CYTO FINAL Flashcards
are the structures that hold all of our genes.
Chromosomes
are simple the instructions that
tell the body how to grow and develop.
Genes
Two basic types of Chromosome abnormalities
numerical and structural which can occur
simultaneously.
Normal human somatic cells have ___chromosomes
46
Germ cells (egg and sperm) have 23 chromosomes: one copy of each autosome
plus a single six chromosomes. This is referred to as the
haploid number.
Normal human somatic cells have 46 chromosomes: 22 pairs, or homologs, of
autosomes (Chromosome 1-22) and two sex chromosomes. This is called the
diploid number.
refers to differences between members of the same species or those of
different species
Genetic variation
are due to mutations in particular genes
Allelic variations
are substantial changes in chromosome structure
Chromosomal aberrations
Chromosomal aberrations are also known as
chromosomal mutations
Chromosomal aberrations typically affect ___________________________ gene
more than one
two primary ways in which the structure of chromosomes can be altered:
1.The total amount of genetic information in the chromosome change
2. Genetic material may remain the same in number, but is re arranged
Examples for decrease in chromosome
Deficiencies/Deletion
Examples for increase in chromosome
Duplication and Insertion
Examples for rearrangement in chromosome
a. Inversions
b. Translocations
involve loss of material from a single chromosome. The effects are typically severe
since there is a loss of genetic material
DELETION
-Deletions ______________ because the DNA is
gone (degraded)
do not revert
Possible causes of Deletion
-Radiation, UV, Chemicals, viruses may
increase breakage
-the effect of a deletion depends on what was
_____________
deleted
Types of Deletion
Terminal Deletion
Interstitial Deletion
It involved a single break and the terminal part of the chromosome is lost.
1.Terminal Deletion-
Deletion that does not involve the terminal parts of a chromosome
2.Interstitial Deletion-
A deletion in one allele of a homozygous wildtype organism may give a ________________
normal phenotype
deletion in the wild-type allele of a heterozygote would produce a ______________________
mutant phenotype.
Deletion of the centromere results in an _____________________ that is lost, usually with
serious or lethal consequences.
acentric chromosome
resulting from deletion of
part of the short arm of chromosome 5
Cri-du-chat
result from doubling of chromosomal segments, and occur in a range of
sizes and locations
Duplications
duplications are adjacent to each other.
Tandem duplications
duplications result in genes arranged in
the opposite order of the original.
Reverse tandem duplications
Tandem duplication at the end of a chromosome
terminal tandem duplication
Example of condition caused by duplication
Drosophila eye shape in flies, Charcot–Marie–Tooth Disease
The lack of muscle, a high arch, and claw toes are signs of this genetic disease.
Charcot–Marie–Tooth Disease
caused by duplication of the gene encoding peripheral myelin protein 22 (PMP22)
on chromosome 17.
Charcot–Marie–Tooth Disease
-occur when there are two breaks within a single chromosome and the broken segment flips 180 degrees (inverts) and reattaches to form a chromosome that is structurally out-
of-sequence.
INVERSIONS
-There is usually no risk for problems to an individual if the inversion is of ________ origin
familial
Inversion involving the centromere
Pericentric Inversion
Inversion not involving the centromere
Paracentric Inversion
a fragment without a centromere.
Acentric Fragment
in an inversion chromosomes separate in
ANAPHASE I
CONSEQUENCIES OF CHROMOSOME INVERSION IN HUMANS
lowered fertility due to production of unbalanced gametes
involve exchange of material between two or more chromosomes.
-Translocation
If a translocation is _________________ the risk for problems to an individual is similar to that with _______________: usually none if _______ and ______________ if de novo.
