Cell Biology
RADL 70
Kyle Thornton
This material will not be covered in
class, but will be on the midterm exam.
Note: This material will not be
covered in class, but will be on
the midterm exam.
Properties Of A Cell
 All living things are made up of protoplasm

A thick viscous, suspension substance that constitutes the
physical basis of all living activities
 The smallest unit of protoplasm is the cell
 Most responses to radiation occur first at the
cellular level

All radiation damage is at the cellular or subcellular level
Cell Properties
 Assimilation
 Growth
 Motility
 Secretion
 Irritability
 Reproduction
The Levels Of Organization
 Simple life forms consist of one cell
 More complex forms are made up of many types of
cells
 Cells are modified and specialized for specific
activities

Muscle cells


Red blood cells


Designed for contraction
Carry oxygen to body tissues
Nerve cells

Receive and send electrical impulses
Levels Of Organization
 Groups of cells that perform the same activity are tissues
 Epithelial, connective, muscular, and nervous
 Groups of tissues that perform a specialized function are organs
 The stomach – composed primarily of epithelial and muscle tissue
 A group of organs form a system
 Consists of organs working together to perform a specific function
 GI or Respiratory system
 The organism is the highest level of organization
 A living being
Chemical Components Of A
Cell
 Organic compounds

Carbon, hydrogen, oxygen
 Inorganic compounds

Salts, water, minerals
 Both are suspended or dissolved in water

Water makes up 80% of a cell



Water helps hold and transport substances in the cell
Chemical activities take place in the cell
Water helps maintain constant temperature
 Without water, cells would be vulnerable to extreme
changes in temperature
Cell Physiology
 Cells move water in and out by osmosis
 The amount is determined by osmotic pressure
 Osmotic pressure is determined by the
concentration of mineral salts inside or outside of
the cell
 Too much water can rupture a cell
 Too little water can make a cell collapse
 Either way, the cell cannot complete its biological
function
Osmotic Pressure
 Too little sodium inside the cell, or too little
potassium outside the cell will cause water to be
pulled outside the cell causing collapse
 Hypertonic

A solution that causes a cell to shrink
 Hypotonic

A solution that causes a cell to swell
 Isotonic

Having an osmotic pressure equal to that of circulating
blood
Benefits of Mineral
Compounds and Salts
 Mineral compounds prevent cramping
 Salts aid in the production of energy and the
conduction of nerve impulses
The Major Classes Of Organic
Compounds
 Proteins
 Lipids
 Carbohydrates
 Nucleic Acids
Proteins
 Macromolecules – Polymers




Large molecules formed by joining together
simple units known as monomers into a long
chain
Make up about 15% of a cell
Considered the building block of a cell
Integral to structure of skin, bone, tendons,
ligaments, hair, silk, and collagen
Protein Functions
 Building of new tissue
 Repair of injured or broken down tissue
 Intercellular messengers
 Composition of enzymes

Enzymes are large protein molecules that control
the speed of most chemical reactions inside the
cell
Other Protein Functions
 Protect the organism as it makes up antibodies

Antibodies protect the organism from infections and are
essential to clotting and wound repair
 Transfer information from one cell to surrounding
cells

Help maintain the well-being of the organism
 Made up of enzymes

Essential to the chemical release of energy from food
Amino Acids
 The basic composition of proteins
 About 80 are found in nature, 20 are essential
to humans
Lipids
 Fats

Makes up about 2% of a cell
 Excess energy is stored for later use
 Sugar molecules, from which cells usually get their
energy, are converted into lipids for storage if not
needed for current use
 Lipids are not water soluble, but are in alcohol,
ether, oil, and chloroform
Classifications Of Lipids
 Those stored in the inside the cell for energy
 Those used to form the cell membranes and as a
thermal cushion

