Term
| Where are the majority of monosaccharides absorbed? |
|
Definition
| at the end of the jejunum |
|
|
Term
| What transport system brings glucose and galactose into the bloodstream? What is the name of the transporter(s)? |
|
Definition
Active transport
SGLT 1 & GLUT 2 |
|
|
Term
| What transport system brings fructose into the bloodstream? What is the name of the transporter(s)? |
|
Definition
Facilitated Transport
GLUT 5 & GLUT 2 |
|
|
Term
| When might glucose be absorbed into the bloodstream through facilitated diffusion? |
|
Definition
| Early in the small intestine, when concentrations of glucose are very high, there might be some facilitated diffusion through GLUT-5 |
|
|
Term
True or False
Glucose is an essential nutrient |
|
Definition
False
It is an essential metabolite |
|
|
Term
| What is the importance of carbohydrates in the diet? |
|
Definition
Glucose = primary energy source for cells
Prevents breakdown of protein for energy
Prevents ketosis (ketone bodies produced by fat catabolism)
Sole source of energy for the brain
Ensures healthy bacteria growth in gut |
|
|
Term
|
Definition
| Elevated of ketone bodies as a result of catabolizing fat to gain energy, blood becomes more acidic |
|
|
Term
| What are the 4 fates of glucose in a cell? |
|
Definition
1. Glycogenesis for energy storage
2. Glycolysis for energy production
3. Hexhose monophosphate shunt to produce biogenesis precursors
4. Conversion to acetyl CoA to form triglycerides |
|
|
Term
|
Definition
| The conversion of glucose to glycogen to lower blood sugar levels |
|
|
Term
| What enzymes are involved in glycogenesis? |
|
Definition
Glucokinase (liver)
Hexokinase (muscle) |
|
|
Term
| What regulates glycogenesis? |
|
Definition
|
|
Term
|
Definition
| Conversion of glycogen to glucose to raise blood sugar levels |
|
|
Term
| If blood glucose levels are high, what will happen? |
|
Definition
| Insulin will be released, stimulating the uptake of gluocse from blood and the formation of glycogen (glycogenesis) |
|
|
Term
| If blood glucose levels are low, what will happen? |
|
Definition
| Glucagon will be released, stimulating the breakdown of glycogen to raise blood sugar |
|
|
Term
| What hormone regulates glycogenolysis? |
|
Definition
|
|
Term
| What processes generate energy in the form of ATP? |
|
Definition
substrate level phosphorylation
-Kreb's cycle & Glycolysis
Oxidative phosphorylation
-ETC |
|
|
Term
| Describe the input/output of products in the glycolysis of 1 mole of glucose |
|
Definition
-use 2 ATP
-produce 4 ATP
-produce 2 NADH (aerobic conditions)
-produce 2 pyruvate |
|
|
Term
| What are the products of anaerobic metabolism of glucose? |
|
Definition
lactic acid
ethanol (yeast only) |
|
|
Term
|
Definition
| anaerobic metabolism of glucose in the human body |
|
|
Term
| What is the fate of lactate produced in the Cori cycle? |
|
Definition
| Will be transported back to liver for gluconeogenesis to convert pyruvate into glucose |
|
|
Term
| How much ATP is required to form glucose from 2 molecules of lactate? |
|
Definition
|
|
Term
| Why can't the Cori cycle be sustained forever? |
|
Definition
| more energy is consumed than is produced |
|
|
Term
| What is the Hexose Monophosphate shunt? |
|
Definition
| Converts glucsose to pentose sugars & produces NADPH |
|
|
Term
| What is pyruvate dehydrogenation? |
|
Definition
| conversion of pyruvate to acetyl CoA |
|
|
Term
| What cofactors are important in pyruvate dehydrogenation? |
|
Definition
TPP (thiamine)
NAD (niacin)
FAD (riboflavin)
CoA (pantothenic acid) |
|
|
Term
| What proportion of energy in food is released during the Krebs cycle? |
|
Definition
|
|
Term
