life science “structure and function in organisms

Life Science“Structure and Function in

Organisms

Active Transport

The movement of molecules or ions

against a concentration

gradient, that is, from an area of

lower concentration to higher

concentration, and therefore requiring

energy.

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Adenosine Triphosphate (ATP)

The molecule that carries the energy

produced by respiration in its

third, high-energy phosphate bond; used by cells to provide energy necessary for

chemical reactions.

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Autotroph

An organism that produces its own food, including photosynthetic

organism such as green plants and

phytoplankton and chemosynthetic

organisms such as sulfur bacteria.

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Capsule

The outermost protective layer found on some prokaryotic cells. Click here to reveal the definition!

Cell Wall

A structure in plant cells that surrounds the cell membrane,

important for external cell

structure and the protection of the

cell’s contents; also present in algae

and certain bacteria.

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Cellular Respiration

The process in which carbon-rich sugar molecules react with oxygen to make energy for a cell’s use;

occurs in heterotrophs and autotrophs.Click here to reveal the definition!

Centriole

A cell structure that helps separate the contents of the nucleus during cell divisions. Click here to reveal the definition!

Chloroplast

The structure in plants that contains chlorophyll and is

the site of photosynthesis.

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Concentration Gradient

The varying levels of concentration of a substance on either side of a membrane or in an area. Click here to reveal the definition!

Cytoplasm

A jellylike material that surrounds the nucleus of a cell

and contains most of the cell’s organelles.

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Cytoskeleton

The support framework inside

the cell made up of microfilaments and

microtubules.

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Diffusion

The general process by which all materials transfer passively in and out of cells. Click here to reveal the definition!

Eukaryote

A cell that has membrane-bound organelles and generic material contained inside a nucleus. Click here to reveal the definition!

Flagella

The whiplike structures on some prokaryotic cells that help the organism move.Click here to reveal the definition!

Glucose

A six-carbon sugar that is the usual

form in which organisms process

carbohydrates.

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Golgi Apparatus

An organelle that stores, modifies, packages, and ships enzymes and other molecules. Click here to reveal the definition!

Heterotroph

An organism requiring complex organic compounds of nitrogen and carbon for metabolic synthesis; it must get its energy from plants or

animals.

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Homeostasis

Detection and maintenance of a

body’s internal environment.

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Instinct

A complex animal behavior triggered

by external stimuli.

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Lysosome

A membrane-bound organelle that digests sugars and wastes. Click here to reveal the definition!

Mitochondrion

A membrane-bound organelle that is the

site of aerobic respiration.

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Nucleoid

The bundle of fibers of DNA found within a prokaryotic cell.Click here to reveal the definition!

Nucleus

The control center of a eukaryotic cell that contains the cell’s DNA. Click here to reveal the definition!

Organ

A group of tissues that works together to complete a specific task.Click here to reveal the definition!

Organ System

A group of organs that works together

to complete a specific task.

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Organelle

A compartmentalized

structure in eukaryotic cells that performs a specific function for the cell.

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Osmosis

The passive transport of water molecules through a membrane.Click here to reveal the definition!

Passive Transport

The movement of molecules from higher concentration to lower concentration; does not

require energy.Click here to reveal the definition!

Peroxisome

A membrane-bound organelle containing enzymes that break down peroxides, which can damage

cells.Click here to reveal the definition!

Photosynthesis

The process by which plants make high energy carbohydrates in their chloroplasts from sunlight,

water, and carbon dioxide.Click here to reveal the definition!

Pili

Hollow, hairlike structures used by bacteria to attach to other cells.Click here to reveal the definition!

Plasma Membrane

A combination of lipids and proteins that separates the cell from its environment and helps regulate the

traffic of molecules between the inside and the outside of the cell.

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Prokaryote

A cell that does not have a nucleus in which its hereditary material in stored; a single-celled

organism such as bacteria.Click here to reveal the definition!

Protein Channel

A membrane passageway that

opens and closes to allow necessary

molecules to move in and out of the

cell.

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Ribosome

An organelle, made of RNA and

proteins, that is involved in protein

synthesis.

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Rough Endoplasmic Reticulum (RER)

A series of membranous sacs that are covered

with ribosomes and are an important

producer of proteins.

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Smooth Endoplasmic Reticulum (SER)

A series of membranous

tubules that assist in the synthesis of

lipids and other molecules needed

by the cell.

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Stimulus

A change in the internal or external environment, detectable by an organism or a cell within an

organism.Click here to reveal the definition!

Tissue

A group of cells that works together to

perform a task that requires many cells.

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Vacuole

A membrane-bound organelle in a cell that serves as a storage area for

materials such as water, food, and waste products;

helps to maintain cell rigidity in

plants.

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Virus

A particle consisting of DNA encased in a

protein coat that must inject its DNA into a living cell in

order to reproduce.

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