Also for production of steroids, cholesterol, testosterone,
and estrogen
 Long chain lipids important for pigmentation such
as eye color
 A type of fatty acid involved with muscle
contraction, blood vessel constriction, cell
reproduction, and inflammatory response
Functions Of Lipids
 Storage of energy
 Integral component of cell membrane
 Protection against cold and heat
 Assistance in digestive process
 Components of substances such as hormones
Carbohydrates
 Make up about 1% of the cell
 Provide most of the cell’s energy
 Sugars and starches are typical carbohydrates
 Stored primarily in the liver and muscles
 They release large amounts of energy when
the bonds are broken through metabolism
Classifications of
Carbohydrates
 Monosaccharides

Glucose or fructose

Primary source of cell energy
 Disaccharides

Sucrose, lactose, and maltose


Not easily metabolized
Storage form of energy that can be converted to glucose and used
for energy requirements
 Polysaccharides

Starch, dextrin, cellulose, and glycogen


Used as an energy source
Cellulose is used for structural purposes
Nucleic Acids
 Macromolecules





Blueprint for reproduction
A template for protein synthesis
Transport mechanism to join materials necessary to build
proteins
Control mechanism to regulate the cell’s metabolism and
reproduction
Two types of nucleic acids

DNA and RNA
Cell Structure
 Two major sections of the cell


Cytoplasm
Nucleus

Both are filled with protoplasm
 Nucleoplasm – protoplasm inside the nucleus
 Cytoplasm – protoplasm outside the nucleus

Structures within the protoplasm are called organelles
 Each organelle has a function necessary for cell health and
survival
The Cell
The Nucleus
 Contains the genetic and metabolic
information of the cell
 Similar to the brain of the organism

This controls how that organism functions in its
environment
Nuclear Components
 Nuclear envelope
 Chromosomes
 Nucleolus
 Nuclear sap – the liquid portion of a cell
nucleus
Nuclear Envelope
 Membrane



Separates the nucleus from the cytoplasm
A double-walled structure with a space within
the walls
The only known materials that can pass through
this membrane are RNA’s and some proteins that
are incorporated into the nuclear structure
Chromosomes
 Linear threads in the nucleus
 Composed of protein and DNA
 DNA encodes the
information that controls that
cell’s metabolism and
reproduction
 DNA is considered the
genetic material
 It serves as a template to
produce an exact copy of
itself used in cell division
 Humans contain 46 (23 pairs) of
somatic chromosomes
DNA Structure
 Consists of deoxyribose

Sugar in the backbone
 Phosphoric acid

A phosphate in the backbone
 Four nitrogenous bases

Adenine, guanine, thymine, cytosine

The actual genetic code
DNA Structure
 DNA looks like a twisted ladder
 The bases are the rungs
 The backbones are the sides
 The backbones are made up
of sugar, deoxyribose, and
phosphoric acid
 The backbones are twisted
around each other, forming a
double helix
Genes
 The basic unit of heredity
 Made up of long sequences
of DNA on a chromosome
 Genes are found in pairs
 Some govern the number
of organs and limbs
 Others determine height,
skin and eye color, and
gender
Nucleolus
 A single spherical structure
usually found in the nucleus
 Composed of RNA (ribonucleic
acid)





Controls protein synthesis
Similar to DNA in structure
Its sugar is ribose as opposed
to deoxyribose
The base uracil replaces
thymine
It is a single helix
DNA v. RNA
The Forms Of RNA
 Messenger RNA

Carries the code for specific
amino acid sequences from
DNA to cytoplasm for
protein synthesis
 Transfer RNA

Transfer amino acid groups
to ribosome for protein
synthesis
 Ribosomal RNA


Exists in the ribosomes
Thought to assist in protein
synthesis
Cytoplasm
 All metabolic functions occur
here

The duplication of DNA,
production of hormones, and
converting of sugars to starches


Anabolism
The breaking of the carbonhydrogen bond to release the
energy of glucose

