SAT Biology Vocabulary Flashcards
Structures in grasshoppers for removal of the nitrogenous waste uric acid.
malpighian tubule
mitosis
Type of cell division for growth and repair that produces two genetically identical daughter cells with the same chromosome number as the parent cell. Consists of four phases: prophase, metaphase, anaphase, and telophase.
dehydration synthesis
Also known as synthesis. Process by which molecules are bonded together to form a larger molecule with the removal of water.
Specialized region in the root of a plant for storage.
pith
glyceraldehyde-3-phosphate
(Also G3P or PGAL.) First sugar produced by photosynthesis.
introns
Intervening, noncoding sequences of DNA located between genes.
parallel evolution
Two related species that have made similar evolutionary adaptations after their divergence form a common ancestor.
Process by which ATP is produced as a special enzyme moves a phosphate from one molecule to ADP. How energy is produced during glycolysis and the Krebs cycle.
substrate level phosphorylation
Myofilaments that make up the thick filaments in skeletal muscle.
myosin
The outermost layer of an embryo, which develops into skin and nervous system.
ectoderm
acoelomate
An animal that has no true coelom. Flatworms are an example.
anther
Male part of flower where sperm (pollen) is produced by meiosis. Sits atop the filament.
Part of the testes where sperm become mobile.
epididymis
electron transport chain
(Also ETC.) Consistes of a series of molecules within the crustal membrane of mitochondria that provides the energy to phosphorylate ADP into ATP during oxidative phosphorylation.
phenotype
The traits an organism expresses.
glycerol
Combines with fatty acids to make lipids.
Plant whose seed does not break into two parts. An example is corn.
monocotyledon
spermatogenesis
Formation of sperm by meiotic cell division.
Process by which cells continue to differentiate, producing organs from the three embryonic germ layers.
organogenesis
Pressure exerted when a plant cell sweats.
turgor pressure
An inherited disease characterized by the inability to break down the amino acid phenylalanine. Requires elimination of phenylalanine from diet, otherwise serious mental retardation will result.
Phenylketonuria
Type of cell division in sexually reproducing organisms that produces haploid (n) gametes.
meiosis
pathogen
Organism that causes disease.
Characteristic of proteins; a change in shape that stops the protein from functioning.
denature
vegetative propagation
Asexual reproduction in a plant where a piece of the root, stem, or leaf produces an entirely new plant genetically identical to the parent plant. Examples are grafting, cuttings, bulbs, and runners.
active transport
Movement of particles against a gradient, from low concentration to high concentration. This always requires the expenditure of energy.
Expressed sequences of DNA. DNA that codes for particular polypeptides.
exons
meristem tissue
Plant tissue that is always dividing. An example is cambium tissue.
Noncoding regions of DNA. Most of the human genome consists of noncoding regions.
junk
Incorporation of carbon dioxide into a sugar. It occurs during the cyclical process called the Calvin cycle.
carbon fixation
multiple alleles
When there are more than two allelic forms of a gene. For example in humans, there are more than 2 alleles for blood type. There are A, B, and O.
A degenerative inherited disease of the nervous system resulting in certain and early death. The gene that causes it is dominant.
Huntington’s disease
Cellular process of engulfing food and encapsulating it in a vacuole.
phagocytosis
An error that sometimes happens during meiosis in which homologous chromosomes fail to separate as they should.
nondisjunction
An organism’s genetic material.
genome
parasitism
Symbiotic relationship (+/-) where one organism, the parasite, benefits while the host is harmed.
A fragment of a chromosome becomes attached to a non homologous chromosome.
translocation
spliceosomes
Special molecules that assist in the editing of mRNA during RNA processing.
Extra embryonic membrane in bird’s egg. It exchanges respiratory gases to and from the embryo.
allantois
Symbiotic bacterium that lives in the nodules on roots of specific legumes and that fixes nitrogen gas from the air into a form of nitrogen the plant requires.
rhizobium
Sinuses. Cavities in the body of insects, like grasshoppers, for exchange of nutrients and wastes.
hemocoels
This type of natural selection eliminates the extremes and favors the more common intermediate forms.
stabilizing selection
adenosine triphosphate
(Also called ATP.) Special high-energy molecule that stores energy for immediate use in the cell.
Levels of organization in our system of classification: domain, kingdom, phylum, class, order, family, genus, and species. Domain or kingdom includes the most different organism, while species includes the most similar organisms.
Taxon (Taxa, plural)
A small population, which is not representative of the larger population, breaks away from the larger one to colonize a new area. Rare alleles may be under- or overrepresented.
founder effect
Combines with fatty acids to make lipids.
glycerol
Anything that triggers an antibody response.
antigens
A normal process in which homologous chromatids exchange genetic material.
crossing-over
Carries messages directly from DNA in the nucleus to the cytoplasm during protein synthesis.
messenger RNA or mRNA
Symbiotic structures consisting of the plant’s roots intermingled with the hyphae (filaments) of a fungus, which greatly increase the quantity of nutrients that a plant can absorb.
mycorrhizae
Solutions containing equal concentrations of solute.
isotonic
ovule
The structure within the ovary of a flower where the ova (female gametophyte) are produced.
excited state
When an atom absorbs energy, its electrons move to a higher energy level.
Structure in birds, insects, and earthworms where mechanical digestion of food occurs.
gizzard
Cessation of the menstrual cycle.
menopause
The way in which DNA replicates itself.
semiconservative replication (The new DNA molecule consists of one old strand and one new strand.)
hydrophilic
Soluble in water. Hydrophilic substances are either polar or ionic.
Modification for dry environments. C-4 plants exhibit modified anatomy and biochemical pathways, which enable them to minimize excessive water loss and maximize sugar production.
C-4 photosynthesis
population
Group of individuals of one species living in one area that have the ability of interbreeding and interacting with each other.
homeotherm
Endotherm. Animals that maintain a consistent body temperature. Examples are birds, mammals, and some reptiles.
synapsis
The process in which homologous chromosomes pair up. This occurs during prophase I.
agonistic behavior
Aggressive behavior.
hermaphrodites
Organisms that contain both female and male sex organs.
anion
A Negative ION.
erythrocytes
Red blood cells.
translation
The process in which the DNA code is translated into an amino acid sequence and a polypeptide is formed. Occurs at the ribosome.
golgi apparatus
Cell organelle that packages and secretes substances for the cell.
polymerase chain reaction
A cell-free, automated technique by which a piece of DNA can be rapidly copied or amplified. Useful in genetic engineering.
bacterial transformation
The ability of bacteria alter their genetic makeup by up taking foreign DNA from another bacterial cell and incorporating it into their own. Discovered by the scientist named Griffith.
NAD
(Also nicotinamide adenine dinucleotide.) Coenzyme that shuttles protons or electrons from glycolysis and the Krebs cycle to the electron transport chain.
Animals that normally eat both meat and vegetables in their diet.
omnivores
secretin
Digestive hormone that stimulates the pancreas to release bicarbonate to neutralize acid in the duodenum.
A property of plant cells, swollen.
turgid
Intake and distribution of substances in cells or tissue.
transport
gel electrophoresis
Process that separates large molecules of DNA on the basis of their rate of movement through an agarose gel in an electric field.
Anthophyta or flowering plants.
angiosperms
sclerenchyma cells
Plant cells that have very thick primary and secondary cell walls fortified with lignin. Their function is purely support.
Coenzyme that shuttles protons and electrons from glycolysis and the Krebs cycle to the electron transport chain.
flavin adenine dinucleotide or FAD
An error in the DNA in which the entire reading frame is altered. This can be caused by an insertion or deletion.
frameshift
Diffusion of water across a membrane.
osmosis
The sum total of all the life functions.
metabolism
grana
Membranes within chloroplasts that consist of thylakoid membranes and are the sites of the light-dependent reactions of photosynthesis.
Swollen part of pistil of a flower that contains the ovule, where one or more ova are produced.
ovary
microtubules
Thick hollow tubes that make up the cilia, flagella, and spindle fibers.
cystic fibrosis
The most common lethal genetic disease in the United States, 1 out of 25 Caucasians is a carrier. Characterized by build-up of extracellular fluid in the lungs and digestive tract.
chemiosmosis
This is how ATP is produced during oxidative phosphorylation. Protons only flow through the special ATP synthetase channels and transfer energy to molecules of ATP.
messenger RNA
(Also mRNA.) Carries messages directly from DNA in the nucleus to the cytoplasm during protein synthesis.
triploblastic
An animal consisting of three cell layers. This includes every animal more sophisticated than flatworms.
Extracted from bacteria; they cut DNA at specific recognition sequences or sites, such as GAATTC.
restriction enzymes
Lateral growth of a plant.
secondary growth
Chemicals that resist a change in pH.
buffers
hemocoels
Sinuses. Cavities in the body of insects, like grasshoppers, for exchange of nutrients and wastes.
convergent evolution
Type of evolution where unrelated species occupying the same environment and subjected to similar selective pressures show similar adaptations. The classic example is the whale (a mammal) and the fish.
peptidases
Enzymes that break down proteins into amino acids.
Family tree that indicates the phenotype of one trait being studied for every member of a family.
pedigree
mitochondrion
Cell organelle that produces ATP. Present in both plants and animals.
Special sites where replication begins in eukaryotic cells.
origins of replication
Millions of fingerlike projections that line the small intestine and absorb all nutrients that were previously released from digested food.
villus (villi, plural)
dipeptide
A molecule consisting of two amino acids.
The specific sites on DNA that restriction enzymes cut.
recognition sequences or recognition sites
Special high-energy molecule that stores energy for immediate use in the cell.
adenosine triphosphate or ATP
commensalism
Symbiotic relationship in which one organism benefits and one is not affected by the other organism (+/o).
