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Radiobiology
Radiobiology: Study of Effects of Ionizing Radiation
Question | Answer |
---|---|
the study of effects of radiation on humans | radiobiology |
suggests that low levels of radiation(<50 mGy or 5 rad)provides a protective effect by simulating molecular repair mechanisms | radiation hormesis |
at what level do all effects of radiation begin | at the atomic level of a structure |
what are the three catagories of human response to radiation | *early *late(chronic/delayed) *embryo-fetal |
what are some symptoms of early effects of radiation | *acute radiation syndrome *local tissue damage *hematologic damage(drops blood count) *cytogenic(cellular change) |
what are some symptoms of late/delayed effects of radiation | *cancer *local tissue damage *life span shortening *genetic effects |
what is a point lesion | change in genetic code |
what does prodrome mean | early symptom |
what is something if it is latent | dormant |
what are the three stages of radiation effects | *prodrome *latency *manifest |
what is something if it is acute | sudden onset |
what are the dose effects discussed | *250 mSv= drop in cell count *1500 mSv= erythema adn NVD *3000 mSv= lethal dose, 50% of exposed population will die within 30 days(LD 50/30) |
how many levels of cellular composition are there | 7 |
what is the 1st level of cellular composition | chemical or atomic |
what happens at level 1(chemical or atomic) | interactions between elements to combine into molecules |
what is a large molecule with a major function | macromolecule |
what is homeostasis | constancy of internal environment |
what is catabolism | breakdown of molecules |
what is anabolism | building up of molecules |
what is metabolism | process of building up and breaking down of molecules (catabolism and anabolism working together) |
what is the composition of a macromolecule | *80% water *15% proteins *2% lipids *1% carbohydrates *1% RNA *1% DNA |
what is the importance of water within a cell | *provides form and cell shape *maintains temperature *enters into biochemical reactions |
what is the only non-organic molecule in the body | water |
what role does protein play within a cell | *chain of 22 amino acids connected by peptide chain *provides structure and support |
what do enzymes do | allow biochemical reactions |
what do hormones do | regulate and control body functions |
what are antibodies | primary defense against antigens |
antigen | foreign substance that causes body to produce antibodies, when introduced to body |
what role do lipids play within the cell | *structural component of cell membrane *thermal insulator *provide energy storage and fuel |
what role do carbohydrates play within the cell | *fuel for cell metabolism *provide shape and stability for cells/tissues *poly or monosaccharides |
what is the role of RNA within a cell | *Single strand(helix) *found in nucleus and cytoplasm *messanger and transfer RNA *protein synthesis |
what is the role of DNA within a cell | *found only in nucleus *double helix *hold nitrogenous bases *contain 5-carbon sugar(pentose, which is a monosaccharide) *phosphoric acid bonds *contains all hereditary info *found on chromosome *most radiosensitive MM *contains codon |
what makes up the side rails of DNA ladder | alternating sugar and phosphate molecules |
what makes up rungs of DNA ladder | pairs of nitrogenous bases(one purine and one pyrimidine) |
a series of 3 adjacent bases in one polynucleotide chain of a DNA or RNA molecule, which codes for a specific amino acid | codon |
basic unit of matter, consists of nucleus and surrounded by negatively charged electrons | atom |
(A#) number of protons and neutrons in a nucleus | atomic mass |
(Z#) number of protons in a nucleus | atomic number |
two atoms that have same number of protons but different number of neutrons/same atomic number different atomic mass | isotope |
group of 8 e- in outermost shell, cannot chemically combine | octet |
determines the chemical binding ability of an atom | valence |
constancy of internal environment | homeostasis |
what is the second level of cellular composition | organelles |
what is an organelle | small organ within a cell with specific functions |
what are the different types of organelles within a cell | *endoplasmic reticulum *golgi aparatus *lysosomes *mitochondria *ribosomes |
organelle found within the cytoplasm that functions as channels whereby nucleus communicates with cytoplasm | endoplasmic reticulum |
organelle that concentrates and packages secretion products (mailman) | golgi apparatus |
organelle that contains enzymes capable of digesting cellular fragments and sometimes the cell itself | lysosomes |
where macromolecules are digested to produce cellular energy, known as the workhorse or engine of the cell | mitochodria |
small organelle, which is the site of protein synthesis | ribosomes |
