The study of the effects of ionizing radiation on biological tissues.
The effects of x-rays on humans is the result of interactions at the ______ _____
_____ are the building blocks of all matter
_____ are the building blocks of living matter
______ _____ was the first person to identify the cell as the biological building block in 1665
_____ ___ __________ accurately described the cell with the aid of his microscopic observations.
Anton van Leeuwenhoek
_________ & _______ showed conclusively that in all plants & animals, cells are the basic functional units of life. (this is the cell theory)
Schneider & Schwann
The cell theory
1. All living organisms are composed of cells
2. Cells arise from pre-existing cells
3. The cell is the basic unit of life
In 1953 ______ & _____ described the structure of DNA.
Watson & Crick
In the year 2000, this project resulted in the precise mapping of the 40,000 human genes?
the Human Genome Project
What percentage of the body is made up of hydrogen & oxygen?
A group of cells that have the same purpose/perform the same activity?
A Group of tissues working together in close association in order to perform a specialized function?
What is the term defined as a group of organs that work together to perform a common function?
What is the term that describes the production of large molecules from smaller molecules?
What is the term that describes the process of breaking larger molecules down into smaller molecules?
Anabolism & catabolism are collectively known as?
All metabolic activity takes place in the?
This lipid-protein structure selectively allows small molecules & water to pass in & out of the cell
Proteins, lipids, carbohydrates, & nucleic acids are all calssified as what type of molecules?
An organic molecule is life supporting & contains?
What percentage of the body/cell is made up of water?
What macromolecule comprises 15% of the molecular composition of the body/cell?
What 2 macromolecules comprise 1% of the molecular composition of the body/cell?
carbohydrates & nucleic acid
What macromolecule comprises 2% of the molecular composition of the body/cell?
The chief function of this macromolecule in the human body is to provide fuel for cell metabolism.
Carbohydrates are also called saccharides (monosaccharides & disaccharides) which are?
glucose & fructose
lactose, maltose, & sucrose
____ is the radiation-sensitive target molecule
DNA has what type of structural configuration?
DNA is found where?
Besides DNA, what is the other type of nucleic acid found in the cell?
RNA is mostly located where?
Besides the cytoplasm, where else is the RNA housed?
DNA & RNA are macromolecules and are classified as what type of organic molecule?
What are the side rails of the DNA strain composed of?
The nitrogen-containing bases adenine & guanine are classified as?
The nitrogen-containing bases thymine & cytosine are classified as?
Cytosine is always paired with which nitrogen-contiaining base?
The nitrogen-containing base Adenine is always paired with what other base?
What is the name of the channels that allow the nucleus to communicate with the cytoplasm?
What is the name of the large, bean-like structure, also known as the "engines of the cell"?
Small dot-like structures that consist of 2/3 RNA & 1/3 protein are known as?
Ribosomes are the site of?
What is the name of the tubes/channels that extend from the nucleus to the cell membrane & serve as a connection to the outside of the cell?
The small pea-like sacs that are resposible for digesting cellular wates & are known as the "garbage disposals".
The act of a single cell or group of cells reproducing and multiplying in number.
What cells of the human body undergo mitosis?
Genetic/reproductive cells undergo what type of cell proliferation?
This phase of the cell cycle is made up of G1, S, & G2 phases & is known as a period of growth & rest of the cell between divisions?
This phase of the cell cycle is also known as the pre-DNA synthesis phase?
During the cell cycle, which phase is considered to be the DNA synthesis phase?
What is the name of the cell cycle phase that is considered post-DNA synthesis?
This phase starts the division process, the nucleus swells & the DNA becomes more prominent.
During this phase, chromosomes appear & are lined up along the equator of the nucleus.
During this phase, the chromosomes are split & pulled to their respective poles.
What attaches to the chromatids & pulls them to their respective poles?
The final phase of mitosis is known as _________, whish is when the nucleus starts taking shape & the cytoplasm divides equally.
Mitosis results in?
2 daughter cells
During what phase of mitosis can the process be stopped & chromosomes can be studied?
Somatic cells contain how many total chromosomes?
Meiosis is the process whereby genetic cells undergo what?
Genetic cells contain how many chromosomes?
Meiosis results in what?
23 SINGULAR chromosomes
During the second division of meiosis, some chromosomal material is exchanged among chromatids through a process called?
