Units of Instruction
Unit 1 - Review of Cell Biology
Unit 2 - Basic Biological Interactions of Radiation
Unit 3 - Cellular Response to Radiation
Unit 4 - Tissue Radiation Biology
Unit 5 - Modification of Cell and Tissue Responses to Radiation
Unit 6 - Radiation Pathology
Unit 7 - Total Body Radiation Response
Unit 8 - Late Effects of Radiation
Unit 9 - Clinical Radiobiology I - Diagnostic Radiology
Unit 1 Learning Objectives
At the completion of this unit, the student will be able to:
- List the basic unit of all living matter.
- List various cell characteristics.
- Define “protoplasm.”
- List the number of elements comprising protoplasm and be able to further list four of these elements considered to be especially important.
- List what is meant by the term “universal solvent.”
- Compare inorganic with inorganic compounds.
- Define what is meant by an “isotonic solution.”
- List the importance of proteins as related to cellular functioning.
- Recognize the importance of chromosomes and genes in protein synthesis.
- Define “amino acid” and “polymerization” and explain how they are related.
- List the functions of structural and enzymatic proteins.
- List the various characteristics/functions of carbohydrates.
- List the various characteristics/functions of lipids.
- List two types of nucleic acids and explain their importance.
- List the two purines and the two pyrimadines.
- Explain the process of DNA replication.
- Explain protein synthesis as related to RNA production.
- List the two major divisions of the cell.
List various characteristics/functions of the following:
- nuclear envelope
- cell membrane
- endoplasmic reticulum
- Golgi Complex
- Explain and diagrammatically recognize various phases of mitosis and meiosis.
- Explain the various parts of the cell cycle.
Unit 1 - Review of Cell Biology
The Cell is divided into 2 major sections: the nucleus and the cytoplasm
The nucleus is contained within the cytoplasm.
The cytoplasm is the site of cell anabolism (building up of organic substances) and catabolism (breaking down of organic substances.
Nuclear Envelope: separates the nucleus from the cytoplasm
structures within the cell are termed organelles
Cell Membrane: semi-permeable membrane which monitors all exchanges of intracellular/ extracellular
- composed of lipids and proteins
- can conduct electrical impulses
Endoplasmic Reticulum (ER): -a double membrane system
-irregular network branching throughout cytoplasm
-space between membranes thought to be continuous with the nuclear
envelope (extension of the nuclear envelope)
- 2 types: Granular ER (rough) - ribosomes on
Agranular ER (smooth) - no ribosomes
Ribosomes: composed of protein and RNA in equal amounts
attached to ER or freely floating in cytoplasm
site of protein synthesis in cell
Mitochondria: powerhouse of the cell
catabolizes nutrients through a process termed oxidation
elliptical in structure
- double membrane with inward folds termed cristae
location of enzymes for energy production
the number of mitochondria in a cell is determined by the amount of energy required by
Lysosomes: contains enzymes which have the ability to digest proteins, DNA, some carbohydrates
and the cell itself
Early Theory: radiation broke the lysosome membrane, thus releasing enzymes and
Golgi Complex: a stacked set of double membrane structures with small vesicles (spheres)
acts as a packaging plant for the cell
cellular by-products are “packaged” and secreted from the cell
Nucleus: contained within the cytoplasm, but physically separated from it (semi-permeable membrane)
Nucleolus: contained within the nucleus
supervises what occurs in cell
Two cell types: somatic and germ (genetic)
- each differ in the amount of genetic material they contain
somatic cells: contain the diploid number of chromosomes
- a constant number for a given species of plant or animal
Humans = 46
Cats = 38
Dogs = 78
Gorillas = 48
germ cells: contain the haploid number of cells (1/2 the diploid number)
humans - sperm cell = 23 egg cell = 23
Mitosis: process by which somatic cells reproduce
1 parent cell divides and forms 2 daughter cells which are identical to the parent
Reproduction Process = 1. Prophase
Prophase: three phases
Early - genetic material (DNA) becomes granular and forms strands in the
Mid - chromosomes form rodlike structures which become doubled and form
46 pairs of chromatids
- separate except at a single point termed the centromere
Late - nuclear envelope breaks down
centrosome divides and migrates to opposite sides of the cell
spindle is formed
- delicate fibers which extend from the cell’ poles
and between divided centrosome now termed centrioles
Metaphase: nuclear membrane entirely breaks down
chromatids line up in the center of the cell forming the equatorial plate
2 chromatids attached to the spindle via the centromere
two chromatids begin to repel each other
Anaphase: 2 chromatids repel each other and travel to opposite sides of the cell via the spindle fibers
Telophase: completion of cell division
46 chromosomes form a new nucleus close to the centrosome
nuclear membrane forms around 46 chromosomes at end of the dividing cell
cytoplasm divides and the cell membrane pinches into two separate daughter cells
new cells are an exact duplicate of the parent cell
Interphase: resting stage - no mitotic process occurring
DNA is duplicated during this phase
a duplication of each chromosome is produced termed a chromatid
double helix unwinds - spare free, floating bases in nucleus are attracted to unmatched
bases and therefore form exact copies of the original DNA
Cell Cycle: the sequence of events in dividing cells in which an interphase period is divided into
G-1, S, G-2
G-1 and G-2 are time gaps between actual mitosis and S (DNA synthesis period)
G-O - theoretically suggested for cells which do not normally undergo division, but
retain the ability to undergo division (i.e liver cells)
Germ Cells: reproduce via meiosis - the reduction division of the nucleus in sexual organisms which
produces daughter nuclei having ½ of the number of
chromosomes as the original nucleus, process consists of
two division processes in succession (chromosomes are
duplicated only once, however)
Crossing-Over: important event occurring meiosis
- exchange of genes occurs between sister chromatids
- allows for increased genetic variability within a species