Human Biology Flashcards
The affects of x-rays on humans is the result of interactions at what level
The atomic level
These atomic interactions take the form of ionization for excitation of
Orbital electrons and result in the deposition of energy in tissue
Deposited energy can produce
A molecular change
When an atom is ionized
It’s chemical binding properties change
If atom is a part of a large molecule. Ionization may result in
breakage of the molecule or relocation of the atom within the molecule.
The abnormal molecule may eventually
Function improperly or cease to function, leading to serious impairment or cell death
How can ionized atoms become neutral
By attracting free electrons
Molecules can mend by
Repair enzymes
Or electrons attaching to a free electron
If the radiation response increases in severity with increasing radiation dose, it is called a
Deterministic Effect
If the incidence of the radiation response increases with increasing radiation dose it is called
Stochastic effect
Which effect occurs within days or weeks
Deterministic
What type of effect is not observed for moths or years
Stochastic
Name 4 types of deterministic effects of radiation
Acute radiation syndrome
Local tissue damage (skin)
Hematologic depression
Cytogenetic damage
Name 3 Acute Radiation syndromes
Hematologic syndrome
Gastrointestinal syndrome
CNS syndrome
Name 5 Stochastic effects of radiation
Leukemia Malignant diseases Local tissue damage (eyes, gonads, skin) Shortened life span Genetic damage
Define Radiobiology
The study of the effects of ionizing radiation on biological tissue
At the most basic level, the human body is composed of
Atoms
The top 4 atomic composition of the body
Hydrogen 60% Oxygen 25.7% Carbon 10.7% Nitrogen 2.4% Then calcium, phosphorus. Sulfur trace elements
Robert Hooke
Named the cell as the biologic building block, in 1665
Anton van Leeuwenhoek
Accurately described a living cell on the basis of his microscopic observation. 1673
Schneider and Schwann
Showed that in all plants and animals, cells are the basic functional unit.
The Cell Theory
In all plants and animals, cells are the basic functional units.
Watson and Crick
Description of the molecular structure of deoxyribonucleic acid as the genetic substance of the cell.
1953
5 principle types of molecule found in the body
Water 80% Protein 15% Lipids 2% Carbohydrates 1% Nuclei acid 1%
Which of the 5 molecules in the body are macromolecules
Protein
Lipids
Carbohydrates
Nucleic acids
Define macromolecules
Very large molecules that sometime consist of hundreds of thousands of atoms.
One of the rarest molecules
DNA
— is the most critical and radiosensitive target molecule
DNA
What molecule playing a big role in delivering energy to the target molecule, thereby contributing to radiation effects.
Water
Proteins are
Long-chain of amino acids connected by peptide bonds
What are 3 functions of proteins
Function as :
Enzymes
Hormones
Antibodies
Lipid are
carbon, hydrogen, and oxygen
Where are lipids present?
In structural components of cell membranes.
Not permeable to
Water
2 functions of lipids
Subcutaneous lipid layer provides insulation.
Serve as fuel
How are carbohydrates similar and different from lipids
Similar because they are composed of carbon, hydrogen and oxygen
Different in structural arrangement that that of lipids
Chief function of carbohydrates
To provide fuel for cell metabolism
— is the main molecule that fuels the body.
Glucose
DNA contains all
Of the hereditary information that represents a cell
DNA of a germ cell contains
All the hereditary information of the whole individual
RNA is located mostly in
The cytoplasm, but is also in the nucleus
M RNA and T RNA are involved in
The growth and development of the cell.
DNA consists of a backbone composed of
Alternating segments of deoxyribose and phosphate,.
For each deoxyribose-phosphate formed, a molecule of water is removed.
Attached to each deoxyribose molecule is
One of 4 different nitrogenous organic bases: Adenine Guanine Thymine Cytosine
Purines
Guanine
Adenine
Pyrimidines
Thymine
Cytosine
2 essential nucleic acids
Ribonucleic acid
Deoxyribonucleic acid
DNA structure
Double helix
Sides are alternating sugar and phosphates.
The rings are bases joined by hydrogen bonds.
The sequence of base bonding is limited to— in DNA
Adenine - Thymine
Cytosine - Guanine
How does RNA have a Key role in protein synthesis
RNA carries the DNA blueprint from the nucleus to the cytoplasm where the building materials are.
2 major structures of the cell
Nucleus
Cytoplasm
The principle molecular component of the nucleus is
DNA= genetic materials of cell
The nucleus also contains some
RNA, protein and water
MOST RNA is located in
Nucleolus
Nucleolus
- Rounded structure
- often attached to the nuclear membrane
- Connects to ER, which controls the passage of molecules, mostly RNA, from nucleus to cytoplasm.
Cytoplasm
Contains all molecular components except DNA
mRNA and tRNA are found there
Endoplasmic Reticulum
A channel or series of channels that allows the nucleus to communicate with the cytoplasm
Mitochondria
Large bean-shaped structures.
