CH2 Human Bio GLOSSARY

glossary of key words and descriptions

Active process

A process that involves the expenditure of energy

Active Transport

the movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration, requiring energy.

Bilayer

Two layers that make up a single membrane

Cardiac muscle

The muscle that forms the wall of the heart

Carrier mediated transport

Transport of ions or molecules across a cell membrane by special carrier proteins

Carrier protein

A protein that carries substances from one side of the cell to the other

Cell membrane

A membrane that forms the outer boundary of a cell, regulating the movement of substances in and out. Also called the plasma membrane.

Cell theory

The principle that all living things are composed of cells, and the materials produced by cells and that cells are the basic unit of life.

Cellular Respiration

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water. It is essential for producing ATP, the energy currency of the cell.

Channel protein

A protein that allows ions, water and small molecules to pass through the cell membrane

Chromosome

One of the 46 rod-like structures that appear in the nucleus of a human cell at the commencement of cell division

• containing genetic material

• composed of nucleic acids and proteins

Cillia

Hair-like projections on the outside of a cell

• beat rhythmically to move the whole cell or fluids or materials/mucus across the cell surface.

• Singular: Cilium

Concentration

A measure of the number of particles in a given volume

Concentration Gradient

• A difference in concentration of a solution

• often between the inside and outside of a cell

• also called diffusion gradient

Connective tissue

Tissue providing support for body organs

Cytoplasm

the contents of a cell, excluding the nucleus; also called protoplasm

Cytoskeleton

An internal scaffolding of protein fibres within the cytoplasm of the cell

Cytosol

The liquid part of the cytoplasm of the cell

Deoxyribonucleic acid

A molecule in the nucleus of the cell that determines the type of proteins that a cell can make

Deferentially permeable membrane

Membrane that permits the passage of certain substances (usually small molecules) but restricts the passage of others (large molecules)

• also called, partially permeable, semipermeable, or selectively permeable membrane

Diffusion

• the movement of particles of a liquid or gas so that they are distributed evenly over the available space

• usually taken to mean the net movement of ions or molecules from a higher or lower concentration until they are evenly distributed

Diffusion gradient

• a gradient in the rates of diffusion of multiple groups of molecules through a medium or substrate

• The bigger the difference, the steeper the concentration gradient and the faster the molecules of a substance will diffuse.

• The direction of diffusion is said to be 'down' or 'with' the concentration gradient. Diffusion stops when the concentration of the substance is equal in both areas.

• difference in concentration of a solution, often between inside and outside of a cell

DNA

• contains the instructions needed for an organism to develop, survive and reproduce

• determines the type of proteins a cell can make

Endocytosis

the process by which a cell takes in materials by enfolding and enclosing them

• includes phagocytosis and pinocytosis

Endoplasmic reticulum

• network of membranes forming channels through the cytoplasm of the cell

• used for storage

• support

• synthesis

• transport within the cell

Epithelium

• tissue that forms the outer part of the skin and lines hollow organs and ducts

• covering tissue

• also called epithelial tissue

• plural; epithelia

Exocytosis

The process whereby the contents of the vesicles of cells are pushed out through the cell membrane

Extracellular fluid

• Fluid found outside the cells

• includes tissue fluid and blood plasma

• also called tissue fluid

Facilitated diffusion

• the process whereby proteins allow the movement of substances

• through the cell membrane

• also along the concentration gradient

Facilitated transport

• proteins in the cell membrane allow molecules to be transported across the membrane

Flagella

• A long projection from a cell

• often has the function of a moving cell

• means tail (sperm cell)

Fluid mosaic model

• pattern like structure

• currently accepted model of a cell membrane structure

• considered mosaic due to components such as:

  • phospholipids

  • carbohydrates

  • cholesterol

  • proteins

Golgi Body

• A structure in the cytoplasm of a cell consisting of a stack of flattened channels; it packages materials for secretion from the cell; sometimes called Golgi apparatus

Heart muscle

• the muscle that forms the wall of the heart

Homeostasis

• The maintenance of a relatively constant internal environment despite fluctuations in the external environment