Outermost circle of leaves around a flower that are green and closely resemble ordinary leaves.
sepals
Consists of all the organisms living in one area.
community
net primary productivity
Gross primary productivity minus the energy used by the primary producers for respiration.
Chemical produced in the liver and released from the gallbladder that emulsifies fats. It is NOT an enzyme.
bile
reproduction
Ability to generate offspring.
Relaxation of the ventricles of the heart. Normal diastolic pressure is 120 mm Hg.
diastole
biological magnification
Organisms at higher trophic levels have a greater concentration of accumulated toxins stored in their bodies that those at lower trophic levels.
denature
Characteristic of proteins; a change in shape that stops the protein from functioning.
Organisms that obtain food from decaying organic matter.
saprobes
The branch of science that uses recombinant DNA techniques for practical purposes.
biotechnology or genetic engineering
CAM
(Also crassulacean acid metabolism.) A form of photosynthesis that is an adaptation for dry conditions. These plants keep their stomates closed during the day and open at night, the reverse of how most plants behave.
Where components of ribosomes are synthesized. This is a prominent region within the nucleus of a cell that is not dividing.
nucleolus
Openings in leaves to exchange photosynthetic gases; water vapor, carbon dioxide, and oxygen.
stomates
auxins
Growth hormones in plants that are responsible for phototropism and apical dominance, the preferential growth of a plant upward (toward the sun) rather than laterally.
System of taxonomy that we use today, developed by Carl von Linne. In this system, every organism has a two-part name, like Homo sapiens.
binomial nomenclature
In primitive plants, a protective jacket of cells in which gametes and zygotes develop and which prevents drying out.
gametangia
turgor pressure
Pressure exerted when a plant cell sweats.
Organisms that thrive in environments with high salt concentrations like Utah’s Great Salt Lake.
halophiles
ovary
Swollen part of pistil of a flower that contains the ovule, where one or more ova are produced.
digestion
Enzymatic breakdown, hydrolysis, of food so it is small enough to be assimilated into the body.
adventitious roots
Roots that arise above ground; examples are aerial roots and prop roots.
angiosperms
Anthophyta or flowering plants.
One type of organic molecule. It consists of one glycerol plus three fatty acids.
lipid
leucoplast
Type of plastid that stores starch.
Modified epithelium containing chloroplasts that control the opening and closing of the stomates by a change in shape.
guard cells
carrying capacity (K)
A limit to the number of individuals that can occupy one area at a particular time.
testes (testis, singular)
Male gonads; the site of sperm formation.
oogenesis
Formation of ova by meiotic cell division.
organogenesis
Process by which cells continue to differentiate, producing organs from the three embryonic germ layers.
sister chromatids
A replicated chromosome consists of two fo these, where one is an exact copy of the other.
crassulacean acid metabolism
(Also CAM.) A form of photosynthesis that is an adaptation for dry conditions. These plants keep their stomates closed during the day and open at night, the reverse of how most plants behave.
visible spectrum
Wavelengths of light that humans can see: 380 nm to 750 nm.
uterus
Where the blastula stage of the embryo implants and develops during the nine-month gestation if fertilization occurs.
Enzymes that break down proteins into amino acids.
peptidases
Amount of energy converted to chemical energy by photosynthesis per unit in an ecosystem.
gross primary productivity
Where the blastula stage of the embryo implants and develops during the nine-month gestation if fertilization occurs.
uterus
hemophilia
An inherited disease caused by the absence of one or more proteins necessary for normal blood clotting.
autonomic nervous system
Part of the nervous system that controls automatic functions, such as heart and breathing rate.
regulation
Ability to maintain internal stability, homeostasis.
symplast
System of transport within a plant consisting of openings in cell walls called plasmodesmata.
A phenomenon in bacteria. They have the ability to transform themselves by transferring genetic factors from one bacteria cell to another.
transformation
Sign stimuli exchanged between members of the same species.
releaser
Made of microtubules, these assist in cell division.
spindle fibers
Vertical growth of a plant.
primary growth
Structures located on the tips of a gametophyte plant that produces eggs.
archegonia
final transcript
The strand of mRNA that is sent to the ribosome after processing. The final transcript is much shorter than the initial transcript.
initial transcript
Strand of mRNA before it is processed. The initial transcript is much longer than the final transcript.
Procedure that analyzes the size, shape, and number of chromosomes.
karyotype
Rapid mitotic cell division of the zygote that begins immediately after fertilization.
cleavage
Published a treatise on population growth, disease, and famine in 1798 that influenced Darwin in the development on his theory of natural selection. Malthus stated that populations tend to grow exponentially, to overpopulate, and to exceed their resources.
Malthus
reabsorption
In the nephron of the kidneys, a process by which most of the water and solutes (glucose, amino acids, and vitamins) that initially entered the tubule during filtration are transported back into the capillaries and, thus, back to the body.
Condition of an electron when it is not excited. It is in its lowest energy level.
ground state
Specialized membranes that make up the grana in chloroplasts, the site of the light-dependent reactions.
thylakoids
Microscopic air sacs in the lung where diffusion of the respiratory gases, oxygen and carbon dioxide, occurs.
alveolus (alveoli, plural)
trichomes
Tiny, spikelike projections on some leaves for protection.
Cavities in the body for exchange of fluid. Called hemocoel in grasshoppers.
sinuses
thylakoids
Specialized membranes that make up the grana in chloroplasts, the site of the light-dependent reactions.
The structure within the ovary of a flower where the ova (female gametophyte) are produced.
ovule
cotyledon
Food for the growing embryo in a dicot seed. The cells that make up the cotyledon are triploid (3n).
Intervening, noncoding sequences of DNA located between genes.
introns
The heritable material, passed from parent to offspring.
deoxyribonucleic acid or DNA
A negative ion.
anion
Vascular cylinder in a plant root.
stele
photosynthetic pigments
Chemicals that absorb light energy and use it to carry out photosynthesis. Examples are chlorophyll a, chlorophyll b, carotenoids, and phycobilins.
DNA in the nucleus that is wrapped with special proteins called histones into a visible network.
chromatin network
leukocyte
White blood cells.
accurate
Correct; not in error
Proteins that play a key role in electron transport chains in mitochondria and chloroplasts.
cytochromes
Membrane that encloses the yolk of an egg; food for the growing embryo.
yolk sac
photolysis
The process that occurs during the light-dependent reactions in which water is ripped apart to provide electrons to replace those lost by chlorophyll a. Oxygen is released.
prions
Misfolded proteins that cause mad cow disease.
gastrin
Digestive hormone that stimulates sustained secretion of gastric juice from the stomach.
Taxon (Taxa, plural)
Levels of organization in our system of classification: domain, kingdom, phylum, class, order, family, genus, and species. Domain or kingdom includes the most different organism, while species includes the most similar organisms.
Ability to generate offspring.
reproduction
villus (villi, plural)
Millions of fingerlike projections that line the small intestine and absorb all nutrients that were previously released from digested food.
molecule
The name given to two or more atoms joined by a covalent bond.
Male part of flower where sperm (pollen) is produced by meiosis. Sits atop the filament.
anther
Any change in a gene or chromosome.
mutation
Semiliquid portion of the cytoplasm.
cytosol
macroevolution
Refers to speciation, the formation of an entirely new species.
Coenzyme that shuttles protons or electrons from glycolysis and the Krebs cycle to the electron transport chain.
NAD or nicotinamide adenine dinucleotide
diffusion
The flow of molecules from a higher concentration to a lower concentration. There are two types: simple and facilitated.
An animal with a false coelom.
pseudocoelomate (An example is a roundworm.)
Also known as the citric acid cycle; the first stage of the aerobic phase of cellular respiration. It occurs in the inner matrix of mitochondria.
Krebs cycle
Structure in birds, insects, and earthworms, among others, for temporary storage of food.
crop
Cell organelle that packages and secretes substances for the cell.
golgi apparatus
Food for the growing embryo in a dicot seed. The cells that make up the cotyledon are triploid (3n).
cotyledon
chitin
A polysaccharide that makes up the exoskeleton of insects and the cell walls of fungi.
The middle layer of an embryo that develops into blood, bones, and muscle.
mesoderm
Duct that carries sperm during ejaculation from the testes to the penis.
vas deferens
A Y-shaped region where the new strands of DNA are elongating during DNA replication.
replication fork
gametangia
In primitive plants, a protective jacket of cells in which gametes and zygotes develop and which prevents drying out.
Hormone released by the pancreas that lowers blood sugar.
insulin
polarized
The condition of an axon of a nerve when it is at rest, also known as resting potential. Sodium and potassium are pumped to opposite sides of the membrane.
epididymis
Part of the testes where sperm become mobile.
saprobes
Organisms that obtain food from decaying organic matter.
An intermolecular attraction between molecules that exert a strong pull on their electrons. This attraction keeps the two strands of a DNA molecule together.
hydrogen bonding
reduction
Gain of electrons.
lysosome
Cell organelle that consists of digestive (hydrolytic) enzymes and is the principal site of intracellular digestion in the cell.
Any abnormal condition of the chromosomes.
aneuploidy
Organisms that play a vital role in the ecosystem and that recycle dead organic mater. Examples are bacteria and fungi.
decomposer
Movement of cytoplasm around the cell.
cyclosis
territory
Area an organism defends and from which other members of the community are excluded.
polymers
Molecules that are chains of repeating units; proteins and DNA are examples.
genetic drift
Change in the gene pool due chance. Two examples are the bottleneck effect and the founder effect.
When an atom absorbs energy, its electrons move to a higher energy level.
excited state
sex-influenced trait
Inheritance is influenced by the sex of the individual carrying the trait.