what is the third level of cellular composition | the cell |
what is a cell | basic living subunit, within any living organism |
has single helix strand, found in and outside of nucleus, and comes in messanger, and transfer varieties | ribonulceic acid(RNA) |
the most radiosensitive of all macromolecules, since it contains genetic info. found inside of nucleus and controls cell function | deoxyribonucleic acid(DNA) |
this part of the cell is made of lipid-protein that selectively allows small molecules and water to diffuse and provide structure and form | cell membrane |
outside of nucleus but within plasma membrane, contains organelles and all living things within a cell, made of 70%-90% water | cytoplasm/protoplasm |
what are the basic functions of the cell membrane | *protein synthesis- genetic code contained in DNA tells which protein to be produced *code transfers to mRNA within nucleus, mRNA leaves via ER on way to ribosome, where it is tranferred to tRNA. tRNA searches cytoplasm for the coded amino acid. |
what is the next step after tRNA finds the amino acid that matches the code it carries | it attaches to the amino acid and carries it to the ribosome, where it joins other amino acids in sequence by peptide bonds to form protein molecule. |
what happens if there is any interference with any of the sequences of protein synthesis | could result in damage to the cell |
all cells of the body except the oogonium and the spermatogonium | somatic cells |
what type of cells are oogonium(ovum) and spermatogonium(sperm) | genetic cells |
which type of cells undergo mitosis | somatic cells |
what are the phases of mitosis | *prophase *Metaphase *anaphase *telophase |
*genetic material forms strands in nucleus, the 1st sign of chromosome formation *nucleus and chromosomes enlarge *membrane begins to break down *chromosomes move toward equatorial plate | prophase |
*chromosomes at equatorial plate *membrane completely broken down *chromatids attach to spindle fibers by centromere *duplication | metaphase |
*splitting of each chromosome at centromere, so that a centromere and two chromatids are attached to a spindle fiber, which is attached to a spindle or pole *newly formed chromosomes migrate to opposite poles or spindles | anaphase |
*structural chromosomes disappear into mass of DNA *nuclear membrane is pinched in middle and two new nuclei are formed | telophase |
*towards the end of telophase *cytoplasm is divided into two equal parts(daughter cells), each one keeping one of the nuclei *not a part of mitosis, but a seperate part of proliferation | cytokinesis |
what is the life cycle of a cell | *gap 1-preperation for synthesis(part of interphase) *DNA is synthesized(part of interphase) *gap 2-preperation for mitosis(part of interphase) *mitosis |
genetic cells undergo what type of proliferation | meiosis- reduction division*chromosomes are reduced from 46 to 23 after to cycles(mother cells divide into two daughter cells, which are then each divided into two grandaughter cells, each with 23 chromosomes) |
*exchange of chromosomal material between chromatids, resulting in changes to genetic make-up and inherited traits*happens in second cycle of meiosis | crossing over |
what happens in level 4 of cellular organization | groups of similar cells form tissues |
what happens in level 5 of cellular organization | two or more tissues with common function form organs |
what happens in level 6 of cellular organization | groups of organs form the 10 body systems |
what are the 10 body systems | *immune *skeletal *nervous *digestive *cardiovascular *integumentary *respiratory *endocrine *reproductive *excretory |
what happens at level 7 of cellular organization | living organism |
what are the most radiosensitive cells in the body | *lymphocytes *spermatogonia *erythroblasts |
what are the most radioresistant cells in the body | *muscle cells *nerve cells *chondrocytes *erythrocytes |
*the part of the cell cycle between one mitotic phase and the next, from the end of cytokinesis to the beginning of the next prophase *period of growth of the cell, between divisions | interphase |
what is RBE | relative biologic effectiveness- dose of radiation necessary to produce an effect vs. dose of a different type of radiation to produce same effect |
what are the embryo/fetal radiation dose effects during 1st two weeks of pregnancy | no known effects |
what are the embryo/fetal radiation dose effects during weeks 2 to 10 | congenital abnormalities, such as mental retardation or most commonly skeletal deformities |
what are the embryo/fetal radiation dose effects during 2nd and 3rd trimesters | malignant childhood disease, most commonly leukemia |
which two nitrogenous bases are purines | adenine and guanine |
which two nitrogenous bases are pyrimidines | thymine and cytosine |
a unit formed from a nitrogenous base, a five carbon sugar molecule, and a phosphate molecule | nucleotide |