Macronutrition Flashcards
In what two ways does the body store excess carbohydrates?
as glycogen (with an upper limit) or triglycerides (no upper limit)
Between glucose and fructose, ________ will cause a more rapid increase in blood sugar.
glucose
Sucrose is a disaccharide composed of _______ and _______.
glucose and fructose
Lactose contains one _______ unit and one _______ unit. It is primarily found in _____.
glucose, galactose, milk
Maltose is made of repeating disaccharide units of what sugar?
glucose
Maltose is a breakdown product of starch, which is a long polymer of glucose.
What are the two polymers of starch?
amylose and amylopectin
Compare and contrast amylose and amylopectin.
They are both made entirely of glucose, but differ in structure. Amylose consists of long chains of glucose linked by alpha-1,4 linkages. Amylopectin is structured the same way, but with 1,6 branch linkages about every 20 glucose residues.
What is the name of the glucose polysaccharide in animals? How does it differ from that in plants?
glycogen: In glycogen, the glucose chains are covalently linked to a protein core.
What enzymes in the human body are involved in carbohydrate digestion to monosaccharides for absorption?
alpha-amylase: present in saliva for initial breakdown of starch and glycogen
maltase, sucrase, and lactase: present on luminal surface of intestinal cells
How do bacteria contribute to digestion? What is one example of a carbohydrate that we rely on bacteria to break down?
Some dietary carbohydrates are indigestible by human enzymes, but can be broken down by our gut flora into usable monosaccharides. Raffinose (glucose + fructose + galactose).
What is the glycemic index?
The glycemic index is a measure of how quickly certain foods cause an increase in blood glucose levels relative to pure glucose. It is calculated by (AUC of food)/(AUC of glucose).
Describe the three glucose transporters present in the body.
GLUT2-present in the liver, insulin-independent
GLUT3-brain, insulin-independent
GLUT4-muscle and adipose tissue, insulin-dependent
Describe the effects and sources of cellulose/hemicellulose, lignin, pectin.
cellulose: cereals, whole wheat, bran…increases stool bulk and decreases intestinal transit time
lignin: woody part of vegetables, binds cholesterol and carcinogens
pectin: fruit, decreases rate of sugar absorption (aka lowers glycemic index) and decreases serum cholesterol
Are saturated or unsaturated fatty acids more harmful for health?
Saturated fatty acids are more dangerous. They are solid fats and have a higher chance