Moving from place to place.
locomotion
The ability of bacteria alter their genetic makeup by up taking foreign DNA from another bacterial cell and incorporating it into their own. Discovered by the scientist named Griffith.
bacterial transformation
An animal that has a true coelom, or body cavity. All chordates are coelomates.
coelomate
redox
A combination of reduction and oxidation reactions.
endoplasmic reticulum
System of transport channels within the cytoplasm of a eukaryotic cell.
polyploid
An organism with extra sets of chromosomes (3n, 4n, etc.) Commonly occurs in plants.
tRNA
(Also transfer RNA.) Shaped like a cloverleaf and carries amino acids to the mRNA at the ribosome as proteins are synthesized.
fragmentation
A single parent organism breaks into parts that regenerate into new individuals. Reproduction in sponges, planaria, and sea stars.
endoderm
The innermost layer of an embryo, which develops into the viscera or the digestive system.
A single parent organism breaks into parts that regenerate into new individuals. Reproduction in sponges, planaria, and sea stars.
fragmentation
phagocytosis
Cellular process of engulfing food and encapsulating it in a vacuole.
cleavage
Rapid mitotic cell division of the zygote that begins immediately after fertilization.
ionic bonds
Bonds between atoms that form by transferring electrons.
tracheids
Cells that, along with vessel elements, make up xylem.
The release of substances from a cell.
exocytosis
Correct; not in error
accurate
directional selection
Changing environmental conditions give rise to the type of natural selection. One phenotype replaces another in the gene pool.
The anaerobic phase of aerobic respiration. One molecule of glucose breaks apart into two molecules of pyruvate.
glycolysis
Radioactive substance that can be used to track a substance as it moves through an organism or through a metabolic pathway. They can be used research or as a diagnostic tool in medicine.
tracer
exocytosis
The release of substances from a cell.
nematocysts
Stingers found in cnidocytes of cnidarians.
Band of muscle at the top of the stomach that keeps acidified food in the stomach from backing up into the esophagus and burning it.
cardiac sphincter
geographic isolation
Separation by mountain ranges, canyons, rivers, lakes, or glaciers, may cause significant isolation.
cytokinesis
Division of the cytoplasm. In animal cells, a cleavage furrow forms down the middle of the cell as the cytoplasm pinches inward and the two daughter cells separate from each other. In plant cells, a cell plate from down the middle of the cell.
Specialized region in a plant root or stem for storage and support.
cortex
Structures within the villi that line the small intestine and that absorb fatty acids and glycerol into the lymphatic system.
lacteal
sieve tube elements
Make up phloem, along with companion cells.
Combining of small molecules or substances into larger, more complex ones.
synthesis
Refers to speciation, the formation of an entirely new species.
macroevolution
Includes all the organisms with which an organism might react in an ecosystem.
biotic factor
In the newest system of classification, all organisms are classified in one of three domains, which are further divided into kingdom, phylum, class, order, family, genus, and species.
domain
centrioles
Responsible for division of the cytoplasm in animal cells; they are not present in plant cells. They consist of 9 triplets of microtubules arranged in a circle.
Plant whose seed easily breaks in two.
dicotyledon
Having two different alleles. Example: B/b.
heterozygous hybrid
gymnosperms
Confers or cone-bearing trees.
A molecule consisting of two amino acids.
dipeptide
lacteal
Structures within the villi that line the small intestine and that absorb fatty acids and glycerol into the lymphatic system.
One of the simplest forms of learning in which an animal comes to ignore a persistent stimulus so it can go about its business.
habituation
FAD
(Also flavin adenine dinucleotide.) Coenzyme that shuttles protons and electrons from glycolysis and the Krebs cycle to the electron transport chain.
serum
Plasma without the clotting factors.
Organelles found only in plant cells; chloroplast is one example.
plastids
Throat.
pharynx
Traits carried on the X chromosome.
sex-linked
Amount of heat that must be absorbed in order for 1 gram of a substance to change its temperature by 1 degree Celsius.
specific heat
somatic cells
Body cells.
puberty
Onset of the menstrual cycle in girls and sperm production in boys.
Internal stability.
homeostasis
Also known as synthesis. Process by which molecules are bonded together to form a larger molecule with the removal of water.
dehydration synthesis
sign stimuli
Initiate a fixed action pattern.
heterozygous hybrid
Having two different alleles. Example: B/b.
Krebs cycle
Also known as the citric acid cycle; the first stage of the aerobic phase of cellular respiration. It occurs in the inner matrix of mitochondria.
Flap of cartilage in the back of the throat that directs food to the esophagus.
epiglottis
cyclosis
Movement of cytoplasm around the cell.
Loss of electrons.
oxidation
Make up phloem, along with companion cells.
sieve tube elements
Body cells.
somatic cells
hypothalamus
Major gland in the brain that is the bridge between the endocrine and nervous system.
Huntington’s disease
A degenerative inherited disease of the nervous system resulting in certain and early death. The gene that causes it is dominant.
Traditional-looking plant cell. Have a primary cell wall that is thin and flexible but lack a secondary cell wall.
parenchyma cells
semiconservative replication
The way in which DNA replicates itself. The new DNA molecule consists of one old strand and one new strand.
genome
An organism’s genetic material. The human genome consists of 3 billion base pairs of DNA and about 30,000 genes.
taxonomy
System by which we name and classify all organisms, living and extinct.
stabilizing selection
This type of natural selection eliminates the extremes and favors the more common intermediate forms.
incomplete dominance
An inheritance pattern characterized by blending of traits. An example is crossing an animal with black fur with one with white fur, producing offspring with gray fur.
Major gland in the brain that is the bridge between the endocrine and nervous system.
hypothalamus
Organisms that must take in all their nutrients.
heterotrophs
Initiate a fixed action pattern.
sign stimuli
flavin adenine dinucleotide
(Also FAD.) Coenzyme that shuttles protons and electrons from glycolysis and the Krebs cycle to the electron transport chain.
insertion
A mutation where one nucleotide inserts itself into an existing strand. This mutation can cause a frameshift.
A polysaccharide that makes up the exoskeleton of insects and the cell walls of fungi.
chitin
Long, usually thin stalk of the pistil of a flower.
style
medusa
Upside-down bowl-shaped body type.
Area an organism defends and from which other members of the community are excluded.
territory
Class of nucleotides, includes thymine and cytosine.
pyrimidines
Special molecules that assist in the editing of mRNA during RNA processing.
spliceosomes
xylem
Vessels in plants that carry water and nutrients from the soil to the rest of the plant.
polysaccharides
Molecules that consist of many monosaccharides joined together. Starch and chitin are examples.
A measure of clarity of an image seen under a microscope.
resolution
budding
Splitting off of new individuals from existing ones. How reproduction occurs in hydra.
Ability to maintain internal stability, homeostasis.
regulation
chromatin network
DNA in the nucleus that is wrapped with special proteins called histones into a visible network.
founder effect
A small population, which is not representative of the larger population, breaks away from the larger one to colonize a new area. Rare alleles may be under- or overrepresented.
Part of the chloroplasts that holds the grana.
stroma
imprinting
Learning that occurs during a sensitive or critical period in the early life of an individual and is irreversible for the length of that period.
Increase in average temperature of Earth. It is due to the greenhouse effect.
global warming
genotype
The kind of genes an organism has.
cortex
Specialized region in a plant root or stem for storage and support.
The strand of mRNA that is sent to the ribosome after processing.
final transcript
ATP
(Also called adenosine triphosphate.) Special high-energy molecule that stores energy for immediate use in the cell.
Cell shrinking, occurs when a cell is in a hypertonic environment.
plasmolysis
sinoatrial (SA) node
Pacemaker of the heart.
Type of plastid that stores pigments that are responsible for the bright colors in fruit and flowers.
chromoplasts
The process in which the DNA code is translated into an amino acid sequence and a polypeptide is formed. Occurs at the ribosome.
translation
alcohol fermentation
The process by which certain cells convert pyretic acid or pyruvate from glycolysis into ethyl alcohol and carbon dioxide in the absence of oxygen.
The theory that organisms descended from a common ancestor gradually, over a long period of time, in a linear of branching fashion.
gradualism
stamen
Male part of the flower, consists of anther and filament.
antheridia
Structures located on the tips of a gametophyte plant and that produce sperm.
Elaborate molecule that sits within neuron membranes and pumps sodium and potassium ions across the membrane.
sodium-potassium pump
Amount of time it takes for a radioactive isotope to decay to half its mass.
half-life
classical conditioning
Type of associative learning. Pavlov trained dogs to associate the sound of a bell with food. The result of this conditioning was that dogs would salivate upon merely hearing the sound of the bell even though no food was present.
nephridia
Structure in earthworms for excretion of the nitrogen waste urea.
tropic hormones
Hormones that stimulate other glands to release their hormones.
greenhouse effect
Carbon dioxide and water vapor in the air absorb much of the infrared radiation reflecting off Earth, causing the average temperature on Earth to rise.
plasma
Liquid portion of the blood.
Eohippus
A transition fossil that demonstrates that the ancient horse is an ancestor of the modern horse, Equus.
Structures that are remnants of an earlier active structure, such as the appendix. They are evidence that animals have evolved.
vestigial structures
vessel elements
Structures that, along with tracheas, make up xylem.
Platelets.
thrombocytes
isotonic
Solutions containing equal concentrations of solute.
gradualism
The theory that organisms descended from a common ancestor gradually, over a long period of time, in a linear of branching fashion.
Special proteins that wrap around DNA, forming chromatin network.
histones
osmosis
Diffusion of water across a membrane.
Plant hormones that promote stem and leaf elongation.
gibberellins
Insoluble in water.
hydrophobic (Hydrophobic substances are non polar.)
conjugation
A primitive form of sexual reproduction where individuals exchange genetic material.
thermophiles
Organisms that thrive in very high temperatures, like in the hot springs in Yellowstone Park or in deep-sea hydrothermal vents.
companion cells
Make up phloem vessels, along with sieve tube elements.
cytosol
Semiliquid portion of the cytoplasm.
