Important Terms AP Biology

All information is directly from Ms. Johnson's / College board notes. All key terms, important concepts, and vocabulary from all parts of AP Bio. I was kinda sleep deprived when I made this so if there's any errors or anything LMK.

Absorption Spectrum

A graph that plots a pigment's light absorption versus wavelength.

Acetyl Coenzyme A (Acetyl CoA)

A 2-carbon molecule attached to coenzyme A, formed from pyruvate oxidation, which serves as the starting point for the Krebs Cycle.

Acid

A substance that gives away H+. On the pH scale, substances with a pH < 7 are acids.

Activation Energy

The energy required for a chemical reaction to occur. Enzymes lower this energy.

Active Site

The region on an enzyme where the substrate binds.

Active Transport

A type of cellular transport that requires the cell to use its own metabolic energy (ATP).

Adenosine Triphosphate (ATP)

An energy molecule in the cell. An important nucleic acid composed of the sugar ribose, the nitrogenous base adenine, and three phosphate groups. ATP's role is to store and transfer energy. It is made during cellular respiration and powers almost every cellular activity. ATP is also one of the common nucleic acids found in living organisms.

ADP

Adenosine diphosphate; ATP releases energy when it is broken down into this and inorganic phosphate.

Aerobic Cellular Respiration

A process usually discussed in three steps

Alkaline (Base)

A solution is alkaline if it contains a lot of OH-. A substance that gives away OH-. On the pH scale, substances with a pH > 7 are bases.

Alleles

Different versions of a gene. For example, versions of a gene controlling eye color might cause brown, blue, or green eyes. Dominant alleles are represented with capital letters, recessive alleles with lower case letters.

Amino Acid

The monomer of proteins. There are 20 kinds of naturally occurring amino acids. Amino acids contain Carbon, Hydrogen, Oxygen, and Nitrogen. They have four parts centered around a central carbon

Amino Terminus (N-terminus)

One end of a polypeptide chain that has a free amino group.

Ammonification

A process in the nitrogen cycle where decomposers break down organic matter into ammonia.

Anabolic Pathways (Anabolism)

Chemical reactions which build molecules. Photosynthesis is an anabolic process.

Anaphase

A stage in cell division, occurring in both mitosis and meiosis, where genetic material is separated and moved to opposite poles of the cell

Annealing

A step in PCR where the reaction is cooled so primers can bind to complementary sequences on the single-stranded template DNA.

Antiport

A transport protein where two substances are transported across a membrane in opposite directions during co-transport.

Antiparallel

Describes the two strands of a DNA molecule which run parallel to each other but have opposite directional orientations (5' to 3' and 3' to 5').

Aquatic Solution

A solution where water is the solvent.

Asexual Reproduction

A type of reproduction that is common in clones. It involves inheriting all DNA from a single parent.

Autotrophs

Organisms that can produce their own food, usually through photosynthesis. Also called primary producers. Examples include plants, algae, and cyanobacteria. Some perform chemosynthesis.

Autosomes

Chromosomes that are not involved in gender determination. Human cells contain 44 of these.

Axon

The part of a neuron that transmits the signal to the next neuron or muscle cell. It typically releases neurotransmitters.

Bacteria

A domain of prokaryotic cells. All prokaryotes, including these, are unicellular. Possess a single circular chromosome, ribosomes, and cytoplasm, but lack membrane-bound organelles. Its cell walls are mostly composed of complex carbohydrates. Utilizes quorum sensing as a local signaling mechanism.

Base

A substance that gives away OH-. Describes substances, on the pH scale, with a pH > 7.

Base Pairing (Chargaff's Rules)

Each base can only bond with a specific complementary base

Bioenergetics

A field of Biology concerning energy flow through living systems, including enzymatic processes, metabolic pathways, cellular respiration, and photosynthesis. Its goal is to describe how organisms acquire, transfer, and transform energy for biological work.

Biogeochemical Cycles

Cycles that involve the movement of matter through the environment, such as the Carbon, Nitrogen, Phosphorus, and Water cycles.

Biological Magnification

The increasing concentration of a substance in organisms at successively higher levels in a food chain.

Biomass

The amount of matter stored in organisms. In a food chain, only about 10% of energy is transferred from one level to the next, with the other 90% used for metabolic activities, represented by the 10% Rule of Energy Transfer and depicted by a trophic pyramid or energy pyramid. A Pyramid of _______ also depicts relationships between trophic levels.

Biomes

Distinct biological communities formed in response to a shared physical climate. Terrestrial ecosystems are grouped into these largely based on climate.

Blastocoel

A fluid-filled cavity that forms inside the blastocyst/blastula.

Blastocyst

The ball of cells formed during blastulation in mammals, consisting of the trophoblast and inner cell mass, surrounding the blastocoel.

