Honors Biology - Midterm Vocab

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Biology

The study of life and living things

Levels of organization

Atom, Molecule, Macromolecule, Organelle, Cell, Tissue, Organ, Organ System, Organism/Individual, Population, Community, Ecosystem, Biome, and Biosphere

Homeostasis

Maintaining a relatively constant internal environment

Hypothesis

Uses a tentative answer to a well-framed question to help design an experiment. Leads to prediction that can be tested by observation or experimentation.

Theory

An explanation that is broader in scope than a hypothesis, generates new hypotheses, and is supported by a large body of evidence.

Scientific Law

A statement that describes what scientists expect to happen every time under a particular set of conditions

Observation

Step in the scientific method by which data are collected before a conclusion is drawn

Inference

A conclusion based on observation or evidence.

Principle

A general or basic truth on which other truths, theories, or hypotheses can be based on. What should happen in nature.

Fact

A piece of information provided objectively, presented as true.

Eukaryote

Cells have a nucleus; animals, plants, fungi, protists

Prokaryote

Cells without a nucleus; bacteria, archaea

Independent variable

The variable that is the cause of change in the system.

Dependent variable

The variable in an experiment measured to determine if it changes as a result of manipulations by the experimenter.

Control group

The group in an experiment that is exposed to the same conditions as the experimental group except for one independent variable.

Evolution

Change in an organism over time; process by which modern organisms have descended from ancient organisms.

Natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

Producer

An organism that can make its own food.

Consumer

An organism that eats other organisms.

Decomposer

An organism that breaks down wastes and dead organisms.

Autotroph

An organism that makes its own food from inorganic reactants.

Heterotroph

An organism that obtains organic food molecules by eating other organisms or substances derived from them.

Food web

A community of organisms where there are several interrelated food chains.

Food chain

Series of steps in an ecosystem in which organisms transfer energy by eating and being eaten.

Biotic

Living things in an ecosystem.

Abiotic

Non-living things in an ecosystem.

Habitat

An area that provides an organism with its basic needs for survival.

Biome

A group of ecosystems with similar climates and organisms

Keystone species

Not necessarily abundant, but exert a strong control on community structure due to a pivotal ecological role.

Ecological pyramids

Show the relative amount of energy or matter contained within each trophic level in a given food chain or food web.

Biogeochemical cycles

The movement of abiotic factors between the living and nonliving components within ecosystems; also known as nutrient cycles (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle).

Limiting factors

Any biotic or abiotic factor that restricts the existence, numbers, reproduction, or distribution of organisms.

Symbiotic relationships

An interaction between two different organisms living in close phycical proximity; mutualism, parasitism, commensalism, herbivory.

Niche

An organism's particular role in an ecosystem, or how it makes its living.

Succession

A series of predictable and orderly changes within an ecosystem over time.

Carrying capacity

Largest number of individuals of a population that a environment can support.

Law of conservation of matter

Matter is neither created nor destroyed.

Atom

Basic unit of matter.

Mass number

The sum of the numbers of protons and neutrons in the nucleus of an atom.

Atomic number

The number of protons in the nucleus of an atom.

Molecule

A combination of two or more atoms covalently bonded together.

Element

A pure substance made of only one kind of atom.

Compound

A substance made up of atoms of two or more different elements joined by any type of chemical bond.

Proton

A subatomic particle that has a positive charge and that is found in the nucleus of an atom.

Nucleus

Center of an atom that contains protons and neutrons.

Neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom.

Electron

A subatomic particle that has a negative charge.

Ion

A charged atom that has lost or gained an electron.

Isotope

Atoms of the same element that have different numbers of neutrons.

Types of bonds

covalent, ionic, hydrogen, peptide, phosphodiester

Valence shell

Outermost electron shell of an atom.

Electronegativity

A measure of the ability of an atom in a chemical compound to attract electrons.

Adhesion

An attraction between molecules of different substances.

Cohesion

Attraction between molecules of the same substance.

Hydrophilic

Having an affinity for water; all polar substances.

Hydrophobic

Having an aversion to water; tending to coalesce and form droplets in water.

Chemical reaction

The process by which one or more substances change to produce one or more different substances.

