328 terms

Masta Vocaba: All of Dem


Terms in this set (...)

Ionic Bond
Bond where electrons are more thrown at each other. (Ions.)
Covalent Bond
Bond where electrons are shared.
Attraction between different particles.
Attraction between the same particles.
Hydrogen Bond
Weak bonds between hydrogen atoms and other atoms from different molecules.
Repelled from water.
Attracted to water.
Highest level of organization; contains everything.
A group of ecosystems that have the same climate and similar communities.
Groups of individuals of the same species in the same area.
Assemblages of different species in the same area.
A collection of all the organisms in a particular place together with the nonliving or abiotic environment.
Primary Producer/Autotroph
Organisms that obtain energy directly from sunlight.
Organisms that must acquire energy from other organisms by eating them.
Trophic Level
Each step in a food chain or web.
Total amount of living tissue within a given trophic level.
Biogeochemical Cycle
Elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another.
Limiting Nutrient
The nutrient whose supply limits productivity.
Dermal Tissue
The protective outer covering of the plant body.
A waxy coating that protects against water loss.
Vascular Tissue
Tissue that transports materials throughout the plant.
Transports water and minerals up from roots.
Transports (food) sugar, water, amino acids, and hormones throughout the plant.
Ground Tissue
Plant tissue that is neither dermal nor vascular.
Site of photosynthesis.
Pores (on the underside of leaves) that allow for gas exchange.
Guard Cells
Regulate the opening and closing of the stoma.
The principal photosynthetic pigment in plants.
The energy molecule of all life.
Light-dependent Reactions
Energy-capture phase of Photosynthesis; Takes place in thylakoids.
Light-independent Reactions
Calvin Cycle; Energy-storage phase; Takes place in Stoma.
Diffusion of water.
The probabilistic process by which molecules go from high concentration to low concentration.
Passive Transport
Transport requiring no energy.
Evaporation of water from leaves (to encourage gas exchange through the stoma).
Capillary Action
Tendency of water to rise in a thin tube.
Growth responses by plants to environmental stimuli.
Plants with flowers. (Enclosed seeds.)
Plants without flowers. (At least semi-open seeds; eg, ferns.)
Male pollen-producing part of the flower.
Female part of the flower.
The full range of physical and biological conditions in which an organism lives
Competitive Exclusion Principle
No two species can occupy exactly the same niche in exactly the same habitat at exactly the same time.
Two species live closely together.
Both species benefit.
One organism benefits and the other is neither helped nor harmed.
One species lives on or in another and harms it.
Primary Succession
Succession that occurs in an area in which no trace of a previous community is present.
Secondary Succession
Succession that occurs in an area that was only partially destroyed by disturbance.
A special kind of wetland, where the river meets the sea.
The average, year-after-year temperature and precipitation in a region.
The day-to-day condition of Earth's atmosphere at a particular time and place.
Exponential Growth
The larger a population gets, the faster it grows.
(To be technical, how fast it grows is proportional to its size.)
Logistic Growth
Where a population's growth slows and then stops, following a period of exponential growth.
Carrying Capacity (K)
Maximum number of individuals that a particular environment can support.
Biological Magnification
Concentrations of a harmful substance increase in organisms at higher trophic levels.
Ozone Layer
Layer of ozone in the upper atmosphere that protects the surface from UV radiation.
The basic unit of matter.
A pure substance made of only one type of atom.
A substance formed by the chemical combination of two or more elements in definite proportions.
Atomic Number
The number of protons in the atom.
Ionic Bond
Chemical bond formed when one or more electrons are transferred from one atom to another.
Covalent Bond
Chemical bond formed when the electrons are shared between atoms.
The small units.
The large units.
Atoms of the same element that differ in the number of neutrons they contain.
An element that exists in two or more forms.
Dehydration Synthesis
A chemical reaction that builds up molecules by losing water molecules.
The process of splitting a compound into fragments with the addition of water. (Breaks down water.)
The process of creating large molecules from smaller molecules, utilizing energy.
The process of breaking large molecules down into smaller molecules, releasing energy.
Primarily composed of: Carbon, Hydrogen, Oxygen. [CH2O]n format.
Known for energy storage.
Monomer carbohydrate. (One unit)
Polymer carbohydrate. (Multiple units.)
(Note: Disaccharide has 2 units.)
