Carbohydrates Flashcards
1
Q
Carbohydrate nomenclature normally ends in “ose,” with some exceptions such as:
A
Glycogen and amylopectin
2
Q
Carbohydrates are made up of
A
Carbon
Hydrogen
Oxygen
3
Q
Simple sugars consist of:
A
Monosaccharides
Disaccharides
4
Q
Monosaccharides consist of:
A
Glucose, fructose, galactose
5
Q
Disaccharides consist of:
A
Sucrose, lactose, maltose
6
Q
Sucrose is made up of:
A
Glucose and fructose
7
Q
Lactose is made up of:
A
Glucose and galactose
8
Q
Maltose is made up of:
A
Glucose x 2
9
Q
Complex sugars aka polysaccharides consist of:
A
Starch, glycogen
10
Q
Starches consist of _____ and _____ which stores carbohydrates in plants
A
Amylose and amylopectin
11
Q
Glycogen stores carbohydrates in humans or other ____
A
Animals
12
Q
Polysaccharides in sports drinks consist of _____ and _____ which are chains of glucose molecules sometimes used in sports drinks
A
Glucose polymers and maltodextrins
13
Q
Sources of digestible carbohydrates
A
Primary: Grains, fruit, vegetables
Others: dairy, alternative protein (nuts, legumes), sweets, sports drinks/foods
Fiber: Soluble, insoluble
14
Q
Insoluble fiber consists of:
A
Cellulose, hemicellulose, lignin (not a carb, woody part of plants)
14
Q
Soluble fiber consist of:
A
Pectins, gums, algal polysaccharides
Key sources – fruits, grains, beans
15
Q
Fiber is an _________ form of carbohydrate that the large intestine breaks down through fermentation in the colon, up to 50%
A
Indigestible
16
Q
T/F: You should recommend high-fiber foods to athletes before comps.
A
False, because it may trigger GI symptoms (gas, bloating, discomfort)
17
Q
Dietary CHO goals for Athletes
A
45-65% of kcals
Daily reference value (DRV) = 300g for 2000 kcal diet
18
Q
Fiber (DRV) per day
A
25g women
38g for men
- fiber DRV is the same for athletes
19
Q
T/F: All CHOs need to be digested except for monosaccharides.
A
True
20
Q
Where does CHO absorption occur?
A
Small intestine
21
Q
What are 3 factors that may impact performance
A
Rate of stomach emptying, rate of absorption, and water absorption
22
Q
Which part of a triglyceride can be used for glucose production? The fatty acid or glycerol?
A
Glycerol
23
Q
Lactate and glycogen are metabolized in the
A
Liver
24
_____ mainly gets converted into lactate in the gut cells before absorption
Fructose
25
Nutrients absorbed into the bloodstream through the GI tract stop through _____ before moving on to the rest of the body
Liver
26
50% of fructose becomes
Glucose
27
25% of fructose becomes
Lactate
28
15% of fructose becomes
Glycogen
29
How many grams of carbs can be absorbed per hour of exercise?
120 grams
30
Fructose and galactose mostly converted to
Glucose
31
T/F: Glucose polymers are polysaccharides prepared commercially by controlled hydrolysis of starch
True
32
T/F: The glycemic load is calculated by the following formula:
GL = gly ind x gram of non fiber carb in 1 service/ 100
True
33
T/F: A single bout of exercise can activate the genes that produce GLUT-4 receptors which can exert an insulin effect
True
34
T/F: It is now generally thought that the component of fatigue correlated with lactate results from the lactate itself rather than the effects of an increased free hydrogen ion and the associated acidity
False, It is generally thought that fatigue associated with lactate accumulation is primarily due to the increased concentration of free hydrogen ions (H⁺), leading to a decrease in muscle pH (acidosis), rather than from the lactate itself.
35
3 main depots of carbohydrate storage are:
1. Blood glucose
2. Liver Glycogen
3. Muscle Glycogen
36
If the blood glucose level decreases, the liver will increase through _________
Glycogenolysis
37
Glucose stores may be replenished from glycogen ______
Absorption
38
T/F: Muscle lacks the glucose-6-phosphatase enzyme, so glycogen can not exit the cell
True
39
T/F: Muscle glycogen can be distributed to other muscles for energy
False, muscle glycogen is specific to the muscle doing the work
40
In what ways do the fuels of carbohydrates influence fatigue?
