Rad Bio Quiz Flashcards
4 levels of organization of the body
Cell
Tissue
Organs
Systems
Basic structural unit of all organisms
Cell
Aggregate of similar cells and cell products forming a definite kind of structural material with a specific function in a multicellular organism
Tissue
Grouping of tissues into a distinct structure that performs a specialized task; ex: heart, lungs, stomach, etc.
Organs
Group of organs that work together and provide an organism with an advantage for survival, most complex organization in body
Ex: cardiovascular, respiratory, gastrointestinal, etc.
Systems
2 parts of cell composition
Protoplasm
Sodium and potassium
Chemical building material for all living things, 70-85% dissolved or suspended in water
Protoplasm
Protoplasm surrounding the cell nucleus where metabolic function takes place
Cytoplasm
Protoplasm inside the nucleus
Neoplasm
2 materials protoplasm consists of
Organic compounds
Inorganic materials
Compounds that contain carbon, hydrogen, and oxygen
Organic compounds
Compounds that don’t contain carbon
Inorganic materials
Water helps to modulate when there’s drastic ______ changes
Temperature
Balances osmotic pressure outside cell
Sodium
Balances osmotic pressure inside cell
Potassium
4 organic compounds
Protein
Carbohydrate (carb)
Nucleic acid
Lipid
Most elementary building blocks of cells that constitute about 15% of cell content, most plentiful of carbon-containing compounds
Protein
22 known organic compounds that are the building blocks of protein
Form protein when they combine into long, molecular chains held by peptide bonds
Amino acids
Covalent chemical bond linking two consecutive amino acid monomers along a peptide or protein chain
Peptide bonds
Molecular units that can chemically combine with other such units in a sequential manner resulting in polymers
Monomers
Process of reacting monomer molecules together in a chemical reaction to form polymer chains
Polymerization
Substance that has a molecular structure consisting chiefly or entirely of a large number of similar units bonded together
Polymers
Function as organic catalysts and control the cell’s various physiologic activities that increase cellular activity that in turn causes biochemical reactions to occur more rapids to meed the needs of cells, proper cell functioning depends on these
Enzymes
Agents that affect the rate or speed of chemical reactions without being altered
Catalysts
Any of a large group of organic compounds occurring in foods and living tissues and including sugars, starch, and cellulose; contain hydrogen and oxygen and typically can be broken down to release energy in the body
Carbohydrates/saccharides
3 categories of carbohydrates
Monosaccharides
Disaccharides
Polysaccharides
Simple sugar, glucose
Monosaccharides
Two units of a simple sugar linked together
Disaccharides
Several or many molecules of sugar
Polysaccharides
2 types of nucleic acids
Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA)
Contains all the information the cell needs to function, carries the genetic information necessary for cell respiration and regulates all cellular activity needed to direct protein synthesis
Composed of two long sugar-phosphate chains which twist around each other in a double-helix and are linked by pairs of nitrogenous organic bases
Deoxyribonucleic acid (DNA)
Single-stranded macromolecular structure that functions as a messenger between DNA and the ribosomes where synthesis occurs
Ribonucleic acid (RNA)
Structural components of cell membrane
Lipids/fats
3 functions of lipids
Storage of energy
Insulates and guards body
Assists with digestion
10 cell parts
Cell membrane Cytoplasm Endoplasmic reticulum (ER) Ribosomes Mitochondria Lysosomes Golgi complex Nuclear membrane Nucleolus Nucleus
Functions as a barricade to protect cellular contents from their environment and controls the passage of water and other materials into and out of cell; semipermeable membrane for proteins, fats, and carbs
Cell membrane
2 metabolic functions
Catabolism
Anabolism
Break down organic material to produce energy
Catabolism
Building up cell
Anabolism
Extension of nucleus, vast irregular network of tubules and vesicles spreading and interconnecting in all directions throughout the cytoplasm and enables the cell to communicate and transfer food and molecules from one part of cell to another
Endoplasmic reticulum (ER)
2 types of ER
Rough
Smooth
ER with numerous ribosomes present
Rough ER
ER without ribosomes present
Smooth ER
Synthesizes proteins
Ribosomes
Powerhouse of cell with two membranes, inner membrane produces energy for cellular activity through oxidation
Mitochondria