The diploid (2n) generation of a plant.
sporophyte
buffers
Chemicals that resist a change in pH.
A mutation where one nucleotide is substituted for a correct one in the DNA strand.
base-pair substitution
biotic potential
The maximum rate at which a population could increase under ideal conditions.
An inheritance pattern characterized by blending of traits. An example is crossing an animal with black fur with one with white fur, producing offspring with gray fur.
incomplete dominance
Single, large root.
taproot (Like a carrot.)
Symbiotic relationship where both organisms benefit (+/+). An example is the bacteria that live in the human intestine and that produce vitamins.
mutualism
Band of muscle at the bottom of the stomach that keeps food in the stomach long enough to be digested.
pyloric sphincter
G3P
(Also glyceraldehyde-3-phosphate or PGAL.) First sugar produced by photosynthesis.
vacuoles
Organelles in cells whose function is storage.
A chromosomal fragment breaks off and reattaches to its original chromosome but in the reverse orientation.
inversion
sinuses
Cavities in the body for exchange of fluid. Called hemocoel in grasshoppers.
Phenylketonuria
An inherited disease characterized by the inability to break down the amino acid phenylalanine. Requires elimination of phenylalanine from diet, otherwise serious mental retardation will result.
ground state
Condition of an electron when it is not excited. It is in its lowest energy level.
Structures, such as a bat’s wing and a fly’s wing, that have the same function but not the same underlying structure. The similarity is merely superficial and reflects adaption to a similar environment. Analogous structures are NOT evidence of a common origin or common ancestry.
analogous structures
punctuated equilibrium
Theory that proposes that new species appear suddenly after long periods of stasis. Replaced gradualism theory in popularity.
A population whose members have the potential to interbreed in nature and produce viable, fertile offspring.
species
urethra
Tube that carries semen and urine in males. In females it carries only urine.
coelomate
An animal that has a true coelom, or body cavity. All chordates are coelomates.
amylase
Enzyme that digests starch.
pioneer organisms
The first to colonize a barren environment in primary ecological succession.
Red blood cells.
erythrocytes
gibberellins
Plant hormones that promote stem and leaf elongation.
Part of the nervous system that controls voluntary muscles.
somatic system
apoptosis
Programmed cell death.
Chromosomes other than the sex chromosomes. Humans normally have 44 in each body cell.
autosomes
Alternate forms of a gene. For example, there are two alleles for height in pea plants, tall and dwarf.
alleles
An animal consisting of three cell layers. This includes every animal more sophisticated than flatworms.
triploblastic
Innate, highly stereotypical behavior, which once begun is continued to completion, no matter how useless or silly looking.
fixed action pattern
histamine
An important chemical in the immune system that triggers vasodilation (enlargement of blood vessels), which increases blood supply to an area. Histamine is also responsible for the symptoms of the common cold.
The mutual evolutionary set of adaptations of two interacting species.
coevolution
A mutation where a piece of a gene, or chromosome, is lost.
deletion
Having less concentration of solute than another solution.
hypotonic
Organisms that thrive in very high temperatures, like in the hot springs in Yellowstone Park or in deep-sea hydrothermal vents.
thermophiles
theory of endosymbiosis
This theory states that cell organelles, like mitochondria, were once tiny, free-living prokaryotic organisms that took up permanent residence inside larger prokaryotic organisms.
Structures located on the tips of a gametophyte plant and that produce sperm.
antheridia
Cells that contain internal membranes. The opposite of prokaryotic cells.
eukaryotes
carpel
Female part of the flower, produce the female gametophytes, ova. Each carpel consists of an ovary, stigma, and style. Also called the pistil.
Plant tissue that is always dividing. An example is cambium tissue.
meristem tissue
Vessels in plants that carry water and nutrients from the soil to the rest of the plant.
xylem
The three-nucleotide sequence associated with tRNA.
anticodon
Misfolded proteins that cause mad cow disease.
prions
purines
The nucleotides adenine and guanine.
sex-linked
Traits carried on the X chromosome.
Theory that the first cells on Earth were anaerobic, heterotrophic prokaryotes.
heterotroph hypothesis
food chain
Pathway along which food is transferred from one trophic or feeding level to another.
Digestive hormone that stimulates the pancreas to release bicarbonate to neutralize acid in the duodenum.
secretin
Substance that does the dissolving.
solvent
carbon fixation
Incorporation of carbon dioxide into a sugar. It occurs during the cyclical process called the Calvin cycle.
law of independent assortment
Best demonstrated by the dihybrid cross. A cross that is carried out between two individuals hybrid for two or more traits that are not on the same chromosome – the resulting phenotype ratio is 9:3:3:1.
karyotype
Procedure that analyzes the size, shape, and number of chromosomes.
heat of vaporization
The amount of energy required to change a specified amount of liquid into a gas. Water has a high heat of vaporization.
Type of evolution where unrelated species occupying the same environment and subjected to similar selective pressures show similar adaptations. The classic example is the whale (a mammal) and the fish.
convergent evolution
Having a chromosome in triplicate instead of duplicate.
trisomy (Down syndrome is caused by trisomy of the 21st chromosome.)
gastrulation
The process by which a blastula develops into a gastrula with the formation of three embryonic layers.
antennae
(Also called accessory pigments.) Molecules that assist in photosynthesis by capturing and passing on photons of light to chlorophyll a and expanding the range of light that can be used to produce sugar. Examples are chlorophyll b and the carotenoids.
limiting factors
Those factors that limit population growth. They are divided into two categories, density-dependent and density-independent factors.
pseudopods
Means “false feet.” This is how amoeba and white blood cells move from place to place.
chorion
Membrane that lies under the shell of an egg and allows for diffusion of respiratory gases between the outside environment and the inside of the shell.
eukaryotes
Cells that contain internal membranes. The opposite of prokaryotic cells.
The maximum rate at which a population could increase under ideal conditions.
biotic potential
inversion
A chromosomal fragment breaks off and reattaches to its original chromosome but in the reverse orientation.
operant conditioning
Trial and error learning.
mRNA
(Also messenger RNA.) Carries messages directly from DNA in the nucleus to the cytoplasm during protein synthesis.
Consistes of a series of molecules within the crustal membrane of mitochondria that provides the energy to phosphorylate ADP into ATP during oxidative phosphorylation.
electron transport chain or ETC
nucleolus
Where components of ribosomes are synthesized. This is a prominent region within the nucleus of a cell that is not dividing.
coenzymes
Vitamins that assist in the normal functioning of enzymes.
law of segregation
During the formation of gametes, the traits carried on homologous chromosomes separate.
System by which we name and classify all organisms, living and extinct.
taxonomy
Enzymatic breakdown, hydrolysis, of food so it is small enough to be assimilated into the body.
digestion
yolk sac
Membrane that encloses the yolk of an egg; food for the growing embryo.
ETC
(Also electron transport chain.) Consistes of a series of molecules within the crustal membrane of mitochondria that provides the energy to phosphorylate ADP into ATP during oxidative phosphorylation
Made of the protein actin and help support the shape of the cell. They enable animal cells to form a cleavage furrow during cell division or the amoeba to move by sending out pseudopods.
microfilaments
plasmodesmata
Openings in cell walls of plants for the passage of materials from one cell to another.
Programmed cell death.
apoptosis
Organisms at higher trophic levels have a greater concentration of accumulated toxins stored in their bodies that those at lower trophic levels.
biological magnification
Molecules that are chains of repeating units.
polymers (Proteins and DNA are examples.)
Single supercontinent on ancient Earth that slowly separated into seven separate continents over the course of 150 million years. This is evidence of the theory of continental drift.
Pangaea
Gaseous plant hormone that promotes fruit ripening.
ethylene
cofactors
Minerals that assist in the normal functioning of enzymes.
metabolism
The sum total of all the life functions.
synthesis
Combining of small molecules or substances into larger, more complex ones.
The first 10 inches of small intestine. Where all digestion is completed.
duodenum
Structure in earthworms for excretion of the nitrogen waste urea.
nephridia
An inherited disease with onset early in life that is caused by lack of the enzyme necessary to break down lipids necessary for normal brain function. It is common in Ashkenazi Jews and results in seizures, blindness, and early death.
Tay-Sachs disease
cohesion tension
The attraction of like molecules to stick together. Water molecules tend to stick together because they exhibit strong cohesion tension.
An inheritance pattern where both traits show at once. In humans, a person who has 2 different genes for blood type, A and B, has type AB blood.
codominance
mutualism
Symbiotic relationship where both organisms benefit (+/+). An example is the bacteria that live in the human intestine and that produce vitamins.
Structure in the membranes of mitochondria and chloroplasts where ATP is formed.
ATP synthetase
Tube that carries semen and urine in males. In females it carries only urine.
urethra
Best demonstrated by the dihybrid cross. A cross that is carried out between two individuals hybrid for two or more traits that are not on the same chromosome – the resulting phenotype ratio is 9:3:3:1.
law of independent assortment
Plant cells that have very thick primary and secondary cell walls fortified with lignin.
sclerenchyma cells (Their function is purely support.)
Cyclical process that produces sugar. It occurs during the light-independent reactions.
Calvin cycle
gastrovascular cavity
Gastrocoel, primitive digestive cavity in hydra.
Includes all the organisms in a given area as well as the abiotic (nonliving) factors with which they interact.
ecosystem
Type of plastid that carries out photosynthesis.
chloroplasts
amnion
Membrane that encloses the embryo in protective amniotic fluid.
anticodon
The three-nucleotide sequence associated with tRNA.
Structure found in freshwater protista, like paramecia and amoeba, that pumps out excess water that diffuses inward because the organisms live in an environment that is hypotonic.
contractile vacuole
objective lens
The sense on a light microscope that is closest to the stage.
telomeres
Special nonsense nucleotide sequences (TTAGGG) located at the ends of chromosomes that repeat thousands of times. These ends protect the DNA during cell division.
gross primary productivity
Amount of energy converted to chemical energy by photosynthesis per unit in an ecosystem.
