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GI module 3 part 3: Green
Terms in this set (102)
How do we make nucleotides?
through good nutrition, proteins
What happens to dietary nucleates in our digestive tract?
we excrete it as uric acid
where are nucleotides synthesized?
in cytoplasm of all tissues
what are the source of components for pyrimidines and purine?
Atp, Amino Acids, and folic acid
What are salvage pathways?
Recycle free bases by reattaching them to an activated ribose
why do we need salvage pathways?
it takes a lot of energy to make bases from brand new
What is orotic aciduria?
autosomal recessive disease where individuals have low activities of BIFUNCTIONAL protein and are impaired in the ability to make pyrimidines
symptoms for orotic acuduria
"failure to thrive" macrocytic megaloblastic anemia
treatment of orotic aciduria
what happens during Lesch-Nyhan syndrome
HGPRT deficiency--> catalyzes two reactions with purine bases
--- in boys and x-linked
symptoms of Lesch-Nyhan syndrome
mild to severe mental impairment, involuntary movements, self mutilation
Why do patients of lesch-nyhan develop these syndromes?
the brain is dependent on purine salvage and they have very high uric acid levels. they cannot recycle hypoxanthine or guanine and will convert to uric acid
what is folic acid?
a vitamin that carries one carbon units in a variety of enzymatic reactions. they help purine and pyrimidine biosynthesis and good for rapid cell growth
Structure of folate
pterin ring, p-aminobenzoate, and a polyglutamate tail
diff between folate and folic acid?
folic acid is the oxidized form in vitamin pills
How can a folic acid deficiency affect pregnancy?
it can cause neural tube defects
Examples of neural tube defects?
1. anencephaly: usually fatal
2. spina bifida: individuals who are mentally impaired and variable amounts of paralysis
How do we prevent birth defects with folic acid deficiency?
we supplement breads and cereals with folic acid
How do we treat cancer with folic acid?
Cytotoxic anti-folate chemotherapies
Side affects of anti-folate chemotherapies
they kill all cells, not just cancer
1. gastric mucosa: nausea and vomiting
2. hair follicle cells: hair loss
What is fluorouracil?
chemotherapy drug that inhibits thymidylate synthesis which is needed for cancer cells to make DNA
how does flurouracil work?
it is converted into a toxic form in the body and will bind irreversibly to thymidlate synthase
What is methotrexate?
cancer cells need DHFR to regenerate tetrahydrofolate. but methotrexate will inhibit DHFR and starve cells for folate and cause cell death
What is hydroxyurea?
inhibits ribonucleotide reductase, which is important because it is needed by all cells to make all the deoxyribonucleotides
-DATP is a powerful inhibitor
How can we treat folate with antibiotics?
drugs are not poisonous to humans since humans cannot make folic acid, but bacteria do
What are sulfa drugs?
acts as a substrate for a folate biosynthetic enzyme and incorporates itself into the growing folate molecule. bacteria cannot transport folate and will diet and be starved
What is the difference between the way purines and pyrimidines are metabolized?
1. Humans can break down the pyrimidine into energy-yielding metabolite but it is not a major source of ATP
2. Humans cannot break down purine to make ATP and will convert it into uric acid
What is more common, diseases with purine breakdown or pyrimidine?
What is SCID (Severe combined immunodeficiency disease)
-defiecency with Adenosine Deaminase--- cannot generate functional B or T cells. Children cannot fight off infections and die by 2 years
how do you diagnose SCID?
initial diagnosis by early recurring infections. confirmed by measurement of enzyme levels of blood cells
what is the pathogenesis of SCID?
Ribonucleotide reductase is inhibited and cells are unable to divide
What are the three ways to treat SCID?
1. Enzyme replacement therapy: provide the enzyme intravenously
2. Stem cell transplantationL: inject stem cells from compatible donor, which can make the missing enzyme
3. Gene therapy
What is Gout?
chronic hyperuricemia with acute attacks of inflammatory arthritis due to grate crystals in joints
what is hyperuricemia?
high serum urate
What can cause too much serum urate?
1. production of too much uric acid (Excessive cellular breakdown)
2. excretion of too little uric acid (excessive renal retention)
What are the factors that gout can depend on?
1. age( more older than younger)
2. sex (more in male)
4. drug use
5. physiology of individual may vary
How do drugs make gout?