Any chemical reaction in which an atom loses electrons
Oxidation
Sequence of reactions by which most living cells generate energy during the process of aerobic respiration
Krebs cycle
Breaks down unwanted/foreign materials that penetrate cell through microscopic channels or are drawn in by the cell membrane (ex: bacteria) and contain enzymes for digestion
Lysosomes
Extend from nucleus to cell membrane and consist of tubes and a tiny sac near nucleus, unites large carb molecules and combines them with proteins to form glycoprotein
When cell manufactures enzymes and hormones, this concentrates, packages, and transfers them through the cell membrane so they can exit the cell, enter the bloodstream, and be carried to the areas of the body where they’re required
Golgi complex
Largest structure within nucleus where RNA is contained
Nucleolus
separation of nucleus from cytoplasm, permits selective passage of molecules from nucleus to cytoplasm and vice versa
Nuclear membrane
Heat of living cell separated from the other parts of the cell by a nuclear envelope/double-walled membrane
Spherical mass of neoplasm that contains the genetic material DNA and protein
Controls cell division and multiplication and the biochemical reactions that occur within the cell
Nucleus
Purines link with _______ only in certain specific combination
Pyrimidines
2 purines that link with 2 pyrimidines of DNA in certain specific combination
Adenine (A) - thymine (T)
Guanine (G) - cytosine (C)
Tiny rod-shaped bodies that carry genes visible during cell division joined by two arms at centromere
Chromosome
Region of a chromosome to which the microtubules of the spindle attach during cell division
Centromere
2 types of cells
Germ cells
Somatic cells
Reproductive cells
Germ cells
Mature haploid male or female germ cell that is able to unite with another of the opposite sex in sexual reproduction to form a zygote; have 23 chromosomes
Gametes (1n)
Female and male germ cells
Female: oocytes
Male: spermatozoa
Diploid cell resulting from the fusion of two haploid gametes
Zygotes (2n)
Any cell of a living organism other than the reproductive cells; diploid, 46 chromosomes
Somatic cells
Type of somatic cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth
Division usually no longer than one hour, when cell is most sensitive
Mitosis
Type of germ cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes
Meiosis
4 phases of mitosis
Prophase
Metaphase
Anaphase
Telophase
Each of the two threadlike strands into which a chromosome divides longitudinally during cell division held together by a centromere
Chromatid
Missing, extra, or irregular portion of chromosomal DNA before and after DNA synthesis
Before: chromosome aberration
After: chromatid aberration
First stage of cell division
Nucleus and chromosomes enlarge, DNA complex coils up more tightly, DNA begins to take structural form, nuclear membrane disappears, and the centrioles migrate to opposite sides of the cell and begin to regulate the formation of the mitotic spindle
Prophase
Chromosomes line up and form equilateral plate along middle of cell, nucleus disappears, and centromeres start duplicating and each chromatid attaches itself individually to the spindle
Metaphase
Chromatids repel each other and migrate to opposite ends of cell
Microtubules start shortening, pulling chromatids to respected centrioles
Cell membrane divides
Anaphase
Chromatids lose appearance and form strands, cytoplasm splits and cell membranes begin to form, and nuclear membrane and nucleolus reappear
Results in two identical daughter cells with same number of chromosomes
Telophase
Resting phase
When DNA’s synthesized, doubles amount of DNA
Interphase
5 phases of cell cycle
Mitosis G1 Synthesis (S) G2 G0/resting
Pre-DNA synthesis phase after telophase
G1
DNA replication can take up to 15 hours, most radioresistant
Synthesis (S)
DNA not replicating, 1-5 hours
G2
Accounts for cells that show no evidence of progressing through cell cycle
G0/resting
Cells in G0 that can be pulled in cell cycle if needed for reproduction
Quiescent cell
Adding or removing an electron to alter cell which becomes charged
Ionization
Biologic damage occurs as a result of ionization of atoms on essential molecules such as DNA, RNA, proteins, and enzymes that may potentially cause these molecules to become inactive or functionally altered
High LET like alpha particles and neutrons
Direct interaction
2 interactions with living cells
Direct
Indirect
Effects produced by free radicals that are created by the interaction of radiation with water molecules because 85% of cell is water
Low LET