System of transport channels within the cytoplasm of a eukaryotic cell.
endoplasmic reticulum
Division of the cytoplasm. In animal cells, a cleavage furrow forms down the middle of the cell as the cytoplasm pinches inward and the two daughter cells separate from each other. In plant cells, a cell plate from down the middle of the cell.
cytokinesis
cation
A positive ion.
centromere
Specialized region of a chromosome that holds two sister chromatids together.
Organisms that contain both female and male sex organs.
hermaphrodites
Make up phloem vessels, along with sieve tube elements.
companion cells
contractile vacuole
Structure found in freshwater protista, like paramecia and amoeba, that pumps out excess water that diffuses inward because the organisms live in an environment that is hypotonic.
insulin
Hormone released by the pancreas that lowers blood sugar.
exons
Expressed sequences of DNA. DNA that codes for particular polypeptides.
Liquid portion of the blood.
plasma
DNA
The heritable material, passed from parent to offspring.
Vase-shaped body.
polyp
Trial and error learning.
operant conditioning
Cell organelle that consists of digestive (hydrolytic) enzymes and is the principal site of intracellular digestion in the cell.
lysosome
nondisjunction
An error that sometimes happens during meiosis in which homologous chromosomes fail to separate as they should.
chloroplasts
Type of plastid that carries out photosynthesis.
Pangaea
Single supercontinent on ancient Earth that slowly separated into seven separate continents over the course of 150 million years. This is evidence of the theory of continental drift.
pyrimidines
Class of nucleotides, includes thymine and cytosine.
pedigree
Family tree that indicates the phenotype of one trait being studied for every member of a family.
Stingers found in cnidocytes of cnidarians.
nematocysts
Primitive digestive cavity in hydra.
gastrovascular cavity or gastrocoel
The development of an egg without fertilization. The resulting adult is haploid.
partheonogenesis
Type of cell division for growth and repair that produces two genetically identical daughter cells with the same chromosome number as the parent cell. Consists of four phases: prophase, metaphase, anaphase, and telophase.
mitosis
A machine that spins mashed tissue so quickly that it separates the homogenate into separate pellets of different organelles.
ultracentrifuge
Loss of water from a leaf of a plant through stomates.
transpiration
The first to colonize a barren environment in primary ecological succession.
pioneer organisms
prokaryotes
Cells that have no internal membranes or internal organelles, like nuclei or mitochondria.
irritability
Ability to respond to stimuli.
cytoplasm
The entire region between the nucleus and plasma membrane.
bottleneck effect
Natural disasters such as fire, earthquake, and flood reduce the size of a population non selectively, resulting in a loss of genetic variation. The resulting population is much smaller and not representative of the original one. Certain alleles may be under or overrepresented compared with the original population.
Changing environmental conditions give rise to the type of natural selection. One phenotype replaces another in the gene pool.
directional selection
Structural RNA that is synthesized in the nucleolus. Along with proteins, it makes up the ribosome.
ribosomal RNA or rRNA
Type of associative learning. Pavlov trained dogs to associate the sound of a bell with food. The result of this conditioning was that dogs would salivate upon merely hearing the sound of the bell even though no food was present.
classical conditioning
Immunoglobins. Part of the third line of defense, the specific immune response. Each antibody molecule is a Y-shaped molecule consisting of four polypeptide chains.
antibodies
Onset of the menstrual cycle in girls and sperm production in boys.
puberty
C-4 photosynthesis
Modification for dry environments. C-4 plants exhibit modified anatomy and biochemical pathways, which enable them to minimize excessive water loss and maximize sugar production.
Minerals that assist in the normal functioning of enzymes.
cofactors
A transition fossil that demonstrates that the ancient horse is an ancestor of the modern horse, Equus.
Eohippus
biosphere
The global ecosystem.
Bonds formed between atoms where electrons are shared.
covalent bonds
Calvin cycle
Cyclical process that produces sugar. It occurs during the light-independent reactions.
covalent bonds
Bonds formed between atoms where electrons are shared.
Tay-Sachs disease
An inherited disease with onset early in life that is caused by lack of the enzyme necessary to break down lipids necessary for normal brain function. It is common in Ashkenazi Jews and results in seizures, blindness, and early death.
hypertonic
Having greater concentration of solute than another solution.
autotrophs
Organisms that make their own food.
habituation
One of the simplest forms of learning in which an animal comes to ignore a persistent stimulus so it can go about its business.
Changes in one gene pool of a population over generations.
microevolution
secondary growth
Lateral growth of a plant.
guard cells
Modified epithelium containing chloroplasts that control the opening and closing of the stomates by a change in shape.
nicotinamide adenine dinucleotide
(Also NAD.) Coenzyme that shuttles protons or electrons from glycolysis and the Krebs cycle to the electron transport chain.
Process by which cells take in specific molecules for which the cell has a specific receptor.
receptor-mediated endocytosis
The condition of an axon of a nerve when it is at rest, also known as resting potential. Sodium and potassium are pumped to opposite sides of the membrane.
polarized
Intake of nutrients.
ingestion
domain
In the newest system of classification, all organisms are classified in one of three domains, which are further divided into kingdom, phylum, class, order, family, genus, and species.
ectotherm
An animal, such as fish, amphibian, or reptile, that must use environmental energy or behavioral adaptations to its body temperature, cold-blooded.
hypotonic
Having less concentration of solute than another solution.
Threadlike structure that holds up the anther in the male part of a flower.
filament
epicotyl
Part of the embryo in a seed that becomes the upper part of the stem and leaves.
Anaerobic phase of cell respiration.
fermentation
wave of depolarization
The condition of an axon when an impulse is passing, also referred to as an action potential.
species
A population whose members have the potential to interbreed in nature and produce viable, fertile offspring.
System of transport within a plant consisting of openings in cell walls called plasmodesmata.
symplast
Attraction between molecules. One example is hydrogen bonding.
intermolecular attraction
Mendel’s first law that states that when two organisms, each homozygous (pure) for two opposing traits are crossed, the offspring will be hybrid but while exhibit only the dominant trait. The trait that remains hidden is the recessive trait.
law of dominance
gametophyte
Haploid (n) generation of a plant.
haploid
Having half the chromosome number.
deoxyribonucleic acid
(Also DNA.) The heritable material, passed from parent to offspring.
Means “false feet.” This is how amoeba and white blood cells move from place to place.
pseudopods
archegonia
Structures located on the tips of a gametophyte plant that produces eggs.
The process by which cells take in various molecules and particles by forming new vesicles made from the plasma membrane.
endocytosis
Organisms that obtain energy in a unique way by producing methane from hydrogen.
methanogens
crossing-over
A normal process in which homologous chromatids exchange genetic material. Crossover is important because it increases variation in the gametes.
Movement of particles against a gradient, from low concentration to high concentration. This always requires the expenditure of energy.
active transport
antigens
Anything that triggers an antibody response.
Roots that arise above ground; examples are aerial roots and prop roots.
adventitious roots
An important chemical in the immune system that triggers vasodilation (enlargement of blood vessels), which increases blood supply to an area. Histamine is also responsible for the symptoms of the common cold.
histamine
continental drift
The theory that states that the continents are floating and moving very slowly. Over millions of years, seven separate continents formed from one original continent Pangea.
crop
Structure in birds, insects, and earthworms, among others, for temporary storage of food.
filament
Threadlike structure that holds up the anther in the male part of a flower.
Group of individuals of one species living in one area that have the ability of interbreeding and interacting with each other.
population
extremophiles
Organisms that live in extreme environments, like methanogens, halophiles, and thermophiles. These organisms make up the domain Archaea.
Plant hormone that inhibits growth.
abscisic acid (ABA)
light-independent reactions
Part of photosynthesis that does NOT require light directly, only the products of light-dependent reactions. Sugar (PGAL) is the product.
recognition sequences or recognition sites
The specific sites on DNA that restriction enzymes cut.
coevolution
The mutual evolutionary set of adaptations of two interacting species.
One type of learning in which one stimulus becomes linked to another through experience.
associative learning
Tough polymer that is resistant to almost all kinds of environmental damage and that protects plants in a harsh terrestrial environment.
sporopollenin (It is found in the walls of spores and pollen from which it gets its name.)
transcription
The process by which DNA makes RNA.
Two related species that have made similar evolutionary adaptations after their divergence form a common ancestor.
parallel evolution
plastids
Organelles found only in plant cells; chloroplast is one example.
During the formation of gametes, the traits carried on homologous chromosomes separate.
law of segregation
Layer of tissue between two cell walls of adjacent plant cells.
middle lamella
The theory that living things emerge from nonliving or inmate objects.
spontaneous generation
The traits an organism expresses.
phenotype
Growth hormones in plants that are responsible for phototropism and apical dominance, the preferential growth of a plant upward (toward the sun) rather than laterally.
auxins
Gain of electrons.
reduction
stomates
Openings in leaves to exchange photosynthetic gases; water vapor, carbon dioxide, and oxygen.
Occurs during strenuous exercise when the body cannot keep up with the increased demand for oxygen by skeletal muscles and pyretic acid converts to lactic acid, with builds up in the muscle and causes fatigue and burning.
lactic acid fermentation
meiosis
Type of cell division in sexually reproducing organisms that produces haploid (n) gametes.
collenchyma cells
Plant cells that have unevenly thickened cell walls but lack secondary cell walls. The strings of celery consist of collenchyma cells.
Movement of alleles into or out of a population.
gene flow
resolution
A measure of clarity of an image seen under a microscope.
primary growth
Vertical growth of a plant.
decomposer
Organisms that play a vital role in the ecosystem and that recycle dead organic mater. Examples are bacteria and fungi.
