Ch 1: Life Flashcards
Biology
The science of life.
Biologist
A scientist who studies life.
Observation
The act of perceiving the world around us.
Experiment
A disciplined and controlled way of learning about the world and testing hypotheses in an unbiased manner.
Hypothesis
A hypothesis, then, is a statement about nature that can be tested by experiments or by new observations
Variable
The feature of an experiment that is changed by the experimenter from one treatment to the next.
Test Group
The experimental group that is exposed to the variable in an experiment.
Control Group
The group that is not exposed to the variable in an experiment.
Scientific Inquiry
A deliberate, systematic, and careful way of learning about the natural world.
Theory
A deliberate, systematic, careful, and unbiased way of learning about the natural world.
How does a scientist turn an observation into a hypothesis and investigate that hypothesis?
Observations form the basis of questions that allow for testable explanations (hypothesis) through the use of experiments.
What are the differences among a guess, hypothesis, and theory?
Each is an explanation for observations that differ in the amount of evidence to support that explanation.
Mice that live in sand dunes commonly have light tan fur. Develop a hypothesis to explain this coloration.
The color of fur allows the mice to hide from predators by blending in better with the environment.
What are the first and second laws of thermodynamics, and how do they apply to living organisms?
The first law of thermodynamics is that matter and energy can be neither created nor destroyed. The second law is that the transformation of energy in a closed/isolated system increases the entropy of that system. Living organisms must use energy to metabolize and maintain homeostasis, some of this energy is lost as heat.
What experimental evidence demonstrates that living organisms come from other living organisms?
The experiments done by Francesco Redi and Louis Pasteur.
First Law of Thermodynamics
The law of conservation of energy: energy can neither be created nor destroyed—it can only be transformed from one form into another.
Second Law of Thermodynamics
The principle that the transformation of energy is associated with an increase in the degree of disorder in the universe.
Cell
The simplest self-reproducing entity that can exist as an independent unit of life
DNA
A linear polymer of four subunits; the information archive in all organisms.
Protein
The key structural and functional molecules that do the work of the cell, providing structural support and catalyzing chemical reactions. The term “protein” is often used as a synonym for “polypeptide.”
RNA
A molecule chemically related to DNA that is synthesized by proteins from a DNA template.
Central Dogma
Originally, the idea that information flows from nucleic acids to proteins, but not in the opposite direction. More generally, the view that information transfer in a cell usually goes from DNA to RNA to protein.
Transcription
The synthesis of RNA from a DNA template.
Translation
Synthesis of a polypeptide chain corresponding to the coding sequence present in a molecule of messenger RNA.
Gene
The unit of heredity; the stretch of DNA that affects one or more traits in an organism, usually through an encoded protein or noncoding RNA.
Replication
The process of copying DNA so genetic information can be passed from cell to cell or from an organism to its progeny.
Mutation
Any heritable change in the genetic material, usually a change in the nucleotide sequence of a gene.
Plasma Membrane
The membrane that surrounds the cytoplasm of the cell, separating the inside of the cell from the outside of the cell; also called the cell membrane.
Nucleus
The compartment of the cell that houses the DNA in chromosomes.
Cytoplasm
The contents of the cell other than the nucleus.
Prokaryote
An organism whose cell or cells do not have a membrane-bound nucleus; sometimes used to refer collectively to archaeons and bacteria.
Eukaryote
An organism whose cells have a true nucleus.
Bacteria
One of the three domains of life, consisting of single-celled organisms with a single circular chromosome but no nucleus that divide by binary fission and differ from archaeons in many aspects of their cell and molecular biology.
Archaea
One of the three domains of life, consisting of single-celled organisms with a single circular chromosome and no nucleus that divide by binary fission and differ from bacteria in many aspects of their cell and molecular biology.
Eukarya
The eukaryotes; one of the three domains of life, in which cells have a true nucleus and divide by mitosis.
Metabolism
The chemical reactions occurring within cells that convert molecules into other molecules and transfer energy in living organisms.
ATP
The molecule that provides energy in a form that all cells can readily use to perform the work of the cell.
What does it mean to say that a cell is life’s functional unit?
A cell is the simplest living entity that can exist independently and all more complex organisms are composed of cells.
How does the central dogma help us to understand how mutations in DNA can result in disease?
The central dogma describes the order from DNA to synthesis of proteins. Changes in DNA can result in changes to proteins which can in turn lead to disease.
Evolution
Changes in the genetic make-up of populations over time, sometimes resulting in adaptation to the environment and the origin of new species.
Natural Selection
The process in which, when there is genetic variation in a population of organisms, the variants best suited for growth and reproduction in a given environment contribute disproportionately to future generations. Of all the evolutionary mechanisms, natural selection is the only one that leads to adaptations.
Environmental Variation
Variation among individuals that is due to differences in the environment.
Genetic Variation
Differences in genotype among individuals in a population.
How does evolution account for both the unity and the diversity of life?
Evolution demonstrates the common ancestry of all living things.
How might the heavy-handed use of antibiotics result in the increase of antibiotic-resistant cells in bacterial populations?
Overuse of antibiotics can result in a selection pressure for resistance to the antibiotic.
Ecology
The study of how organisms interact with one another and with their physical environment.
