Module 1 - The Microbial World Flashcards
Define Microbiology
The study of microbes
Define microbes
Forms of life too small to be seen with the naked eye
Smallest units of life
Cells
6 Characteristics of life
- Metabolism
- Growth
- Reproduction
- Genetic Variation
- Response to external stimuli/adaptation to external environment
- Homeostasis
Define Metabolism
A controlled set of chemical reactions that extract energy and nutrients from the environment and transform them into new biological systems
Define Growth
An increase in the mass of a biological material
Define Genetic Variation
Allows the possibility of evolution, or inherited change within a population, through natural selection over the course of multiple generations
Define Homeostasis
Active regulation of their external environment to maintain relative constancy
Cells are built from …
Macromolecules
Define Macromolecules
Large, complex molecules composed of simpler subunits
4 Types of Macromolecules in order (largest, smallest)
- Polypeptides
- Nucleic Acids
- Lipids
- Polysaccharides
Define Polypeptides
Polymers of amino acids; most abundant class of macromolecules
What are polypeptides referred to as? What are the main functions? Examples?
Proteins
- Some functions are enzymes: help catalyze chemical reactions within the cell
- Other proteins facilitate the movement of material into/out of the cell
- Comprise structures called microfilaments
- FtsZ, Flagellin
What is the function of microfilaments? Which macromolecule are microfilaments involved with?
- Facilitate cell movement
- Polypeptides
What does polymers of nucleotides acids include?
DNA and RNA
Define Nucleic Acids
- Polymers of nucleotides
What are individual nucleotides composed of?
- Sugar molecule (deoxyribose in DNA, and ribose in RNA)
- A phosphate moiety
- One of the four nitrogen-containing bases (A,T,C,G in DNA/ A,U,C,G in RNA)
Define Lipids. What is the function?
- Hydrophobic hydrocarbon molecules
- Forms the foundation to the plasma membrane
- Prevents the products of metabolism from escaping
Define Polysaccharides
Polymers of monosaccharides, or sugars
What are the functions of polysaccharides?
- Serves as energy storage molecules (glycogen and starch)
- Others serve as structural molecules (chitin and cellulose)
What are the structural polysaccharides and their functions?
- Cellulose: primary structural component of plant cell walls and a polymer of glucose monomers
- Chitin: primary structural component of fungal cell walls
What kind of macromolecule is RNA polymerase? Where is it located. What is the function?
- Polypeptide
- Cytoplasm of bacteria and archaea, nucleus of eukarya
- Produces RNA molecules from DNA template
What kind of macromolecule is glycogen phosphorylase? Where is it located? What is the function?
- Polypeptide
- Cytoplasm
- Converts glycogen into glucose monomers
What are the three domains of life?
Bacteria, Archaea, and Eukarya
What were the original two categories of life?
Prokaryotes and Eukaryotes
What kind of macromolecule is K+ channel?
Polypeptide
What is the direction of movement in Passive Transport?
High concentration to low concentration
When you’re passive your end energy is low
Where is the K+ channel located?
Plasma membrane
What is the function of the K+ channel?
Passive transport of K+ across the membrane, from an area of high concentration to an area of low concentration
Where is it Glycogen phosphorylase located?
Cytoplasm
What is the function of Glycogen phosphorylase?
Conversion of glycogen into glucose monomers
Where is RNA Polymerase located?
Cytoplasm of bacteria and archaea, nucleus of eukarya
What is the function of RNA Polymerase?
Produces RNA molecules from DNA template
Where is NA+ /K+ ATPase located?
Plasma membrane
What it the function of NA+ /K+ ATPase?
Active transport of Na+ and K+ across the membrane, from areas of low concentration to areas of high concentration
What is the direction of movement in Active Transport?
Low concentration to high concentration
When you’re active your end energy is high
Define Flagellin
Monomers polymerize to form flagellum
What is the function of flagellum?
Aids in bacterial mobility
Where is flagellin located?
Bacterial flagellum
Where is FtsZ located?
Plasma membrane of bacteria?
What kind of macromolecule is FtsZ associated with?
Polypeptides
What is the function of FtsZ?
Key component of cell division
What kind of DNA molecule do prokaryotes contain?
Singular chromosomal DNA molecule
What kind of DNA molecules do Eukaryotes contain?
Multiple linear DNA molecules
Have a single copy (n) of their genetic material?
Prokaryotes
Have two copies (2n) of their genetic material?
Eukaryotes
What cells have a membrane-bound nucleus?
Eukaryoyes
What cells lack a membrane-bound nucleus
Prokaryotes
What cells include organisms in the domains Bacteria and Archaea?
Prokaryotes
What cells include organisms in the domain Eukarya?
Eukaryotes
Another word for evolutionary history of organisms?
Phylogeny
Which of the three domains always has a cell wall, but the other two vary?
