Biology - Midterm Exam 2022

Key Terms

Biology

the scientific study of life

Hypothosis

An educated guess that attempts to explain an observation or answer a question.

The Scientific Method

A series of steps followed to solve problems including collecting data, formulating a hypothesis, testing the hypothesis, and stating conclusions.

independent variable

The experimental factor that is manipulated; the variable whose effect is being studied.

Dependant variable

the variable that relies on the independant variable

Control

In an experiment, the standard that is used for comparison

Proton (positive)

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

Neutron (neutral)

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

Electron (negative)

A subatomic particle that has a negative charge

valance electrons

the number of electrons in the outermost energy level

atomic number

the number of protons in the nucleus of an atom

atomic mass

The average mass of all the isotopes of an element

Isotopes

Atoms of the same element that have different numbers of neutrons

Electronegativity

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

covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

ionic bond

Formed when one or more electrons are transferred from one atom to another

Polar bonds

a covalent bond in which electrons are shared unequally

nonpolar covalent bond

a covalent bond in which the electrons are shared equally by the two atoms

surface tension

A measure of how difficult it is to stretch or break the surface of a liquid

specific heat ionization

The amount of energy required to raise the temperature of 1 gram of a substance by 1 degree celsius; the heat required to ionize a substance; the amount required to ionize one mole.

pH

a measure of how acidic/basic water is

Acid

A substance that increases the hydrogen ion concentration of a solution.

Base

A substance that decreases the hydrogen ion concentration in a solution.

Eukaryotic cells

Contain a nucleus and other organelles that are bound by membranes.

prokaryotic cell

A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles; found only in the domains Bacteria and Archaea.

Organelle

A tiny cell structure that carries out a specific function within the cell

Cytosol

Fluid portion of cytoplasm

plasma membrane

A selectively-permeable phospholipid bilayer forming the boundary of the cells

Cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended

nuclear envelope

layer of two membranes that surrounds the nucleus of a cell

Nucelus

Control center of the cell

Nucleoli

dense masses of RNA and protein that manufacture ribosomes, several of these are located in the nucleus.

Nuclear Pore

a protein-lined channel in the nuclear envelope that regulates the transportation of molecules between the nucleus and the cytoplasm

Ribosomes

site of protein synthesis; makes protein

coupled transport

The movement of a substance against its electrochemical gradient (from lower to higher concentration, or from opposite charge to like charge) using the energy provided by the simultaneous movement of a different chemical down its electrochemical gradient.

receptor proteins

Proteins that transmit information in and out of cells. They allow communication between cells.

Ligands (cargo)

A molecule that binds specifically to a receptor site of another molecule.

Receptor - mediated endocytosis

The movement of specific molecules into a cell by the inward budding of membranous vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific substances.

Pinocytosis

A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

Phagocytosis

A type of endocytosis in which a cell eats large particles or whole cells

Exocytosis

Process by which a cell releases large amounts of material

potential energy

stored energy

Enthalpy

The heat content of a system at constant pressure

Entropy

A measure of disorder or randomness.

free energy

energy that is available to do work

Exergonic

releases energy

Endergonic

requires energy

ATP

(adenosine triphosphate) main energy source that cells use for most of their work

coupled reactions

pairs of chemical reactions in which some of the energy released from the breakdown of one compound is used to create a bond in the formation of another compound

Rate

A ratio that compares two quantities measured in different units

Enzymes

Catalysts for chemical reactions in living things

activation energy

Energy needed to get a reaction started

transition state

a high-energy intermediate state of the reactants during a chemical reaction that must be achieved for the reaction to proceed

Substrate

reactant of an enzyme-catalyzed reaction

Cofactors

nonprotein enzyme helpers

Inhibitor

A substance that slows down or stops a chemical reaction

competative inhibition

when molecules similar to a substrate compete for placement on the active site of an enzyme

noncompetitive inhibitor

A substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing its conformation so that it no longer binds to the substrate.

uncompetative inhibition

results when the inhibitor binds only with the enzyme susbtrate complex (vmax decreased, Km decreased)

feedback inhibition

A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.

allosteric interactions

the modification of an enzyme's configuration through the binding of an activator or inhibitor at a specific binding site on the enzyme

Chloroplast (will need to draw/ label a diagram)

An organelle found in plant and algae cells where photosynthesis occurs

Chlorophyll

A green pigment found in the chloroplasts of plants, algae, and some bacteria

Thylakoid

A flattened membrane sac inside the chloroplast, used to convert light energy into chemical energy.

Granum

stack of thylakoids

Stroma

fluid portion of the chloroplast; outside of the thylakoids

light reactions

reactions of photosynthesis that use energy from light to produce ATP and NADPH

Calvin Cycle

reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugars

Photosystem

One of two light-harvesting units of a chloroplast's thylakoid membrane; it uses the P700 reaction-center chlorophyll.

Photosystem II

One of two light-harvesting units of a chloroplast's thylakoid membrane; it uses the P680 reaction-center chlorophyll.

reaction center

The location of the first light driven chemical reaction of photosynthesis.

climate

Overall weather in an area over a long period of time

Microclimate

Climate within a small area that differs significantly from the climate of the surrounding area

Biome

A group of ecosystems that share similar climates and typical organisms

disturbance

an event, caused by physical, chemical, or biological agents, resulting in changes in population size or community composition

Thermocline

a layer in a large body of water, such as a lake, that sharply separates regions differing in temperature, so that the temperature gradient across the layer is abrupt.

turnover

Seasonal changes in warm and cool water layers in lakes.

Distribution

The arrangement of something across Earth's surface.

Density

the degree of compactness of a substance; mass/volume

Dispersion

the pattern of spacing among individuals within the boundaries of the population

survivorship curve

Graph showing the number of survivors in different age groups for a particular species.

exponential growth

Growth pattern in which the individuals in a population reproduce at a constant rate

intrinsic rate of increase

rate at which the population of a species would grow if it had unlimited resources

carrying capacity

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

logistic growth

Growth pattern in which a population's growth rate slows or stops following a period of exponential growth

life history

Traits that affect an organism's schedule of reproduction and survival.

Semelparous

single reproductive episode before death

Iteroparous

Repeated reproduction throughout lifetime

K-selection

Selection for life history traits that are sensitive to population density; also called density-dependent selection.

r-selection

Selection for life history traits that maximize reproductive success in uncrowded environments; also called density-independent selection.

density dependent

Referring to any characteristic that varies according to an increase in population density.

density-independent

Referring to any characteristic that is not affected by population density.

metapopulation

a group of spatially distinct populations that are connected by occasional movements of individuals between them

age structure

number of males and females of each age in a population

ecological footprint

the impact of a person or community on the environment, expressed as the amount of land required to sustain their use of natural resources.

interspecific interactions

relationships between species in a community

competition

the struggle between organisms to survive in a habitat with limited resources

exploitation

Taking advantage of a weaker group

Predation

An interaction in which one organism kills another for food.

Herbivory

interaction in which one animal (the herbivore) feeds on producers (such as plants)