Catabolism
 These functions are used in
energy conversion

This serves to store or release
energy
Cell Membrane
 A selectively permeable
structure
 Analogous to the skin of an
organism – a limiting
mechanism
 Composed of lipids and
membranes
 Transport proteins assist in
the passage of substances
through the membrane and
throughout the cell
Ribosomes
 Function to synthesize
proteins
 Made of ribosomal
RNA
Endoplasmic Reticulum
 A connecting network
between the nucleus
and cytoplasm
 Used to build
carbohydrates and
lipids and
detoxification
Mitochondria
 The source of energy in
the cell
 Contain their own
DNA
 Cardiac muscle cells
have the greatest
number of
mitochondria because
of their great need for
energy
Golgi Apparatus
 Located near the nucleus
 Collect molecules
produced in one part of the
cell, modify, or synthesize
new molecules, package
and distribute them to other
parts of the cells
 Analogous to the digestive
system
Lysosomes
 Part of the intracellular digestive system
 Break down proteins, carbohydrates, lipids,
and nucleic acids and recycle them
 Analogous to the stomach
http://www.youtube.com/watch?v=ekdIEpSf-1I
Location and Function of
Organelles
Cell Division
Somatic Cells
 Mitosis
 Each daughter cell contains the same number of
chromosomes as the parent cell
 This cycle has 5 phases

Four are cell-reproduction phases





Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
 The period between cell division
 Three subphases



G1 – The first subphase where the cell spends most of its
life and where it grows
S – The DNA is replicatedbut stays attached to the
centromere – a region in the middle of each chromosome
G2 – The final subphase in which the organelles are
reporduced
 Spiral filaments called chromatids reproduce
Prophase
 The chromatin granules of the nucleus become
organized into chromosomes
 Each consist of two chomatids
 Chromosomes become shorter and more compact
 The nuclear membrane and nucleoli disappear, the
centriole divides, and two daughter cells move to
opposite poles of the cell
Metaphase
 The paired chromatids arrange themselves in
an equatorial plane midway between the two
centrioles forming the plane
 Cell division can be stopped and radiation
damage can be examined under a microscope
Anaphase
 The chromotids are now called daughter
chromsomes
 They move toward their respective
centrosomes
 The end of their migration marks the
beginning of the next phase
Telophase
 Each daughter cell now contains the same
genetic material as the parent cells
 Two complete cells result from the
cytoplasm’s becoming separated into two
parts
Mitosis
 http://www.cellsalive.c
om/mitosis.htm
The Cell Cycle
Germ Cells
 Meiosis



Cell division that produces germ cells or
reproductive cells
Consists of two successive divisions of the
mother cell
Produces four daughter cells

Contains only half the number of chromosomes
present in somatic cells
Malignant Cells
 Cancer cells
 Divide abnormally and much
more often than normal cells
 Differ physically from normal
cells by virtue of having an
increased number of chromatin
and an increased ratio of nuclear
material to cytoplasm
 In normal tissue, cells usually
stick together
 Some types of cancers
metastasize by allowing cells to
break free of the tumor cite
 Cancer cells show increased
mitotic activity
 http://www.youtube.co
m/watch?v=rrMq8uA_
6iA
 http://www.youtube.co
m/watch?v=r_2bUhSw
dvY
Normal Cells v. Cancer Cells
Cell Death - Apoptosis
 http://www.youtube.com/watch?v=qjjHKDn
12qI
Helpful Websites
 http://www.des.umd.edu/rs/material/tmsg/rs5.html
 http://radtechstudy.nci.nih.gov/
 http://suite101.com/article/understanding-lenzslaw-a54846

This is actually for 50B, but thought you could use it for
Registry review later on
 http://www.nrc.gov/reading-rm/doccollections/cfr/part020/part020-1201.html
Helpful Websites
 http://www.srs.gov/general/pubs/radreport.pd
f
 http://www.nrc.gov/reading-rm/basicref/glossary/total-effective-dose-equivalenttede.html
 http://w3.health.state.ny.us/dbspace/NYCRR
10.nsf/0/8525652c00680c3e8525653000653
1d8?OpenDocument
Helpful Websites
 http://www.ucsf.edu/news/2009/12/8215/new
-research-ct-radiation-exposures-risks-fuelsgrowing-concern
 http://www.ratical.com/radiation/CNR/PP/ch
p2.html
 http://www.umich.edu/~radinfo/introduction/
source.htm
Helpful Websites
 http://holbert.faculty.asu.edu/eee460/radeffec
ts.html
 http://www.radiation-scott.org/radsource/10.htm