Fats. Composed of carbon and hydrogen (often in chains); not soluble in water.
(Store energy, used as phospholipids in membranes.)
Macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen.
Do the work in the cell.
Amino Acid
Organic compounds with an amino group (-NH2) on one end and a carboxyl group (-COOH) on the other end.
Primary Structure
The sequence of amino acids.
Secondary Structure
Coils and folding of the amino acid chain.
(What are the types?)
Tertiary Structure
The three-dimensional shape of the protein is stabilized by interactions between R-groups (side chains).
Quaternary Structure
Association between two or more different polypeptide chains (protein subunits) found in only some proteins.
Endothermic Reaction
Chemical reactions that absorb energy.
Exothermic Reaction
Chemical reactions that release energy.
Activation Energy
The energy needed to get a reaction started.
A substance that speeds up the rate of the reaction by lowering the activation energy.
Proteins that act as biological catalysts.
All of the chemical reactions that occur within an organism.
A compound that forms H+ ions in solution.
A compound that forms OH- ions in solution.
A weak acid or base that can react with strong acids or bases.
Prevents sharp, sudden changes in pH.
A substance on which an enzyme acts during a chemical reaction.
Active Site
Pockets in the folds on enzyme surfaces.
Competitive Inhibition
Molecules sit in the active site of the enzyme and prevent the entry of the substrate.
Uncompetitive Inhibition
Molecules attach to an allosteric site and change the shape of the enzyme and thus the shape of the active site.
Enzyme is now less compatible with its substrate.
Allosteric Site
Site on the enzyme used for uncompetitive inhibition. (I think that's all we need to know.)
Nucleic Acid
Made up of nucleotides joined into a chain by covalent bonds. (Polymer of nucleotides.)
One part of a nucleic acid.
(Five-carbon sugar attached to a phosphorous and a nitrogenous base.)
Give the acronym for the list of the most common elements found in the human body.
Positively charged subatomic particle.
Neutrally charged subatomic particle.
Negatively charged subatomic particle. (Lepton)
(2, 8, 18)
Number of electrons in the first 3 electron shells.
(Mass Number)
Total number of protons and neutrons.
(Atomic Weight)
Weighted average of the masses of an element's isotopes
(Valence Shell)
Most outer shell of electrons.
(Why do we care about this?)
The smallest unit of most compounds.
Functional group: COOH.
(How are they arranged?)
Functional group: PO4.
(How are they arranged?)
Functional group: HO.
Functional Group: NH2.
(How are they arranged?)
Carbohydrate with exactly 2 units.
(Saturated Fats)
Lipids with no C=C bonds.
(What does this do to the melting point? Why?)
(Unsaturated Fats)
Lipids with C=C bonds.
(What does this do to the melting point? Why?)
(Polyunsaturated Fats)
Lipids with more than 1 C=C bond.
(What does this do to the melting point? Why?)
The name for the polymer of amino acids.
(Structure isn't necessary.)
(Peptide bond)
Bond between 2 amino acids.
The sidechain that makes each amino acid different.
(Hydrogen Bonds)
Secondary protein structure is held together with ___.
(Adenine, Thymine; Cytosine, Guanine) (Uracil)
Name of the nucleotides.
(Which ones are purines/pyrimidines?
Which form 2 hydrogen bonds? 3?)
Name of the 5-carbon sugar in DNA.
(Law of Conservation of Energy; First Law of Thermodynamics.)
Energy can neither be created nor destroyed.
(Second Law of Thermodynamics)
In a closed, isolated, system entropy is strictly increasing.
(Think about your headphones tangling together: The closed, isolated system of your headphones grow in entropy over time by tangling together.)
The ability/capacity to cause a change.
(Chemical Reaction)
Process that changes or transforms one set of chemicals into another.
(2H2O2 -> 2H2O + O2)
Equation of the reaction catalase catalyzes.
(Temperature, pH, concentration)
Examples of things that affect enzyme performance.
Neutral pH.
(What has this?)
Higher pH indicates the substance is a(n) ___.
Lower pH indicates the substance is a(n) ___.
Suffix to indicate enzymes.
(Induced Fit Model)
A model for enzyme-substrate interaction.
The proper substrate induces the proper alignment of the active site that enables the enzyme to perform its catalytic function.