Human cells are most sensitive to radiation exposure during the M phase of mitosis. What is the next most sensitive phase of the cell cycle?
What is the region on a chromosome that joins two sister chromatids?
These are the most sensitive types of cells in the body
What are the names of the 2 French scientists who theorized & observed that the radiosensitivity of of living tissue varies with the maturity as well as the metabolic & proliferation rate?
Bergonie & Tribondeau
If a radiation response occurs within minutes or days after the exposure, it is classified as an?
If a radiation response occurs months or years after the exposure, it is classified as a?
What is the term that is defined as the relative constancy of the internal environment?
This term is defined as a measure of the rate at which energy is tranfered from ionizing radiation to soft tissue.
Linear Energy Transfer (LET)
What is the LET for diagnostic x-rays?
This term is defined as the ability of radiation to produce biologic damage.
Relative Biologic Effectiveness (RBE)
What is the RBE for diagnostic x-rays?
As LET _________, the ability to produce biologic damage _________.
LET & RBE have what type of relationship?
High LET is = to
Low LET is = to
______ hits are associated with high LET & they interact with the target molecule/DNA.
________ hits are associated with low LET & they interact with water molecules.
If a dose is delivered CONTINUOUSLY but at a lower dose rate, it is classified as?
If a dose is delivered in equal portions at regular INTERVALS, it is classified as?
Dose protraction & fractionation cause less effect becuase the longer irradiation time allows for?
intracellular repair & tissue recovery
This term describes the tissues response to radiation when irradiated in the oxygenated state.
Oxygen Enhancement Ratio (OER)
The presence of oxygen is going to increase the number of ________ hits.
What is the relationship between OER and LET?
high OER = low LET
List the biological factors that affect radiosensitivity:
OER, age, gender, inherent recovery, & chemical agents
Agents that enhance the effects of radiation are called?
When are humans most sensitive to radiation?
Females are more resistant to radiation than males by approximately what percent?
If a cell is exposed during interphase & it is not able to recover, then it is known as?
For chemical agents to be effective, they must be _______ at the time of exposure.
This vitamin is considered to be a radiosensitizer.
Agents that protect against the effects of radiation are called?
What type of drug group is considered to be a radioprotector?
This classification of radiation response usually follows a HIGH-dose exposure which produces an EARLY response. It can also be defined as a response that SEVERITY is increasing with the increaseing dose.
This classification of radiation response usually follows a LOW-dose exposure which produces a LATE response. It can also be defined as a response that FREQUENCY is increasing with the increasing dose.
The theory or belief that a little radiation is good for you.
On a dose-response chart, what type of curve demonstrates a directly proportional response to the increasing dose?
Diagnostic x-ray follows what type of dose-response curve?
For this type of dose-response relationship there must be a known dose.
For this type of dose-response it is assumed that a response to radiation exposure will occur at any dose regradless of size. (natural response)
S-type dose-response: when it starts to curve down is called?
________ is the most prominent type of low dose exposure cancer.
The breakage of the backbone of the long-chain macromolecule into smaller molecules is know as?
How does main-chain scission effect the viscosity?
This type of effect of radiation on macromolecules results in the production of spur-like structures.
How does cross-linking effect the viscosity?
Radiation interactions with macromolecules can also result in the disruption of chemical bonds which can produce what?
When water is irradiated, it dissociates into smaller molecules; this action is called?
radiolysis of water
What are the 2 byproducts of water radiolysis?
hydrogen peroxide & hydroperoxyl
What is the principle effect/interacrion of radiation on humans?
When the ionizing event occurs on the target molecule, the effect of radiation is?
The concept that the cell contains KEY sensitive molecules is termed?
With this process, the lethal effects of radiation are determined by observing cell survival & not cell death.
What type of cell survival model is applied to simple bacteria, enzymes, & viruses?
single target, single hit
What type of cell survival model is applied to more complex cells such as human somatic & genetic cells?
multi-target, single hit
Because radiation interacts randomly with matter, the probability of cell survival is governed by what law?
poisson distribution law
This acronym is a way of describing cellular radiosensitivity in which the dose results in a 37% survival?
What is the acronym for the mean leathal dose?
What does the acronym DQ represent?
recovery from a sub lethal dose
When looking at a cell survival chart, which type of shoulder would represent a cells ability to withstand or recover from more sublethal damage?