- Saccharides- quick energy - Sugars- (monosaccharides and disaccharides) - Polysaccharides- Plant starches/animal glycogen

- resides in the nucleus- control center of cell - contains cell's hereditary info

Physics Test 3 Flashcards by Kayla Thompson

Ionization of an atom in a molecule may…

cause breakage or atom relocation-may result in improper function or non function of molecule- may lead to cell dysfunction of death.

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what is the body mostly composed of?

85% hydrogen and oxygen- radiation interacts with atoms.

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on molecular level, body is what?

80% water- atom is arranged so that the majority of the space is empty space

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Macromolecules that are VERY large

proteins, lipids (fats), carbs (sugars and starches), nucleic acids

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Macromolecules- Organic molecules

life supporting and contain carbon- proteins, lipids and carbs

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Macromolecules- DNA

most critical and radiosensitive target molecule (but radiation interaction is random- does not seek out DNA)- a nucleic acid concentrated in the nucleus

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Homeostasis

attempt to maintain constant internal environment in body by perspiration (to keep temp and respiration level in exercise) and raplacement

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Metabolism

=Catabolism + anabolism

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catabolism

break down of macromolecules ending in water and carbon dioxide

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anabolism

production of large molecules

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Proteins

amino acids connected by peptide bonds- 15% of body (organic)

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what are proteins used for?

1) muscles (structure and support)
2) enzymes (catalysts which speed up reactions)
3) hormones (regulatory control - produced by endocrine (pituitary, adrenal, thyroid, parathyroid, pancreas, gonads)
4) antibodies (defense system- may be for one antigen- invasive or infectious agent)

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what are proteins composed of?

carbon, hydrogen, oxygen, nitrogen, and trace elements.

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Lipids

consist of one molecule of glycerol and three molecules of fatty acids; Part of cell membrane in every body tissue; Thermal insulation (just under skin); Secondary energy source (easier to get energy from carbs)

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what are lipids composed of?

carbon hydrogen, and oxygen

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Carbohydrates

Saccharides- quick energy
Sugars- (monosaccharides and disaccharides)
Polysaccharides- Plant starches/animal glycogen

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what is the chief function of carbs?

cell metabolism

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Carbohydrates- glucose

simple sugar- main fuel for body- composed of carbon, hydrogen, and oxygen BUT ratio of hydrogen to oxygen is always 2:1 (same as water molecules so it is “hydrated” water)

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Body Fuels (in order of use)

1) glucose
2) polysaccharide (glycogen)
3) lipids (most difficult to use)

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Nucleic Acids- DNA

resides in the nucleus- control center of cell

- contains cell’s hereditary info

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Nucleic Acids- RNA

-mostly in cytoplasm- mRNA & tRNA

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Nucleotides

(base-sugar-phosphate combinations) strung together - two chains attach at bases (rungs of ladder) and then spiral to form DNA

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Bases only allowed in

adenine+thymine OR cytosine + guanine

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The order of base combinations in DNA carries what?

genetic code

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What is the basic component of all living material?

Human cell

What is the normal number of chromosomes in the human cell

Mammalian cells

may be killed by doses of less than 100 rad (1Gy)

Effects are much greater when a macromolecule is irradiated in a cell than

when irradiated individually

cell death occurs with doses

less than 100 rad to nucleus; may require 1000 rad or more if only cytoplasm is irradiated.

Protein Synthesis

Critical for cell survival and requires: -DNA(codes for proteins cell will make -mRNA(carrying code thru endoplasmic reticulum to ribosome) -tRNA -amino acids Radiation to any of these could interfere with synthesis but radiation of DNA is most effective in producing response.

Mitosis- Somatic Cell Reproduction

Mitosis and Interphase

Mitosis

a. prophase b. metaphase c. anaphase d. telophase

Mitosis- Prophase

nucleus swells, DNA becomes prominent

Mitosis- Metaphase

chromosomes line up along nucleus' equator- easy to study for damage, anomalies here

Mitosis- Anaphase

chromosomes split and migrate toward nuclear spindles by way of spindle fibers

Mitosis- Telophase

chromosomes disappear into mass of DNA and nuclear membrane closes off to form two nuclei

Interphase (between mitotic events)

a. G1- pre-DNA synthesis gap b. S- DNA synthesis phase- DNA is duplicated c. G2- post-DNA synthesis gap

Meiosis- Genetic Cells

Oogonium and spermatogonium

Meiosis- Reduction Division

46 chromosomes germ cell must be reduced to 23 chromosomes in order to unite with another germ cell and result in 46 chromosomes again

First goes through a regular mitosis so you have two cells just alike but then those two divide again without "S" phase (DNA reproduction) Results in four cells with 23 chromosomes.

cells combine to form...

tissues to organs to organ systems to organisms

Immature cells

- undifferentiated - precursor, or - stem cells

Generally, Immature cells are more or less radiosensitive than mature cells?

Cell types with HIGH radiosensitivity

- Lymphocytes - Spermatogonia - Erythroblasts - Intestinal crypt cells

Cell types with intermediate radiosensitivity

- Endothelial cells - Osteoblasts - Spermatids - Fibroblasts

Cell types with Low radiosensitivity

muscle cells | nerve cells

Organ structure

- Parenchyma (actual tissue of the organ) | - Stroma (connective tissue and vasculature that provides structure to organ)

Low radiosensitivity means

less sensitive (sometimes equated to radioresistant)

what types of cells are least sensitive to radiation exposure?

muscle, brain, spinal (nerve) tissue. Takes more radiation to damage these types of cells

Mostly due to low cell reproduction, the cells of this type in your body are

relatively mature

Bergonie and Tribondeau

1) stem cells are raadiosensitivie 2) radiosensitivity is high when metabolic activity is high 3) cells which reproduce fast and tissues that grow fast are more radiosensitive than those which reproduce and/or grow more slowly

What affects radiation response?

LET, RBE, fractionation and protraction, OER, age, gender, recovery, and chemical agents

LET (Linear Energy Transfer)

- Ability of radiation to give up its energy per micrometer of tissue - the more energy it gives up, the higher the LET - As LET increases, biologic damage produced increases.

Dx X-rays LET

~3keV/umeter

RBE (Relative Biologic Effectiveness)

- Quantitatively state- as LET goes up RBE goes up (but not directly proportional) - RBE levels out at about 3- cant get any higher

RBE of diagnostic x-rays is

Ways to increase tolerance

protraction and fractionation- either of these reduce the biological effect of the exposure

Protraction

give the same dose slower- continuously over an extended period of time- less damaging

fractionation

use the same dose rate (rad/min) but split the dose into several fractions (portions). Allows for recovery and repair between doses so radiation damage is less.

OER (Oxygen Enhancement Ratio)

-Numeric description of effect of oxygen

Physics Test 3 Flashcards

(60 cards)