Module 2- Cells and Tissues Flashcards
(41 cards)
Smallest unit of life
Cell
Parts of a cell
plasma membrane, cytoplasm and nucleus
The very thin, semi-permeable boundary of the cell which separates two of the body’s major fluid compartments; the intracellular fluid within the cells and extracellular fluid outside the cells.
Plasma membrane
Substances diffuse directly through the lipid bilayer.
Simple diffusion
The transported substance either attaches to carrier proteins in the membrane and is ferried across or moves through water-filled channel proteins.
Facilitated diffusion
The passive transport (diffusion) of a solvent, such as water, through a selectively permeable membrane, from an area of lower concentration to higher concentration (or vice versa)
Osmosis
The ability of a solution to change the shape of cells by altering the cells’ internal water volume.
Tonicity
Cells retain their normal size and shape in isotonic solutions. They have same solute/water concentration as inside cells; no net movement of water.
Isotonic solutions
Cells lose water by osmosis and shrink in a hypertonic solution. They contain a higher concentration of nonpenetrating solutes than are present inside the cells. Eg. Sea water.
Hypertonic solutions
Cells take on water until they become bloated and burst in a hypotonic solution. They contain a lower concentration of nonpenetrating solutes than are present inside cells. Eg. Pure water.
Hypotonic solutions
Requires transport proteins that combine specifically and reversibly with the transported substances. Uses energy and moves substances across membrane against concentration gradient.
Active transport
The process where solutes are moved across cell membrane against electrochemical gradients using energy supplied directly by ATP.
Primary active
Transport is driven by energy stored in concentration gradients of ions created by primary active transport pumps.
Secondary active
‘Little organs’. Specialised cellular compartments or structures; each performing its own job to maintain the life of the cell.
Organelles
The internal environment of the cell, excluding the nucleus. It is a gel-like fluid, with a variety of organelles and inclusions within it.
Cytoplasm
The viscous, semitransparent fluid in which the other cytoplasmic elements are suspended.
Cytosol
Other bodies (chemical substances) that may appear in it temporarily and aren’t part of the permanent metabolic machinery of the cell.
Inclusions
The powerhouse of a cell, function in the production of most of the ATP (energy) supply. Enclosed in a double membrane.
Mitochondria
Small organelles composed of granules of RNA which have an important role in protein synthesis.
Ribosomes
System of interconnected tubes and parallel sacs which function in the transport and networking of molecules. 2 types; smooth & rough.
Endoplasmic Reticulum
Modifies substances produced in other parts of the cell and prepares/packages these products (protein) for secretion.
Golgi apparatus
Contains enzymes that breakdown toxic hydrogen peroxide molecules, a substance often generated in the degradation of large organic molecules.
Peroxisomes
Products of golgi apparatus and contain digestive enzymes to break down substances that need to be removed from the cell- particularly damaged organelles and pathogens.
Lysosomes
A system of organelle that work together mainly to 1) produce, degrade, store and export biological molecules, and 2) degrade potentially harmful substances.
Endomembrane system