(Lock-and-Key Model)
A model for enzyme-substrate interaction. (Obsolete)
Enzymes and substrates have corresponding shapes like a lock and key.
Process in which one strain of bacteria changes due to information from another strain of bacteria.
(Why does this happen?)
Virus that infects bacteria by injecting genetic information into the cell.
(5'; 3')
The ___ carbon bonds from the first nucleotide to the ___ carbon from another nucleotide.
(Sugar-phosphate backbone.)
The bonds between the phosphate groups and the sugars makes the ___ in nucleic acids.
The two strands of DNA run in opposite directions. The nitrogenous bases contact in the middle.
Examples of nucleic acids.
(Adenine, Guanine)
(Cytosine, Thymine) (Uracil)
(Chargaff's Rule, 1949)
The observation that the number of adenine and thymine are roughly the same.
(Similarly, guanine and cytosine.)
(Rosalind Franklin, 1950s)
The scientist who used X-Ray diffraction and found an X-shape, indicating 2 twisted strands.
(Watson and Cirk, 1953)
Built a model of DNA using Franklin's research.
(Griffith, 1928)
Discovered transformation by observing harmless R stains turn into S strains ones and give a mouse pneumonia.
(Avery, 1944)
Discovered that DNA caused transformation by trial-and-error destroying things until it stopped happening.
(Hershey & Chase, 1952)
Discovered that bacteriophages inject their genetic information into bacteria by marking the information with radioactive isotopes.
Key: No membrane-bound organelles.
Key: Membrane-bound organelles.
Cell Theory
1. All things made of cells.
2. Cells are the basic unit of life.
3. New cells come from other ones.
A diverse domain of prokaryotes that contain peptidoglycan in their cell walls.
A domain of prokaryotes without peptidoglycan in their cell walls that are often able to survive in extreme environments.
Binary Fission
Asexual reproduction with DNA replication and cell division resulting in two genetically identical daughter cells.
Formation of a pili between bacterial cells allows for the exchange of plasmids to move genetic information between cells.
Thick walls that protect DNA and some cytoplasm of bacterial cells to allow cells to survive harsh conditions.
Endosymbiotic Theory
Mitochondria and chloroplasts are the descendants of small, symbiotic bacteria living inside large cells.
Cell part. Think "cell organ."
Organelle that stores DNA; control center of cell.
Composed of RNA and proteins; produces proteins.
Smooth Endoplasmic Reticulum
ER part that helps build lipids; sends tp golgi apparatus. (Ribosomes or no?)
Rough Endoplasmic Reticulum
ER part that helps build proteins; sends to golgi apparatus. (Ribosomes or no?)
Golgi Apparatus
Takes in proteins, packages them, ships them out of cell or to other areas.
Contains digestive enzymes that break down materials.
Storage of water and chemicals. (The big ones are in plants.)
Produce ATP from glucose via cellular respiration.
Produce glucose from light via photosynthesis.
Cytoplasm (Cytosol)
Aqueous (liquid) portion of the cell outside the nucleus.
Network of protein filaments in a eukaryotic cell that gives it shape and internal organization. Allows the cell to move.
Cell Membrane
More or less a semi-permeable boundary between in the cell and not in the cell; protection and support. (Made of?)
Lipid with a polar phosphate attached at the glycerol head and nonpolar fatty acid tails.
Cell Wall
Provide support/protection; present in plants/fungi/bacteria; outside of the cell membrane. (Made of? What can pass through?)
Passive Transport
Does not require energy; molecules move with the concentration/charge gradient. (Diffusion; facilitated diffusion.)
Does not require energy; molecules move straight through the membrane with the concentration/charge gradient.
Facilitated Diffusion
Method to transport large or polar molecules with a gradient.
Concentration Gradient
Distribution of particles across a space from high to low distribution.
Active Transport
Requires energy to transport; requires energy; often moves against a gradient. (eg, Na/K)
Taking material into the cell. (What are the types?)
Sending material out of a cell, often by fusing a vacuole (with material) with the cell membrane.
Diffusion of water.
Higher solute concentration. (Comparative term.)
Lower solute concentration. (Comparative term.)
Equal solute concentration. (Comparative term.)
Selectively permeable membrane
Describing a membrane that lets only some things in and keeps other out. (Example?)
ATP (Adenosine Triphosphate)
Is energy for you and me!
(Energy unit that "powers" many reactions by turning into ADP.)