| What is the final catabolic pathway for lipids, carbohydrates and proteins? |
|
Definition
|
|
Term
| Where does the Krebs Cycle occur? |
|
Definition
|
|
Term
| What kind of phosphorylation takes place during the Krebs cycle? |
|
Definition
| substrate level phosphorylation |
|
|
Term
| What are the products of the metabolism of 1 acetyl CoA in the Krebs Cycle? |
|
Definition
|
|
Term
| How many molecules of ATP will be produced by the products of the Kreb's Cycle? |
|
Definition
3 NADH X 3 = 9 ATP
1 GTP X 1 = 1 ATP
1 FADH X 2 = 2 ATP
12 total |
|
|
Term
|
Definition
Generation of glucose from non-carbohydrate carbon sources
e.g. lactate, pyruvate |
|
|
Term
| What organs or tissues are involved with gluconeogenesis? |
|
Definition
|
|
Term
True or False
Muscle & adipose tissue don't have the required enzymes for gluconeogenesis |
|
Definition
|
|
Term
| What is the key step required to initiated gluconeogenesis? |
|
Definition
| moving oxaloacetate from the mitochondria into the cytoplasm |
|
|
Term
True or False
Monosaccharides are easily hydrolyzed |
|
Definition
|
|
Term
| What type of carbohydrate is glucose? |
|
Definition
|
|
Term
| Is sucrose a disaccharide or polysacchaaride? |
|
Definition
|
|
Term
| What is the term for structures with are isomers, but not mirror images of each other |
|
Definition
|
|
Term
| How do you determine whether a sugar is in L or D form? |
|
Definition
If the OH group on the highest numbered chiral carbon is...
on the right = D sugar
on the left = L sugar |
|
|
Term
| Why are D sugars nutritionally more important? |
|
Definition
| We have more enzymes suitable for acting on D sugars |
|
|
Term
| How do you determine the number of possible stereoisomers? |
|
Definition
2^n
where n is the number of central chiral carbons |
|
|
Term
| How do you determine if a sugar is an aldose or ketose? |
|
Definition
| Whether carbon #2 has a hydroxyl group (aldose) or is double bonded to an oxygen (ketose) |
|
|
Term
| What are the 3 types of insoluble dietary fibre? |
|
Definition
cellulose
hemicellulose
lignin |
|
|
Term
| What are the 3 types of soluble dietary fibre? |
|
Definition
pectins
gums
mucilages
(some hemicelluloses_ |
|
|
Term
| What are the traits of soluble fibres? |
|
Definition
-ability to hold water
-ability to bind enzymes & nutrients (absorbtive ability) |
|
|
Term
| What effect does soluble fibre have on the GI tract? |
|
Definition
-slows nutrient absorption
-increases mineral availability
-binds acids & cholesterol in the gut to lower blood cholesterol |
|
|
Term
| What effect does insoluble fibre have on the GI tract? |
|
Definition
| -decreases mineral availability through GI tract -stimulates muscle contraction of intestines -decreases risk of bacterial infection in GI tract |
|
|
Term
| If the anomeric carbon has a hydroxyl group which is RIGHT in the Fischer model, what will its position be in the Haworth model? |
|
Definition
|
|
Term
| What digestion occurs in the mouth? |
|
Definition
| salivary breakdown of alpha 1-4 glycosidic bonds by alpha-amylase |
|
|
Term
True or False
Cellulose and lactose are digested by salivary enzymes |
|
Definition
|
|
Term
| What are the Brush Border enzymes & their products? |
|
Definition
| Sucrase: glucose & fructose Maltase: glucose & glucose Lactase: glucose & galactose Peptidases: shorter peptides |
|
|
Term
| Where are Brush Border enzymes found? |
|
Definition
Very close to nutrient transporters!
tethered to the plasma membrane of microvilli in the small intestine |
|
|
Term
| What causes lactose intolerance? |
|
Definition
-inadequate amounts of lactase available for catabolyzing lactose
-lactose travels to SI where fermentation causes irritation of the bowels |
|
|