Wavelengths of light that humans can see: 380 nm to 750 nm.
visible spectrum
substrate level phosphorylation
Process by which ATP is produced as a special enzyme moves a phosphate from one molecule to ADP. How energy is produced during glycolysis and the Krebs cycle.
chromoplasts
Type of plastid that stores pigments that are responsible for the bright colors in fruit and flowers.
heterotroph hypothesis
Theory that the first cells on Earth were anaerobic, heterotrophic prokaryotes.
abscisic acid (ABA)
Plant hormone that inhibits growth.
oxytocin
Hormone secreted by the posterior pituitary that stimulates the uterus and causes contractions during labor.
Sac outside the abdominal cavity that holds the testes. The cooler temperature there enables sperm to survive.
scrotum
Consist of two centrioles at right angles to each other. Important during cell division into animal cells.
centrosome
Bacteria that causes the most ulcers.
Heliobacter pylori
locomotion
Moving from place to place.
microfilaments
Made of the protein actin and help support the shape of the cell. They enable animal cells to form a cleavage furrow during cell division or the amoeba to move by sending out pseudopods.
codon
The three-nucleotide sequence associated with mRNA.
homeostasis
Internal stability.
vagina
Birth canal.
Tiny, spikelike projections on some leaves for protection.
trichomes
Formation of sperm by meiotic cell division.
spermatogenesis
Radioactive isotopes, those that are decaying as they emit particles from the nucleus.
radioisotopes
Pacemaker of the heart.
sinoatrial (SA) node
The enzyme that catalyzes the elongation of the new DNA strands during replication.
DNA polymerase
replication bubbles
Sections of DNA where the two strands separate in order to enable replication to occur rapidly. There are thousands of these bubbles along the DNA molecule, which speed up the process of replication along the giant human DNA molecule.
Part of the embryo in a seed that becomes the lower part of the stem and the roots.
hypocotyl
accessory pigments
(Also called antennae.) Molecules that assist in photosynthesis by capturing and passing on photons of light to chlorophyll a and expanding the range of light that can be used to produce sugar. Examples are chlorophyll b and the carotenoids.
Occurs when a population becomes isolated (for any reason) from the rest of the species and becomes exposed to new selective pressures, causing it to evolve into a new species. Homologous structures are evidence of divergent evolution.
divergent evolution
In the nephron of the kidneys, a process by which most of the water and solutes (glucose, amino acids, and vitamins) that initially entered the tubule during filtration are transported back into the capillaries and, thus, back to the body.
reabsorption
A mutation in one nucleotide on DNA.
point mutation (Sickle cell anemia is caused by a point mutation.)
pistils
Female part of the flower. Each pistil consists of an ovary, stigma, and style. Also called carpel.
sporopollenin
Tough polymer that is resistant to almost all kinds of environmental damage and that protects plants in a harsh terrestrial environment. It is found in the walls of spores and pollen from which it gets its name.
There are more than two allelic forms of a gene.
polygenic (Examples include height or hair color in humans. The trait exhibits a multitude of variation.)
Substance that is dissolved in a solvent.
solute
Carbon dioxide and water vapor in the air absorb much of the infrared radiation reflecting off Earth, causing the average temperature on Earth to rise.
greenhouse effect
halophiles
Organisms that thrive in environments with high salt concentrations like Utah’s Great Salt Lake.
testcross
Backcross. A technique to determine whether an individual plant or animal showing the dominant trait is homozygous dominant (BB) or hybrid (Bb). The organism of unknown genotype is crossed with a recessive individual.
aneuploidy
Any abnormal condition of the chromosomes.
polygenic
There are more than two allelic forms of a gene. Examples include height or hair color in humans. The trait exhibits a multitude of variation.
taproot
Single, large root like a carrot.
somatic system
Part of the nervous system that controls voluntary muscles.
Exact or detailed.
precision (often expressed as a degree of precision, i.e., to the hundredths.)
The process that occurs during the light-dependent reactions in which water is ripped apart to provide electrons to replace those lost by chlorophyll a. Oxygen is released.
photolysis
White blood cells.
leukocyte
mesoderm
The middle layer of an embryo that develops into blood, bones, and muscle.
Removal of metabolic waste.
egestion
ribosomal RNA
(Also rRNA.) Structural RNA that is synthesized in the nucleolus. Along with proteins, it makes up the ribosome.
Hormones that stimulate other glands to release their hormones.
tropic hormones
The most common lethal genetic disease in the United States, 1 out of 25 Caucasians is a carrier. Characterized by build-up of extracellular fluid in the lungs and digestive tract.
cystic fibrosis
endocytosis
The process by which cells take in various molecules and particles by forming new vesicles made from the plasma membrane. There are three examples: pinocytosis, phagocytosis, and receptor-mediated endocytosis.
Change in the gene pool due chance. Two examples are the bottleneck effect and the founder effect.
genetic drift
frameshift
An error in the DNA in which the entire reading frame is altered. This can be caused by an insertion or deletion.
endosperm
Food for the growing embryo in a monocot seed. The cells that make up the endosperm are triploid (3n).
parenchyma cells
Traditional-looking plant cell. Have a primary cell wall that is thin and flexible but lack a secondary cell wall.
mesoglea
The middle layer of a two-layered animal, like sponges or hydra, which holds the two layers together.
restriction enzymes
Extracted from bacteria; they cut DNA at specific recognition sequences or sites, such as GAATTC.
solvent
Substance that does the dissolving. In a solution of salt and water, the salt is the solute and the water is the solvent.
malpighian tubule
Structures in grasshoppers for removal of the nitrogenous waste uric acid.
Separation by mountain ranges, canyons, rivers, lakes, or glaciers, may cause significant isolation.
geographic isolation
menopause
Cessation of the menstrual cycle.
oxidation
Loss of electrons.
hypocotyl
Part of the embryo in a seed that becomes the lower part of the stem and the roots.
A technique to determine whether an individual plant or animal showing the dominant trait is homozygous dominant (BB) or hybrid (Bb). The organism of unknown genotype is crossed with a recessive individual.
testcross or backcross
spindle fibers
Made of microtubules, these assist in cell division.
Cellular process by which cells take in large dissolved molecules, referred to as cell drinking.
pinocytosis
Photosynthetic antennae pigments. They are orange and yellow.
carotenoids
The type of natural selection increases the numbers of extreme types in a population at the expense of intermediate forms.
disruptive selection
The amount of energy required to start a reaction.
energy of activation
A positive ion.
cation
The nucleotides adenine and guanine.
purines
Male part of the flower, consists of anther and filament.
stamen
disruptive selection
The type of natural selection increases the numbers of extreme types in a population at the expense of intermediate forms.
egestion
Removal of metabolic waste.
Animals that maintain a consistent body temperature. Examples are birds, mammals, and some reptiles.
homeotherm or endotherm
Sophisticated process in which the responses of the organism are modified as a result of experience.
learning
Gross primary productivity minus the energy used by the primary producers for respiration.
net primary productivity
gene flow
Movement of alleles into or out of a population.
Having greater concentration of solute than another solution.
hypertonic
endotherm
An animal that uses metabolic energy to maintain constant body temperature; warm-blooded.
Enzyme that digests starch.
amylase
turgid
A property of plant cells, swollen.
rhizobium
Symbiotic bacterium that lives in the nodules on roots of specific legumes and that fixes nitrogen gas from the air into a form of nitrogen the plant requires.
ultracentrifuge
A machine that spins mashed tissue so quickly that it separates the homogenate into separate pellets of different organelles.
Removal of metabolic waste.
excretion
antibodies
Immunoglobins. Part of the third line of defense, the specific immune response. Each antibody molecule is a Y-shaped molecule consisting of four polypeptide chains.
Having half the chromosome number.
haploid
A technique to determine whether an individual plant or animal showing the dominant trait is homozygous dominant (BB) or heterozygous (Bb).
backcross or testcross
cytokinins
Plant hormones that stimulate cell division and cytokinesis.
Birth canal.
vagina
Aggressive behavior.
agonistic behavior
gizzard
Structure in birds, insects, and earthworms where mechanical digestion of food occurs.
fission
Division of an organism into two new cells. Reproduction in protists.
A primitive form of sexual reproduction where individuals exchange genetic material.
conjugation
community
Consists of all the organisms living in one area.
pith
Specialized region in the root of a plant for storage.
Organisms that live in extreme environments, like methanogens, halophiles, and thermophiles. These organisms make up the domain Archaea.
extremophiles
Learning that occurs during a sensitive or critical period in the early life of an individual and is irreversible for the length of that period.
imprinting
Theory that proposes that new species appear suddenly after long periods of stasis. Replaced gradualism theory in popularity.
punctuated equilibrium
Division of an organism into two new cells. Reproduction in protists.
fission
Plasma without the clotting factors.
serum
oviduct
(Also fallopian tube.) Where fertilization occurs. After ovulation, the egg moves through the oviduct to the uterus.
Cells that house the stingers in cnidarians.
cnidocytes
alveolus (alveoli, plural)
Microscopic air sacs in the lung where diffusion of the respiratory gases, oxygen and carbon dioxide, occurs.
Male gonads; the site of sperm formation.
testes (testis, singular)
Membrane that encloses the embryo in protective amniotic fluid.
amnion
Part of the nervous system that controls automatic functions, such as heart and breathing rate.
autonomic nervous system
An organism with extra sets of chromosomes (3n, 4n, etc.)
polyploid (Commonly occurs in plants.)
stroma
Part of the chloroplasts that holds the grana.
cutin
Waxy coating ont eh leaves that helps prevent excess water loss from the plant.
light-dependent reactions
Part of photosynthesis that requires light, produces ATP, and releases oxygen.
