RT206: M2 - RADIATION BIOLOGY

Protoplasm

________ is defined as thick, vicious substance, constituting the physical basis of all living activities and contains 70-85% water, depending upon the type of cell.

Radiobiology

__________ is a branch of science dealing with the modes of action and the effects of ionizing radiation on living matter.

Cell

It is the basic unit of structure and function of all living things

Cell

It is the smallest unit of protoplasm capable of independent existence.

• Growth

• Repair

• Irritability

• Metabolism

• Adaptability

• Reproduction

It is at cellular level that the fundamental life functions occur:

Water

It acts as a solvent.

Water

It acts as a transport medium for substances

Water

It serves as lubricant for joints and the digestive tract

Water

It regulates body temperature.

Water

It cushions organs.

carbon

Organic compounds denote chemical substances which contain _________.

Proteins

_______ are composed of CHON. It comprises 15% of the cell.

15%

Proteins are composed of CHON. It comprises _____ of the cell.

Proteins

It is considered as the basic building block of cells and tissues.

Proteins

• It assists in growth.

• It constructs new tissues.

• It repairs injured or worn-out tissues

Amino acids

_______ are the building blocks of proteins.

Enzymes

_________ act as organic catalysts.

Enzymes

• Control almost every cell process

• Provides cell energy

• Help make new cell parts

______ contain CHO. It comprises approximately 2% of the cell.

2%

Lipids contain CHO. It comprises approximately _____ of the cell.

Lipids

• It is useful when storing energy.

• It insulates our bodies from cold.

• It assists with the digestive process.

Lipids

It is considered to be one of the many components of various substances such as hormones.

Carbohydrates

________ are composed of CHO, making up approximately 1% of the cell.

Carbohydrates

It is considered to be the major source of energy necessary to all cellular functions, and it is located predominately in the liver and muscles.

• Monosaccharides

• Disaccharides

• Polysaccharides

Carbohydrates are subdivided into:

Monosaccharides

Simple sugars; glucose, fructose, galactose

Disaccharides

Double sugars; sucrose, lactose

Polysaccharides

Hundreds to thousands of simple sugar molecules in a long chain; starch, cellulose)

Nucleic Acid

__________ contain CHOP, and they are the largest known organic molecules.

• purines

• pyrimidines

Two groups of nitrogenous bases:

Deoxyribonucleic Acid

Direct cellular information and transmit genetic information between cells and generations

Ribonucleic Acid

Role in protein synthesis

• Messenger RNA

• Transfer RNA

• Ribosomal RNA

RNA occurs in several forms:

Messenger RNA

Carries code for specific amino acid sequences from DNA to structures for protein synthesis

Transfer RNA

transfers amino acid groups to ribosomes for protein synthesis

Ribosomal RNA

exists in ribosomes and is thought to assist in protein synthesis

Inorganic Compounds

It is also known as mineral salts

Inorganic Compounds

It maintains osmotic pressure of the cell by maintaining correct proportion of water (Na and K)

Inorganic Compount

• It assists in producing cell energy.

• It conducts nerve impulses

Hypertonic

A solution causing a cell to shrink is _______.

hypotonic

A solution causing a cell to swell is _______.

isotonic or isomotic

Osmotic pressure that is equal to that of the circulating blood is called _________.

Cell Membrane

It monitors all exchanges between intracellular and extracellular fluid and its contents, thus maintaining the proper physiologic conditions necessary for life.

Cytoplasm

It is a watery solution found between the nucleus and cell membrane, composing of organic and inorganic compounds.

cytoplasm

The _______ is the site of all metabolic functions in the cell.

Centrioles

________ are described as a pair of cylindrical organelles located near the nucleus. It is perpendicular with each other and it organizes the spindle fibers during cell mitosis.

centrosome

Centrioles are contained in a circular body named the _______.

endoplasmic reticulum

The ___________ is a tubular network that extends from the nuclear membrane to the cell membrane. It assists in channeling proteins and lipids in and out of the nucleus.