reciprocal (balanced), inversions, familial, slightly increased
There are two main types of Translocation:
- Reciprocal (Balanced) Translocation
2.Robertsonian (unbalanced) Translocation
*Both types are capable of causing disease in human
-the transfer of genetic material occurs in only one direction
-are associated with phenotypic abnormalities or even lethality
ROBERTSONIAN TRANSLOCATIONS
Examples of ROBERTSONIAN TRANSLOCATIONS
Familial Down Syndrome
The individual would have three copies of genes found on a large segment of
chromosome 21;
Familial Down Syndrome
In Familial Down Syndrome the majority of chromosome ___ is attached to chromosome ___
21, 14
-This translocation occurs as follows:
- Breaks occur at the extreme ends of the short arms of ______________________ chromosomes
- The __________________ fuse at their centromeric regions to form a single chromosome
- The ______________________ are subsequently lost
two non-homologous
acrocentric, larger fragments, small acrocentric fragments
- This type of translocation is the most common type of chromosomal rearrangement in humans
ROBERTSONIAN TRANSLOCATIONS
-Robertsonian Translocations are confined to chromosomes ________________
13, 14, 15, 21 (the acrocentric chromosomes)
Most human malignant tumors have _________________________ in which most common are ______________________
chromosomal mutations, translocations
Follicular lymphoma is a type of _______________________
non-Hodgkin lymphoma.
It develops when the body makes abnormal B-lymphocytes – the lymphoma cells.
Follicular lymphoma
The most common symptom is a painless swelling
in the neck, armpit or groin.
Follicular lymphoma
- High grade tumor
- Uniform appearance of abnormal cells
- t(8;14); t(8;22) or t(8;2)
- Endemic in equatorial Africa
Burkitt’s Lymphoma
a structure where a chromosome has lost one of its arms, and the replacement arm is
an exact mirror image of the remaining arm
ISOCHROMOSOMES
example of ISOCHROMES
Pallister-Killian mosaic syndrome
o a developmental disorder that affects many parts of the body.
o characterized by extremely weak muscle tone (hypotonia) in infancy and early
childhood, intellectual disability, distinctive facial features, sparse hair, areas of
unusual skin coloring (pigmentation), and other birth defects.
Pallister-Killian mosaic syndrome
involve the loss and/or gain of a whole chromosome or
chromosomes and can include both autosome and sex chromosomes.
Numerical abnormalities
Numerical abnormalities examples
Down Syndrome, Edward’s Syndrome
Changes in number of whole chromosomes is called
heteroploidy
The number of chromosomes
in a basic set is called the
monoploid number
designates genomes containing
chromosomes that are multiples of some basic number
euploidy
Those euploid types whose number of sets is
greater than two
polyploid.
refers strictly to the number of chromosomes in gametes.
haploid
have a single basic set of chromosomes,
Monoploids
_____________ is common in plants and rare in animals.
Monoploidy
Any organism with more than two genomes
Polyploidy
changes that involve parts of a chromosome set results in individuals
ANEUPLOIDY
the loss of one or more chromosomes
hypoploidy
addition of one or more chromosomes to the complete chromosome set
hyperploidy
substraction (or loss) of a single chromosome, 2n-1
monosomy
the loss of one pair of chromosome, 2n-2
nullisomy
addition of a single chromosome 2n+1
trisomy
addition of pair of chromosome 2n+2
tetrasomy
Diploid organisms which are missing one chromosome of a single pair
monosomic
An organism which has lost a chromosome pair
nullosomic.
diploid organisms which have an extra chromosome
Trisomics
Further, when the extra chromosome
is identical to its homologs,
primary trisomic.
means that the extra chromosome should be an isochromosome
secondary trisomic
the extra chromosome should be the
product of translocation.
tertiary trisomic
Trisomy 21
Down Syndrome
the most common
chromosomal abnormality in live births (1/650 births).
Down Syndrome
It is characterized by multiple malformations, primarily low-set ears; small
receding lower jaw; flexed and clenched fingers; cardiac malformations; and
various deformaties of skull, face and feet. Harelip and cleft palate often occurs.
Death takes place around 3 to 4 months of age. Trisomy-18 children show
evidence of severe mental retardation, which is more pronounced in females
(the reason is still not clear).
Edward’s Syndrome
Trisomy 18
Edward’s Syndrome
Individuals appear to be markedly mentally retarded; have sloping forehead, harelip and cleft palate. Polydactyly (both hands and feet) is
almost always present; the hands and feet are deformed. Cardiac and various
internal defects (of kidney, colon, small intestine) are common.