Activation energy

The minimum amount of energy required to start a chemical reaction.

pH

A logarithmic measure of hydrogen ions in a solution.

Biochemistry

Chemistry dealing with chemical compounds and processes in living things.

Monomer

The subunit that serves as the building block of a polymer.

Polymer

A long molecule consisting of many similar or identical monomers linked together.

Dehydration synthesis

A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule.

Hydrolysis

Breaking down complex molecules by the chemical addition of water

Carbohydrates

Compound containing carbon, hydrogen, and oxygen in the approximate ratio of C:2H:O (e.g., sugars, starches, and cellulose)

Lipids

Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen.

Proteins

A macromolecule that is made up of many amino acids joined together, is a necessary part of the diet, and is essential for normal cell structure and function; serve as enzymes, transport functions, structural functions.

Levels of protein structure

Primary (amino acid chain, polypeptide), secondary (alpha helix/beta sheet), tertiary (functional protein), quaternary (two or more tertiary proteins bonded and functioning together)

Enzyme

A type of protein that speeds up a chemical reaction in a living thing by lowering the activation energy. Substrate(s) bond to active site.

Amino acid

Building blocks of protein; consist of amino group (NH2), carboxyl group (COOH) and R group (variable).

Denaturation

In proteins, a process in which a protein unravels and loses its native conformation, thereby becoming biologically inactive.

Nucleic acids

Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), are made up of long chains of molecules called nucleotides.

Nucleotide

A building block of DNA and RNA, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.

RNA

A single-stranded molecule made up of ribonucleotides bonded together with phosphodiester bonds; ribonucleic acid.

DNA

A double-stranded, helical nucleic acid molecule made up of deoxyribonucleic acids capable of replicating and determining the inherited structure of a cell's proteins.

ATP

Main energy source that cells use for most of their work; adenosine triphosphate.

Entropy

A thermodynamic quantity representing the amount of energy in a system that is no longer available for doing mechanical work; second law of thermodynamics states that this is always increasing in a closed system.

Thermodynamics

The study of conversions between energy types.

Metabolism

All of the chemical reactions that occur within an organism (anabolic + catabolic)

Biosynthesis

The process by which living organisms produce larger molecules from smaller ones A + B --> AB

Decomposition

A chemical reaction that breaks down compounds into simpler products. AB --> A + B

Anabolic

The category of metabolism in which large molecules are built from small molecules.

Catabolic

The category of metabolism in which large molecules are broken down.

Photosynthesis

6CO2 + 6H2O + light --> C6H12O6 + 6O2

A process used by plants and other autotrophs to capture light and energy and use it to power chemical reactions that convert carbon dioxide and water into oxygen and energy-rich carbohydrates, such as sugars and starches.

Cellular Respiration

C6H1206 + 6O2 ---> 6CO2 + 6H2O + 36ATP

A complex set of chemical reactions involving an energy transformation where potential chemical energy in the bonds of "food" molecules is released and partially captured in the bonds of adenosine triphosphate (ATP) molecules.

Cell theory

the theory that cells form the fundamental structural and functional units of all living organisms

Surface area to volume ratio

Affects the exchange rate of materials, if cell too large, difficult to move things in and out of the cell. High SA and Low V = highly efficient cell.

Heterotroph Hypothesis

Theory that states that the first organisms on Earth were anaerobic, heterotrophic prokaryotes.

Endosymbiont theory

The theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell. The engulfed cell and its host cell then evolved into a single eukaryotic organism.

Organelle

A subunit within a cell that has a specialized function.

Osmosis

Diffusion of water through a selectively permeable membrane.

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Concentration gradient

A difference in the concentration of a substance across a distance or membrane.

Chemiosmosis

Process by which a Hydrogen pump pumps protons into the thylakoid membrane. H+ passively flows through the ATP synthase which leads to the creation of ATP.

Active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

Passive transport

Requires NO energy, Movement of molecules from high to low concentration, Moves with the concentration gradient

Facilitated diffusion

Diffusion of specific molecules across cell membranes through protein channels.

Endocytosis

A process in which a cell engulfs extracellular material through an inward folding of its plasma membrane.