Parts Of Simple Cells Flashcards
Lysosomes
Breaks down organelles to either be recycled or removed. Lysosomes which are in white blood cells contain enzymes that digest foreign materials such as microbes.
Ribosome
Synthesise amino acids into proteins. When as free units in the cytoplasm, they make proteins for use within the cell.
When on the outer surface of the nuclear envelope and rough endoplasmic reticulum, they manufacture proteins for export from the cell.
Endoplasmic reticulum
A series of interconnecting membranous canals in the cytoplasm which can either be rough or smooth. Smooth synthesises lipids and steroid hormones and associated with the desfoxification of some drugs. Rough is studded with ribosomes.
Golgi apparatus
Consists of stacks of closely folded flattened membranous sacs. Proteins moved from ER to Golgi apparatus and packaged into membrane-bound vesicles. They are stored, and when needed move to the plasma membrane and fuse with it, expelling the contents from the cell; Exocytosis.
Nucleus
All cells have them, apart from mature erythrocytes. Some cells, such as skeletal muscle fibres, have multiple. Largest organelle, contained within the nuclear envelope. Contains DNA as chromatin or chromosomes. RNA is also found in the nucleus.
Nucleolus
A roughly spherical structure contained within the nucleus which is involved in the synthesis and assembly of the components of ribosomes.
Mitochondria
Central to aerobic respiration. Synthesises ATP, which releases energy when it is broken down. The most active tells home the greatest number of mitochondria. E.g. Liver, muscle, spermatozoa.
Cytoskeleton
An extensive network of tiny protein fibres. Provides an internal support system for the cell as well as guiding the movement of materials around the call interior.
Microfilaments
Tiny fibres, made of actin, anchored to the innicle of the cell membrane give the cell support and shape. Actin is also involved in the contractile process in muscle cells.
Microtubules
Large, rigid proteins that give the cell mechanical support and provide the guidance tracking for internal movement of organelles and chromosomes during cell division.
Centrosome
Directs the organisation of microtubules within the cell. It consists of a pair of centrioles (small clusters of microtubules) and plays an important role in cell division.
Microvilli
A type of cell extension. Tiny projections containing microfilaments. Cover the exposed sugar of certain types of cell eg absorptive cells which line the small intestine, increasing the surface area maximising absorption of nutrients.
Cilia
A type of cell extension. Microscopic hair-like projections containing microtubules that lie along the borders of some cells. They beat in unison, moving substances along the surface. Eg, mucus moves upwards in the respiratory tract.
Flagella
A type of cell extension. Single, long whip-like projections containing microtubules which form the tails ofspermatozoa, propelling them through the female reproductive tract.
