8 MUTATION Flashcards
so long diseases.71
refers to any change in the genetic material of the organism
Mutation
may result from a change in the base sequence of the DNA in the chromosome
mutation
may
appear as totally unique from the other members of its species
mutant organism
Mutation can be categorized
into
somatic mutation
germ mutation
mutation occurs in any body cell except egg cell; not passed on to offspring
since it ceases to exist when the organism die.
Somatic mutation
mutation occurs in the reproductive cell; can be transmitted to offspring and
be passed on from one generation to another.
Germ mutation
Classification of Mutation
a) Mutation due to changes in chromosome number
b) Mutation due to change in chromosome structure
c) Gene mutation
Irregularities in the chromosomes may occur during cell division or by accident such
as exposure to radiation resulting to ____
Chromosomal Aberrations/
aberrant chromosome
Aberrations may include the:
a) whole genome,
b) entire single chromosome, and
c) part of the chromosome.
Aberration may be a change in the ____ of the chromosome or a change in the
____ of the chromosome
structure
number
(a change in the entire set of the chromosome
euploidy
loss or addition
of a single whole chromosome)
aneuploidy
euploidy that carry only one genome
Haploid
euploidy that carry 2 genomes
Diploid
euploidy that carry 3 genomes.
Triploid
euploidy that carry 3 or complete set of chromosomes
Polyploids
Polyploidy is a characteristic more common in ____
plants than in animals
at least ____ of
the grasses are polyploids
2/3
polyploids have an imbalance in the sex determining
mechanism resulting to ____ due to aberrant meiosis
sterility
are characterized by the multiplication of a single whole genome or
chromosome set.
Autopolyploids
Polyploid plants are characterized by;
- Increased in the individual cell size.
- Slower growth rate and later maturity than diploids.
-
Thicker leaves, larger but fewer flowers, and larger fruits than diploids, reduce fertility
in varying degrees.
are characterized by the multiplication of two or more genomes or
chromosome sets
Allopolyploids
Allopolyploids are responsible for the formation of the new species such as ____
wheat,
tobacco, and Raphanobrassica
are usually fertile and possess many of the characteristics of the autopolyploids
Polyploidy in Human result to?
a) Spontaneous aborted fetus
b) Stillborn
c) Some live for an hour but gross malformations.
Theories on the origin of polyploid human embryo?
a) Fusion of normal haploid gamete with a diploid gamete (little evidence)
b) Fertilization of normal haploid egg by more than one sperm cell (no evidence for humans, a little evidence for rabbits and rats).
occurs when one or more chromosomes of a normal set (genome) are
lacking or are present in excess
Aneuploidy
they have incomplete genome
Aneuploidy
Trisomy 21
(Down Syndrome)
Trisomy 18
(Edward Syndrome)
Trisomy 13
(Patau Syndrome).
2n = 45, 22II + X
Turner’s Syndrome
2n = 47, 22II +XXY
male with female features
Klienfelter’s Syndrome
47, XXX
Metafemale
Triplo-X Syndrome
mental retardation and premature
menopause
47, XYY
Double Y Syndrome
Jacob’s Syndrome
antisocialism,
aggressiveness, criminal tendency, and low IQ
Each break may produce two ends that may follow any of the
following paths?
- Broken ends may remain not united, leading to eventual loss of segment, which does not include the centromere.
- Same broken ends may reunite immediately.
- Broken ends may join with those produce by another break causing an exchange or non-restitutional union
Types of Structural Changes in the Chromosome:
- Deficiencies or Deletions
- Duplication or Repeats
- Inversion
- Interchange or Reciprocal Translocation
a loss of segment of the chromosome
Deficiencies or Deletions
Examples of chromosomal deficiency in man:
a) Philadelphia 22 chromosome
b) Cri-du-chat Syndrome
a deficiency for the large portion of long arm of
chromosome 22
Philadelphia 22 chromosome
due to the deletion in the short arm of the chromosome 5
Cri-du-chat Syndrome
cat-like cry during infancy, unique facial feature and other form of physical and mental retardation
occur when the section of the chromosome is in excess of the
normal amount
Duplication or Repeats
due to the rotation of chromosome segment to a full 180
degree
Inversion
Genetic consequences of inversion: with normal behavior, with complete fertility but
with a new linkage order, may be ____.
partially or completely sterile
Inversion can be classified as;
paracentric inversion
Pericentric inversion
which occurs when the centromere is not included in the inverted
segment.
paracentric inversion
which occurs when the inverted segment includes the centromere
Pericentric inversion
occurs when the single break in two non-homologous chromosomes produce an exchange sections between them
Interchange or Reciprocal Translocation
mutation involves a change in the nucleotide
Gene mutation
There are two
categories of gene mutation;
(1) base pair substitution and
(2) frameshift mutation
due to copy errors during DNA replication (in gene mutation)
Base pair substitution
There are two
types of base pair substitution
- the transversion mutation
- the transition mutation
is due to the substitution purine with another purine or the
substitution of one pyrimidine with another pyrimidine
Transition mutation
efers to the substitution of purine with
pyrimidine or substitution of pyrimidine with purine.
Transversion mutation
There are three kinds of amino acid substitution?
