NLN-PAX Science

Cell

the smallest living unit and the basic unit of function and structure for all living things.

Nucleus

contains the genetic information, or DNA, and controls the activities of the cell.

Plasma (cell) membrane

separates the contents of the cell from the surrounding fluid (interstitial fluid)

Semipermeable membrane

refers to the selective nature of the plasma membrane. It contains pores and channels that allow only particles of the right size or the right chemical nature to pass through.

Interstitial fluide

contains substances such as amino acids, sugars, fatty acids, hormones, neurotransmitters, and salts.

Cytoplasm

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

Organelles

(little organs) are specialized units in the cell that per form certain functions.

Mitochondria

are the locations for cellular respiration, that is, the conversion of food to energy at the cellular level. The site of energy production and of most of its ATP.

ATP (adenosine triphosphate)

the chemical the cell uses to store and transfer energy within itself.

Ribosomes

are the sites of protein synthesis in the cell

Endoplasmic reticulum (ER)

Ribosomes are attached. Serves as a means for transport within the cell and is made up of many channels. Rough endoplasmic reticulum named for the fact that it has ribosomes on its surface, serves to store and deliver the proteins made by the attached ribosomes. Smooth ER is free of ribosomes it performs varying functions in different cells, including the storage of enzymes and minerals and the folding of proteins, among other things. It is thought to be involved in the detoxification of chemicals and the metabolism of fats.

Golgi complex

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

Lysosomes

are sacs that contain strong digestive enzymes. These sacs are responsible for digesting cell structures that are no longer living or that are malfunctioning, and for digesting waste.

Cell wall

Only plant cells have them. It is responsible for the protection of the cell, the maintenance of the shape, and water balance.

Chloroplasts

contain chlorophyll, which is necessary for photosynthesis.

Vacuoles

plant cells also often large ones. Which are compartments in the cytoplasm that act as places for secretion, excretion, and storage.

Chromatin

DNA is in this loosely structured form when it is not dividing

Chromosomes

DNA is seen in condensed rod-shaped bodies when the cell is dividing

Mitosis

When cells divide, the appropriate amount of genetic material must be passed on to the new, or so-called daughter, cells. In somatic (non reproductive) cells, the new cells are identical copies of the parent cells. This is achieved by a doubling of the chromosomes prior to division. It is useful in the growth and repair of our bodies.

Zygote

the cell created by the union of a sperm and egg contains a full set of chromosomes, half from each parent.

Meiosis

Another type of division takes place in the production of gametes. It contains half of the normal number of chromosomes. It consists first of doubling of chromosomes and then two subsequent divisions. Thus the products are four daughter cells, each with half the normal number of chromosomes.

Muscle tissue

skeletal, cardiac, and smooth

Epithelial tissue

skin, the lining of organs

Nervous tissue

neurons

Connective tissue

cartilage, blood, fat, bone

Organ

performs a specialized function in the body.

Organ system

made up of a number of organs working together to carry out a major function.

Organism

the highest level of organization such as the human body

Evolution

is a theory regarding the processes that have produced the biological diversity we see today.

Natural selection

the process by which the traits that promote or enhance an organism's ability to survive and reproduce are passed on to following generations.

Adaptation

For natural selection to occur, organisms must have variations, some of which give the individuals having them an advantage in the struggle for survival. The struggle for survival occurs because each generation of a species produces more offspring than can survive. In this struggle, the individuals best suited to their environment survive ("survival of the fittest") and pass on the traits to their offspring

Fossil record

consists of remnants or traces of organisms from past geologic ages.

Vertebrates

animals with backbones

Biogeography

the geographical distribution of plants and animals

Comparative anatomy

the comparison of organisms' structures

Comparative embryology

the comparison of organisms' embryos

Molecular biology

biology at the molecular level

Taxonomy

the study of scientific classification. Species are grouped according to their similarities and differences.

King Phillip Came Over For Good Soup

Kingdom, Phylum, Class, Order, Family, Genus, Species

Kingdom

animal, plant, monera, protist, and fungi

Monera

Bacteria

Protist

Protozoa, algae, and some molds

Fungi

Molds, muchrooms, yeasts, and the like

Active transport

involves the use of energy in the form of ATP to move substances across the membrane

Passive transport

does not require energy and makes use of didffusion and filtration

Diffusion

particles move in a random manner, spreading evenly throughout an available space and moving from regions of high concentration to those of low concentration.

