Chapter 1 Flashcards
Macronutrients function
- Provide energy
- Maintain structure
- Provide functional integrity
The human body is mostly made up of what element?
oxygen
The human body is least made up of what element?
nitrogen
Molecules
- Created when two or more atoms are united
- Chemical bonds hold the molecules together
Substances
Substances are formed when two or more molecules are
chemically bonded together
What are examples of substances?
solid, liquid, and gas
Carbon is a component of all nutrients, except what?
water and minerals
Carbon bonds with what to
form carbohydrates, lipids, and proteins?
hydrogen, oxygen, and nitrogen
Oligosaccharides
Combination of 3–9 monosaccharides
Polysaccharides
Combination of 10 to thousands of sugar molecules in chains
* Usually glucose
What are the monosaccharides?
- Glucose – C6H12O6
- Fructose – C6H12O6
- Galactose – C6H12O6
Glucose aka….
dextrose or blood sugar
Glucose function
- Used directly by the cell for energy
- Stored as glycogen in the muscles and liver for later
use - Converted to fat and stored for energy
Fructose aka…..
fruit sugar
Fructose function
The liver converts fructose to glucose.
Galactose forms what?
milk sugar called lactose.
Galactose function
The body converts galactose to glucose for energy metabolism.
Glucose + Fructose =
Sucrose
Glucose + Galactose =
Lactose
Glucose + Glucose =
Maltose
Polysaccharides are classified into what categories?
plant and animal polysaccharides
What are the 2 plant polysaccharides?
starch and fiber
Water-soluble fibers
gums and pectin
Water-insoluble fibers
cellulose, hemicellulose, and lignin
What are the roles of fiber
- Retains considerable water and thus gives “bulk” to the food residues in the intestines
- Exerting a scraping action on the cells of the gut wall
- Binds or dilutes harmful chemicals
- Shortens transit time for food residues (and possibly
carcinogenic materials) to pass through the digestive
tract
What is the one animal polysaccharide?
glycogen
What is glycogen?
is the storage polysaccharide found in mammalian muscle and liver
Recommended Intake of carbs: Regular physical activity
60% of total intake (400–600
grams)
Recommended Intake of carbs: During intense training
70% of total intake
Recommended Intake of carbs: Typical American diet
40–50% of total intake
What can Cause High Blood Glucose?
- from consuming many foods with a high glycemic load
- insulin resistance, insulin deficiency, or both and result in type 2 diabetes
- Metabolic syndrome
Carbohydrates function
- Energy source
- Adequate carbohydrate intake preserves tissue proteins.
- Metabolic primer/prevents ketosis
- Fuel for the central nervous system (CNS) and red blood cells
Hypoglycemia is what?
Low levels of sugar in the blood
Hypoglycemia results in what?
- Can result in weakness, hunger, and dizziness
- Impairs exercise performance
- Prolonged and profound hypoglycemia can result in the
loss of consciousness and irreversible brain damage.
Lipid is a general term for a heterogeneous group of what
compounds?
Oils, fats, waxes, and related compounds
Lipid molecules contain the same structural elements as what?
carbohydrates
What are the three main groups of lipids?
- simple lipids
- compounds lipids
- derived lipids
Simple lipids
Neutral fats – consist primarily of triacylglycerols
* Major storage form of fat in adipose cells
Compound lipids
Consist of a triacylglycerol molecule combined with other
chemicals
Derived lipids
Formed from simple and compound lipids
- Contain hydrocarbon rings (i.e., cholesterol)
Glycerol
a 3-carbon alcohol molecule
How is a triglyceride formed?
Three clusters of carbon-chained atoms, termed fatty
acids, attach to the glycerol molecule to form a
triglyceride.
Saturated fatty acids
contain only single covalent bonds between carbon atoms; all of the remaining bonds attach to hydrogen.
Unsaturated fatty acids
contain one or more double bonds along the main carbon chain.
Monounsaturated fatty acid
contains one double bond
Polyunsaturated fatty acid
contains two or more double
bonds
Oils
- Oils exist as liquid and contain unsaturated fatty acids.
- Omega-3 family of fatty acids
How are Omega-3 fatty acids characterized?
by the presence of a double bond three carbons from the “n” end of the molecule
Fatty acids that the body cannot synthesize
- Linoleic acid
- Alpha-linolenic acid
- Oleic acid
Compound Lipids
Triacylglycerol molecules combined with other chemicals
Compound lipids examples
- phospholipids
- glycolipids
- lipoproteins
Phospholipids
one or more fatty acids, a phosphorus-containing group, and a nitrogenous base
Glycolipids
fatty acid bound with carbohydrate and nitrogen
Lipoproteins
proteins joined with triacylglycerols or
phospholipids
Lipoproteins
HDL, VLDL, LDL
High-density lipoprotein (HDL)
contains more protein and
less lipid and cholesterol than the other lipoproteins
Very-low-density lipoprotein (VLDL)
contains the greatest
percentage of lipid, primarily triacylglycerol
Low-density lipoprotein (LDL)
contains the highest
percentage of cholesterol
Derived Lipids
- Form simple and compound lipids
- Contain hydrocarbon rings
What is the one derived lipid?
cholesterol
Cholesterol
- Allows for the production of steroid compounds
- Found only in animal tissues
Lipids function
- Energy reserve
- Protect vital organs
- Provide insulation from the cold
- Transport the fat-soluble vitamins A, D, E, and K
What makes up each amino acid?
an amine group (NH2)
and an acid group (COOH).
The remainder of the
molecule is called the side chain
The side chain of an amino acid dictates what?
the amino acid’s particular characteristics
How many essential amino acids are there?
8 (the body cannot make)
What are the essential amino acids?
isoleucine, leucine,
lysine, methionine, phenylalanine, threonine,
tryptophan, and valine.
Complete proteins
contain all 8 of the essential amino acids
Incomplete protein
lacks one or more essential amino acid.
Protein functions
- Proteins in nervous and connective tissue generally do not participate in energy metabolism.
- The amino acid alanine plays a key role in providing carbohydrate fuel via gluconeogenesis during prolonged exercise.
- During strenuous exercise of long duration, the alanine-glucose cycle accounts for up to 40–50% of the liver’s glucose release.
When does protein catabolism increase?
during exercise as carbohydrate
reserves deplete.