Organism that causes disease.
pathogen
epiglottis
Flap of cartilage in the back of the throat that directs food to the esophagus.
Part of photosynthesis that requires light, produces ATP, and releases oxygen.
light-dependent reactions
The modern technique of taking DNA from two sources and combining them into one molecule or cell.
recombinant DNA
A mutation where one nucleotide inserts itself into an existing strand. This mutation can cause a frameshift.
insertion
intermolecular attraction
Attraction between molecules. One example is hydrogen bonding.
Food for the growing embryo in a monocot seed. The cells that make up the endosperm are triploid (3n).
endosperm
centrosome
Consist of two centrioles at right angles to each other. Important during cell division into animal cells.
Archaeopteryx
An intermediate fossil that shows both reptile and bird characteristics.
vestigial structures
Structures that are remnants of an earlier active structure, such as the appendix. They are evidence that animals have evolved.
transpiration
Loss of water from a leaf of a plant through stomates.
When there are more than two allelic forms of a gene. For example in humans, there are more than 2 alleles for blood type. There are A, B, and O.
multiple alleles
dicotyledon
Plant whose seed easily breaks in two.
sodium-potassium pump
Elaborate molecule that sits within neuron membranes and pumps sodium and potassium ions across the membrane.
A cell-free, automated technique by which a piece of DNA can be rapidly copied or amplified.
polymerase chain reaction (Useful in genetic engineering.)
partheonogenesis
The development of an egg without fertilization. The resulting adult is haploid.
learning
Sophisticated process in which the responses of the organism are modified as a result of experience.
biotic factor
Includes all the organisms with which an organism might react in an ecosystem.
plasmolysis
Cell shrinking, occurs when a cell is in a hypertonic environment.
Malthus
Published a treatise on population growth, disease, and famine in 1798 that influenced Darwin in the development on his theory of natural selection. Malthus stated that populations tend to grow exponentially, to overpopulate, and to exceed their resources.
hydrogen bonding
An intermolecular attraction between molecules that exert a strong pull on their electrons. This attraction keeps the two strands of a DNA molecule together.
Cells that, along with vessel elements, make up xylem.
tracheids
Inheritance is influenced by the sex of the individual carrying the trait.
sex-influenced trait
Growth of a plant toward or away from a stimulus.
tropism
Part of the embryo in a seed that becomes the upper part of the stem and leaves.
epicotyl
cnidocytes
Cells that house the stingers in cnidarians.
The attraction of like molecules to stick together. Water molecules tend to stick together because they exhibit strong cohesion tension.
cohesion tension
Symbiotic relationship in which one organism benefits and one is not affected by the other organism (+/o).
commensalism
The sense on a light microscope that is closest to the stage.
objective lens
Cells that have no internal membranes or internal organelles, like nuclei or mitochondria.
prokaryotes
An animal, such as fish, amphibian, or reptile, that must use environmental energy or behavioral adaptations to its body temperature, cold-blooded.
ectotherm
The innermost layer of an embryo, which develops into the viscera or the digestive system.
endoderm
The three-nucleotide sequence associated with mRNA.
codon
middle lamella
Layer of tissue between two cell walls of adjacent plant cells.
Heliobacter pylori
Bacteria that causes the most ulcers.
translocation
A fragment of a chromosome becomes attached to a non homologous chromosome.
pseudocoelomate
An animal with a false coelom. An example is a roundworm.
An animal that has no true coelom. Flatworms are an example.
acoelomate
Process that separates large molecules of DNA on the basis of their rate of movement through an agarose gel in an electric field.
gel electrophoresis
transformation
A phenomenon in bacteria. They have the ability to transform themselves by transferring genetic factors from one bacteria cell to another.
Hormone released by the pancreas that raises blood sugar.
glucagon
Part of photosynthesis that does NOT require light directly, only the products of light-dependent reactions. Sugar (PGAL) is the product.
light-independent reactions
colon
Another name for the large intestine.
heterotrophs
Organisms that must take in all their nutrients.
Structures that, along with tracheas, make up xylem.
vessel elements
precision
Exact or detailed; often expressed as a degree of precision, i.e., to the hundredths.
tropism
Growth of a plant toward or away from a stimulus.
biotechnology
The branch of science that uses recombinant DNA techniques for practical purposes, also called genetic engineering.
The process by which a blastula develops into a gastrula with the formation of three embryonic layers.
gastrulation
The flow of molecules from a higher concentration to a lower concentration. There are two types: simple and facilitated.
diffusion
ingestion
Intake of nutrients.
Pathway along which food is transferred from one trophic or feeding level to another.
food chain
energy of activation
The amount of energy required to start a reaction.
junk
Noncoding regions of DNA. Most of the human genome consists of noncoding regions.
A limit to the number of individuals that can occupy one area at a particular time.
carrying capacity (K)
sporophyte
The diploid (2n) generation of a plant.
This theory states that cell organelles, like mitochondria, were once tiny, free-living prokaryotic organisms that took up permanent residence inside larger prokaryotic organisms.
theory of endosymbiosis
analogous structures
Structures, such as a bat’s wing and a fly’s wing, that have the same function but not the same underlying structure. The similarity is merely superficial and reflects adaption to a similar environment. Analogous structures are NOT evidence of a common origin or common ancestry.
solute
Substance that is dissolved in a solvent.
PGAL
(Also glyceraldehyde-3-phosphate or G3P.) First sugar produced by photosynthesis.
The most important buffer in human blood. It is responsible for keeping the pH of the blood at 7.4.
bicarbonate ion
phycobilins
A photosynthetic pigment.
Plant cells that have unevenly thickened cell walls but lack secondary cell walls. The strings of celery consist of collenchyma cells.
collenchyma cells
diastole
Relaxation of the ventricles of the heart. Normal diastolic pressure is 120 mm Hg.
The process by which DNA makes RNA.
transcription
microevolution
Changes in one gene pool of a population over generations.
Nonliving factors in an ecosystem. They include: temperature, water, sunlight, wind, rocks, and soil.
abiotic factors
Formation of ova by meiotic cell division.
oogenesis
transfer RNA
(Also tRNA.) Shaped like a cloverleaf and carries amino acids to the mRNA at the ribosome as proteins are synthesized.
Those factors that limit population growth.
limiting factors (They are divided into two categories, density-dependent and density-independent factors.)
ectoderm
The outermost layer of an embryo, which develops into skin and nervous system.
bicarbonate ion
The most important buffer in human blood. It is responsible for keeping the pH of the blood at 7.4.
Openings in cell walls of plants for the passage of materials from one cell to another.
plasmodesmata
sepals
Outermost circle of leaves around a flower that are green and closely resemble ordinary leaves.
transport
Intake and distribution of substances in cells or tissue, NOT the same thing as locomotion.
Digestive hormone that stimulates sustained secretion of gastric juice from the stomach.
gastrin
bile
Chemical produced in the liver and released from the gallbladder that emulsifies fats. It is NOT an enzyme.
The name given to two or more atoms joined by a covalent bond.
molecule
Soluble in water.
hydrophilic (Hydrophilic substances are either polar or ionic.)
Organisms that make their own food.
autotrophs
cardiac sphincter
Band of muscle at the top of the stomach that keeps acidified food in the stomach from backing up into the esophagus and burning it.
An animal that uses metabolic energy to maintain constant body temperature; warm-blooded.
endotherm
Specialized region of a chromosome that holds two sister chromatids together.
centromere
Thick hollow tubes that make up the cilia, flagella, and spindle fibers.
microtubules
Ability to respond to stimuli.
irritability
fermentation
Anaerobic phase of cell respiration.
First sugar produced by photosynthesis.
glyceraldehyde-3-phosphate or PGAL or G3P
lactic acid fermentation
Occurs during strenuous exercise when the body cannot keep up with the increased demand for oxygen by skeletal muscles and pyretic acid converts to lactic acid, with builds up in the muscle and causes fatigue and burning.
vesicles
Small vacuoles.
codominance
An inheritance pattern where both traits show at once. In humans, a person who has 2 different genes for blood type, A and B, has type AB blood.
An intermediate fossil that shows both reptile and bird characteristics.
Archaeopteryx
specific heat
Amount of heat that must be absorbed in order for 1 gram of a substance to change its temperature by 1 degree Celsius.
DNA polymerase
The enzyme that catalyzes the elongation of the new DNA strands during replication.
receptor-mediated endocytosis
Process by which cells take in specific molecules for which the cell has a specific receptor.
Molecules that consist of many monosaccharides joined together.
polysaccharides (Starch and chitin are examples.)
A combination of reduction and oxidation reactions.
redox
binomial nomenclature
System of taxonomy that we use today, developed by Carl von Linne. In this system, every organism has a two-part name, like Homo sapiens.
myosin
Myofilaments that make up the thick filaments in skeletal muscle.
The same internal bone structure, although the function of each varies. Examples: the wing of a bat, the lateral fin of a whale, and the human arm. If organisms have homologous structures, they have a common ancestor.
homologous structures
style
Long, usually thin stalk of the pistil of a flower.
radioisotopes
Radioactive isotopes, those that are decaying as they emit particles from the nucleus.
Symbiotic relationship (+/-) where one organism, the parasite, benefits while the host is harmed.
parasitism
Metabolic processes that produce energy (adenosine triphosphate or ATP) for all the life processes.
respiration
Haploid (n) generation of a plant.
gametophyte
glucagon
Hormone released by the pancreas that raises blood sugar.
origins of replication
Special sites where replication begins in eukaryotic cells.
prostate gland
Large gland that secretes semen directly into the urethra
Process that provides most of the energy (ATP) produced during cell respiration.
oxidative phosphorylation
Organelles in cells whose function is storage.
vacuoles
abiotic factors
Nonliving factors in an ecosystem. They include: temperature, water, sunlight, wind, rocks, and soil.
