NEET MDS Shorts
39706
Biochemistry
Epinephrine, also known as adrenaline, is a hormone and neurotransmitter that
is synthesized in the body from the amino acid tyrosine. Tyrosine is a
non-essential amino acid, which means that it can be synthesized in the body
from phenylalanine, another essential amino acid. The synthesis of epinephrine
occurs in two main steps:
1. Hydroxylation of tyrosine: Tyrosine is converted into dihydroxyphenylalanine
(DOPA) by the enzyme tyrosine hydroxylase. This is the rate-limiting step in the
synthesis of epinephrine.
2. Decarboxylation and further hydroxylation: DOPA is then decarboxylated to
form dopamine, which is further hydroxylated to produce norepinephrine.
Norepinephrine is the immediate precursor of epinephrine.
3. Formation of epinephrine: Norepinephrine is methylated by the enzyme
phenylethanolamine N-methyltransferase (PNMT) and converted into epinephrine.
The other amino acids listed are not directly involved in the synthesis of
epinephrine:
1. Valine and Leucine are branched-chain amino acids that are primarily involved
in the metabolism of muscles and energy production.
2. Cysteine is a sulfur-containing amino acid that is important for the
synthesis of proteins with disulfide bridges and is a precursor for other
molecules like glutathione and taurine, but not directly involved in the
synthesis of epinephrine.
67413
BiochemistryEpinephrine causes increased blood glucose level due to: 1. Increased glycogenolysis in liver and muscle 2. Activation of phosphorylase 3. Inhibition of glycogen synthesis in liver
19023
BiochemistryThe eye change include an increase in blood vessels and inflammation of the conjunctivae, cornea is invaded by capillaries, producing opaque areas and even ulceration. Dermatitis characterized by a greasy and scaly reddened lesion develops on the skin around the nasolabial folds and may extend to a butterfly shape on the cheeks. There many also be lesions at the corners (canthi) of the eyes and lobes of the mouth.
57919
BiochemistryThe formation of oxyhemoglobin is influenced by 1. pH 2. CO2 concentration 3. Temperature
83015
Biochemistry
Vitamin D is crucial for the maintenance of bone health as it aids in the
absorption of calcium from the digestive tract and facilitates the incorporation
of calcium into bones. A deficiency in vitamin D can lead to osteoporosis, a
condition characterized by weak and porous bones that are more susceptible to
fractures, which is common in the elderly. While vitamin A (Answer 1) is
important for vision and skin health, and niacin (Answer 2) and thiamine (Answer
3) have roles in energy metabolism and nerve function, respectively, vitamin D's
primary role in calcium homeostasis makes it most relevant to bone loss in older
individuals.
93900
BiochemistryAcetylcholinesterase receptor opens an ion channel, undergoes irreversible conformational changes when exposed to carbamates , it is inactivated in myasthenia gravis
83114
Biochemistry
Saturated fatty acids are a type of fat that has a chemical structure with a
single bond between each carbon atom in the fatty acid chain and no double
bonds. These types of fats are typically solid at room temperature. Out of the
given options, stearic acid (C18:0) is the only saturated fatty acid. The others
are:
1. Oleic acid (C18:1) is a monounsaturated fatty acid, which means it has one
double bond. It is commonly found in olive oil, canola oil, and avocados.
2. Linolenic acid (C18:3) is a polyunsaturated fatty acid, specifically an
omega-3 fatty acid, with three double bonds. It is found in plant sources like
flaxseeds, chia seeds, and walnuts.
3. Arachidonic acid (C20:4) is also a polyunsaturated fatty acid, an omega-6
fatty acid with four double bonds. It is found in animal fats, such as meat, and
in smaller amounts in some plant oils like sunflower oil and peanut oil.
Stearic acid, on the other hand, is a common saturated fatty acid found in
various animal fats and certain vegetable oils like coconut oil, palm kernel
oil, and cocoa butter. It is known for its role in the structure of cell
membranes and as a precursor for the biosynthesis of cholesterol in the body.
While it is important to consume fatty acids for good health, excessive
consumption of saturated fatty acids has been associated with higher levels of
LDL (low-density lipoprotein) cholesterol, which is often referred to as "bad"
cholesterol, and an increased risk of heart disease. However, it is important to
maintain a balanced diet that includes both saturated and unsaturated fatty
acids in moderation.
80625
BiochemistryCreatine Phosphate is the major source of glucose for the whole body during starvation
64826
BiochemistryProthrombin production in the liver is dependent upon Vitamin K intake
31789
Biochemistry
Gout is a form of arthritis caused by the accumulation of uric acid crystals,
specifically sodium urate crystals, in the joints. The body produces uric acid
as a waste product during the metabolism of purines, which are substances found
in certain foods and also synthesized by the body. High levels of uric acid can
lead to the formation of these crystals, which cause inflammation and pain in
the affected joints. Urea (Answer 1) is a waste product formed from the
metabolism of proteins and amino acids, while guanine (Answer 3) and
hypoxanthine (Answer 4) are purine bases involved in nucleotide metabolism, but
they do not directly form the crystals seen in gout.