Hydrophilic

• Loves water

• Has a tendency to be wetted by water

Hydrophobic

• water fearing

• does not mix with water

Inclusion

• Chemical substances inside a cell in the form of granules or droplets

Involuntary muscle

• Muscle that is not under our conscious control; found in walls of internal organs; also called non-striated muscle or smooth muscle

Lipid

• Large organic molecules made up of fatty acids and glycerol

Lysosome

• A small sphere formed from a Golgi body; contains digestive enzymes

Matrix

Non-cellular material between the cells of a tissue

Microfilament

Protein fibres that move materials around the cytoplasm or move the whole cell

Microtubule

Fine tubes that help to maintain the shape of the cell and hold the organelles in place

Mitochondrion

• A structure in the cytoplasm of a cell in which the aerobic stage of respiration occurs

• plural: Mitochondria

Muscle Fibres

The long cylindrical cells that make up skeletal muscles

Nervous tissue

• Tissue made up of nerve cells

• Neurons

• Glial cells

Net diffusion

• the movement of particles of a liquid or gas so that they are distributed evenly over the available space

• usually taken to mean the net movement of ions or molecules from a higher or lower concentration until they are evenly distributed

Neuron

A nerve cell

Non-striated muscle

• Muscle that is not under our conscious control; found in walls of internal organs; also called non-striated muscle or smooth muscle

Nuclear membrane

A membrane that separates the nucleus of a cell from the cytoplasm

Nuclear pore

• Gaps in the nuclear membrane

• large complex of proteins

• allows small molecules and ions to freely pass, or diffuse, into or out of the nucleus.

• Nuclear pores also allow necessary proteins to enter the nucleus from the cytoplasm if the proteins have special sequences that indicate they belong in the nucleus.

Nucleolus

A structure within a cells nucleus

• involved in protein synthesis

Nucleus

• large organelle in a cell

• contains DNA

Organ

A structure made up of different tissue working together

Organelle

Structures within the cytoplasm of a cell, each with specific functions

Organism

A living thing, with different body systems all integrated

Osmosis

• The diffusion of water molecules through a deferentially permeable membrane

• from an area of higher water concentration to an area of lower water concentration

Osmotic pressure

The pressure due to the differences in concentration on either side of a deferentially permeable membrane

Passive process

A process that occurs without any input of energy

Passive transport

The transport of substances across the cell membrane without the input of energy

Phagocytosis

The process by which a cell surrounds, and takes in, solid particles

Phospholipid

A lipid molecule that contains a phosphate group

• Has both a head (hydrophilic) and tail (hydrophobic)

Pinocytosis

The process by which cells enfold, and take in, drops of liquid

Plasma memebrane

A membrane that forms the external boundary of a cell; also called the

plasma membrane

Protein channel

A pathway through a protein in the cell membrane that allows the passage of substances across the membrane

Ribosome

Site of protein synthesis; located on the surface of rough endoplasmic reticulum in eukaryotic cells

Rough Endoplasmic Reticulum

A form of endoplasmic reticulum that is covered with ribosomes that give it a rough appearance; involved in the synthesis of proteins

Simple diffusion

• The process of substances moving along the concentration gradient in a solution or across a semipermeable membrane

• without the use of membrane proteins

Skeletal muscle

Muscle attached to bones, under voluntary control; also called voluntary or striated muscle

Smooth Endoplasmic Reticulum

• A form of endoplasmic reticulum that is involved in the synthesis of lipids

• is not covered with ribosomes

Smooth muscle

• Muscle that is not

  under our conscious control

• found in walls of internal organs

• also called non-striated muscle or smooth muscle

Solvent

A substance, often water, in which a solute is dissolved

Striated muscle

• Muscle made up of dark and light bands

• includes skeletal and cardiac muscle

System

A group of organs that work together for a common function; also called an organ system

Tissue

A group of cells that are similar in structure and function

Tissue fluid

• Fluid found in the spaces between the cells

• also called interstitial fluid or extracellular fluid

Vesicle

• A small membrane-bound cavity in the cytoplasm of a cell, smaller than a vacuole

• A sac of proteins created/packaged by the Gogli Apparatus

Vesicular transport

The transport of materials into or out of a cell in membrane-bound sacs; also called bulk transport

Voluntary muscle

Muscle under voluntary control