- Non-sense mutation
- Missense mutation
- Same sense mutation
refers to a base pair substitution that results to the formation of a
termination or non-sense codon
Non-sense mutation
refers to a base pair substitution that results to the substitution of an
amino acid in the polypeptide chain
Missense mutation
refers to a base pair substitution that does not change the type of
amino acid in the polypeptide chain
Same sense mutation
an insertion or deletion of a base that changes the reading frame
of the entire subsequent sequence
Frameshift mutation
. Anything that can
cause or induce mutation is known as?
mutagenic agents
Mutagenic Agents Classification
Physical mutagen
Chemical mutagen
Environmental mutagen
Kinds of Physical mutagen
Ionizing Radiation
Non-ionizing Radiation
examples of ionizing radiation
x-ray
gamma ray
example of non-ionizing radiation
UV rays
can break the DNA strand (produce break in the chromosome rather than a base change). It can effectively killed viruses with single stranded DNA.
Ionizing radiation
does not penetrate deeply into the tissues but effective in killing bacteria and fungus
and may cause skin cancer
Non-ionizing radiation
Non-ionizing radiation can result in the
(a) distortion of DNA
molecule, and
(b) cross-linking between adjacent DNA molecules, which stops DNA
replication.
Mechanism of action of nitrous acid
Changes C to Uracil
Changes CG pair to TA pair
Mechanism of action of base analogues
Substitute for DNA bases
(bromouracil similar to thymine substitute T
during DNA synthesis)
Mechanism of action of proflavin and other dyes
Inhibits spindle formation and prevents
anaphase
Mechanism of action of colchicines
- Blocks mitotic cells in metaphase
- Binds to soluble tubulin to form tubulin-colchicine complexes in a poorly reversible manner preventing the elongation of microtubule polymer
Mechanism of action of mustard gas (sulfur mustard)
Genotoxic mechanism of action (DNA alkylation leading to cross-link formation, inhibition of DNA synthesis and repair, point mutations, and induction of chromosometype and chromatid-type aberrations
component of marijuana
delta – 9 – THC
or
delta-9-tetrahydrocannabinol
Mechanism of action of hair dye components
- Mutagenic in bacteria (induce mutation by chromosome breakage, sister chromatid exchanges)
- Malignant transformation in mammalian cells
- Mutation in Drosophila
- Induce mitotic recombination in yeast
- Induce tumors in rodents
Potentially mutagenic chemical inducing cancer in humans
carcinogen
Mutagenic chemicals
- air and water pollutants
- food additives
- food preservatives
- agricultural chemicals
carcinogens of air and water pollutants
benzo – a – pyrene
carcinogens of food additives
hydrocarbon produced in the cooking of meat
carcinogens of food preservatives
aflatoxin produced in some grains such as peanut and
corn
carcinogens of agricultural chemicals
some components of commercially available dyes
There are ways by which the chemicals in the environment can be screened for its
mutagenicity
host-mediated assay and the Ames Test.
During the biblical times, ____ was considered as the most threatening disease
leprosy
____ or “black death” during the middle ages
bubonic plague
“white death” or ____ on the
last century; and cancer in the modern ages
tuberculosis
is a common term for aggressive and usually fatal form of a large class of disease known as neoplasm
cancer
is a condition by which the biological mechanisms that
govern the growth and metabolism of a normal cell and the overall interactions of living
organisms are not followed
neoplasm
in neoplasm the following may occur?
a) some cells grow rapidly than tissue from where they arise, and
b) others grow at a normal pace
The changes seen in ____ are usually heritable since these characteristics are passed on from its cell to its progeny or daughter cells.
neoplasm
Classification of neoplasm
Benign neoplasm
Malignant neoplasm
encapsulated
its structure is similar to the tissue from where they were derived
do not metastasize (begin to grow at sites other than the point of origin)
Benign neoplasm
not encapsulated
has an abnormal and unstructured appearance with abnormalities in chromosomes
structure (DNA molecule that constitute the genetic material is duplicated and passed
on to later generation)
Grow rapidly than benign forms
metastasize (invade adjacent, normal tissue)
Malignant neoplasm
chemical agents that can cause cancer
components of cigarette smokes
Hydrocarbons and nitrosamines
chemical agents that can cause cancer
component in dye making
Aromatic amines (2 –
naphtylamine )
chemical agents that can cause cancer
Drugs for cancer treatment
Break the DNA strands of cancer cells, thus killing the cell. However, they might also induce cancer in normal cells
chemical agents that can cause cancer
Hormones
Estrogen - female hormone that is being administrated in menopausal women may result in cancer
of the uterus (solution: estrogen is administered together with progesterone)
chemical agents that can cause cancer
molecule produced by the strains of mold Aspergillus
causing liver cancer
Naturally occurring chemicals
in molds and plants (aflatoxin)
causing shistosomiasis may also cause bladder cancer
Blood flukes
may cause cancer of the nose and throat
Epstein barr viruses, Papilloma virus and Herpes virus
Seven Warning Signals of Cancer
- Change in bowel or bladder functions.
- A sore that does not heal
- Unusual bleeding or discharge
- Thickening or lump in the breast or elsewhere
- Indigestion or difficulty in swallowing
- A change in wart or mole
- Nagging cough or hoarseness
common types of cancers
breast cancer
lung cancer
prostate cancer
skin cancer
caused by excessive exposure to sunlight
skin cancer
increases dramatically with age; about 80% diagnose in men over 65 years of age
prostate cancer
Principally caused by tobacco smoking
lung cancer
leading killer of women worldwide
breast cancer
breast cancer should be detected earlier by?
self-examination of the breast or mammography
(successful in detecting tumors at early stage)
breast cancers can be treated by?
mastectomy or lumpectomy, followed by chemotherapy
It is estimated that lifetime smoking of more than ____ cigarettes will always lead to cancer of the lungs unless the smokers died prematurely of another cause.
750,000
has no cure, since at the time of diagnosis cancer might already metastasize
