Chapter 17 - Nutrition and Metabolism Flashcards
assimilation (nutrition)
the absorption and digestion of food or nutrients by the body or any biological system
metabolism
A biochemical process that allows an organism to live, grow, reproduce, heal, and adapt to its environment.
The three main purposes of metabolism are:
1. the conversion of the energy in food to energy available to run cellular processes
2. the conversion of food to building blocks for proteins, lipids, nucleic acids, and some carbohydrates
3. the elimination of metabolic wastes
anabolism vs catabolism
Anabolism and catabolism are two metabolic processes, or phases.
Anabolism refers to the process which builds molecules the body needs; it usually requires energy for completion.
Catabolism refers to the process that breaks down complex molecules into smaller molecules; it usually releases energy for the organism to use.
nucleic acid
Naturally occurring chemical compounds that serve as the primary information-carrying molecules in cells and make up the genetic material. Nucleic acids are found in abundance in all living things, where they create, encode, and then store information of every living cell of every life-form on Earth.
hepatic portal vein
a vessel that moves blood from the spleen and gastrointestinal tract to the liver
nutrients
components of foods that are digested and absorbed by the body
macronutrients vs micronutrients
In basic terms, macronutrients are the nutrients that the body requires in large amounts, while micronutrients are those required in smaller amounts.
The macronutrients are carbohydrates, proteins, fats, and water.
The micronutrients are vitamins and minerals.
essential nutrient
A nutrient required for normal physiological function that cannot be synthesized in the body – either at all or in sufficient quantities – and thus must be obtained from a dietary source.
In the case of humans, there are nine amino acids, two fatty acids, thirteen vitamins and fifteen minerals that are considered essential nutrients. Water is also an essential nutrient.
carbohydrate
The preferred energy nutrient of the body. The larger carbohydrate molecules are composed of smaller “building blocks,” primarily glucose. Human cells catabolize (break down) glucose rather than other substances as long as enough glucose enters them to supply their energy needs.
Carbohydrates are a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms. Carbohydrates are also called saccharides.
oligosaccharide
a saccharide that contains usually three to ten monosaccharide units
triglyceride
any of a group of lipids that are esters formed from one molecule of glycerol and three molecules of one or more fatty acids, are widespread in adipose tissue, and commonly circulate in the blood in the form of lipoproteins
glycerol
One of the sugar alcohols. Sugar alcohols belong to a class of polyols characterized by being white, water-soluble, organic compounds with a general chemical formula of (CHOH)nH2.
polyols
an organic compound containing multiple hydroxyl groups
hydroxyl group
a chemical group that consists of one atom of hydrogen and one of oxygen and is neutral or negatively charged
kilojoule (kJ)
A unit used for measuring calories outside the United States
A simple way to convert kilocalories to kilojoules is kcal × 4.2 = kJ.
(remember the nutritional “calorie” is actually 1000 kilocalories of energy”
glycogenolysis
process by which glycogen, the primary carbohydrate stored in the liver and muscle cells of animals, is broken down into glucose to provide immediate energy and to maintain blood glucose levels during fasting
glycogenesis
the formation of glycogen, the primary carbohydrate stored in the liver and muscle cells of animals, from glucose
carbohydrate loading
A number of athletes and others who must occasionally sustain endurance exercise for a significant period practice carbohydrate loading (also called glycogen loading). As with liver cells, some skeletal muscle fibers can take up and store glucose in the form of glycogen. By ceasing intense exercise and switching to a diet high in carbohydrates 2 or 3days before an endurance event, an athlete can cause the skeletal muscles to store almost twice as much glycogen as usual. This allows the muscles to sustain aerobic exercise for up to 50% longer than usual.
fats
Any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food. They are primarily energy nutrients. As cells begin to run low on adequate amounts of glucose to catabolize a few hours after a meal, they immediately shift to the catabolism of fats for energy.
ester
any of a class of organic compounds that react with water to produce alcohols and organic or inorganic acids
alcohol (chemical)
any of a class of organic compounds characterized by one or more hydroxyl (―OH) groups attached to a carbon atom of an alkyl group (hydrocarbon chain).
alkyl group
a functional group of an organic chemical that contains only carbon and hydrogen atoms, which are arranged in a chain
protein
Any of various naturally occurring extremely complex substances that consist of amino-acid residues joined by peptide bonds; the body uses protein to build its structures.
essential amino acids vs non-essential amino acids
The body uses amino acids to build its structures. Amino acids come from protein. Essential amino acids are amino acids the body cannot produce itself, and thus must consume from outside sources. Non-essential amino acids are produced by the body and do not need to be consumed.
What are the essential amino acids?