Patau’s Syndrome
Trisomy 13
Patau’s Syndrome
Short stature- treated with hormonal therapy
Gonadala dysgenesis, primary amenorrhoea
Average intelligence, short webbed neck (pterygium colli); low posterior
hairline;broad/shield chest; palms and feet edema (newborns)
Turner Syndrome (45, X)
frequency of Turner Syndrome
1:2000-2500
Tall stature; average intelligence; male psychosocial orientation;
hypoplastic testes, cryptochism; sterility- azoospermia; gynecomastia
(enlargement of breast in male)
Klinefelter’s Syndrome (47, XXY)
frequency of Klinefelter’s Syndrome
1:500-1000
Robust growth (proportional) especially to height
Average intelligence; normal sexual development; normal fertility
without risk of chromosomal aberrations in offspring
Controversy- affected psychosocial development
XYY Syndrome (Supermale; 47, XYY)
1:1000; no specific phenotype
Average intelligence; normal sexual development; decreased fertility
(spontaneous abortions) without risk of chromosomal aberrations in
offspring
No increased occurrence of congenital disorder over to population risk
XXX Syndrome (Superfemale; 47, XXX)
The diploid organisms having two extra chromosomes
tetrasomic.
simply a picture of a person’s chromosomes.
Karyotyping
Karyotyping are most often, this is done using the chromosomes in
white blood cells.
is an organized profile of a person’s chromosomes,
karyotype
is nothing more than a rare, uncommon version of a trait as when a person
is born with six toes on each foot instead of five.
A genetic abnormality
is recognized set of symptoms that characterize a given disorder,
syndrome
is an inherited condition that sooner or later will cause mild to severe medical problems.
genetic disorder
is illness caused by infectious disease, dietary, or environmental factors, not caused by inheritance of mutant genes.
disease
is a disease caused by abnormalities in an individual’s genetic material
genetic disorder
This type is caused by
changes or mutations that occur in the DNA sequence of one gene.
Single-gene (also called Mendelian or monogenic)
This type is caused by a
combination of environmental factors and mutations in multiple genes.
Multifactorial (also called complex or polygenic)-
There are more than _____ known single-gene disorders,
6,000
Examples Include: Cystic Fibrosis, Obesity, Alzheimer’s Disease
Single-gene
Examples: Heart Disease, Huntington’s Disease, Marfan Syndrome
Multifactorial
Some types of
major chromosomal abnormalities can be detected by _______________ examination.
microscopic
abnormalities in chromosome structure as missing or extra copies or gross breaks and rejoining (translocations) can result in disease.
Chromosomal
is a common disorder that occurs when a person has three copies of chromosome 21.
Down syndrome or trisomy 21
Examples: Down Syndrome (T21), Klinefelter’s Syndrome, Trisomy 18, Cri-Du-
Chat Syndrome
Chromosomal
This relatively rare type of genetic disorder is caused by mutations
in the non-chromosomal DNA of mitochondria.
