lec 10- nutrition Flashcards
what are the two requirements for animals when it comes to nutrition?
- chemical energy for synthesizing ATP
- carbon-containing compounds for building molecules
what are the four processes needed to obtain energy from food?
ingestion- process of bringing food into digestive tract
digestion- is the breakdown of food
absorption- uptake of specific ions and molecules across the epithelium of the digestive tract
elimination- disposal of waste
what are nutrients?
chemical energy and carbon-containing building blocks needed by the body
what is food?
any material that contains nutrients
what are essential nutrients?
nutrients that cant be synthesized and can only be obtained from diet
what are vitamins?
organic compounds that are vital for health but are required only in minute amounts
what are minerals?
are inorganic substances used as a component of enzyme cofactors, their ions act as electrolytes to the body
why do canadians experience vitamin D deficiency?
because to make vitamin D, UV light is required which canadians experience less due to rainy weather and being inside
how does light make vitamin D?
light strikes a molecule called
7-dehydrocholesterol and changes its shape so it can become vitamin D
why is vitamin D needed by the body?
it helps absorb calcium in our small intestine
do canadians experience insufficient amounts of UV light for most of the year?
yes
how do canadians increase vitamin D?
by adding it into our milk
how does vitamin D act in the cell?
like a steroid, it is membrane soluble, it attaches to a protein called VDR and turns on certain genes. The vitamin D-VDR complex attaches to vitamin D response element which turns on genes
what are the two general designs of the digestive tract?
incomplete digestive tracts- one opening for both ingestion and elimination (eg. starfish)
complete digestive tracts- two openings, one for ingestion, other for elimination (humans)
how does digestion begin?
-in the mouth where food is chewed, salivary amylase breaks down starch and glycogen (carbs)
-lingual lipase breaks lipids down
-salivary glands make it easy to swallow food with slimy substance called mucus