Science Terms

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Science Terms

• TAKS Objective 2

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def Diffusion

• Process by which molecules move from an area of
  high concentration to an area of low
  concentration

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def Osmosis

• The movement of water across the plasma membrane
  from an area of high concentration to an area of
  low concentration.

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def Active transport

• Process requiring energy by which cells move
  materials

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def Homeostasis

• Equilibrium of an organisms internal environment
  that maintains conditions suitable for life

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def Permeability

• Property of a plasma membrane that maintains the
  cells homeostasis

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def Cell membrane

• The boundary between the cell and its external
  environment

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def Organelles

• Internal membrane-bound structures in cells

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def Chloroplasts

• Chlorophyll containing organelle found in green
  plants and some protests

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def Endoplasmic reticulum

• Membranes forming a type of transport system

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def Mitochondrion

• Eukaryotic organelle in which food molecules are
  broken down to produce energy

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def Ribosome

• Organelle involved in protein synthesis

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def Allele

• Gene form for each variation of a trait of an
  organism

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def DNA

• Molecule coding the master copy of an organisms
  information code

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def RNA

• Single Stranded molecule that forms a copy of DNA
  for use in protein synthesis

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def Mitosis

• A part of cell division in which the nucleus
  divides, the end result is 2 identical daughter
  cells that are identical to the parent cell

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def Meiosis

• Process by which the number of chromosomes per
  cell is cut in half, used by organisms to produce
  gametes

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def Mutation

• Error or change in the DNA sequence

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def Punnet Square

• Way to find expected proportions of genotypes of
  offspring of a cross

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def Nondisjunction

• Error in meiosis in which homologous chromosomes
  fail to separate, cause of Downs Syndrome

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def Taxonomy

• Branch of biology dealing with grouping an naming
  organisms

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def Kingdom

• Broadest level of classification

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def Animals

• Multi-cellular consumers that eat other organisms
  for food

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def Archaebacteria

• Group of prokaryotes that produce their food in
  unusual ways. Usually live in extreme
  environments

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def Eubacteria

• Prokaryotes living under normal conditions

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def Fungi

• Heterotrophic eukaryotic consumers that absorb
  nutrients from decomposing wastes and dead
  organisms

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def Plants

• Stationary multicellular eukarotes that
  photosynthesize

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def Protists

• Single celled eukaryotes

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def Prokaryotes

• Single celled organisms lacking membrane bound
  organelles

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def Eukaryotes

• Organism composed of cells with organelles. May
  be unicellular or multicellular

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def Circulatory system

• Includes heart, blood vessels and blood,
  transports nutrients and wastes within the body

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def Digestive system

• Receives and breaks down food and absorbs
  nutrients

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def Endocrine system

• Controls metabolic activities of the body

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def Excretory system

• Filters the blood, collects and excretes wastes

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def Immune system

• Protects the body from infections

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def Integumentary system

• Skin and its associated structures

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def Muscular system

• Provides for movement of the body

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def Skeletal system

• Supports body

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def Nervous system

• Provides sensory function

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def Reproductive system

• Involved in the production of gametes

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def Respiratory system

• Provides area for gas exchange in the organism

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def Tissue

• A group of cells working together

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def Organ

• A group of tissues working together

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def Organ system

• A group of organs working together to maintain
  homeostasis