Blastopore

An opening formed during gastrulation. In protostomes, it becomes the mouth; in deuterostomes, it becomes the anus.

Blastula

The ball of cells formed during blastulation in non-mammal animals, consisting of the trophoblast and inner cell mass, surrounding the blastocoel.

Blastulation

A stage of embryonic development (around day 4) where cells divide and begin to differentiate, forming two layers

Blood Vessels

Carry blood around the body to transport chemical signals, bring supplies to cells, and carry waste away.

Body Plan

The overall layout of an organism's form. Hox genes play a key role in determining this layout.

Bond Ribosomes

Ribosomes attached to the rough endoplasmic reticulum (RER). Found only in eukaryotes. They make proteins that will leave the cell.

Breeds

A subcategory of a species.

Bulk Transport (Large Molecule Transport)

Processes like endocytosis and exocytosis where large molecules are transported across the membrane.

Calvin Cycle (Calvin-Benson Cycle, Light Independent Reactions)

Phase 2 of photosynthesis, occurring in the stroma of chloroplasts (eukaryotes) or cytoplasm (prokaryotes). Energy from ATP and NADPH (from light-dependent reactions) is used to reduce and phosphorylate carbon dioxide gas to create G3P and ultimately glucose.

Catabolic Pathways (Catabolism)

Chemical reactions which break down molecules. Cellular Respiration and Digestion are catabolic processes that release energy from biological macromolecules.

Cell

The smallest unit of living material that can carry out all activities necessary for life. Must maintain a high surface area to volume ratio in order to function efficiently.

Cell Body (Soma)

The portion of a neuron containing the DNA and organelles. Helps produce proteins and substances needed throughout the cell.

Cell Communication

Absolutely essential for multicellular organisms to survive and function properly. Accomplished mainly by chemical means. Can be direct, local, or long distance.

Cell Cycle

The life cycle of a cell. Includes replication of DNA (interphase) and cell division (meiosis and mitosis).

Cell Division

Mechanism to replace dying cells. A small part of the cell's life cycle. Multicellular organisms depend on cell division for development, growth, and repair. This is followed by cytokinesis, which divides the cell or cytoplasm.

Cell Junctions

Result of cells in close contact. Allow neighboring cells to form communication connections, nutrient flow, and fasten cells together.

Cell Surface Marker

Proteins exposed on the cellular surface that play a role in cell recognition and adhesion. Ex. glycoproteins.

Cellular Respiration

A catabolic process of releasing the energy contained in organic molecules, primarily glucose, to do work. It uses the energy from these organic, biological macromolecules to make ATP, which serves as the energy source for most of the body's endergonic reactions.

Cellular Transport

Processes by which substances move into or out of cells. Includes diffusion, osmosis, facilitated diffusion, active transport, cotransport, and bulk transport.

Cellulose

A polysaccharide made up of ß-glucose molecules. Used as a structural component of plant cell walls. It is a complex carbohydrate.

Cell Wall

Provides a structural boundary and permeability barrier for some substances. In plant cells, composed of cellulose. In fungus, composed of chitin. Bacterial ______ are mostly composed of complex carbohydrates.

Centimorgan

A unit used to express distances in linkage maps, equivalent to a 1 percent recombination frequency or 1 map unit.

Central Carbon

The atom around which the four parts of an amino acid are centered.

Central Dogma of Genetics

Originally proposed as DNA → RNA → Protein. Later included reverse transcription. States that all cellular life follows this rule in order to synthesize proteins, though retroviruses, certain primitive viruses, and prions may violate it.

Centromere

A central point where the two copies of a replicated eukaryotic chromosome (chromatids) are attached.

Chain Elongation

A phase of transcription where RNA Polymerase assembles the new RNA molecules. The DNA template strand is read in the 3' to 5' direction.

Channel Proteins

Selectively allows the passage of ions or molecules across the cell membrane. Facilitated diffusion requires the help of this molecule.

Character Table

A table used in cladogram construction to indicate whether an organism possesses a trait (1) or not (0).

Chaperone Proteins (Chaperonins)

Protective structures that allow proteins to fold without water present. They help proteins fold properly and make the process more efficient.

Chemoautotrophs

Organisms that use energy from oxidation of inorganic compounds (e.g., hydrogen gas, hydrogen sulfide, or methane) to build organic compounds from carbon dioxide. Found near undersea vents.

Chemosynthesis

The biological conversion of carbon-containing molecules and nutrients into organic matter using the oxidation of inorganic compounds as the energy source.

Chi Square Analysis

A statistical test used to determine if the observed results in an experiment are significantly different from the expected results.

Chitin

Structural molecule in cell walls of fungi and arthropod exoskeletons. Used as surgical thread because it breaks down in the body. A complex carbohydrate.

Chromatids

The two copies of an original replicated eukaryotic chromosome, connected at the centromere.