Cellular Respiration
Process by which cells turn glucose into ATP.
(Similar to reverse photosynthesis.)
Process by which one molecule of glucose is broken in half, producing two molecules of pyruvate. (O2 not required. Cytoplasm. Net ATP: -2+4=+2.)
Krebs Cycle (Citric Acid)
Process by which pyruvate combines with coenzyme A and becomes Acetyl CoA and then goes though lots of reactions. (Mitochondrial Matrix. 2 NADH and 2 FADH2 produced. )
Electron Transport Chain
Electrons from the carriers (which ones?) are used to move H+ across the inner mitochondrial membrane (from the matrix).
The charge gradient powers ATP synthase. (Facilitated diffusion.)
Aerobic Respiration
Respiration with oxygen. Pyruvate goes to the Krebs Cycle.
Anaerobic Respiration
Respiration without oxygen. Pyruvate goes to fermentation.
Pyruvate is turned into ethanol (alcohol) or lactate. No ATP production; simply regenerates the NAD+.
Cell Cycle
Series of events in a cell leading to division and duplication of DNA (DNA replication) to produce two daughter cells. (Wikipedia!)
Interphase (G1, S, G2)
Longest phase in the cell cycle. Cells grow, develop, and have normal metabolic functions.
Proteins that regulate the timing of the cell cycle.
Stem Cells
Unspecialized (undifferentiated) cells in the body that can regenerate themselves indefinitely.
Specialized Cell
Different cell types that have different roles. Know their job; no mid-life crisis or anything.
S Phase
Phase in which DNA is replicated.
DNA Helicase
Unzips the DNA by breaking hydrogen bonds between the two strands.
DNA Polymerase
Joins nucleotides to synthesize a new complementary strand of DNA and proofreads the strand to ensure accuracy in replication.
Yet still terrible at its job. Everyone has to constantly fix its mess.
Okazaki Fragment
DNA fragments left over on the lagging strand because DNA polymerase nopes out when things get too hard.
M Phase (Mitosis)
Division of the cell's nucleus.
Chromosomes are visible when they become sister chromatids.
Centrioles in animal cells move to opposite ends of cell.
Nuclear membrane dissolves.
Chromosomes line up in middle (equator) of the cell.
The sister chromatids are pulled apart and move toward opposite ends of cell.
Nuclear membrane forms around the chromosomes. Nucleolus reforms.
Chromosomes become chromatin again.
Spindle disappears.
Cytokinesis begins.
The cell with 2 nuclei splits into 2 via cleavage furrow (animal cells) or cell plate (plant cells). (What are those?)
A disorder in which body cells lose the ability to control growth.
A mass of cancer cells.
P53 Gene
Gene that halts the cell cycle if DNA is damaged or chromosomes haven't been replicated correctly via apoptosis.
Describing rod-shaped bacteria.
Describing spheroid bacteria.
Describing spiral-shaped bacteria.
Gram+ looks _______ after gram staining.
Gram- looks _______ after gram staining.
Process in which the number of chromosomes per cell is cut in half through the separation of homologous (below) chromosomes in a diploid cell.
Strands of DNA (and protein) inside the cell nucleus. (Generally a very coiled inaccessible form of the DNA.)
Homologous Chromosomes
One set comes from the male parent and one set comes from the female parent.
(Chromosomes that serve an identical purpose; ie, identical genes.)
A cell with two sets of homologous chromosomes (2N).
A cell that contains only one set of homologous chromosomes (N).
Sex cells; sperm in males, eggs in females. (haploid or diploid?)
A fertilized egg formed from the combination of two gametes. (haploid or diploid?)
The joining of male and female gametes to produce a new cell.
Factors that are passed from parent to offspring.
Different forms of a gene.
An organism with one copy of this allele will exhibit this form of the trait.
(Usually represented by what kind of letter?)
An organism must have two copies of the this allele to exhibit the this form of the trait.
(Usually represented by what kind of letter?)
Organisms that have two identical alleles for a gene. (GG/gg)
Organisms that have two different alleles for a gene. (Gg)
Genetic makeup.
(The specific alleles.)
Physical traits.
(When could this be less useful than the genotype?)
Independent Assortment
Genes for different traits can segregate independently during the formation of gametes.
(When is this broken?)
Incomplete Dominance
Cases in which one allele is not completely dominant over another.
