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What is a cell?
The "lowest" level in the hierarchy of life that can perform the activities required for life.
The oldest fossil, that is about 3.5 billion years old, is a...?
Stromatolite-cyanobacteria (prokaryote)
Name the three subviral agents?
Satellites:depend on a helper virus to infect a cell-they cannot reproduce without the helper virus (Hepatitis D is caused by a satellite that requires the hepatitis B virus to reproduce)
Viroids: Very short, circular strand of naked RNA-no associated proteins to assist with replication; the viral RNA is very hardy and can survive extreme conditions. (Responsible for many plant diseases)
Prions: Proteins can induce misfolding in normal proteins-the misfolded proteins can aggregate and cause damage. (Scrapies, Mad Cow Disease, CJD, Chronic Wasting Disease)
Do prokaryotic cells have a nucleus?
No-DNA is contained in a region known as the nucleoid.
Define symbiosis:
A close association between organisms.
What is a gene?
The mechanism by which traits are passed on; they are composed of DNA.
The theory that life arose from chemical precursors is called...?
Abiogenesis
A-not or without
Bio-Life
Genesis-Beginning or development
Describe the process of uncoating?
A method in which viruses fuses with the cell membrane in a bacteria or animal and in turn allows the virus to enter the cell. Virus lands on outside of the cell and pairs with receptors on the cell and enters the cell, ejecting nucleic acid.
Which of the following contains a cell wall made of peptidoglycan?
Bacteria, Arachaea, Eukarya
Bacteria
What are the two types of cell division that take place in eukaryotic cells?
Mitosis: Produces two genetically identical daughter cells (same ploidy as parent cell)
Meiosis: Produces genetically distinct haploid daughter cells
What is transmission (when considering viruses)?
Movement between hosts
entry into the cell's interior
What are the three domains of life?
Eukarya, Archaea, Bacteria
How do prions reproduce? What is a disease that is caused by a prion?
Attacking a healthy protein and causing it to fold incorrectly and change-this causes malfunction of the protein and then death of the organism. Mad Cow Disease and Chronic Wasting Disease
Describe the following types of Archaea:
Extreme halophiles (Hint:halo- means salt)
Extreme thermophiles
Methanogens
Extreme halophiles-live in highly saline (salty) environments; found in the Great Salt Lake and the Dead Sea
Extreme thermophiles-thrive in very hot environments; often metabolize sulfur
Methanogens-produce methane as a waste product; live in anaerobic environments (swamps, marshes, intestinal tracts of animals, sewage treatment facilities, etc)
What are two ways protists are important?
*Basis of many food webs-autotrophs
*Clarify water by filtering out small particles
*Some are parasites that cause disease in other organisms
*Some are economically important and are used by humans
Name the 5 Characteristics of Science?
1. Testable
2. Falsifiable
3. Measurable
4. Reproductive
5. Objective
How is a fossil produced? Where would the oldest fossil be found?
Organisms are buried quickly under layers of sediment and their hard parts are replaced by minerals. Older rock is deeper-older organisms are deeper in the rock bed.
Describe the difference between the lytic and the lysogenic cycle?
Lytic-the virus uses the hosts reproductive reproductive machinery to replicate itself-destroys the host in the process. Usually takes place relatively quickly (the flu goes through this cycle).
Lysogenic-the viral genome becomes incorporated into the host DNA-it is then called a "provirus". The virus is not actively producing viruses at this stage.
What are the three ways prokaryotes exchange genetic information?
Transformation: Genetic material in a cell is altered by the uptake of foreign DNA from the cell's surroundings
Transduction: Bacteriophages (viruses that infect bacteria) carry bacterial genes from one host cell to another.
Conjugation: Genetic material is transferred between two cells that are temporarily joined.
Note: Bacteria reproduce via binary vision (asexual). In order to increase genetic variation in the population, gene transfer, in one of the ways listed above, is completed.
Define the Endosymbiosis Theory. What two organelles (that we talked about in lecture) came about because of this theory?
Endosymbiotic theory proposes that these organelles were once prokaryotic cells, living inside larger host cells. The prokaryotes may initially have been parasites or even an intended meal for the larger cell, somehow escaping digestion
Mitochondria and chloroplast
Note: Primary endosymbiosis involves the engulfment of a cell by another free living organism. Secondary endosymbiosis occurs when the product of primary endosymbiosis is itself engulfed and retained by another free living eukaryote.
What is the difference between a prokaryote and a eukaryote?
Prokaryote-no membrane bound nucleus or membrane bound organelles
Eukaryote-membrane bound nucleus and organelles; usually much larger than a prokaryote
Name the 7 Characteristics of Living Things.
1. Composed of one or more Cells
2.Use Energy
3.Respond to Environmental Change
4.Regulates internal conditions
5.Grow
6. Reproduce
7. Evolve over time
Name and define the three hypotheses describing where viruses come from?
The Progressive Hypothesis: Viruses originated from mobile genetic elements (transposons) or plasmids. Implies that there were multiple origins (supported by the fact that many viruses are genetically similar to their host species).
The Regressive Hypothesis: Viruses evolved from small cells that were parasites of larger cells. Over evolutionary time the descendants of these cells lost a number of genes for processes that were provided by the host. (Support seen in bacteria that can only reproduce inside their host).
The Virus-First Hypothesis:Viruses evolved before their hosts as simple, self-replicating units that over evolutionary time become more complex-and are the ancestors of the first cells. (Support for this hypothesis is seen in the similarities of the protein structure of viral capsids and genetic similarities between different viruses).
What is an exotoxin? How is this different from an endotoxin?
Exotoxin-proteins produced by an active bacteria (Cholera, botulism)
Endotoxins- Lipopolysaccharide components of the outer membrane of Gram negative bacteria; released at bacterium's death (salmonella, typhoid)
Name three diseases that are caused by a protists.
Malaria (plasmodium-vector: mosquito)
Sleeping sickness (Trypanosoma-vector: tsetse fly)
Leishmaniasis (Leishmania spp-vector: sandflies)
Chagas Disease (Trypanosoma cruzi -vector: reduviid bugs)