any of a large group of nitrogenous organic compounds that are essential constituents of living cells
"programmed cell death", self-destruction by cells for the good of the whole organism. Too little programmed cell deaths can lead to cancer, too much can cause degenerative diseases such as Alzheimer's.
a malignant tumour
organisms made up of one or more cells that have a nucleus and membrane-bound organelles
single-celled organisms that do not have a membrane-bound nucleus
a thin membrane around the cytoplasm of a cell that controls the entry of dissolved substances into and out of the cell. -phospholipid bilayer
consists mainly of water containing many dissolved substances. Organelles are dispersed within.
specialised membrane-bound structures in the cytoplasm
Microfilaments, intermediate filaments & microtubules
a microscopic network of microtubules, actin (micro)filament and intermediate filament in the cytoplasm of many living cells that gives the cell shape and coherence. Prokaryotes lack this.
substances of the plasma membrane that identify a cell as belonging to one particular organism. -usually proteins and carbohydrates
partially permeable membrane
the plasma membrane is termed this because it allows only some dissolved materials to cross.
the net movement of a substance, typically in a solution, from a region of high concentration to low concentration. -does not require energy
substances that dissolve readily in water
substances that have low water solubility or do not dissolve in water but are able to dissolve or mix uniformly with lipid. Also known as hydrophobic. Ex. alcohol and ether. Lipophilic substances can cross plasma membrane boundaries readily.
Some substances that are unable to carry out simple diffusion through the phospholipid bilayer gain free passage across a membrane with the assistance of protein channels. Molecules move from a high concentration to a low concentration.
Sometimes a protein channel alone is insufficient and a carrier molecule is required to move molecules down the concentration gradient through a protein channel. Does not require energy.
The net movement of dissovled substances into or out of cells against a concentration gradient. Because it is against a concentration gradient, it requires energy.
How solid particles are transported into a cell. ENDOCYTOSIS.
the process of bulk transport of material into a cell
Bulk transport out of cells (ie, the export of materials from the Golgi complex)
Primary cell wall
Made of cellulose, in plants, a relatively thin and flexible layer first secreted by a young cell.
Secondary cell wall
In some flowering plants, the primary cell wall in certain tissues becomes thickened and strengthened by the addition of lignin to form secondary cell walls.
The nucleus is enclosed within a double membrane in eukaryotic cells.
During the process o f cell reproduction, the DNA granules become organised into rod-shaped chromosomes.
How ATP is produced. In eukaryote cells, most of this occurs in organelles know as mitochondria, which form part of the cytoplasm.
Powerhouse of the cell, organelle that is the site of ATP (energy) production.
"protein factories", the organelles when protein production occurs. Can only be seen with an electron microscope. Not enclosed within a membrane.
Transport of substances within cells occurs through a system of channels known as the ... The channel walls are formed by membranes.
Prominent in cells that shift proteins out of cells. The structure consists of several layers of membranes. The proteins are packaged into secretory vesicles and may be stored in the cytosol before they eventually fuse with the plasma membrane
Fluid-like sacs that use their enzymes to destroy unwanted cell parts or damaged molecules from within or outside the cell. The unwanted material is enclosed by a lysosome membrane and is digested.
If H202 (Hydrogen peroxide) accumulates it is a poisonous substance