1. Preventing hypoglycemia
2. Liver glycogen depletion
3. Muscle glycogen depletion
4. CNS responses (sensations in the brain)
41
When do carbohydrates become important for athletes?
When intensity is high and activity is prolonged
42
T/F: Lactate can help to improve endurance by delaying the onset of fatigue
True
42
Consuming a CHO-rich meal along with exercise, results in ___________ hypoglycemia, due to insulin and exercise both decreasing blood sugar
Reactive
42
T/F: When you run out of muscle glycogen, fatigue occurs because muscle cells cannot produce ATP rapidly enough to maintain exercise intensity.
True
43
T/F: Eating CHO during exercise spares glycogen to use later in exercise, spares BCAA (prevents fatigue sensations to the brain) and maintains blood glucose
True
44
A decrease in BCAA in the blood leads to fatigue by changing the ratio of BCAA to tryptophan in the circulation, resulting in low BCAA and high tryptophan. The brain then takes tryptophan to produce serotonin (promotes relaxation). This is known as the ____ _____ theory.
Central Fatigue
45
Mouth rinsing (Study)
First evidence Carter el al MSSE 2004
6.4% maltodextrin vs water
Rinsed in mouth every 12.5% of long term endurance bout
Finished exercise faster 59 mins vs 61 mins
46
T/F: The maximum absorption rate of carbs during exercise is around 120g/hour, especially when a mix of glucose and fructose is consumed.
True
47
T/F: Fructose and galactose are converted into glucose, lactate, and glycogen, while glucose is metabolized by the liver or other tissues.
True
48
T/F: Glucose and galactose enter cells via active transport (SGLT1 and GLUT2) and can move against the concentration gradient.
True
49
T/F: Fructose uses facilitated diffusion (GLUT5 and GLUT2) and can only move down its concentration gradient because it doesn't require energy. Absorption may slow when combined with other carbohydrates.
True
50
T/F: Consuming a carbohydrate-rich meal immediately before exercise can lead to reactive hypoglycemia.
True
51
T/F: Carbohydrate consumption is not necessary for athletes during high-intensity or prolonged activities.
False, Carbohydrate use is especially important when exercise intensity is high or prolonged, as it helps maintain energy levels and delay fatigue.
52
T/F: Muscle glycogen depletion is typically a concern only during short-duration, high-intensity exercise.
False, Muscle glycogen depletion is usually a factor during prolonged endurance exercise and can lead to "hitting the wall."
53
T/F: Endurance events and activities with intermittent, high-intensity spurts, like soccer or basketball, benefit from optimal carbohydrate stores and consumption.
True
54
T/F: Training increases the body’s ability to use carbohydrates by increasing VO2 max, enhancing glycogen storage, and improving insulin sensitivity.
True. Training adaptations like increased mitochondria, more GLUT4 receptors, and higher Krebs cycle enzyme activity all contribute to better carbohydrate metabolism.
55
T/F: Carbohydrate consumption before exercise does not affect central fatigue.
False, Carbohydrates help maintain blood glucose and BCAA levels, which can prevent central fatigue by reducing serotonin production in the brain.
56
T/F: Training increases the body’s ability to use carbohydrates by increasing VO2 max, enhancing glycogen storage, and improving insulin sensitivity.
True
57
T/F: Increased exposure to cold increases energy expenditure, making carbohydrate intake even more important.
True
58
T/F: Mouth rinsing with a carbohydrate solution has no impact on exercise performance.
False, Mouth rinsing with a carbohydrate solution has been shown to improve exercise performance, likely through neural signals that enhance motivation and reduce perceived exertion.
59
T/F: Higher intensity exercise increases the rate of glucose uptake by muscles.
True
60
T/F: Ribose supplementation has been proven to significantly increase endurance and recovery in trained athletes.
False, Studies have shown that ribose supplementation did not result in statistically significant improvements in endurance or recovery in trained athletes.
61
T/F: The theory behind lactate supplementation is that it acts as a buffer to delay the onset of fatigue.
True. Lactate supplements are believed to help buffer acidity in muscles, potentially delaying fatigue during exercise.
62
T/F: Studies suggest sodium bicarbonate is more effective than calcium lactate at buffering acidity and delaying fatigue.
True
63
T/F: One precaution when carbohydrate loading is the risk of reactive hyperglycemia, which can occur when consuming high-glycemic index foods.
True
64
T/F: Tapering exercise combined with a diet consisting of 65% carbohydrates can help maximize the benefits of carbohydrate loading.
