Lesson: Chapter - 11

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abiotic

Nonliving materials in the environment—such as elements, sunlight, and soil—that influence and are influenced by living (biotic) entities on the planet.

A neurotransmitter released by neurons to excite an action potential or trigger a muscle to contract.

Hydrogen ion H⁺ donors. Acids are very important in the chemical reactions of life because they are highly reactive. Acids have pH values below 7. They are the opposite of bases.

Protein filaments that, along with myosin, allow muscles to contract.

The part of an enzyme that interacts with, or binds to, a substrate.

The movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration. Because active transport involves moving the molecule against the natural flow of the concentration gradient, the process requires energy.

The evolutionary process by which ancestral forms of an organism are diversified through adaptation to new environments.

The energy storage molecule for the cell. ATP consists of an adenosine molecule bonded to three phosphate groups. Each phosphate bond contains energy; by breaking these bonds, the cell can get the energy it needs for chemical reactions. Cells build ATP during cell respiration, using the raw material of glucose.

Two glands, the adrenal cortex and adrenal medulla, located on the kidney.

A form of cell respiration requiring oxygen (as opposed to anaerobic respiration, which does not need oxygen). Aerobic respiration is much more efficient than anaerobic respiration; it produces 36 ATP for every molecule of glucose. Aerobic respiration proceeds in three stages: glycolysis, the Krebs cycle, and the electron transport chain.

A specific form or possible version of a gene having multiple versions. Alleles may be dominant or recessive.

The frequency with which a particular allele for a certain characteristic appears among all possible alleles for that characteristic in a population.

The fluctuation between the diploid (sporophyte) and haploid (gametophyte) life stages that occur in plants.

The monomer of a protein. A central carbon attached to an amino group (–NH₂), a carboxyl group (–COOH), and a hydrogen atom (–H). The fourth group is variable and defines the amino acid’s chemical identity.

A form of cell respiration that does not use oxygen (as opposed to aerobic cell respiration). Anaerobic respiration is less efficient than the aerobic variety and produces just 2 ATP per molecule of glucose. Anaerobic respiration has two stages: glycolysis and fermentation.

A trait that is morphologically and functionally similar to that of a different species but that arose from a distinct, ancestral condition.

The stage of mitosis in which sister chromosomes are separated and pulled to opposite ends of the cell by microtubules; the fourth stage of the first meiotic division (meiosis I), during which maternal and paternal homologous pairs are separated on microtubules; the fourth stage of the second meiotic division (meiosis II), during which either maternal or paternal sister chromatids are separated on microtubules.

A vascular flowering plant in which seeds are enclosed inside protective ovaries, such as fruit or flowers. Angiosperms can be monocots or dicots.

Pollen-producing structure at the top of the stamen, the male reproductive organ of flowers.

The sequence of three nucleotides on tRNA that pairs with a codon of mRNA at the A site of a ribosome during translation.

A protein coat on the surface of red blood cells; a red blood cell may have a protein coat of type A, B, or AB. If the cell has no antigens, it is called type O. The presence of a foreign antigen in a body will cause blood to clot.

The largest artery in the body; carries oxygenated blood from the left ventricle of the heart.

Literally, zone without light. The aphotic zone is part of the marine pelagic zone and begins 600 feet below the surface of the ocean. Only chemosynthetic organisms, scavengers, and predators are able to survive in this habitat.

Vessel that carries blood away from the heart and has thick, elastic, muscular walls that can dilate or contract to control blood pressure within the vessels. Blood in arteries is oxygenated, with the exception of the blood in the pulmonary artery.

The involuntary half of the peripheral nervous system. The autonomic nervous system is in two antagonistic parts: the sympathetic and parasympathetic nervous systems. Their interactions control smooth and cardiac muscle, glands, and organs and processes such as heartbeat, the movements of the digestive tract, and the contraction of the bladder.

Any chromosome that is not a sex chromosome. Humans have 44 autosomes, in 22 homologous pairs. The two sex chromosomes are the twenty-third pair of chromosomes.

An organism that can produce the organic molecules and energy necessary for life through the processes of photosynthesis or chemosynthesis. Autotrophs do not rely on other organisms for food. In a food web, autotrophs are producers.

One in a class of plant hormones that stimulates (among other things) cell elongation, secondary tissue growth, and fruit development.

An ion or compound that removes H⁺ ions from solution. Often bases are substances that release hydroxide ions (OH^–). Bases have pH values above 7. They are the opposite of acids.

An emulsifier of fats secreted by the liver and stored in the gallbladder for release in the small intestine.

Asexual reproduction found in prokaryotes in which a cell divides into two equal daughter cells by a nonmitotic process.

The amount of living matter in a given ecosystem. Because only 10 percent of energy is transferred between trophic levels, the biomass of lower trophic levels is greater than the biomass of subsequent trophic levels: biomass of producers > biomass of primary consumers > biomass of secondary consumers > biomass of tertiary consumers.

A particular geographic area with a common climate and characteristic plant and animal life. There are six major terrestrial biomes and two aquatic biomes. The six terrestrial biomes are tropical rain forest, savanna, desert, temperate deciduous forest, taiga, and tundra. The two aquatic biomes are marine and freshwater. Each biome is characterized by specific climax communities.

The liquid that carries nutrients and oxygen to the cells and carries carbon dioxide and nitrogenous wastes away. The liquid fluid of blood is called plasma. Red blood cells contain hemoglobin, an iron-containing protein that binds oxygen. White blood cells fight disease. Platelets clot to prevent extreme blood loss resulting from injury.

Rigid structures composed of living cells rooted in a matrix of calcium, phosphate salts, and collagen fibers. Bones are the primary component of most vertebrate skeletons.

The center of the central nervous system. The brain coordinates the processes of the body. It is composed of various distinct regions, all of which have different functions, including the cerebrum, cerebellum, medulla oblongata, and hypothalamus.

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