Flashcards in chapter 4 Deck (21):
In 1902 an english physician and geneticsit studied ALKAPTONURIA a human disease characterized by urine that turns black upon exposure to the air and by a tendency to develop arthritis later in life. because of the urine phenotype the disease is easily detected soon after birth.
Archibald Garrod, geneticist William Bateson
most genetic diseases are recessive-meaning that to develop any "disease" and individual must inherit one recessive mutant allele for the gene responsible for the disease from each parent, making that individual homozygous for the allele.
an individual needs identical alleles from both parents in order for a disease to express itself and it makes an individual homozygous meanning that it has both the same identical alleles.
when a genetic disease is determined it is termed________
inborn error of metabolism
in 1942 heralded the beginnings of biochemical genetics, a branch of genetics that combines genetics and biochemistry to explain the nature of metabolic pathways.
George Beadle and Edward Tatum`
what is a mycelium
a web like growth of fungus like a spider web....
A strain that can grow on a minimal medium is called
prototrophic strain or prototroph
a mutant strain of an organism that cannot synthesize a molecule required for growth and therefore must have the molecule supplied in the growth medium for it to grow.
a mutation that effects an organism's ability to make a particular molecule essential for growth
auxotrophic mutation, or nutritional mutation
an xray that acts as an agent that induces mutants.
an enzyme deficiency caused by a mutation may either have simple effects or ________ effects.
affects children who cannot metabolize phenylalanine and thus will accumulate making it harmful for children. Excess phenylalanine is converted to phenylpyruvic acid which drastically affects the CNS. sereve mental retardation, slow growth rate, and early death
a genetic disease affecting hemoglobin, the oxygen-transporting protein in red blood cells.
why do people with sickle cell anemia have problems with oxygen?
because of the shape of the cell it is not round and will therefore affect oxygen transport because the cell is not able to move freely and they tend to clog capillaries.
In people with sickle cell anemia what is affected?
Mostly the extremities however, oxygen deprivation occurs also at the heart, lungs, brain, kidneys, gastrointestinal tract, muscles, and joints.
a disease that lacks the enzyme tyrosianse that helps convert tyrosine to DOPA from which the brown pigment melanin derives. Melanin absorbs light in the ultraviolet range and protects the skin against harmful UV radiation from the sun
Why will a child born with PKU not exhibit sings of the disease for a couple of weeks to a month?
the child is still using the maternal enzymes to convert the phenylalanine.
Disease that is caused by an increase in uric acid and the inability to break down purines mostly occurs in males why?
Lesch-Nyhan Syndrome and because it is a recessive mutation in the x chromosome of males.
a human disease that causes pancreatic, pulmonary, and digestive dysfunction in children and young adults affects 1/2000 caucasians typical of the disease is an abnormally high viscosity of secreted mucus.
Advise to people based on analysis of 1. the probability that patients have a genetic defect; 2. of the risk that prospective parents may produce a child with a genetic defect.
The study of a family tree and careful compilation of phenotypic records of both families over several generations