1. drugs can increase the acidity of a tissue and can act as a diuretic and decrease the amount of liquid in which the uric acid is dissolved
2. the renal excretion of uric acid is inhibited
What are the symptoms of gout?
1. High serum rate males > 7.0, females >6.0
in females, estrogen blocks urate reabsorption in kidneys
2. urate cyrstals form deposits (tophi) which are destructive to tissue (cells take up crystals by phagocytosis and rupture and release lysosomal enzymes in the tissue and induce inflammatory response)
3. nephropathy- uric acid urate crystals form in kidney and damage it
how is gout diagnosed?
during first inflammatory attack of arthritis and is confirmed when samples of tissue fluid reveal the appropriate crystals
Where is uric acid usually?
in low ph environments such as the liver
What is allopurinol?
a drug that inhibits xanthine oxidase and will produce compounds that are easier to excrete than uric acid
What is febuxostat?
alternative to allopurinol
How does probenecid work?
it blocks reabsorption in kidney and will facilitate excretion of uric acid
what is colchicine>
prevents and blocks the inflammatory response that causes the pain with gout. it inhibits the microtubules preventing the cell from phacoytosing the crystals of uric acid
what is indocin?
a non-steroidal anti-inflammatory agent
why is there usually no disorders in glycolytic enzymes?
they are so important, it would end up resulting in death
what tissue/cell is most dependent on anaerobic glycolysis?
Red Blood Cells
what is released from cells when they are damaged?
What are the symptoms of pyruvate kinase deficiency (partial)?
hemolytic anemia and jaundice
what is the treatment of pyruvate kinase deficiency?
blood transfusions, removal of the spleen
what is the mechanism for pyruvate kinase deficiency?
red blood cells need it for anaerobic glycolysis
What are the symptoms of glucokinase deficiency?
intrauterine growth retardation, insulin-treated diabetes mellitus from birth (MODY2)
what is the mechanism for glukokinase deficiency?
lack of expression in liver and pancreatic B cells results in decreased glucose trapping in liver and impaired insulin secretion
what is the treatment for glukinase deficiency?
what happens to heterozygous parents of glucokinase deficiency?
they lack symptoms but have hyperglycemia
what is sucrase an example of?
a digestive enzyme that uses water to Cleave disaccharide into monosaccharides...they are attached to the brush border of the small intestine
What is a trehalase?
it cleaves trehalose, a disaccharide of glucose.
where is trehalose found?
in fungi (mushrooms), algae, and insects
what are the symptoms of a trehalase deficiency?
diarrhea/ gas upon consumption of Trehalose because it cannot be absorbed but bacterial will
is trehalase deficiency rare or common?
how does lactase expressions vary with age?
in infants it is high and it starts decreasing after and will be mostly lost in adulthood
what race typically has a lactase deficency?
African or asian ancestry
what are symptoms of a lactase deficiency?
diarrhea, gas upon consumption of lactose
what is celiac disease?
auto-immune disease in which antibodies to gluten damage GI villi when gluten is consumed.
where is gluten found?
in grains, especially wheat
what are the symptoms of celiac disease?
pain, bloating, diarrhea, malabsorption, failure to thrive (children)
Where is fructose found in?
sucrose (table sugar), fruit, honey, drinks and food with high fructose corn syrup
how is fructose transported?
not with insulin like glucose
`how is fructose metabolized?
by the liver with two enzymes 1. fructokinase and 2. aldolase B
what does fructokinase do to fructose?
it adds a phosphate
what does aldolase B do to fructose?
cleaves the product into glycolytic intermediates by splitting fructose into 2 pieces
what is essential fructosuria?
what are the symptoms of essential fructosuria?
excrete fructose in urine
what is the mechanism for fructokinase deficiency?
fructose accumulates in blood past renal threshold and is lost in urine but some is taken up into tissues
what is the treatment for fructokinase deficiency?
there is none it is benign
what is hereditary fructose intolerance?
it is aldolase B deficiency
what are the symptoms of aldolase b deficiency?
severe hypoglycemia, vomiting, jaundice, hyperuirciemia, hemorrhage, lactic acidemia, heptomegaly, liver failure, death
what is the mechanism for hereditary fructose intolerance?