Osmosis

A specific type of diffusion is that of water. Water moves from an area of high water concentration (or low concentration) to an area of low water concentration (high particle concentration

Isotonic

When the solute concentration of the water is the same as that inside the cell. Thus, the amount of water that leaves the cell and the amount that enters it are equal.

Hypertonic

When the solute is more concentrated outside the cell than inside it. Water leaves the cell due to osmosis; it moves from the high-water/low-particle concentration to low-water/high-particle concentration. As a result, the cell shrinks.

Hypotonic

If the solute concentration outside the cell is lower than that inside the cell. Water flows into the cell (again high-water/low-particle concentration to low-water/high-particle concentration). If the flow continues long enough, the cell bursts.

Filtration

the movement of water and solutes through the membrane by fluid, or hydrostatic, pressure.

Autotrophs

are organisms that produce their own food from inorganic substances. Plants are these.

Heterotrophs

obtain their food by consuming plants or other animals. They are also referred to as consumers.

Primary consumers

may be herbivores or omnivores

Secondary consumers

are carnivores or omnivores that eat herbivores

Tertiary consumers

are carnivores that eat other carnivores or omnivores

Herbivores

plant eaters

Omnivores

plant and meat eaters

Carnivores

meat eaters

Trophic levels and ecosystem

These divisions, which are made on the basis of how the organism meets its nutritiional needs. The autotrophs are the most improtant trophic level in the ecosystem and are known as producers; the other levels are mad eup of the different types of consumers.

Food chain

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

Food web

The interrelationship of many food chains

Decomposers

An important role in an ecosystem is played by organisms such as bacteria and fungi, which consume nonliving organic material and release inorganic material. Thus material is recycled through the ecosystem, and inorganic material is made available to the plants.

Biotic factors

include the living parts of the ecosystem

Abiotic factors

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

Predator

Eats prey

Prey

gets eaten

Symbiosis

separate species living together

Parasitism

In which one species benefits and one species is harmed, such as a tapeworm in a human host

Commensalism

in which one species benefits and one is unaffected, such as a remora and shark

Mutualism

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

Biosphere

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

Biomes

Within the biosphere are groups of ecosystems that are common to the various types of geographical areas.

Deserts

have little precipitation and are more arid than all of the other biomes

Tropical rain forests

typically have a relatively constant temperature (68F-90F), constant daylight length throughout the year, high humidity, and abundant rain (200-400 cm/year). These forests are known for their biodiversity, having more species than any other area of the world. Trees grow very tall and there is great competition for light. Little light reaches the forest floor.

Deciduous forests

are usually found in the temperate, midlatitude regions of the world, where the air contains enough moisture to support the growth of large trees. Deciduous tress, such as oaks and maples, are ones that drop their leaves during the dry months. The temperatures in this biome can range widely from season to season.

Coniferous forests

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

Tundras

are characterized by very cold temperatures and high altitude. Here the conditions allow shrubs and bushes to grow, but no trees.

Chlorophyll

Pigment in plant cells that absorb light energy. This energy drives the synthesis of food molecules.

Photosynthesis

To produce their own organic molecules from inorganic molecules in the environment

Cuticle

Covers the stems and leaves of most plants are covered by it. Which is a waxy layer that helps prevent water loss through evaporation.

Stomates

Pores on the lower surface of the leaves that allow carbon dioxide to enter and oxygen to be released during photosynthesis without losing too much water

Angiosperms

flower in flowering plants; responsible for reproduction

Sepals

encase the flower before it blooms

Petals

useful in attracting pollinators

Stamin

Consists the filament, which supports the anther

Filament

Support the anther

Anther

where the pollen is produced

Pistil

Consists of the stigma, the style, and the ovary

Stigma

receives pollen

Style

leads to the ovary

Ovary

contains the 0vules and where fertilization occurs

Ovules

after fertilization they become seeds

Seeds

Fruit

After fertilization, the walls of the ovary thicken to protect the seed

Genes

A set of instructions that all living things possess. These determine the characteristics of an organism. These are located on chromosomes.

Alleles

Genes are found in pairs

Homozygous

An individual with two identical genes for a trait is called a purebred.

Dominance

When individuals with contrasting traits are crossed, one trait, called the dominant trait, is expressed, and the other trait, called the recessive trait, is masked.

Heterozygous

contain one allele for tall and one for short. The allele for tall (T, the dominant gene) is expressed, and the allele for short (t) is hidden.

Phenotype

appearance