Macromolecules are digested to produce energy.
Engine of the cell
Ribosomes
Small, dot-like structures
Involved in the protein synthesis
Lysosomes
Small, pea-like sacs
Contain digesting enzymes capable of digesting enzymes
Reaponsible for removal of intracellular contaminants.
Cell membranes consists of
Lipid-protein complexes
When a macromolecules is incorporated into a living cell, a dose of — is needed to produce a measurable change
A few mGY
Human cells can be killed with a dose of less than –Gy.
1
A critical cellular function needed for survival
Protein synthesis
DNA contains
A code that identifies which proteins to make
—- takes the code, called a codon, from DNA
mRNA
Codon
3 base pairs, codes for 1 amino acid
—- identifies one of the 21 amino acids available for protein synthesis
Codon
The genetic message is transferred within the nucleus to
A molecule of mRNA
MRNA leaves the nucleus
Through the endoplasmic reticulum
After the mRNA leaves the nucleus, it
Makes its way to a ribosome, where the genetic message is transferred to tRNA
TRNA searches the cytoplasm for
The amino acids for which it was coded.
After the tRNA attaches to the amino acid, it
Carries the amino acid to the ribosome
At the ribosome, the amino acid
Is linked with other amino acids by peptide bond to form the complete protein molecule
Cell proliferation
The act of a single cell or group of cells to reproduce and multiply in number
2 general types of cells
Somatic
Genetic (sex)
Genetic cells under
Meiosis
Somatic cells proliferate/divide via
Mitosis
What are the 4 subphases of cell division in Mitosis
Prophase
Metaphase
Anaphase
Telophase
What is the period of growth of the cell between divisions/ aka CELL CYCLE
Interphase
What are the 4 phases of the CELL CYCLE
M (mitosis)
G1
S
G2
What phase are the chromosomes not visible
Interphase
During. —phase the nucleus swells, and DNA becomes more prominent
Prophase
During—- the chromosomes appear and align
Metaphase
Very radiosensitive stage of Mitosis
Metaphase
During—splitting of chromosomes
Anaphase
Cellular replication where the daughter cell is exact replica of parent cell.
Mitosis
Teleophase
The final segment of mitosis.
Closing off the nuclear membrane like a dumbbell into 2 nuclei.
Genetic material can change during the division process of genetic cells, which is called
Meiosis
How many pairs of chromosomes do somatic and genetic cells have
23
How many chromosomes do somatic and genetic cells have
46
The process whereby genetic cells undergo reduction division of diploid to haploid number of chromosomes 46 to 23
Meiosis
The reduction to 23 chromosomes allows for
After Fertilization, the union of 2 genetic cells, then the daughter cells will contain 46 chromosomes
Tisssues
Collection of cells of similar structure and function
Organs
Tissues bound together
Organ system
Tissues and organs combine
Name the organ systems
Nervous Reproductive Digestive Respiratory Endocrine
Immature cells are called
—- are more radio sensitive.
Undifferentiated cells
Stem cells
What types of cells are highly radiosensitive
Lymphocytes
Spermatogonia
Erythroblasts
Intestinal crypt cells
Low radiosensitive cells
Muscle cells
Nerve cells
Senstivity of the cell to radiation is determined by
Its state of maturity
Its functional role
Rate of division (high is more radiosensitive)
The principal aim of the study of radiobiology is
To understand radiation dose-response relationships
What law states that the radiosensitivity of living tissue varies with maturation and metabolism
The Law of Begonie and Tribondeau
The radiation effects of bone cancer were observed in
Radium watch dial painters
The radiation effects of lung cancer were observed in
Uranium miners
The radiation effects of liver cancer were observed in
Patients who underwent Thorotrast studies
The radiation effects of cataracts were observed in
Cyclotron workers
The goal of radio biologic research is
To produce radiation dose response relationship is so response to doses can be predicted and managed
Water molecules exist in what two states
- Free state
2. Bound, to other molecules
Organic molecules name three
Proteins
Lipids
Carbohydrates
They are life supporting and contain carbon
The radiation effects of malignant disease were observed in
Atomic bomb survivors
The radiation effects of leukemia and reduced life span were observed in
American radiologists
Why are carbohydrates called watered carbons
Because ratio of hydrogen to carbon is 2:1
What macromolecules are very large and extremely complex?
Nucleic acids
Located primarily in the nucleus of the cell DNA serves as the
Command or control molecules for cell function.
Describe the structure of RNA
Single helix
The sugar component is ribose not deoxyribose)
What are two major components of the human cell?
Nucleus and cytoplasm
Irradiation of more than –Gy, to see measurable change in macromolecules irradiated by themselves.
10kGy
The — is more sensitive than the cytoplasm.
Nucleus
Radiation damage at any part of the —- can damage cell.
Protein synthesis
Radiation to— has more effect in producing a response then is radiation to other molecules involved in protein synthesis.
DNA
