MI240 Unit 2

composition of the body

the atoms and molecules that radiation interacts with will determine the degree and nature of the response

cells are the most

basic unit of living matter

cells are responsible for?

• nerve impules

• contract muscles

• support organ function

what is needed for a cell to function properly

• food

• oxygen

• water

not all damage matters but damage to ____ matters

key cells

the only inorganic molecule in the body is

water

when radiation interacts with the body it is most likely going to interact with molecules of____

water

• 60% hydrogen

• 25.7% oxygen

molecular composition is what?

5 principal types of molecules in the body

what are the 5 principal types of molecules

1. water

2. proteins

3. lipids-fats

4. carbohydrates

5. nucleic acids

water is what?

the simplest and most abundant inorganic compound in the body

• 80-85% of body weight

• 2 hydrogen atoms, 1 oxygen atom

what are the roles of water in the human body

• provides form and shape

• dissolves acids, bases, salts and chemical substances

• functions as a transport vehicle

• maintains body temp

• cushions vital organs

• lubricates digestive systems and joints

proteins are the…

building blocks of cells

• 15% of the body content

proteins are formed when

a sequence of amino acids connect by peptide bonds to combine into long, chainlike molecular complexes (macromolecules)

the arrangement of proteins determines

specific function and type

the structure of proteins is…

C H O N T

• carbon

• hydrogen

• oxygen

• nitrogen

• T= trace elements

proteins are essential for:

• growth

• construction of new body tissues

• repair of injured or weakened tissues

proteins provide

structure and support

lipids are a structural part of the…

cell membrane

• present in all body tissues (2% cell content)

the structure of lipids is

C H O

• carbon

• hydrogen

• oxygen

lipids are composed of what 2 molecule types

• glycerol

• fatty acids

the functions of lipids are

• long term storage of energy

• insulate and protect

• support organs (eyes and kidneys)

• assist with growth and development

• lubricate joints

• assist in digestion

carbohydrates are also called?

saccharides (1% of cell content)

the structure of carbs is

C H O

• carbon

• hydrogen

• oxygen

carbs can be broken down into

• simple carbs (monosaccharides)

• complex carbs (disaccharides)

examples of carbohydrates

• starches

• various sugars

functions of carbs

• short term energy storage

• cell shape and stability

carbs are most abundant in

the liver and muscle tissues

the last 1% of the cell is made up of

nucleic acids

radiation interacts at the _____

atomic level

DNA stands for

deoxyribonucleic acid

DNA is found in the

nucleus of the cell

DNA is a

double stranded macromolecule (large and complex) (double helix)

DNA is regarded as the

command/control molecule for cell function

DNA contains

ALL hereditary information representing a cell/ what a cell needs to function

In a reproductive cell/germ cell…

contains ALL hereditary information for the individual

DNA is a radiosensitive molecule=

critical target molecule

RNA stands for

ribonucleic acid

RNA is found in

cytoplasm of a cell

RNA is a

long, single-stranded chain of cells (large and complex)

RNA helps DNA

translate information

what are the two types of RNA

• messenger RNA (mRNA)

• transfer RNA (tRNA)

chromosomes are

tiny rod-shaped bodies; only visible during mitosis (cell division)

chromosomes are made up of

• protein

• genetic material

human somatic cells have __ chromosomes

46

human reproductive “germ” cells have ___ chromosomes

23

DNA composes→

chromosomes

Genes compose→

DNA

bases compose→

genes

genes have unique sequence of bases-

info responsible for cell activity and development and all hereditary information

mature cells are highly-

specialized

cells need:

• a source of energy

• oxygen to break down food

• water to transport substances

cells maintain

homeostasis

protoplasm is

living contents of a cell surrounding by plasma membrane

cytoplasm-

bulk of cell; structure, mass, and support

• mainly water

• contains proteins, carbs, lipids, salts, minerals

• cellular metabolic function occurs

nucleus-

center of cell; contains DNA

what is number 1?

lysosome

what is number 2?

centriole

what is 3?

mitochondrion

what is 4?

ribosomes

what is 5?

nucleus

what is 6?

smooth endoplasmic reticulum

what is 7?

golgi complex or golgi apparatus

what is 8?

cell membrane or plasma membrane

what is 9?

rough endoplasmic reticulum

function of smooth and rough endoplasmic reticulum

• “highways”

• communicates with outside of cell and helps with transportation

function of ribosomes

responsible for protein synthesis

function of mitochondria

• “power generator”/”power house” of the cell

• supply energy for cellular function

function of golgi apparatus (complex)

• transport hormones through the cell and into the blood stream

function of lysosome

• “garbage bags”

• breakdown large or unwanted molecules

function of centriole

• main organizing and regulator controls cell phases

function of cell membrane

• allows small molecules and water in and out of the cell

what is cell proliferation (division)

the act of a single cell or gorup of cells reproducing and multiplying in number (cell division)

two types of cell proliferation (division)

• mitosis

• meiosis

somatic cells are

• all cells of the body except sperm and ova

• damage affects only exposed individual

somatic cells ungergo

mitosis

• results in a cell with 46 chromosomes

genetic cells are

• sperm and ova ONLY

• damage can affect offspring

genetic cells undergo

meiosis

• results in a cell with 23 chromosomes

mitosis- interphase

• G1 phase, S phase, G2 phase

• period of growth between cell division

• longest phase of life cycle

why does meiosis need to result in 2 cells with 23 chromosomes each?

to ensure the correct chromosome number after fertilization

mitosis- G1 phase description

• occurs between mitosis and DNA replication

• pre DNA synthesis, growth

mitosis- S phase description

• DNA replication/synthesis→ 2 identical daughter molecules

mitosis- G2 phase description

• post DNA synthesis→ cell is preparing for mitosis- producing RNA and proteins

mitosis description

• division phase, more susceptible to damage due to division

S phase is the ____ radiosensitive time

least

mitosis (M phase) is the _____ radiosensitive time

most

mitosis- prophase

• nucleus enlarges

• DNA more prominent and begins to take structural form

• centriols migrate to opposite side of cell and begin to form mitotic spindles

mitosis- metaphase

• mitotic spindle forms between centrioles

• chromosomes appear and line aling the equator of the nucleus

• critical time for damage

mitosis can be stopped, why?

chromosomes can be studied for radiation induced damage

mitosis- anaphase

• each chromosome splits at center

• the halves of the chromosomes migrate towards spindles

mitosis- telophase

• chromosomes disappear into a mass of DNA

• cytokinesis occurs

what is cytokinesis

• nuclear membrane and cytoplasm both divide into two

  • cell division is now complete

  • 2 daughter cells appear as parent and contain exact genetic matieral

a blast is

• immature/ still in development

• not fully specialized

• rapidly dividing/ multiplying

a cyte is

• mature/ fully developed

• specialized

• not rapidly dividing/ multiplying

meiosis is

• a 2 step cell divison

• results in 4 cells

• only occurs in germ cells, genetic cells, s*x cells

what occurs after telophase in meiosis

crossing over

what is crossing over?

• changes in genetic make up and traits occur (2nd division)

damage to DNA in nucleus can result in change with possible death or significant damage:

1. instant death

2. apoptosis (interphase death)

3. mitotic (genetic death)

4. mitotic delay (division delay)

5. interference funciton

improper function=

serious impairment

cease of function=

cell death

what dose does instant death occur

~1000 Gy given wihtin seconds or minutes