The global ecosystem.
biosphere
mycorrhizae
Symbiotic structures consisting of the plant’s roots intermingled with the hyphae (filaments) of a fungus, which greatly increase the quantity of nutrients that a plant can absorb.
This is how ATP is produced during oxidative phosphorylation. Protons only flow through the special ATP synthetase channels and transfer energy to molecules of ATP.
chemiosmosis
homologous structures
The same internal bone structure, although the function of each varies. Examples: the wing of a bat, the lateral fin of a whale, and the human arm. If organisms have homologous structures, they HAVE a common ancestor.
excretion
Removal of metabolic waste.
Process that occurs in the nephron where nutrients and wastes diffuse from the glomerulus into Bowman’s capsule.
filtration
thrombocytes
Platelets.
The theory that states that the continents are floating and moving very slowly. Over millions of years, seven separate continents formed from one original continent Pangea.
continental drift
notochord
A rod that extends the length of the body and serves as a flexible axis. This is a characteristic of all chordates.
A rod that extends the length of the body and serves as a flexible axis. This is a characteristic of all chordates.
notochord
duodenum
The first 10 inches of small intestine. Where all digestion is completed.
point mutation
A mutation in one nucleotide on DNA. Sickle cell anemia is caused by a point mutation.
Sections of DNA where the two strands separate in order to enable replication to occur rapidly. There are thousands of these bubbles along the DNA molecule, which speed up the process of replication along the giant human DNA molecule.
replication bubbles
hydrophobic
Insoluble in water. Hydrophobic substances are non polar.
Contraction of the ventricles of the heart. Normal systolic pressure is 120 mm Hg.
systole
filtration
Process that occurs in the nephron where nutrients and wastes diffuse from the glomerulus into Bowman’s capsule.
Series of inner membranes in mitochondria where cell respiration occurs.
cristae
An inherited disease caused by the absence of one or more proteins necessary for normal blood clotting.
hemophilia
glycolysis
The anaerobic phase of aerobic respiration. One molecule of glucose breaks apart into two molecules of pyruvate.
systole
Contraction of the ventricles of the heart. Normal systolic pressure is 120 mm Hg.
Plant hormones that stimulate cell division and cytokinesis.
cytokinins
omnivores
Animals that normally eat both meat and vegetables in their diet.
Small vacuoles.
vesicles
The process by which certain cells convert pyretic acid or pyruvate from glycolysis into ethyl alcohol and carbon dioxide in the absence of oxygen.
alcohol fermentation
Strand of mRNA before it is processed
initial transcript
Bonds between atoms that form by transferring electrons.
ionic bonds
autosomes
Chromosomes other than the sex chromosomes. Humans normally have 44 in each body cell.
alleles
Alternate forms of a gene. For example, there are two alleles for height in pea plants, tall and dwarf.
The condition of an axon when an impulse is passing, also referred to as an action potential.
wave of depolarization
ethylene
Gaseous plant hormone that promotes fruit ripening.
trisomy
Having a chromosome in triplicate instead of duplicate. Down syndrome is caused by trisomy of the 21st chromosome.
rRNA
(Also ribosomal RNA.) Structural RNA that is synthesized in the nucleolus. Along with proteins, it makes up the ribosome.
fixed action pattern
Innate, highly stereotypical behavior, which once begun is continued to completion, no matter how useless or silly looking. FAP’s are initiated by external stimuli called sign stimuli.
vas deferens
Duct that carries sperm during ejaculation from the testes to the penis.
The kind of genes an organism has.
genotype
Large gland that secretes semen directly into the urethra
prostate gland
The entire region between the nucleus and plasma membrane.
cytoplasm
Cell organelle that produces ATP. Present in both plants and animals.
mitochondrion
Confers or cone-bearing trees.
gymnosperms
Where fertilization occurs. After ovulation, the egg moves through to the uterus.
fallopian tube or oviduct
respiration
Metabolic processes that produce energy (adenosine triphosphate or ATP) for all the life processes.
Natural disasters such as fire, earthquake, and flood reduce the size of a population non selectively, resulting in a loss of genetic variation. The resulting population is much smaller and not representative of the original one. Certain alleles may be under or overrepresented compared with the original population.
bottleneck effect
Another name for meiosis I, the division where homologous pairs separate.
reduction division
cytochromes
Proteins that play a key role in electron transport chains in mitochondria and chloroplasts.
Membranes within chloroplasts that consist of thylakoid membranes and are the sites of the light-dependent reactions of photosynthesis.
grana
Molecules that assist in photosynthesis by capturing and passing on photons of light to chlorophyll a and expanding the range of light that can be used to produce sugar. Examples are chlorophyll b and the carotenoids.
antennae or accessory pigments
Another name for the large intestine.
colon
Hormone secreted by the posterior pituitary that stimulates the uterus and causes contractions during labor.
oxytocin
global warming
Increase in average temperature of Earth. It is due to the greenhouse effect.
stele
Vascular cylinder in a plant root.
The middle layer of a two-layered animal, like sponges or hydra, which holds the two layers together.
mesoglea
law of dominance
Mendel’s first law that states that when two organisms, each homozygous (pure) for two opposing traits are crossed, the offspring will be hybrid but while exhibit only the dominant trait. The trait that remains hidden is the recessive trait.
The process in which homologous chromosomes pair up. This occurs during prophase I.
synapsis
Waxy coating ont eh leaves that helps prevent excess water loss from the plant.
cutin
recombinant DNA
The modern technique of taking DNA from two sources and combining them into one molecule or cell.
carotenoids
Photosynthetic antennae pigments. They are orange and yellow.
mutation
Any change in a gene or chromosome.
lipid
One type of organic molecule. It consists of one glycerol plus three fatty acids.
Special nonsense nucleotide sequences (TTAGGG) located at the ends of chromosomes that repeat thousands of times. These ends protect the DNA during cell division.
telomeres
Type of plastid that stores starch.
leucoplast
The amount of energy required to change a specified amount of liquid into a gas. Water has a high heat of vaporization.
heat of vaporization
half-life
Amount of time it takes for a radioactive isotope to decay to half its mass.
A replicated chromosome consists of two fo these, where one is an exact copy of the other.
sister chromatids
A photosynthetic pigment.
phycobilins
scrotum
Sac outside the abdominal cavity that holds the testes. The cooler temperature there enables sperm to survive.
monocotyledon
Plant whose seed does not break into two parts. An example is corn.
pharynx
Throat.
methanogens
Organisms that obtain energy in a unique way by producing methane from hydrogen.
spontaneous generation
The theory that living things emerge from nonliving or inmate objects.
Female part of the flower, produce the female gametophytes, ova. Each one consists of an ovary, stigma, and style.
carpel or pistil
deletion
A mutation where a piece of a gene, or chromosome, is lost.
Chemicals that absorb light energy and use it to carry out photosynthesis. Examples are chlorophyll a, chlorophyll b, carotenoids, and phycobilins.
photosynthetic pigments
tracer
Radioactive substance that can be used to track a substance as it moves through an organism or through a metabolic pathway. They can be used research or as a diagnostic tool in medicine.
sessile
Nonmoving.
oxidative phosphorylation
Process that provides most of the energy (ATP) produced during cell respiration.
Splitting off of new individuals from existing ones. How reproduction occurs in hydra.
budding
pyloric sphincter
Band of muscle at the bottom of the stomach that keeps food in the stomach long enough to be digested.
Responsible for division of the cytoplasm in animal cells; they are not present in plant cells. They consist of 9 triplets of microtubules arranged in a circle.
centrioles
histones
Special proteins that wrap around DNA, forming chromatin network.
Nonmoving.
sessile
actin
Protein that makes up the thin myofilaments in skeletal muscle.
Upside-down bowl-shaped body type.
medusa
base-pair substitution
A mutation where one nucleotide is substituted for a correct one in the DNA strand.
replication fork
A Y-shaped region where the new strands of DNA are elongating during DNA replication.
ATP synthetase
Structure in the membranes of mitochondria and chloroplasts where ATP is formed.
divergent evolution
Occurs when a population becomes isolated (for any reason) from the rest of the species and becomes exposed to new selective pressures, causing it to evolve into a new species. Homologous structures are evidence of divergent evolution.
reduction division
Another name for meiosis I, the division where homologous pairs separate.
Protein that makes up the thin myofilaments in skeletal muscle.
actin
releaser
Sign stimuli exchanged between members of the same species.
backcross
Testcross. A technique to determine whether an individual plant or animal showing the dominant trait is homozygous dominant (BB) or heterozygous (Bb).
Shaped like a cloverleaf and carries amino acids to the mRNA at the ribosome as proteins are synthesized.
transfer RNA or tRNA
allantois
Extra embryonic membrane in bird’s egg. It exchanges respiratory gases to and from the embryo.
fallopian tube
(Also oviduct.) Where fertilization occurs. After ovulation, the egg moves through the oviduct to the uterus.
Asexual reproduction in a plant where a piece of the root, stem, or leaf produces an entirely new plant genetically identical to the parent plant.
vegetative propagation (Examples are grafting, cuttings, bulbs, and runners.)
pinocytosis
Cellular process by which cells take in large dissolved molecules, referred to as cell drinking.
associative learning
One type of learning in which one stimulus becomes linked to another through experience.
Vitamins that assist in the normal functioning of enzymes.
coenzymes
cristae
Series of inner membranes in mitochondria where cell respiration occurs.
polyp
Vase-shaped body.
A form of photosynthesis that is an adaptation for dry conditions. These plants keep their stomates closed during the day and open at night, the reverse of how most plants behave.
crassulacean acid metabolism or CAM
Membrane that lies under the shell of an egg and allows for diffusion of respiratory gases between the outside environment and the inside of the shell.
chorion
ecosystem
Includes all the organisms in a given area as well as the abiotic (nonliving) factors with which they interact.
