NEX Science

Cell

The smallest, living functional and structural unit for all living things, composed of approximately 60% water.

Mitochondria

The locations for cellular respiration, converting food to energy at the cellular level, producing ATP.

Chromatin

Loosely structured DNA in the nucleus when the cell is not dividing.

Nucleus

Contains genetic information (DNA) and controls the activities of the cell.

Ribosome

Sites of protein synthesis in the cell; some float freely, others are attached to the endoplasmic reticulum (ER).

Chromosomes

Condensed rod-shaped bodies of DNA seen when a cell is dividing.

DNA

Deoxyribonucleic acid, the genetic information found in the nucleus.

Endoplasmic Reticulum (ER)

Serves as a means for transport within the cell, made up of many channels; can be rough (with ribosomes) or smooth (without ribosomes).

Mitosis

Type of cell division in somatic cells that results in identical copies of the parent cells, important for growth and repair.

Plasma (cell) membrane

The semipermeable membrane that separates the contents of the cell from the surrounding interstitial fluid.

Golgi complex

Modifies and packages proteins destined for use in the cell or for export from the cell.

Zygote

The cell created by the union of a sperm and egg, containing a full set of chromosomes.

Interstitial fluid

The fluid surrounding the cell, containing substances such as amino acids, sugars, fatty acids, hormones, neurotransmitters, and salts.

Lysosome

Sacs containing strong digestive enzymes, responsible for digesting waste and malfunctioning cell structures.

Meiosis

Type of cell division that takes place in the production of gametes, resulting in four daughter cells each with half the normal number of chromosomes.

Selectively permeable (semipermeable)

Refers to the selective nature of the plasma membrane, allowing only certain particles to pass through.

Cell wall

Essential for protection of the cell, maintenance of shape, and water balance in plant cells.

Cytoplasm

The fluid matrix found between the plasma membrane and the nucleus that acts as scaffolding for the organelles.

Chloroplast

Contain chlorophyll necessary for photosynthesis in plant cells.

ATP

Adenosine triphosphate, a chemical the cell uses to store and transfer energy within itself.

Organelles

Specialized units in the cell that perform certain functions; “little organs”.

Vacuole

Compartments in the cytoplasm of plant cells that act as places for secretion, excretion, and storage.

Tissue

Groups of cells with a common structure and function.

Nervous Tissue

Tissue specialized for transmitting electrical signals; includes neurons.

Organ

A structure made of various tissues combined to perform a specialized function.

Organ System

A group of organs working together to carry out a major function; the highest level of organization is the organism itself.

Muscle Tissue

Tissue responsible for movement; includes skeletal, cardiac, and smooth types.

Connective Tissue

Tissue that supports, connects, or separates different types of tissues and organs in the body.

Organism

A complete living being, such as the human body.

Epithelial Tissue

Tissue that covers the surface of the body and lines internal organs and structures.

Diffusion

The movement of particles from an area of high concentration to an area of low concentration.

Passive Transport

Does not require energy and makes use of diffusion and filtration.

Osmosis

The diffusion of water across a selectively permeable membrane from an area of high-water concentration to an area of low-water concentration.

Filtration

The movement of water and solutes through a membrane by fluid or hydrostatic pressure.

Active Transport

Involves the use of energy in the form of Adenosine Triphosphate (ATP) to move substances across the membrane.

Facilitated Transport

A form of passive transport that involves the use of membrane proteins to aid the movement of substances across the membrane.

Isotonic

A solution with the same solute concentration as that inside the cell. There is no net movement of water, so the cell neither shrinks nor swells.

Hypertonic

A solution in which the solute concentration is higher outside the cell than inside; water moves out of the cell, causing it to shrink.

Hypotonic

A solution in which the solute concentration is lower outside the cell than inside; water moves into the cell, causing it to swell and potentially burst.

Natural Selection

The process by which traits that enhance survival and reproduction are passed on to future generations.

Vertebrates

Animals with backbones; their fossil record shows an evolutionary timeline from fish to amphibians to reptiles, then birds and mammals.

Comparative Anatomy

The comparison of organisms' structures to find evidence of evolution.

Comparative Embryology

The comparison of organisms' embryos to find evidence of evolution.

Adaptation

The evolutionary process of an organism to survive in a given environment.

Biogeography

The geographical distribution of plants and animals; used as evidence for evolution.

