HUEC 1110 Final Study Guide

Pro-vitamin A is:

Bound to fatty acids.

Women of child-bearing age need extra______.

Folate.

Beta-Carotene

A carotenoid that has more provitamin A activity than other carotenoieds--also containing an antioxidant.

Vitamin A is:

A fat soluble vitamin

Symptoms of Vitamin K Deficiency:

Abnormal blood coagulation is the major symptom of vitamin K deficiency.

How does Vitamin A affect gene expression?

It can change the amount of messenger RNA (mRNA) that is made by the gene.

What is true about the function of Vitamin D?

It works with parathyroid hormone (PTH) to decrease calcium retention by the kidneys.

What are a few sources of Vitamin D in the diet?

Liver, fatty fish (salmon), mackerel, sardines, cod liver oil, and egg yolks. The predominant food sources of vitamin D in the United States are fortified milk and fortified breakfast cereals.

Vitamin K deficiency can be caused by:

Long term use of antibiotics.

Sources of Vitamin E in the diet:

Nuts, peanuts, plant oils (soybea, corn, and sunflower oils), leafy green vegetables.

How could Vitamin A Deficiency cause eye infections and blindness?

Vitamin A maintains epithelial tissues.

Why is vitamin D called the "Sunshine Vitamin"?

Vitamin D is known as the sunshine vitamin because it can be produced in the skin by exposure to ultraviolet light.

What is the Function of Vitamin E?

Vitamin E functions primarily as a fat-soluble antioxidant.

What is a function of vitamin E?

Vitamin E neutralizes reactive oxygen compounds to prevent cell damage.

How does Vitamin D's effect on gene expression alter calcium absorption?

Active vitamin D function by binding to vitamin D receptor proteins at target tissues and affecting gene expression. It's effect at the intestines can cause calcium absorption to increase because vitamin D increases the expression of genes in the intestinal cells that code for the production of intestinal calcium transport proteins, enhancing the active transport of dietary calcium from the intestinal lumen into the body.

Food sources of preformed Vitamin A and two of Provitamin A

Animal foods such as: liver, fish, egg yolks, dairy products contain preformed Vitamin A. Plant foods such as: dark orange fruits and vegetables (mangos, apricots, cantaloupe, carrots, red peppers, pumpkins and sweet potatoes), as well as leafy greens contain Pro-vitamin A

Why are fat-soluble vitamin deficiencies occurring in the developed world?

Because rising reliance on fast food has reduced our intake of fruits and vegetables.

Vitamin A Deficiency

Can cause night blindness because of the delay in the regeneration of rhodopsin, which causes difficulty in adapting to dim light after experiencing a bright light;it's role in cell differentiation causes the mucus-secreting cells on the surface of the eye to be replaced by keratin secreting cells causing the cornea to dry and leaving the eye open to infection.

Why is beta-carotene non-toxic, but preformed vitamin A is.

Carotenoids are non-toxic because their absorption from the diet decreases at high doses and once in the body, their conversion to retinoids is limited; whereas preformed vitamin A is toxic because it is absorbed more efficiently than beta-carotene and does not need to be converted to an active form once inside the body.

Vitamin D Deficiency:

Causes weaker bones because they do not contain enough calcium and phosphorus. This syndrome in children is called rickets and it's characterized by bone deformities such as narrow rib cages known as pigeon breasts, and bowed legs.

Why is vitamin D deficiency on the rise?

Due to lower consumption of milk fortified with vitamin D.

How is Vitamin A involved in the perception of light?

In the eye, the retinal form of the vitamin combines with the protein opsin to form the visual pigment rhodopsin. Rhodopsin helps transform the energy from light into a nerve impulse that is sent to the brain--the nerve impulse allows us to see.

Why do certain groups need supplements to meet their nutrition needs?

Supplements may be necessary for people who have low intakes, increased needs, or excess losses: cigarette smokers require extra vitamin C, Iron and folic acid is recommended for pregnant women, vegans may take vitamin B12 to compensate for the lack of animal products in their diet.

What is the primary function of Vitamin D?

The principle function of vitamin D is to maintain levels of calcium and phosphorus in the blood that favor bone mineralization.

What is true about night vision?

The regeneration of rhodopsin is delayed when vitamin A is deficient.

How does Vitamin A affect the proteins made by a cell?

Vitamin A affects protein synthesis through its effect on gene expression. The retinoic acid of vitamin A enters the nucleus of the cell and binds to a protein receptor; the complex then binds to a regulatory region of DNA, changing the amount of mRNA made by the gene and hence the amount of protein synthesized. The production of certain proteins that regulate functions within cells can be turned on and off by vitamin A. Also, by affecting gene expression, vitamin A can determine what type of cell an undifferentiated cell will become.

How is vitamin K involved in blood clotting?

Vitamin K helps to produce the blood-clotting protein prothrombin.

What is the main function of Vitamin K?

Vitamin K is the coenzyme needed for the production of the blood-clotting protein prothrombin and other specific blood-clotting factors.