A living thing; anything that can carry out life processes independently
organism
The organ system whose primary function is movement and flexibility.
muscular system
One of the alternative forms of a gene that governs a characteristic, such as hair color
allele
A phospholipid layer that covers a cell's surface and acts as a barrier between the inside of a cell and the cell's environment
cell membrane
The organs that break down food so that it can be used by the body
digestive system
A genetically determined characteristic
trait
The mainly underground organ of vascular plants that holds plants in place and absorbs and stores water and minerals from the soil.
root
A specialized structure that contains the ends of sensory neurons and that responds to the specific types of stimuli.
sensory receptor
The maintenance of a constant internal state in a changing environment.
homeostasis
In eukaryotic cells, the organelle that is the site of cellular respiration, which releases energy for use by the cell
mitochondria
A group of similar cells that perform a common function.
tissue
An action that an individual carries out in response to a stimulus or to the environment.
behavior
The trasfer of pollen from the male reproductive structures to the female structures of seed plants.
pollination
The body system made up of the heart, the blood vessels, and the blood
circulatory system
In a eukaryotic cell, a membrane-bound organelle that contains the cell's DNA and has a role in processes such as growth, metabolism, and reproduction
nucleus
A haploid reproductive cell that unites with another haploid reproductive cell to form a zygote
gamete
The process by which a characteristic is passed from parent to offspring.
inheritance
An organelle found in plant and algae cells where photosynthesis occurs
chloroplast
An organism that consists of a single cell
unicellular organism
a rigid structure that surrounds the cell membrane and provides support to the cell
cell wall
In biology, the smallest unit that can perform all life processes.
cells
A molecule that is made up of amino acids and that is needed to build and repair body structures and to regulate processes in the body.
protein
One of the smallest bodies that are found in the cytoplasm of a cell and that are specialized to perform a specific function
organelle
A plant organ that is the main site of photosynthesis and transpiration.
leaf
A new organism that results from sexual or asexual reproduction.
offspring
In a eukaryotic cell, a membrane-bound organelle that contains the cell's DNA and that has a role in processes such as growth, metabolism, and reproduction.
nucleus
A plant embryo that is enclosed in a protective coat.
seed
A collection of organs whose primary function is to take in oxygen and expel carbon dioxide; the organs of this system include the lungs, the throat, and the passageways that lead to the lungs.
respiratory system
The system that collects and excretes nitrogenous wastes and excess water from the body in the form of urine.
excretory system
A plant structure that provides support and transports nutrients.
stem
The ability to store and recall past experience.
memory
In a eukaryotic cell, one of the structures in the nucleus that are made up of DNA and protein; in a prokaryotic cell, the main ring of DNA
chromosome
Reproduction that does not involve the union of sex cells and in which one parent produces offspring that are genetically identical to the parent
asexual reproduction
One set of instructions for an inherited trait.
gene
An organism that consists of more than one cell
multicellular organism
The structures that control the actions and reactions of the body in response to stimuli from the environment. it is formed by billions of specialized nerve cells called neurons.
nervous system
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