 5 steps?

1) RNA forms from inorganic sources

2) RNA self-replicates (via ribozymes)

3) RNA catalyzes protein synthesis

4) membrane function changes internal chemistry, allowing new functionality

5) RNA codes both DNA and protein

what is modern day RNA associated with inside the cell?

ribosomes

what is ATP?

a ribonucleotide

what can RNA regulate?

gene expression

do ribozymes still exist today?

yes

what kind of conditions were the earliest energy sources obtained under?

harsh conditions

why is photosynthesis important?

Oxygen

when did cyanobacteria evolve?

2\.7 billion years ago

true or false: cyanobacteria are photosynthetic

true

how do we classify organisms into the 3 domains?

by sequencing SSUrRNA and comparing it to other known organisms by aligning the sequences and counting the differences

sequening SSUrRNA determines _____________,__ but not ____ __ __________.

relatedness, time of divergence

which two domain groups diverged from common ancestry?

Archaea and Eukarya

_______ and _______ evolved independently of ________.

Archaea, Eukarya, Bacteria

where is the one place on Earth that life has not been found? what does this place look like?

Dallol, Ethiopia. ponds extended across a volcanic crater

what is the purpose of the endosymbiotic hypothesis?

to theorize how prokaryotes evolved into eukaryotes

what is the endosymbiotic hypothesis?

different bacteria (proteobacteria, cyanobacteria) were taken up into ancient cells and made their genomes smaller and smaller while living in the cell until they were no longer bacterial cells and now organelles (mitochondria, chloroplast)

bacteria can make its _______ smaller when living inside another cell

genome

what is the evidence that supports the endosymbiotic hypothesis?

* mitochondria and chloroplasts have a double membrane
* they possess proteins that resemble bacterial proteins
* they have their own DNA and ribosomes

what bacteria are mitochondria similar to?

proteobacteria

what bacteria are chloroplasts similar to?

cyanobacteria

true or false: mitochondria can live independently outside of the cell

false

what kind of relationship is represented in the endosymbiotic theory?

a symbiotic relationship in which the larger cell provides protection and the mitochondria/chloroplasts provide energy

_________ of DNA led to selected traits

mutation

what are two examples of genes and genotypes evolving?

antibiotic resistance, plastic digesting bacteria

bacteria and archaea increase their genetic pool by __________ _____ ___________ within the same generation.

horizontal gene transfer

what are the 3 types of horizontal gene transfer?

transformation, conjugation, and transduction

what is transformation (gene transfer)?

bacterial cells release parts of their genetic material end other bacterial cells accept this genetic material into their genome.

what is conjugation?

one bacterial cell sends genetic information to the other through direct contact.

what is transduction?

a situation in which a virus accidentally takes its host’s genome instead of the virus genome and gives that genome to a different bacteria cell

true or false: bacteria and archaea are capable of sexual reproduction

false

what is binomial nomenclature?

a two-word naming system consisting of an organism’s genus and species (genus is capitalized, species is not)

what does a strain consist of?

descendants of a single, pure, microbial culture

bacteria and archaea do not reproduce sexually and are referred to as _______.

strains

design a set of experiments that could be used to place a newly discovered cellular microbe on a phylogenetic tree based on SSUrRNA.

1) lyse the cell to isolate the DNA

2) PCR to amplify (make copies of) the SSUrRNA gene (DNA)

3) sequence DNA rRNA gene

4) compare DNA to known organisms using stats and math to determine relation

5) determine which domain the novel organism belongs in based on data (matches)

what did Antony van Leeuwenhoek accomplish?

he was the first person to observe microorganisms accurately

who was the first person to observe microorganisms accurately?

Antony van Leeuwenhoek

what is spontaneous generation?

the idea that living organisms can develop from nonliving matter

describe the experiment performed by Pasteur.

he applied vigorous heat to microbes in swan-necked flasks that were NOT sealed. if the neck of the flask was left intact, airborne microbes were trapped at the base and the broth inside the flasks were sterile. however, if the neck of the flask was broken, bacterial growth occurred

what else did Louis Pasteur discover?

microorganisms carried out fermentation. he also developed pasteurization

what did Joseph Lister accomplish?

he provided indirect evidence that microorganisms are the causal agents of disease and he developed an antiseptic surgery system to prevent microorganisms from entering wounds.

who discovered microorganisms carry out fermentation?

Louis Pasteur

who developed an antiseptic surgery system to prevent microbes from entering wounds?

Joseph Lister

what is the importance of Louis Pasteur’s discoveries?

through the discovery that microorganisms carry out fermentation, we are introduced to pasteurization which makes foods/drinks like milk safer to drink.

what is the importance of Joseph Lister’s discoveries?

through Lister’s discoveries that microorganisms are causal agents of disease, we are introduced to a more sterile surgical environment, so the risk of infections post-operation is much lower than it was before

who estimated the relationship between *Bacillus anthracis* and anthrax?

Robert Koch

What are Koch’s Postulates?

1. the microorganism must be present in every case of the disease but absent from healthy organisms
2. organism must be isolated and grown in a pure culture
3. same disease must result when the isolated microorganism is inoculated into a healthy host
4. same microorganisms must be isolated again from the diseased host

why can some organisms not be grown in pure cultures?

they might require other things such as a host cell or another organism to grow on

true or false: carrying out Koch’s Postulates on a human is acceptable

false

what did Charles Chamberland discover?

he developed porcelain bacterial filters to study tobacco mosaic disease

who developed porcelain bacterial filters?

Charles Chamberland

why is Charles Chamberland’s discovery important?

the filters he discovered made it possible to filter bacteria out of water

what did Elie Metchnikoff discover?

bacteria-engulfing, phagocytic cells in the blood

what did Sergei Winogradsky and Martinus Beijerinck discover?

metabolic processes of microorganisms in soil (nitrogen fixation, carbon cycle, etc). they also pioneered the use of environment cultures and selective media

what percentage of the microbial universe is able to be grown?

5-10%

what does microbial physiology study?

metabolic pathways

_______ are considered a model organism of genomics.

microbes

what are the 2 major types of microscopy?

light and electron

which type of microscopy has better magnification: light or electron?

electron

how many times better magnification do electron microscopes have compared to light microscopes?

1000x better

staining increases or provides _________.

details

amplitude is the ______ of each peak.

height

wavelength is the ________ between peaks.

distance