True. Reducing exercise volume while increasing carb intake helps optimize glycogen storage.
65
T/F: It is advised to start carbohydrate loading 3-7 days prior to competition.
True. This time frame allows for optimal glycogen storage in the muscles and liver.
66
T/F: Female athletes are recommended to consume 8-10 grams of carbohydrates per kilogram of body weight per day when carbohydrate loading.
True
67
T/F: Carbohydrate loading is suitable for all types of exercise, regardless of intensity or duration.
False. It is more beneficial for endurance activities or sports with high-intensity intermittent exercise, such as tennis.
68
T/F: Tapering exercise combined with a diet consisting of 65% carbohydrates can help maximize the benefits of carbohydrate loading.
True. Reducing exercise volume while increasing carb intake helps optimize glycogen storage.
69
T/F: One precaution when carbohydrate loading is the risk of reactive hyperglycemia, which can occur when consuming high-glycemic index foods.
True, High-glycemic foods can lead to spikes in blood sugar, potentially causing reactive hyperglycemia.
70
T/F: The addition of fructose to carbohydrate intake may reduce gastrointestinal (GI) distress when consuming high amounts of carbohydrates.
True. Fructose can help lessen GI distress during recovery when high carbohydrate intakes are needed.
71
T/F: Adding fructose to recovery nutrition does not enhance liver glycogen re-synthesis after exercise.
False. Fructose can enhance liver glycogen re-synthesis, aiding in a quicker recovery.
72
T/F: For the best recovery, it is recommended to consume carbohydrates every two hours if fast recovery is needed.
True
73
T/F: Fructose does not contribute to making glycogen more readily available during recovery.
False, Fructose can make glycogen more readily available, which is beneficial for recovery.
74
T/F: Hydrogels are designed to bypass some of the typical gastrointestinal responses that slow down the absorption of high-carbohydrate drinks.
True
75
T/F: When hydrogels come into contact with gastric fluid, they form a hydrogel that encapsulates the carbohydrate solution, allowing it to pass into the duodenum without reducing gastric emptying.
True
76
T/F: Sports drinks typically contain a carbohydrate concentration of 6-8%, but concentrations can go up to 10%.
True
77
T/F: In the duodenum, the hydrogel remains intact, preventing the absorption of carbohydrates.
False. In the higher pH environment of the duodenum, the hydrogel dissolves, allowing carbohydrate absorption through intestinal transport proteins.
78
Muscle glycogen can only be used by the muscle cell in which it is being stored, specifically for _______.
Glycolysis
79
Blood glucose levels are tightly regulated by the _______. If glucose levels decrease, the liver will increase glucose through _______.
liver, glycogenolysis
80
When glycogen stores are depleted, the body can obtain more glucose through ________, using amino acids, glycerol and lactate; or by eating more carbohydrates.
Gluconeogesis
81
T/F: During exercise gluconeogesis is too slow to maintain blood glucose alone during strenuous exercise so athletes need to eat (exogenous CHO).
True, During strenuous exercise, the rate of glucose utilization by the muscles can exceed the rate at which gluconeogenesis produces new glucose.
82
T/F: Activities that require optimal carbohydrate stores and consumption are: endurance events, thermo-hot/thermo-cold events, intermittent and high intensity sports
True, Adequate carbohydrate intake before and during these activities helps maintain glycogen stores, supports energy levels, and delays fatigue.
83
T/F: It is not recommended to eat high glycemic foods 50-60 minutes before exercise
True
84
T/F: Nutrition recommendations for female athletes include: 8-10 g of carbs per kg of body weight per day, 65% carbs, 15% protein, 20% fat, Eat mixed diet, with moderately high consumption of carbs, and tapering exercises with rest.
True
85
T/F: Trehalose is a disaccahride of 2 glucose units linked at number 1 carbons, and is more likely to reduce the glycemic/insulenic response
True
86
Although _______ is absorbed through the active transport with glucose, it produces a lower glycemic response and may enhance glycogen during recovery
Galactose
87
T/F: During intense exercise, the production of hydrogen ions (H+) increases, which can lower the pH in muscles and lead to acidosis—a contributing factor to muscle fatigue.
Lactate itself is not the cause of acidosis; rather, it helps buffer the acidity by facilitating the removal of excess hydrogen ions from the muscle cells, thus helping maintain a more stable pH. This buffering capacity can help reduce the onset of fatigue.
True
