Learning objectives
Upon completion of this chapter, you should be able to:
1.
Identify the parts of the human cell.
2.
Describe the role of each organelle found within the cell cytoplasm.
3.
Explain the unique properties of the cell membrane.
4.
Describe three processes used by the cell to move things across the cell membrane.
5.
Outline the cell cycle, including the activities going on within the cell in each phase.
Glossary of key terms
cell cycle:
life cycle of a cell, which includes the phases G
0
, G
1
, S, G
2
and M; during the M phase, the cell divides into two identical
daughter cells
cell membrane:
lipoprotein structure that separates the interior of a cell from the external environment; regulates what can enter and
leave a cell
cytoplasm:
lies within the cell membrane; contains organelles for producing proteins, energy and so on
diffusion:
movement of solutes from an area of high concentration to an area of low concentration across a concentration gradient
endocytosis:
the process of engulfing substances and moving them into a cell by extending the cell membrane around the substance;
pinocytosis and phagocytosis are two kinds of endocytosis
endoplasmic reticulum:
fine network of interconnected channels known as cisternae found in the cytoplasm; site of chemical
reactions within the cell
exocytosis:
removal of substances from a cell by pushing them through the cell membrane
genes:
sequences of DNA that control basic cell functions and allow for cell division
Golgi apparatus:
a series of flattened sacs in the cytoplasm that prepare hormones or other substances for secretion and may produce
lysosomes and store other synthesised proteins
histocompatibility antigens:
proteins found on the surface of the cell membrane; they are determined by the genetic code and
provide cellular identity as a self-cell (i.e. a cell belonging to that individual)
lipoprotein:
structure composed of proteins and lipids; the bipolar arrangement of the lipids monitors substances passing in and out
of the cell
lysosomes:
encapsulated digestive enzymes found within a cell; they digest old or damaged areas of the cell and are responsible for
destroying the cell when the membrane ruptures and the cell dies
mitochondria:
rod-shaped organelles that produce energy within the cell in the form of adenosine triphosphate (ATP)
nucleus:
the part of a cell that contains the DNA and genetic material; regulates cellular protein production and cellular properties
organelles:
distinct structures found within the cell cytoplasm
osmosis:
movement of water from an area of low solute concentration to an area of high solute concentration in an attempt to
equalise the concentrations
phagocytosis:
the engulfing of pathogens or other particles by phagocytes (white blood cells)
pinocytosis:
the introduction of fluids into a cell by invagination of the cell membrane, followed by formation of vesicles within the cells
ribosomes:
membranous structures that are the sites of protein production within a cell
selective toxicity:
ability of a chemical or drug to kill a microorganism without harming its host. See Chapter 2
Test your current knowledge of cell physiology with a PrepU Practice Quiz!
Introduction to cell physiology
7