Rough Endoplasmic Reticulum

___________ has numerous ribosomes attached to its outer surface. It is found in cells that are active secretors of proteins (endocrine and exocrine glands)

Smooth Endoplasmic Reticulum

___________ has no ribosomes attached to it. It is a sire for enzyme reactions in steroid hormone production and inactivation, and is the part of the cell where many drugs are inactivated.

Mitochondria

_________ are the powerhouses of the cell, producing energy for cellular functions by breaking down (catabolizing) nutrients through a process called oxidation.

oxidation

Mitochondria are the powerhouses of the cell, producing energy for cellular functions by breaking down (catabolizing) nutrients through a process called ________.

Golgi Apparatus

It is a series of flat, membranous layers, and synthesized within are carbohydrates.

Golgi Apparatus

It serves as a packaging area for products manufactured by the cell for export, carbohydrate synthesis, and the binding of other organic compounds to proteins.

Lysosomes

_________ are single-membrane oval or spherical bodies within the cytoplasm which contain digestive enzymes that digest protein molecules.

Lysosomes

It also assists in digesting old, worn-out cell parts, dead cells, bacteria, and foreign materials.

Lysosomes

_______ are also known to be suicide bags.

nucleus

The _______ is considered to be the most vital cell organelle.

Nucleus

It is the brain for the cell's metabolic activity and cell division, usually located in or near the cell's center.

Nucleus

It floats within the cytoplasm, and is surrounded by a double-layered nuclear membrane.

chromatin

DNA and protein are arranged in long threads called _______.

Genes

_______ are enclosed in chromosomes.

Genes

It is the basic unit of heredity.

Chromosomes

________ are only visible in cells capable of dividing.

Germ Cells

gametes; oocytes, spermatozoa

Somatic Cells

Normal number of chromosomes for humans is 46 (23 pairs). This number is termed the diploid number, or 2n.

mitosis

In ________, a cell with the diploid number of chromosomes divides into two identical cells, containing the diploid number of chromosomes. In order for the body to grow and repair tissue, the production of identical cells is essential.

radiosensitive

It is during mitosis that cells are the most _________.

interphase

The non-dividing cell is in the segment of the cell known as the ________.

G1 phase

Cells in _______ are performing the physiological purposes necessary to maintain cell homeostasis.

G1 phase or resting phase

Cells in this phase are not yet undergoing

visible phases of mitosis.

S-phase

If a cell is to divide, it replicates its DNA in the ________.

late S-phase

The most radioresistant phase of the cell cycle is in the _______.

G2 Phase

After the DNA has been synthesized, there is another period before the cell begins mitosis. This period is termed as ______

Prophase

The centrioles migrate toward opposite poles of the cell, producing spindle fibers that extend across the cell's equator

Prophase

The nuclear membrane begins to disappear.

Prophase

The nucleolus is no longer visible.

Metaphase

Paired chromosomes are lined up at the equator of the spindle.

Metaphase

Spindle fibers attaches to the centromeres.

Metaphase

Nuclear Membrane has entirely disappeared.

Anaphase

Centromeres divides, and sister chromatids detach as they are pulled to an opposite pole.

Telophase

Sets of chromosomes become much longer, thinner, and indistinct as they reach the poles of the cell.

Telophase

DNA unravels to form chromatin.

Telophase

Formation of new nuclear membranes.

Telophase

Reappearance of nucleolus.

Oogenesis

_______ for females

Spermatogenesis

_______ for males

meiosis

In the formation of germ cells, _______ transpires in the gonads of sexually matured people.

meiosis

During _______, the cell divides twice in succession but chromosomes are duplicated only once.

Malignant or cancer cells

_________ are those which are dividing abnormally (usually much more often than normal cells).

• Increased amount of chromatin

• Increased ratio of nuclear material to cytoplasm

Malignant differs from normal cells in a way: