Lecture 4 Flashcards
PKU.
Lack of phenylalanine hydroxylase will cause a saturation of the blood brain barrier by phenylalanine, which affects protein synthesis and leads to mental issues.
Hemochromatosis.
A genetic disorder in which the blood contains too much iron.
Iodine.
Micromineral, necessary for thyroid function and synthesis of thyroid hormones (T3 and T4; the numbers refer to amount of iodine in the molecule).
Thyroid hormones.
Control carbohydrate and fat metabolism; ligands of TR receptor.
Sources of iodine.
Seafood, kelp, dairy products; most common source is iodized salt.
Cretinism.
Mental retardation.
Effects of iodine deficiency due to thyroid-related disorders.
Anemia, arthritis, ye enlargement and inflammation, hair loss, and pre-mature greying.
Goiter.
Caused by both excess and inadequate intake of iodine. When caused by iron deficiency: leads to impaired thyroid hormone synthesis. When caused by excessive iodine: causes inhibition of thyroid hormone production.
Iodine excess.
Kelp acne; issue in Japan. Impairs thyroid hormone synthesis and causes Goiter in response to decreased thyroid hormone concentration.
Major reason for acquired metabolic disorders.
Obesity; the problem is actually malnutrition.
Is obesity contagious?
In some ways, yes. Social influences, transmission o bacterial infections can all lead to obesity.
Obesity caused by bacteria.
An obese mouse (infected with the bacteria) housed with a lean mouse: both became obese.
Storage of excess fat.
Excess fat is stored in adipose tissue, which has a life span of 2-3 years.
Obesity and its associated metabolic diseases.
heart attack, atherosclerosis, stroke, kidney failure, etc.
High LDL concentration in the blood.
LDL is a risk factor for atherosclerosis; it transports cholesterol from the liver to the cells, where it is stored.
Where in the human body is cholesterol produced?
In the liver.
Microbacteria and red meat.
A certain strain causes an increase in TMAO in meat eaters when the wrong bacteria is present.
Inherited metabolic disorders.
Inborn errors of metabolism caused by genetic factors. Examples: PKU, Type I diabetes.
Acquired metabolic syndromes.
Manifestation of overnutrition; there is a genetic factor, but it is not the main cause of the disease. Severity depends in gene variance.
Super tasters.
Ability to taste better is caused by variations in the genes that code for taste receptors.
Taste perception.
The sugar (for example) binds with the receptor due to conformational compatibility; we are then able to perceive the taste.
Taste receptors and nutrient deficiencies.
People will not like certain foods, causing them to avoid them, which may lead to a nutrient deficiency.
Lactose intolerance.
Not a disease; the gene just shuts itself off. Variations in the gene have led to a retention of lactose enzymes.
Digestion of lactose.
LCT gene encodes lactose; this gene normally shuts down after weaning. Variations in the gene have led to lactase persistence.
Gene responsible for lactase production.
LCT.
LCT and MCM6 region.
Variations in lactose intolerance do not happen within the gene itself, but in a gene very far away: MCM6. SNPs in introns of MCM6 cause this variation.
Gene responsible for lactase persistence.
MCM6 due to SNPs in the introns.
Encode project purpose.
To identify the functions of introns; most of the genome is actually composed of regulatory elements.
Chromatids.
Histone proteins and DNA.
NPC1L1.
Controls cholesterol uptake of dietary cholesterol into the intestine. Cholesterol uptake can be inhibited by ezetimibe.
T61M.
At position 61, threonine is replaced with methionine.
Variations in NPC1L1.
Influence the quantity of nutrients available for metabolism.
Genes control nutrient availability.
There is a sensing mechanism: certain transcription factors are activated in the presence of certain nutrients.
Loss of sensitivity to nutrient cues.
Can result in inappropriate metabolic response to nutrient availability or deficiency.
Cellular response to amino acid starvation.
The cell sends a signal to increase translation of the mRNAs coding for Fil1/ATF4, which is a stress gene. Once Fil1/ATF4 is activated, it will launch transcriptional programs that promote cellualr survival mechanisms.
ATF4.
Controls autophagy: the cell eats itself.
Are gain-in-function genes, like lactase persistence, common?
No, they are rare.