Chromatin

Refers to DNA in its loose, non-chromosome formation. In this state, DNA can be replicated and transcribed. Looks like spaghetti noodles.

Chromosomal Rearrangements (Chromosomal Mutations)

Changes affecting large chunks of chromosomes. Often happens when crossing over doesn't work correctly. There are four main types: duplication, deletion, inversion, and translocation.

Chromosome

Each separate chunk of DNA. The packaged and organized structures of DNA found in cells. Consist of chains of linked genes and associated proteins. Eukaryotic _____ are linear and wrapped around histones. Prokaryotic _____ are typically single and circular. These are only visible (tightly coiled state) just before and during cell division. Human cells contain 46 of these (2n=46).

Circulatory System

Carries blood around the body via blood vessels to transport chemical signals, bring supplies to cells, and carry waste away. Blood flow is controlled by the heart.

Cisternae

Network of small tubes that compose the endoplasmic reticulum (ER).

Cladogram

A diagram used to depict phylogenetic relationships based on shared derived traits. Can be constructed based on morphology or molecular evidence.

Class

A taxonomic rank below phylum and above order.

Cleavage Furrow

Begins to form during telophase using actin and myosin microfilaments in plant cells. Cleavage means "split," referring to the division of the cytoplasm in cytokinesis.

Clone

Group of genetically identical individuals from the same parent. Common in asexual reproduction.

CO2 (Carbon Dioxide)

The original source for Carbon in all life forms. Released from organic intermediates oxidized during the Krebs Cycle. Used by photoautotrophs along with light energy to make organic molecules. Reduced and phosphorylated to create G3P and glucose during the Calvin Cycle. Lungs are responsible for gas exchange of O2 and this.

Codon (Triplet)

Each set of three mRNA nucleotides. Each codon corresponds to a particular amino acid. There are 64 different codons, 61 code for amino acids.

Coenzymes

Organic molecules (vitamins) that attach to and activate specific enzymes. Examples include NAD+ and FAD.

Cofactors

Inorganic metal minerals (such as Mg, Fe, and Zn) that attach to and activate specific enzymes.

Community

A group of different populations interacting in the same area. The structure of this is measured in terms of species composition/richness and species diversity.

Comparative Biochemistry and Molecular Biology

Comparing DNA, RNA, amino acid sequences, and metabolic pathways of related organisms to find evolutionary relationships. Organisms sharing these characteristics likely inherited them from a common ancestor.

Comparative Embryology

The study of similarities and differences among organisms during embryonic development. More similar development patterns indicate closer relatedness.

Compartmentalization

The formation of different areas or compartments within a cell, often by membranes.

Complementary Strands

Describes the two strands of a DNA molecule (A pairs with T, C with G).

Concentration Gradient

The difference in concentration of a substance across a space or membrane. Diffusion operates upon an established ____ ____, moving from high to low concentration.

Conformation Change

A change in shape. For example, after a signal molecule attaches to a membrane receptor, the intracellular domain of the receptor protein undergoes this, initiating signal transduction. An enzyme undergoes a slight ____ ___ (induced fit) when the substrate binds, helping catalyze the reaction.

Constants

All the factors that the experimenter attempts to keep the same in all groups of an experiment.

Consumer

An organism that must eat other organisms to obtain nutrients and energy. Includes primary, secondary, tertiary, and quaternary consumers. Also called heterotrophs.

Continental Drift

A geological event that affects habitat change and ecosystem distributions.

Cotransport

A type of active transport where two substances are simultaneously transported across a membrane by one protein complex that does not have ATPase activity. Usually, one substance moves with its concentration gradient, providing energy to transport the other against its gradient. Can use symport or antiport proteins.

Coupled Reaction (Coupling)

Using the energy from an exergonic reaction (energy releasing) to power an endergonic reaction (energy requiring). The hydrolysis of ATP is often coupled to endergonic reactions.

Covalent Bonds

The strongest type of chemical bond. Result from the sharing of valence electrons between atoms.

Crossing Over

Occurs during meiosis. Chromosomal rearrangements often happen when this doesn't work correctly. Introns may be involved in the regulation of this.

Cytokinesis

The division of the cytoplasm. Follows mitosis.

Cytoplasm (Cytosol)

The fluid-filled space in a cell that contains the nucleus and other organelles. Makes up most of the cell's volume. Glycolysis occurs here and translation by free ribosomes occurs here.

Cytoskeleton

Network of fibers that maintain cell shape. Includes microtubules and microfilaments. Peripheral proteins can be structural components of the this.

Decomposers

Break down organic matter into simple products. Ex. fungi and bacteria. They eat dead matter and waste products and recycle nutrients/minerals.

Degrees of Freedom

Used in Chi Square analysis. Equal to the number of phenotypes/categories minus one.