Mitochondrial
Examples Include: Leigh Syndrome, Pearson Syndrome
Mitochondrial
(inability to see color)
Achromatopsia
(reduction in adrenal gland function)
Adrenal Hypoplasia Congenita
(no melanin pigment in eyes, skin and hair)
Albinism/Hypopigmentation
(degenerative disease starting with memory loss)
Alzheimer’s
(poor or indistinct vision)
Amblyopia
(immunodeficiency disorder)
Ataxia Telangiectasia
(brain development disorder)
Autism
(Fatal, autosomal recessive neurodegenerative disorder)
Batten Disease
(progressive vision loss)
Best’s Disease
(physical disability in human development)
Cerebral Palsy
(formation of abnormal hemoglobin molecules)
Cooley’s Anemia/Thalassemia
(progressive disability due to multisystem failure)
Cystic Fibrosis
(autosomal recessive disorder of the renal tubules)
Cystinosis
(Impairment of cognitive ability, physical growth & facial
appearance)
Down Syndrome
(disorder of the autonomic nervous system)
Epidermolysis Bullosa & Familia Dysautonomia
(Deficiency Anemia)
G6PD (Glucose-6-phosphate Dehydrogenase)
(deficiency of the enzyme glucocerebrosidase)
Gaucher’s Disease
(disease of the optic nerve)
Glaucoma
(inefficient control over blood clotting or
coagulation)
Hemophilia/Bleeding Disorders
(abnormal body movements)
Huntington’s Disease
(abnormal body movements)
Hurler Syndrome
(small testicles and reduced fertility)
Klinefelter Syndrome
(fatal degenerative disorder of nervous system)
Krabbe Disease
(loss of vision)
Leber Congenital Amaurosis
(progressive degeneration of the white matter of the brain)
Leukodystrophies
(progressive muscle weakness)
Muscular Dystrophy
(disorder affecting lipid metabolism)
Neimann-Pick Disease
(benign hamartomatous polyps in gastrointestinal tract)
Peutz-Jeghers Syndrome
(deficiency in enzyme phenylalanine hydroxylase)
Phenylketonuria (PKU)
(accelerated aging)
Progeria
(dropping upper eyelid or breasts)
Ptosis
(abnormal, rigid, sickle shape of red blood cells, abnormal hemoglobin)
Sickle cell Anemia
(Abnormal bone and cartilage development)
Skeletal Dysplasias
(incompletely formed spinal cord)
Spina Bifida
(usually affects nervous tissue of the brain)
Tay-Sachs Disease
(premature aging)
Werner Syndrome
(“elfin” facial appearance, with low nasal bridge)
Williams Syndrome
is defined as the modification of the genetic information of living organisms by
direct manipulation of their DNA rather than by the more indirect method of breeding
Genetic engineering
is also called as gene cloning, recombinant DNA technology or gene
manipulation.
Genetic engineering
is the general name for taking a piece of one DNA and combining it with
another strand of DNA.
Recombinant DNA
Recombinant DNA is also sometimes referred to as _____________________
“chimera”.
- TRANSFORMATION
o First step in transformation is to select a _____________________to be inserted to a vector.
o Second step is to cut that piece of DNA with a ___________________ and then ligate
the DNA insert into the vector with ______________. The insert contains a selectable
marker which allows for identification of recombinant molecules; an antibiotic
marker is often used so a host cell without a vector dies when exposed to a
certain antibiotic, and the host with the vector will live because it is resistant.
o The vector is inserted into a host cell, in a process called _______________. One
example of a possible host cell is _______________. The host cells must be specially prepared
to take up the foreign DNA.
piece of DNA , restriction enzyme, DNA ligase, transformation, E. coli
This is a process very similar to Transformation, which was described above.the
only difference between the two is that non-bacterial does not use bacteria such
as E.coli for host.
Non-Bacterial Transformation
the DNA is injected directly into the nucleus of the cell being transformed.
microinjection
the host cells are bombarded with high velocity
microprojectiles, such as particles of gold or tungsten that have been coated
with DNA.
biolistics
is the process of transfection, which is equivalent to
transformation except a phage (a virus that infects a bacteria) is used instead
of bacteria.
Phage Introduction
is the process of identifying and isolating DNA from living or dead cell and
introducing it into another living cell.
Genetic engineering
is a treatment that involves altering the genes inside your body’s cells to stop
disease.
Gene therapy
such as exonuclease, endonucleases,
Enzymes-
is the insertion of genes into an individual’s cells and tissue to treat a disease,
such as a hereditary disease in which a deleterious mutant allele is replaced with a functional
one.
Gene therapy
A normal gene may be inserted into a __________________ within the genome to replace
a nonfunctional gene. This approach is most common
nonspecific location
An abnormal gene could be swapped for a normal gene through ______________________
homologous recombination.
The abnormal gene could be repaired through _______________________, which returns
the gene to its normal function.
selective reverse mutation
is used to replace the entire mitochondria that carry defective mitochondrial DNA
Spindle transfer
cells with healthy genes may be introduced in the
affected tissue, so that the healthy gene overcomes the defect without affecting the
inheritance of the patient.
Patient therapy-
the genetic constitution of embryo at the post-
zygotic level is altered so that the inheritance is altered.
Embryo therapy
Conditions or disorders that arise from mutations in a ____________ are the best candidates for gene therapy.
single gene
