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- A proposed explanation for a broad class of phenomena or observations
- *Proposed explanation for broad patterns in nature
- A proposed explanation for a phenomenon or for a set of observations.
- *A provisional explanation
- *The merit of the hypothesis requres more work by the researcher to confirm or disprove the hypothesis
- A measurable or observable result of an experiment based on a particular hypothesis. A correct prediction provides support for the hypothesis being tested
- *A testable outcome of the hypothesis (if it is to be proven valid)
- *It must be measurable
What is the first great founding idea in biology? Describe it.
- Cell theory
- 1) All living organisms are made up of cells
- 2) All cells come from pre-existing cells
Where do cells come from? Spontaneous generation or all cells come from cells?
- All cells are derived from existing cells
- Pasteur proved this
- Swan neck didn't produce new cells
- Straight neck flask allowed air and bacteria to mix in the broth, giving a liveable area for bacteria
IF cells come from pre-existing cells, then...
- All cells in a multicellular organism are related by common ancestry
- All individuals in a population are related by common ancestry
Describe the second great founding idea in biology
- Charles Darwin and Alfred Russel Wallace
- All species are related by a common ancestry
- 1. Species are related by common ancestry
- 2. Characteristics of species change over time (descent with modification)
- Species are NOT independent entities
- Species are NOT fixed throughout time
- The theory that all organisms on Earth are related by common ancestry and that they have changed over time, predominantly via natural selection
- Any change in the genetic characteristics of a population over time, especially, a change in allele frequencies
Define natural selection
- Variation in heritable traits among individuals within a population
- Certain versions of heritable traits allow individuals to survive/reporoduce better in a particular environmental condition
- Natural selection acts on individuals, but evolutionary change affects only populations
- Evolution occurs when heritable variation leads to increased success in reproduction
Ability to produce offspring
A trait that increases the fitness of an individual in an environment
Was the mutation in the bacterial RNA polymerase gene present in the bacterial population before or after treatment with the patient with rifampin?
- Before - the mutation must have been present in order to survive the rifampin
- The concentration of mutated cells was low, because they did not grow as well
- After the regular RNA polymerase cells were killed off, the mutated ones survived and were able to reproduce
List the order of events in the TB case
- Mycobacterium tuberculosis in patient's lung make him sick (a few bacteria, by chance, have the C-T mutation)
- Rifampin kills most of the bugs, patient is "cured"
- Mutant cells proliferate, new major infection established in lungs.. patient becomes sick again
- Second round of drug therapy is ineffective because bacteria carry mutation that prevents rifampin from bindings to its target
Is selection random?
No. Events that cause selection are not random.
Are mutations random?
Yes, cellular mutations are random
What is RNA polymerase?
- RNA polymerase is the enzyme that unzips the DNA
- It then copies the DNA and forms RNA from it
- The RNA is then made into protein for cells
- Cells need protein to survive
- Cells can't make RNA because rifampin is blocking RNA polymerase
- Stops infection from spreading, cells die
What component of the evolution of the antibiotic resistant TB is nonrandom?
- Selection for the drug resistant TB is non random. The mutation selection is non random
- Mutation of RNA polymerase gene is mostly random
What are the basic properties of cells?
- Cells are complex
- Cells are organized
- Cells have genetic blueprint and ability to translate
- Cells can reproduce themselves from pre-existing cells
- Cells can acquire, transform, and utilize energy
- Cells can carry out chemical reactions
- Cells can engage in mechanical activities
- Cells can respond to stimuli
- Cells can self-regulate
Why would inhibition of RNA polymerase be "bad" for bacteria?
Cells can't survive if they can't make protein
What makes living systems unique?
What is the order of events for producing protein?
- DNA -> RNA -> mRNA -> protein (from ribosome)
- Rifampin binds to and inhibits bacterial RNA polymerase.
- The mutation of codon 153 prevents rifampin from blocking the reaction site
Any heritable trait that increases the fitness of an individual with that trait, compared with individuals without that trait, in a particular environment
Define artificial selection
Deliberate manipulation by humans, as in animal and plant breeding, of the genetic composition of a population by allowing only individuals with desirable traits to reproduce
A highly organized compartment bounded by a thin, flexible structure (plasma membrane) and containing concentrated chemicals in an aqueous (watery) solution. The basic structural and functional unit of all organisms
A member of the domain Eukarya; an organism whose cells contain a nucleus, numerous membrane-bound organelles, and an extensive cytoskeleton. May be unicellular or multicellular
Referring to traits that can be transmitted from one generation to the next
Define natural selection
The process by which individuals with certain heritable traits tend to produce more surviving offspring than do individuals without those traits, often leading to a change in the genetic makeup of the population. A major mechanism of evolution
Define null hypothesis
A hypothesis that specifies what the results of an experiment will be if the main hypothesis being tested is wrong. Often states that there will be no difference between experimental groups
Any living entity that contains one or more cells
The evolutionary history of a group of organisms
A group of individuals of the same species living in the same geographic area at the same time
A member of the domain Bacteria or Archaea; a unicellular organism lacking a nucleus and containing relatively few organelles or cytoskeletal components
- A measurable or observable result of an experiment based on a particular hypothesis
- A correct prediction provides support for the hypothesis being tested
A RNA molecule that forms part of the structure of a ribosome
The evolution of two or more distinct species from a single ancestral species
Define tree of life
A diagram depicting the genealogical relationships of all living organisms on Earth, with a single ancestral species at the base