Evolution

A theory regarding the processes that have produced the biological diversity we see today; the process by which species change over time.

Fossil Record

Remnants or traces of organisms from past geologic ages, providing a timeline for the appearance of different species.

Molecular Biology

Biology at the molecular level, used as evidence for evolution.

Taxonomy

The study of scientific classification.

Protist

A kingdom including protozoa, algae, and some molds.

Family

A taxonomic rank below order and above genus.

Kingdom

The broadest unit of classification in taxonomy.

Fungi

A kingdom including molds, mushrooms, yeasts, and the like.

Genus

A taxonomic rank below family and above species.

Animal

A kingdom comprising all animals.

Phylum

A taxonomic rank below kingdom and above class.

Species

The most specific rank in the classification system.

Plant

A kingdom including all plants.

Class

A taxonomic rank below phylum and above order.

Order

A taxonomic rank below class and above family.

Monera

A kingdom including bacteria.

Microbiology

The study of microorganisms, which are organisms too small to be seen with the naked eye. Microscopes are required for visualization.

Microorganism

Organisms that are too small to be seen by the naked eye. Some cause disease (pathogens), but many are beneficial.

Bacteria

Single-celled microorganisms with a cell wall but no organelles or nucleus. Can be spherical (cocci), rod-shaped (bacillus), or spiral (spirochetes).

Virus

Genetic material (DNA or RNA) surrounded by protein. They require a host cell to replicate and are not responsive to antibiotics.

Fungi

Microorganisms that can be single-celled or multicellular, with a nucleus and organelles surrounded by a cell membrane and rigid cell wall. Common examples include yeast, mushrooms, and mold.

Algae

Microorganisms that can be microscopic or very large, single-celled or multi-cellular, and contain a nucleus. Most live in water and use sunlight to produce food.

Protozoa

Single-celled microorganisms, like animal cells, lacking cell walls. Many are motile and ingest food particles; some obtain energy from photosynthesis.

Bacteriology

The study of bacteria.

Virology

The study of viruses.

Pathogens

Organisms that cause disease.

Autotroph

Organisms that produce their own food from inorganic substances (i.e., plants).

Heterotroph

Organisms that obtain their food by consuming plants or other animals.

Herbivore

Plant eaters.

Omnivore

Plant and meat eaters.

Carnivore

Meat eaters.

Food Chain

The path along which food is transferred from level to level.

Food Web

The interrelationship of many food chains.

Decomposer

Consume nonliving organic material and release inorganic material.

Biosphere

The entire portion of our planet that is inhabited by living things in a variety of ecosystems and communities.

Biome

Groups of ecosystems that are common to the various types of geographical areas.

Biotic

Living parts of the ecosystem.

Abiotic

Nonliving influences, such as temperature, humidity, or soil composition.

Predator

An animal that hunts other animals.

Prey

An animal that is hunted by other animals.

Symbiosis

Separate species living together.

Parasitism

One species benefits and the other species is harmed, such as a tapeworm in a human host

Commensalism

One species benefits and one is unaffected, such as a remora and shark.

Mutualism

Both species benefit, such as lichen, which is made up of a fungus and an alga and is found on a tree or rock.

Trophic Level

Levels in an ecosystem which are divided based on how an organism meets its nutritional needs

Deserts

Has little precipitation and is more arid than all of the other biomes.

Tropical Rain Forest

Typically has a relatively constant temperature (68°F-90°F), constant daylight length throughout the year, high humidity, and abundant rain (200-400 cm/year).

Deciduous Forest

Usually found in the temperate, mid-latitude regions of the world, where the air contains enough moisture to support the growth of large trees.

Coniferous Forest

Found at high and cool elevations, where the seasons consist of short summers and long, chilly winters. They are characterized by conifers, such as pine and firs, which do not shed their leaves in the cold, dry months.

Tundra

Characterized by very cold temperatures and high altitude. The conditions allow shrubs and bushes to grow, but no trees.

Primary Consumer

Consumers that eat only plants

Secondary Consumer

Carnivores (meat eaters) or omnivores that eat herbivores.

Tertiary Consumer

Carnivores that eat other carnivores or omnivores.

Ecosystem

A community of living organisms, such as animals, plants, and microorganisms, that interact with each other and their physical environment.

Photosynthesis

Process where autotrophs produce organic molecules from inorganic molecules using light energy absorbed by chlorophyll.