(Ex: Pink flowers from red and white ones.)
Phenotypes produced by both alleles are clearly expressed.
(Ex: AB blood type.)
Multiple Alleles
A gene with more than two alleles.
(Ex: I think eye color works.)
Polygenic Traits
Traits controlled by two or more genes.
Messenger RNA (mRNA)
RNA that carries copies of instructions for assembling amino acids into proteins.
Ribosomal RNA (rRNA)
RNA that makes up ribosomes, the location of protein assembly.
Transfer RNA (tRNA)
RNA that transfers amino acids to the ribosome in the order specified by the mRNA.
The process by which segments of DNA produce complementary RNA molecules.
RNA Polymerase
Binds to DNA during transcription, separates DNA strands, and then uses one strand of DNA to form a complementary strand of RNA.
(Where?) (What kind(s) of RNA are involved?)
Removed portions of the mRNA during splicing.
Kept portions of the mRNA during splicing.
Three-letter (base) mRNA sequences that correspond to a specific amino acid.
Process by which the mRNA is turned into a protein.
(Where?) (What kind(s) of RNA are involved?)
The codon opposite the one found on the mRNA.
(Where is this found?)
The complete diploid set of chromosomes grouped together in pairs, arranged in order of decreasing size.
Sex Chromosomes
Two of the chromosomes (46 for humans) that determine an individual's sex.
Consists of X and Y chromosomes.
The 44 chromosomes that are not sex chromosomes.
Barr Body
In organisms homozygous with respect to their sex chromosome (eg, XX), the sex-linked alleles often for fight for dominance, which creates areas where one allele is shut off and condensed.
Dominant Lethal
A trait in which the homozygous dominant individuals do not exist in the population due to the deleterious nature of gene expression.
(In more extreme cases, a dominant itself could be detrimental for the individual; eg, make an organism more susceptible to some disease.)
Heritable changes in genetic information.
Gene Mutations
Mutations that produce changes in a single gene.
Chromosomal Mutations
Mutations that produces changes in whole chromosomes.
Point Mutations
Gene mutations that involve changes in one or a few nucleotides.
One base is changed to a different base.
(How many amino acids are affected?)
Silent Mutations
Are substitutions that do not change the amino acid.
(How could this happen?)
One base is added to the DNA sequence.
(How many amino acids are affected?) (Why?)
One based is removed from the DNA sequence.
(How many amino acids are affected?)
Deletion (chromosomal)
Some part of the chromosome disappears.
(When could this happen?)
Some part of the chromosome is repeated.
(How could this happen?)
Some part of the chromosome is reversed (more like "moved").
(How could this happen?)
Some part of the chromosome is inserted.
(How could this happen?)
An error in meiosis when homologous chromosomes fail to separate.
(What is trisomy? Monosomy?)
Wild Type
Describes a trait that is not a "mutation." For example, in fruit flies, red eyes are the wild type while white eyes are a mutation.
(In general, this term describes the trait that is more common in natural conditions.)
Restriction Enzymes
Highly specific substances that cut DNA molecule into precise pieces.
Polymerase Chain Reaction (PCR)
A technique that amplifies (makes many copies) of a specific segment of DNA.
(Process: Heat to separate, primer binding, polymerase copying, repeat.)
Recombinant DNA
DNA pieces that contain DNA of more than one organism.
(Ex: Bacterial plasmids come from everywhere.)
Small, circular, extra-chromosomal DNA found in some bacteria.
Gel Electrophoresis
A technique that separates DNA fragments of different sizes.
DNA Sequencing
The process to determine the order of the nucleotide bases (A, T, C, G) in a gene or segment of DNA.
DNA Fingerprinting
Tool used by biologists to analyze an individual's unique collection of DNA restriction fragments; used to determine whether two samples of genetic material are from the same person.
This quizlet is for studying for the bell ringers exclusively; do not expect to do well on the quizzes or tests by only using this quizlet.
James Hutton
Geologist who developed the idea of "deep time." (Earth's history is ancient.)
Charles Lyell
Popularised uniformitarianism (geological processes shaping today's Earth shaped the ancient one).
Known for the the Theory of Inheritance of Acquired Characteristics (and Use-Disuse). (Giraffes stretch and pass down long necks.)
Made everyone scared of overpopulation. (Food is linear and population is exponential.)