Interaction of radiation with water results in the formation of an ion pair, hydrogen, and hydroxyl ion (H+ or OH-) and two free radicals, a hydrogen radical and a hydroxyl radical (H* and OH*)
Indirect interaction
Configuration with one or more atoms having an unpaired electron but no net electrical charge, highly interactive because the unpaired electron will pair up with another electron even if it has to break a chemical bond
Free radical
The amount of energy deposited by radiation per unit length of travel, expressed in keV per micron (keV/um)
Linear energy transfer (LET)
2 types of LET
High LET
Low LET
Particles that possess substantial mass and charge, can produce dense ionization along its path and is therefore much more likely to interact significantly with biologic tissue
Loses energy more rapidly because they produce more ionization per unit distance travelled
High LET
Electromagnetic radiation causes damage to biologic tissue through indirect action or directly induce single-strand breaks in DNA
Repair enzymes can usually reverse the damage
Sparsely ionizing, low mass and no charge
Low LET
Describes the relative capabilities of radiation with different LETs to produce a particular biologic reaction
Relative biologic effectiveness (RBE)
2 units of RBE
Rem
Sievert (Sv)
Rad x quality factor (QF)
Rem
RBE formula
Orthovoltage or dose in Gy from 250 keV/dose in Gy from another radiation source delivered under the same conditions that produce the same biologic effect
LET of radiation
Quality factor (QF)
1 Sv = ___ rem
1 rem = ___ Sv
1 rem = ___ mSv
1 Sv = 100 rem
1 rem =0.01 Sv
1 rem = 10 mSv
Max RBE
Alpha particles = 3
2 target theories
Single
Multiple
Only one target in the cell that’s associated with cell death and a single hit on this target’s, usually DNA, adequate to inactivate the target (viruses and some bacteria); helps determine population survival with high LET
Single target theory
Over one target per cell and a single hit to any of these targets is required for cell death
Not all targets are hit, some are killed while others are damaged by low doses (mammalian cells)
Determines cell population survival with low LET, how well cell repairs
Multiple target theory
4 ways RT damages DNA from least to most severe
Base damage
Single strand break/point mutation
Double strand mutation
Cross-linking
Direct action, change in nucleic acid results in loss of general information
Base damage
Energy from ionizing radiation can rupture one of DNAs chemical bonds and possible sever one of the sugar-phosphate chain side rails/strands, can result in a gene abnormality
Commonly occurs with low LET radiation but repair enzymes are often capable of reversing this damage
Single strand break/point mutation
When high LET radiation interacts with DNA, the interactions may be so closely spaced that both strands of the DNA chain are broken
Can heal or cross-link (cell damage)
Double strand break/mutation
Chemical unions created between atoms by the single sharing of one or more pairs of electrons
Most severe, chan be interstrand or with another strand
Can affect cell, pass on to daughter, or have no effect
Cross-linking
5 chromosome/chromatid structural changes from RT
Acentric/dicentric fragment Ring formation Chromosome stickiness Translocation Inversion
Chromosome with none or two centromeres, loss of information because arms of chromosome break off
None: acentric fragment
Two: dicentric fragment
Radical figures in which chromosomes aren’t obviously broken, but are linked by a tiny filament
Induced in mid to late G2, metaphase and anaphase
Result from recombinations occurring at nonrandom chromosome regions
Radiation changes protein structure in chromosome
Chromosome stickiness
Rearrangement of parts between nonhomologous chromosomes
Two complete chromosomes form
Affects germ cells because of meiosis
Translocation
Segment of a chromosome is reversed end to end
Deletion results in information loss, greater effect on germ cells
Occur when a single chromosome undergoes breakage and rearrangement within itself
Inversion
Chromosomes rejoin when broken, occurs 95% of time in human cells
No loss of general information
Restitution
Broken arms join to form a ring, while the remaining fragments join but are left without a centromere (acentric fragment)
Loss of general information and will replicate; one daughter cell has too much information and the other doesn’t have enough
Ring formation
2 types of inversion
Paracentric
Pericentric
3 affects chromosome structural changes from RT can have
Fatal
Pass on mutation/change to daughter cell
No affect
What does the consequence of translocation and inversion depend on?