Bacteria
Which two domains have histones?
Archaea and Eukarya
RNA polymerases in Bacteria?
Single polymerase
RNA polymerases in Archaea
Single polymerase, Eukaryal-like RNA pol II
RNA polymerases in Eukarya
Three main polymerases, (RNA, pol 1, II, and III)
Which domain lacks histones but has a histone-like proteins?
Bacteria
What is the function of Nucleic Acids?
Storage of genetic information
What are the subunits for Polysaccharides?
Sugars
What are the subunits for Polypeptides?
Amino Acids
What are two of the most-studied microbial model organisms?
- Bacterium Escherichia coli
- Eukarya Saccharomyces cerevisiae (yeast)
What are the advantages of microbes?
- Easily cultivated in the lab
- Facilitate the production of enzymes
- Can be genetically manipulated
- Industrial and medial uses
What are the three domains of life based on?
- Differences in the sequence of nucleotides
- Cell membrane lipid structure
How was the phylogenetic tree of life created?
Sequence similarity of the SSU rRNA gene
Are viruses living? Why?
Yes and no; depends on host cells
- An isolated virus has no metabolism, takes up no nutrients, and extracts no energy from its environment
-
How do viruses replicate?
- Does not grow and reproduce in the same way cellular organisms do
- Virus particles disassemble in the host cell
- They only assemble after the genetic information has been replicated and the host cell has synthesized new viral proteins
Early conditions and atmosphere of the Earth?
4.5 billion years ago; hot and sterile place
When did oceans form and how?
4 ybp; once the crust and atmosphere had cooled sufficiently for liquid water to condense
What bacteria is responsible for the eventual oxygenating of Earth’s atmosphere?
Cyanobacteria
Define cyanobacteria
Oxygen-releasing photosynthetic bacteria
What did the Miller-Urey experiment envision?
An early earth where organic molecules accumulated in the oceans
- Spontaneous generation
How did the Miller-Urey experiment describe Earth’s oceans?
“Prebiotic soup”
Define endosymbiotic theory
Two of the most distinctive organelles in eukaryal cells are derived from bacterial dells
Evidence for the endosymbiotic theory?
- Mitochondria and chloroplasts have their own circular DNA
- Lead to algae and plant development
Role of iron-containing surfaces
Life evolved with positively charged surface with affinity for organic compounds. Many enzymes (DNA polymerases) require bound metals for activity
From what did RNA come from? What is the name of this hypothesis? Which man is related to this hypothesis?
Carl Woese and others; suggested that information was initially stored in RNA molecules rather than DNA; RNA world
- Served as two functions: primary informational molecule AND catalyzing important reactions
Define Ribozymes
RNA molecule that can catalyze chemical reactions much life the protein-based enzymes
Define micelles
Spherical units with polar surfaces and non-polar cores; bilayer membranes that close back upon themselves to form a sealed compartment
Why did cells evolve to store their genetic information in DNA rather than in RNA?
- DNA is more stable than RNA
- ‘Backup copy’ of the genetic information
Why did organisms develop aerobic respiration?
Allows cells to generate much more ATP from
pyruvate
Define pyruvate
Output of metabolism of glucose
What was considered to be the cause of diseases before the 19th century?
Angry gods to bad air
Anton Van Leeuvenhoek
1600s
- Uses microscopes to see microorganisms
Louis Pasteur
1860s
- Disproves the idea of spontaneous generation
- Swan-necked flasks
Joseph Lister
1860s
- Discovered the value of cleanliness and disinfection measures in reducing mortality rates
Robert Koch
1876
- Demonstrated that a particular microorganism causes a particular disease
- Bacillus anthracis as a cause of anthrax
Alexander Fleming
1928
- Discovers penicillin
Jonas Salk and Albert Sabin
1950s
- Develop poliovirus vaccines
Lynn Margulis
1966
- Proposes endosymbiotic theory
Kary Mullis
1983
- Invents PCR
- Mirrors the process of DNA replication
Carl Woese
1990
- Proposes three-domain classification of living organisms
Craig Venter
1995
- Published first complete bacterial genome sequence
What are the energy storing polysaccharides?
Starch and glycogen
Why is the term “prokaryote” considered outdated?
Carl Woese and other microbiologists noted that the molecular machinery of prokaryotes resembled that of eukaryotes more than it did other prokaryotes
How was the phylogenetic tree of life created?
Comparison of SSU rRNA sequences from diverse organisms
- Previously accepted five kingdoms, now the tree supports three primary branches of life
When is a virus considered living?
- When it invades the host cell
- Before that, it is incapable of life processes
How can bacterial infections be treated?
- Improvements in personal hygiene
- Public sanitation
- Food and water safety
- Pasteurization
What is the process in which milk is heated briefly to kill most microorganisms?
Pasteurization