Artificial Selection
The (human) breeding of plants and animals to produce desirable traits.
A change or the process of change by which an organism or species becomes better suited to its environment.
Natural Selection
Process whereby better-adapted organisms survive and produce more offspring.
Convergent Evolution
Evolution of organisms adapted to similar environments produces similar adaptations even though the organisms are only distantly related (share no recent common ancestor).
Divergent Evolution
Evolution of organisms that are closely related (share a recent common ancestor) but have adapted to different environments.
Adaptive Radiation
A single ancestral species diverges into several different forms adapted to slightly different environments.
Homologous Structure
A structure similar in form but not necessarily function that was inherited from a common ancestor.
Analogous Structure
A structure similar in function but was not inherited from a common ancestor.
Vestigial Structure
A homologous structure without a purpose.
Gene Pool
The stock of different genes in an interbreeding population.
Allele Frequency
Relative frequency of a gene variant in a population (expressed as a fraction or percentage).
Hardy-Weinberg Principle
Allele/genotype frequencies in a population will remain constant and predictable in the absence of other evolutionary influences.
Genetic Drift
Isolation causes random change in allele frequency (due to the chance disappearance of particular genes as individuals die or do not reproduce).
Non-Random Mating
Individuals choose mates based on specific features.
Causes the introduction of new alleles into the population. (Random genetic change.)
Gene Flow
The transfer of alleles or genes from one population to another.
Natural Selection
Process whereby better-adapted organisms survive and produce more offspring.
Genetic Bottleneck
A sharp reduction of a population (due to environmental events or human activities).
The Founder Effect
Loss of genetic variation when a new population is established by a very small number of individuals from a larger population.
The largest group of organisms in which two individuals can produce fertile offspring.
The formation of new and distinct species in the course of evolution.
Directional Selection
One extreme phenotype is favored over other ones, causing the allele frequency to trend to the first of phenotype.
Stabilizing Selection
Selection that favors the intermediate variants. (Reduces phenotypic variation and maintains status quo.)
Disruptive Selection
Extreme values for a trait are favored over intermediate values. (The variance of the trait increases, and population is divided into distinct groups.)
Adaptive Radiation
A single ancestral species diverges into several different forms adapted to slightly different environments.
Large-scale transformation in a taxonomic group including the evolution of new species.
Mass Extinction
Many species become extinct in a short time period.
Slow and steady evolutionary pace.
(The idea that evolution proceeds chiefly by the accumulation of gradual changes.)
Punctuated Equilibrium
Evolutionary pace with periods of equilibrium (no change) disrupted by periods or rapid change.
Two (or more) species evolve in response to one another.
Evolutionary history.
(The history of the evolution of a species or group.)
Groups of organisms with a common ancestor and all of its descendants.
A branching diagram used to depict evolutionary relationships.
Derived Character
A trait that is new in the most recent common ancestor to a group and was then passed on to the descendants of the group.
The science of naming and classifying organisms.
Binomial Nomenclature
A two-name system for identifying organisms.
Closely related kingdoms are grouped into one ______.
(The highest taxonomic rank of organisms.)
Domain that contains one prokaryotic kingdom—Eubacteria.
Domain that contains one prokaryotic kingdom—Archaebacteria.
Domain that contains four eukaryotic kingdoms—"Protista", Fungi, Plantae, Animalia.
Continental Drift
The slow motion of the Earth's plates leading to the movement of the continents.
Symbiosis in which one of the symbiotic organisms lives inside the other.
(Mitochondria and chloroplasts are the descendants of small, symbiotic bacteria living inside large cells.)
A nonliving particle composed of nucleic acids surrounded by a protein coat that sometimes are also made of lipids.
The protein coat around a virus.
A lipid coat that surrounds the capsid, found only in some viruses.
Lytic (Cycle)
An infection in which a virus enters a cell, copies itself, and causes lysis of the cell.
(Also when a virus turns on the kill switch.)
Lysogenic (Cycle)
An infection in which a virus inserts viral DNA into the host cell's DNA where it is replicated until the prophage is triggered into activity.
(Also when a virus does not have the kill switch on.)
An animal lacking a backbone.
An animal with a backbone (and sea squirts and lancelets).
An animal with 4 feet.
Any of various extinct hominids that existed 2-4 million years ago in southern and eastern Africa.
Genus Homo
Humans (sorta).