Number of bases
DNA effects occur during _______, chromosome effects during _______ and _______
Interphase
Meta- and anaphase
2 things chromosome damage is affected by
Dose rate
LET
Chromosome damage _______ with dose rate and LET
Increases
Low LET produces _______ and _______, high LET causes _______ amounts of damage
Deletions and inversions
High
2 groups cell cycle studies have been done on
Asynchronous
Synchronous
Cells in all phases of cell cycle, useful for in vivo studies
Asynchronous
Cells grouped in specific stages of cell cycle useful for in vitro studies
Synchronous
Drug that syncs cells to help determine reaction to radiation dose
Hydroxurea
Delay cell from division; mitotic index altered because of exposure to ionizing radiation and division is delayed, leading to a false surge in division once it resumes
Division delay
During radiation if cell is in _______, it will complete cycle; if in _______, division delay occurs
Mitosis, G2
How does RT work in the treatment of cancer (rad bio effect)
First dose of radiation syncs cells and makes them more sensitive
Cell death before cell divides, can happen in nondividing or rapidly dividing cells
Programmed cell death usually from chemical change
Interphase death
Apoptosis
Non-mitotic death
Non-division death
3 things that can happen to irradiated cell
Division delay
Interphase death
Reproductive failure
Ratio of the number of cells in mitosis at a given time to total number of cells in the population
Mitotic index
When a percent of the cell population in mitosis is artificially increased due to division delay
Mitotic overshoot
Interphase death dose for lymphocytes and parotids
Lymphocytes = 0.5 Gy Parotids = 9 Gy
Inability of cell to undergo repeated division after irradiation
Reproductive failure
Cells that are alive but can’t divide
Nonsurvivors/dead cells
Radiosensitivity of early and late G1
Early: radioresistant
Late: moderately sensitive
Radiosensitivity of early and late S
Early: moderately sensitive
Late: most radioresistant
Radiosensitivity of early and late G2
Early: second most resistant
Late: more sensitive
Radiosensitivity of early and later mitosis
Most sensitive
Graphically represents radiation effects
Cell survival curves
Dose of radiation, amount of radiation exposure to cell
X-axis
Percent of surviving cells, non-logarithmic
Higher up = more survival
Y-axis
Dose of radiation that’s required to destroy all except 37% of cell population
Degrees of steepness/reciprocal of slope
Final/terminal portion of curve that starts approximating straight line; helps describe radiosensitivity
1/slope = 1/(rise/run)
Do/D37
Cellular damage proportional to radiation dose Measures width (not shape) of shoulder region of curve; measure of cell's population to accumulate and recover from SLD Dose at which extrapolation of terminal/lower portion of curve intersect dose axis Measures shoulder width above 100%
Dq
Quasithreshold dose
Threshold dose
Number of key targets in the cells that must be struck by the radiation to produce the response the curve demonstrates, 2-10 for mammalian cells
N/extrapolation number
Dose range of radiation that kills mammalian cells
1-2 Gy (daily fractions)
Initial exponential slope before approximated straight line, shoulder
1 Do
Do increase = ______ survival
Increases
Shallow curve/broader shoulder = _______ survival
More
Steep curve/straighter line ______ Do and more cells die
Decreases
2 things that can happen to Dq
No change; if Dq same for both exposures, cells completely repaired SLD because not enough dose, too much time between dose, environment, etc.
Gets smaller/shallower because not as much repair/cells dying
Decrease Dq = _______ repair of SLD
Decrease
Value obtained by extrapolating the exponential portion of the curve to the vertical line
Bottom of curve never reaches x-axis because we never kill all cells, some survive
N number
Definition
Target number
High LET = _______ fractions
Decrease
Increase oxygen = _______ damage/less repair
Increase
With oxygen and high LET = _______ effect, low LET with oxygen = _______ effect
No great
Drastic
Damage that can be repaired by cell, passed on; has to be determined by two radiation exposures
Same shoulders = repair
Sublethal damage (SLD)
Type of repairable damage that can be observed after a single radiation dose dependent on cells environment
Only works for sparsely ionizing radiation (low LET)
Potentially lethal damage (PLD)
Oxygen = _______ environment, hypoxic = _______ environment
Good, poor
Does a good or poor environment help cells repair?
Poor environment after radiation exposure slows down division process and gives cells more time to repair