Use the mnemonic PVT TIM HLL ("private Tim Hall"). They are:
P: Phenylalanine
V: Valine
T: Tryptophan
T: Threonine
I: Isoleucine
M: Methionine
H: Histidine
L: Lysine
L: Leucinevitaminosis
Any disease caused by either excess vitamin intake (hypervitaminosis) or deficient vitamin intake (avitaminosis or hypovitaminosis).
vitamins
Organic molecules needed in small quantities for normal metabolism throughout the body. Most vitamins cannot be made by the body, so we must eat them in our food. Vitamins are divided into fat-soluble vitamins and water-soluble vitamins.
antioxidant
a substance that prevents highly reactive oxygen molecules called free radicals from damaging DNA and molecules in cell membranes
fat-soluble vitamins
A, D, E, and K. They are four vitamins the body can store in the liver for later use.
Vitamin A is important for vision.
Vitamin D regulates calcium and phosphorus in the body. It can be acquired from sunlight.
Vitamin E is an antioxidant.
Vitamin K plays a key role in helping the blood clot, preventing excessive bleeding.
water-soluble vitamins
Water-soluble vitamins are excreted in the urine after use and cannot be held by the body. There are 9 water-soluble vitamins. They include the 8 B-vitamins and Vitamin C (ascorbic acid, used for immune system) [mnemonic 8B-C].
Use the following mnemonics to remember the B vitamins:
Then Roland n Peter played bowling for Chester. Score: 123-567-9-12
T: Thiamine (B1) [helps enzymes in the citric acid cycle]
R: Riboflavin (B2) [helps enzymes in the citric acid cycle]
N: Niacin (B3) [helps enzymes in the citric acid cycle]
P: Pantothenic acid (B5) [essential for fatty acid metabolism]
P: Pyridoxine (B6) [helps enzymes that catabolize amino acids]
B: Biotin (B7) [helps enzymes that catabolize amino acids]
F: Folic Acid (B9) [helps enzymes that catabolize amino acids]
C: Cobalamin (B12) [involved in blood production]
The score is the vitamin numbers.
minerals (nutrition)
Inorganic elements or salts found naturally in the earth and that are required as an essential nutrient by organisms to perform functions necessary for life.
The five major minerals in the human body are calcium, phosphorus, potassium, sodium, and magnesium. (CPPSM: “Can people please stop mocking?”)
All of the remaining elements in a human body are called “trace elements”. The trace elements that have a specific biochemical function in the human body are sulfur, iron, chlorine, cobalt, copper, zinc, manganese, molybdenum, iodine, and selenium.
(SICCCZMMIS: “So I can can can zip my mad idiotic singing.”)
basal metabolic rate (BMR)
the rate at which nutrients are catabolized under basal conditions (that is, when the individual is resting but awake, is not digesting food, and is not adjusting to a cold external temperature)
total metabolic rate (TMR)
the total amount of energy used by the body per day
body mass index (BMI)
a measure of body fat based on height and weight that applies to adult men and women
four mechanisms of heat loss from the body
- Radiation—flow of heat waves from the blood and skin
- Conduction—transfer of heat energy to the skin and then to cooler external environment
- Convection—transfer of heat energy to cooler air that is continually flowing away from the skin
- Evaporation—absorption of heat from blood and skin by water (sweat) vaporization
agriculture
the science or practice of farming, including cultivation of the soil for the growing of crops and the rearing of animals to provide food, wool, and other products
constipation
having hard, dry bowel movements or passing stool fewer than three times a week
diarrhea
loose, watery stools (bowel movements)
protease
(also called a peptidase or proteinase)
an enzyme which breaks down proteins and peptides
What are the two essential fatty acids?
Only two fatty acids are known to be essential for humans: alpha-linolenic acid (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid). They are needed for normal skin function. Omega-3 can be gotten from fish and Omega-6 from vegetable oils.
lipase
an enzyme primarily produced by the pancreas to help digest dietary fats
trypsin
an enzyme that helps us digest protein
emulsification
- The process of making an emulsion, allowing fat and water to mix.
- The breaking down of large fat globules in the intestine into smaller, uniformly distributed particles, largely accomplished through the action of bile acids, which lower surface tension.
Kwashiorkor
A form of severe protein malnutrition characterized by edema and an enlarged liver with fatty infiltrates. It is thought to be caused by sufficient calorie intake, but with insufficient protein consumption (or lack of good quality protein), which distinguishes it from marasmus.
Kwashiorkor is associated with a high risk of mortality and long-term complications. Treatment under the guidelines of the World Health Organization has proven to reduce this mortality risk and affected children tend to recover faster than children with other severe malnutrition diseases. However, physical and intellectual capabilities are not fully restored. Growth stunting and chronic disruption of microbiota are commonly observed after recovery.
marasmus
A form of severe malnutrition characterized by energy deficiency. It can occur in anyone with severe malnutrition but usually occurs in children. Body weight is reduced to less than 62% of the normal (expected) body weight for the age.
The prognosis is better than it is for kwashiorkor but half of severely malnourished children die due to unavailability of adequate treatment.
weaning
the process of gradually introducing an infant human or another mammal to what will be its adult diet while withdrawing the supply of its mother’s milk
analogous
similar or comparable to something else either in general or in some specific detail
