Cell Structures
Relative large organelle found in eukaryotic cells, but absent from prokaryotic cells; contains the cells DNA and therefore controls the activities of the cell; it is surrounded by two membranes which together form the nuclear envelope
What is the nucleus?
The contents of the cell excluding the nucleus
What is cytoplasm?
The production of organic substances from inorganic ones, using energy from light
What is photosynthesis?
A functionally and structural part of the cell; e.g. a ribosome or mitochondria, separated from the cytoplasm by compartmentalization
What are organelles?
A very thin membrane (about 7 nm in diameter) surrounding all cells; it is partially permeable and controls the exchange of materials between the cell and its environment
What is the cell surface (plasma ) membrane?
In the nucleus of the cells of eukaryotes, a structure made of tightly coiled chromatin (DNA, proteins and RNA) visible during cell division; the term ‘circular DNA’ is now also commonly used for the circular strand of DNA present in a prokaryotic cell
What are chromosomes?
A wall surrounding prokaryote, plant and fungal cells; the wall contains a strengthening material which protects the cell from mechanical damage, supports it and prevents it from bursting by osmosis if the cell is surrounded by a solution with a higher water potential made of cellulose, freely permeable, found in plant cells
What is the cell wall?
A spherical organelle found in eukaryotic cells; it contains digestive (hydrolytic) enzymes and has a variety of destructive functions, such as removal of old cell organelles
What are lysosomes?
Pores found in the nuclear envelope which control the exchange of materials, e.g. mRNA, between the nucleus and the cytoplasm
What are nuclear pores?
An organelle found in eukaryotic cells; a large, permanent structure is a typical feature of plant cells, where it has a variety of functions, including storage of biochemicals such as salts, sugars and waste products; temporary structures, such a phagocytic structures (also known as phagocytic vesicles), may form in animal cells
What are vacuoles?
All the living material inside a cell (cytoplasm plus nucleus)
What is protoplasm?
A tiny organelle found in large numbers in all cells; prokaryotic structures are about 20nm in diameter while eukaryotic structures are about 25nm in diameter
What are ribosomes?
The material of which chromosomes are made, consisting of DNA, proteins (histones) and small amounts of RNA; visible as patches or fibers within the nucleus when stained
What is chromatin?
A small structure, one or more of which is found in the nucleus; usually visible as a densely stained body; its function is to manufacture ribosomes using the information in its own DNA
What is the nucleolus?
A network of flattened sacs called cisternae running through the cytoplasm of eukaryotic cells; molecules, particularly proteins, can be transported through the cell inside the sacs separate from the rest of the cytoplasm; Is continuous with the outer membrane of the nuclear envelope
What is the ER?
An organelle, bounded by an envelope(i.e. Two membranes), in which photosynthesis takes place in eukaryotes
What is chloroplast?
The basic unit of living organisms. It is surrounded by a cell surface membrane and contains genetic material (DNA) and cytoplasm containing organelles
What is a cell?
The two membranes, situated close together, that surround the nucleus; the envelope is perforated with nuclear pores
What is the nuclear envelope?
Stacked of membranes inside a chloroplast
What are grana?