Basis of Disease Flashcards
What is meant by the term ‘Mendelian inheritance’? What are the exceptions to this?
Exceptions- not every gene has alleles that are dominant or recessive.
Blood types
that allele pairs separate randomly, or segregate, from each other during the production of gametes: egg and sperm. Because allele pairs separate during gamete production, a sperm or egg carries only one allele for each inherited trait. When sperm and egg unite at fertilization, each contributes its allele, restoring the paired condition in the offspring.
This is called the Law of Segregation.
Mendel also found that each pair of alleles segregates independently of the other pairs of alleles during gamete formation. This is known as the Law of Independent Assortment.
Meaning of ; Symbiotic Commensal Prions Viraemia
Symbiotic - involving interaction between two different organisms living in close physical association.
“the fungi form symbiotic associations with the roots of plant species”
Commensal - Hamless bacteria
Prions - A prion is an infectious agent composed entirely of protein material, called PrP (short for prion protein), that can fold in multiple, structurally distinct ways, at least one of which is transmissible to other prion proteins, leading to disease that is similar to viral infection.
Viraemia - Presence of virus in the blood
Define:
Phenotype
Genotype
Concordance
Discordance
The genotype is the set of genes in our DNA which is responsible for a particular trait.
The phenotype is the physical expression, or characteristics, of that trait.
Concordance, as used in genetics, usually means the presence of the same trait in both members of a pair of twins
Discordance - Absence of disease in twins
Define:
Trisomy
Translocation
Penetrance
Oncogenes
Frmaeshift mutation
trisomy is a type of aneuploidy (an abnormal number of chromosomes)
translocation is a chromosome abnormality caused by rearrangement of parts between nonhomologous chromosomes.
the extent to which a particular gene or set of genes is expressed in the phenotypes of individuals carrying it
An oncogene is a gene that has the potential to cause cancer. In tumor cells, they are often mutated or expressed at high level
a mutation caused by the addition or deletion of a base pair or base pairs in the DNA of a gene
Define:
Downs Syndrome
marfans disease
Turner’s syndrome
Klinefelter’s syndrome
Hemophilia
Down’s syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21.
Marfan syndrome is an inherited disease that affects the body’s connective tissue,
Turner syndrome is a chromosomal condition that affects development in females. The most common feature of Turner syndrome is short stature, which becomes evident by about age 5. An early loss of ovarian function (ovarian hypofunction or premature ovarian failure) is also very common.
Most often, Klinefelter syndrome results from the presence of one extra copy of the X chromosome in each cell ( lack of sexual developmet)
Hemophilia (heem-o-FILL-ee-ah) is a rare bleeding disorder in which the blood doesn’t clot normally.
Sickle cell anaemia
Thalassaemia
Haemolytic disease of the Newborn
Osteogenesis imperfecta
Ehlers Danlos syndrome
Duchenne muscular dystrophy
The term sickle cell disease (SCD) describes a group of inherited red blood cell disorders. (fatigue) affects lungs. heart
Thalassemia is caused by variant or missing genes that affect how the body makes hemoglobin, the protein in red blood cells that carries oxygen. - aneamia - bone problems.
Rhesus disease doesn’t harm the mother, but it can cause the baby to become anaemic and develop jaundice. alloimmune condition that develops in a fetus, when the IgG molecules (one of the five main types of antibodies) produced by the mother pass through the placenta.
Osteogenesis - Weak bones
Ehlers–Danlos syndrome (EDS) is a group of genetic connective tissue disorders. Symptoms can vary from mildly loose joints to life-threatening complications such as aortic dissection
DMD) is a recessive X-linked form of muscular dystrophy, affecting around 1 in 3,600 males, which results in muscle degeneration and premature death. The disorder is caused by a mutation in the dystrophin gene, located on the human X chromosome, which codes for the protein dystrophin.
A patient presents at clinic with a female baby who has cystic fibrosis. Neither the
patient nor their partner has the disorder. What is the likelihood of the next child
having cystic fibrosis? What are the possible reasons for this situation arising?
You need to inherit two copies of the faulty allele to be born with CF. If you have just one copy, you are a carrier, but will not experience any symptoms. If two carriers have a child together, there is a one in four chance (or 25 per cent) of it inheriting the disorder.
The parents are carriers. I
What is a sex linked disorder?
sex-linked disorder - any disease or abnormality that is determined by the sex hormones; “hemophilia is determined by a gene defect on an X chromosome”
What is meant by the ‘Binomial system’ of classification?
The first part of a scientific name is called the genus. The second part of a species name is the specific epithet
What is the difference between:
a) A facultative and obligate parasite
b) Gram negative and Gram positive bacteria
c) Pyrogenic and pyogenic
d) Flagella and pili
If an obligate parasite cannot obtain a host it will fail to reproduce. This is opposed to a facultative parasite, which can act as a parasite but does not rely on its host to continue its life-cycle.
Gram negative cell walls contain a thin peptidoglycan layer (without techoic acids) that is surrounded by a thick plasma membrane. Gram positive bacteria will stain purple because of their thick peptidoglycan cell wall
Pyogenic makes pus and, pyrogenic makes fever/heat
Flagella actually extend from the interior of the cell body. They are mostly composed of flagellin protein. Pili are short, thick straight hair like surface appendages. They are found in gram negative bacteria
Difference between:
e) Vertical and horizontal transmission
f) Bacteraemia and Septicaemia
g) Exotoxin and Endotoxin
In horizontal transmission, viruses are transmitted among individuals of the same generation, while vertical transmission occurs from mothers to their offspring.
Bacteremia is the simple presence of bacteria in the blood while Septicemia is the presence and multiplication of bacteria in the blood. Septicemia is also known as blood poisoning
Exotoxins are toxic substances secreted by bacteria and released outside the cell. Whereas Endotoxins are bacterial toxins consisting of lipids that are located within a cell
How do bacteria differ from other kinds of living organism? How do they reproduce?
Bacterial cells have a cell wall made of polysaccharides and proteins. They do not have a nucleus, but instead they have a circular chromosome of DNA.
Most bacteria reproduce asexually by dividing in two, a process called binary fission. These two new cells grow and then each divides to form two new cells, resulting in a total of four cells with identical DNA from a single parent cell.
. In what ways may bacteria cause dysfunction/disease?
How do they differ in appearance?
athogenic bacteria may enter the body in many ways, such as through the mouth or through cuts in the skin. If they multiply sufficiently they can cause an infection. The infection may be caused by the microbes themselves, or by poisons called toxins that they produce.
Lactobacillus bulgaricus (a rod-shaped
Pneumococcus (a spherical bacterium
What diseases are caused by:
Staphylococcus aureus
Neisseria
Mycobacterium
Minor skin infections, such as pimples, impetigo etc.
It may cause boils (furuncles), cellulitis folliculitis, carbuncles.
It is the cause of scalded skin syndrome and abscesses.
It may lead to lung infections or pneumonia.
Brain infections or meningitis.
Bacteria and viruses are the two main causes of meningitis. The bacterium Neisseria meningitidis, also called meningococcus, causes meningococcal meningitis.
Mycobacterium - Leprosy
What is unique about fungus?
How cna it harm?
Fungal cells have a cell wall made of chitin (remember that plant cell walls are made of cellulose).
Some fungi are pathogens, for example the fungal infection which causes athlete’s foot