high phosphorylated fructose accumulates in liver, and inhibits other pathways, leading to damage
what is the treatment for aldolase b deficiency?
eliminate fructose from diet
what are galactose dietary sources?
milk and dietary products
how is galactose transported?
not need insulin
how is galactose metabolized?
in the liver and is phosphorylated and attached to UDP
what is galactokinase deficiency symptoms?
elevation of galactose in blood (galactosemia) and urine (galactosuria)
-galactitol accumulate if galactose present in diet
-galactitol can cause cataracts
what is classic galactosemia?
accumulation of galactose-1-phosphate and galactitol in nerve, lens, liver, and kidney tissue causes liver damage, severe intellectual disability, and cataracts
what is aldose reductase?
will convert galactose to galactitol. and can cause cataracts
what are common features of glycogen storage diseases?
enlarged organs due to accumulated glycogen which can't be used.
symptoms usually manifested in liver and muscle
what is von gierke disease (deficiency in glucose-6-phosphatase)
high levels of glycogen in liver and kidney
what are the symptoms of von gierke disease ( deficiency glucose-6-phosphatase)?
fasting hypoglycemia, ketosis, lactic acidemia, hyperlipidemia, hyperuricemia
what is the mechanism of von gierke disease ( deficiency glucose-6-phosphatase?
glucose-6-phosphate is essential for liver/kidney to release glucose in the blood
it is important for gluconeogensis and glycogen breakdown
what is the treatment for von fierce disease ( deficiency glucose-6-phosphatase?
nocturnal infusions of glucose
what is mcardle syndrome (deficient in skeletal muscle glycogen phosphorylase)
high levels of glycogen in skeletal muscle because glycogen phosphorylase breaks down glycogen in muscle
what are the symptoms of mcardle syndrome (deficient in skeletal muscle glycogen phosphorylase)
during excercise, patient experiences weakness and cramping
what are the lab results for mcardle syndrome (deficient in skeletal muscle glycogen phosphorylase)
myoglobinemia and myoglobinuria (because it relates myoglobin in blood)
what is the treatment for mcardle syndrome (glycogen phosphorylase deficiency)
avoid intense excessive excerice
what is pope disease (deficient in lysosomal a glucosidase)
high levels of glycogen (normal structure) in abnormal lysosomal vacuoles
what are the symptoms of pomp disease (lysosomal a deficiency glucosidase)
severe cardiomegaly (infantile form results in early death from cardiac failure)
what is the treatment for pompe disease (lysosomal a deficiency glucosidase)
enzyme replacement therapy
what is cori disease (hepatic debranching enzyme deficiency)
elevated glycogen (abnormal structure) in liver
-glycogen has 1 or 4 glucoses at branching points
what are the symptoms of cori disease (hepatic debranching enzyme deficiency)
fasting hypoglycemia (hepatomegaly, hyperlipidemia, elevated liver enzymes)
what is the treatment for glycogen storage diseases>
dietary management--high protein diet may promote gluconeogenesis as an alternative for blood glucose maintenance
hypoglycemia indicates which affected tissue?
exercise related issues indicates which affected tissue?
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GI module 3
There often appear to be greater differences between different breeds of dog than there are between different species of the Canis genus. Why then are dogs all considered one species?
Galactosemia is a recessive human disease that is treatable by restricting lactose and glucose in the diet. Susan Smithers and her husband are both heterozygous for the galactosemia gene. a. Susan is pregnant with twins. If she has fraternal (nonidentical) twins, what is the probability both of the twins will be girls who have galactosemia? b. If the twins are identical, what is the probability that both will be girls and have galactosemia? For parts c–g, assume that none of the children is a twin. c. If Susan and her husband have four children, what is the probability that none of the four will have galactosemia? d. If the couple has four children, what is the probability that at least one child will have galactosemia? e. If the couple has four children, what is the probability that the first two will have galactosemia and the second two will not? f. If the couple has three children, what is the probability that two of the children will have galactosemia and one will not, regardless of order? g. If the couple has four children with galactosemia, what is the probability that their next child will have galactosemia?
Describe three ways that people can change their shopping habits and dietary choices to reduce greenhouse gas emissions. In each case, explain how the change reduces emissions.
Give one example of a hazardous chemical that can be used safely.
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