Carbohydrates EXS 357 - Dr. Augustine - Chapter 3

Flashcards covering Carbohydrate functions, classification, digestion, absorption, blood glucose regulation, and athlete recommendations based on lecture notes.

Carbohydrates are the primary __ source, especially during exercise.

energy

At rest, the brain and other neural tissue utilize __ 60% of glucose.

carbohydrates

Consistent, adequate CHO intake prevents __ in the body.

protein catabolism

Disaccharides are formed when two monosaccharides are bonded together by a __ bond.

glycosidic

__ are classified as simple carbohydrates and consist of 2 monosaccharides.

Disaccharides

Polysaccharides are classified as __ carbohydrates and contain ≥10 glucoses.

complex

__ is the primary sugar used by the body and is also known as dextrose.

Glucose

__ is a monosaccharide mainly found in fruits and honey.

Fructose

Lactose, found in milk and dairy products, is a disaccharide composed of glucose plus __.

galactose

Sucrose, or table sugar, is a disaccharide made up of glucose plus __.

fructose

__ is the storage form of glucose in plants.

Starch

The storage form of glucose in animals is __.

Glycogen

__ refers to structural components of plants that are mostly indigestible by humans.

Fiber

The __ of grains contains most of the fiber, protein, vitamins, minerals, fats, and antioxidants, but is removed during refining.

bran and germ

__ is when certain vitamins and minerals lost in the refining of grain are added back.

Enrichment

When some vitamins and minerals not naturally found in a food are added, the food is said to be __.

fortified

Dietary fiber is mostly __ carbohydrates.

non-digestible

For men, the adequate intake of fiber is __ g·day⁻¹.

38

One health benefit of fiber is that it slows the breakdown of starch into glucose, which prevents a rapid increase in __.

blood glucose

Fiber helps lower __ cholesterol.

LDL

Starch digestion begins in the mouth with the enzyme __.

salivary amylase

__ is a brush border enzyme that breaks down maltose into glucose.

Maltase

The enzyme __ breaks down sucrose into glucose and fructose.

sucrase

Lactose is broken down into glucose and galactose by the enzyme __.

lactase

Only __ can be absorbed through enterocytes in the small intestine.

monosaccharides

__ is a type of transport where molecules move from high to low concentration directly across the membrane without assistance.

Simple diffusion

Fructose is mainly absorbed into enterocytes via the __ transporter on the apical membrane.

GLUT5

Glucose and galactose enter enterocytes via the __ transporter, which is a Na⁺-dependent cotransport system.

SGLT1

On the basolateral side of enterocytes, __ allows glucose, galactose, and fructose to leave the cell into the portal vein.

GLUT2

When glucose is consumed alone, the maximum absorption rate is 1 g·min⁻¹, or __ g·hr⁻¹.

60

Combining glucose and fructose in a 2:1 ratio can increase the maximum CHO absorption rate to __ g·hr⁻¹.

105

The process of fatty acid and triglyceride synthesis from excess carbohydrates is called __.

lipogenesis

__ is considered more lipogenic than glucose.

Fructose

Most High-Fructose Corn Syrup (HFCS) consists of 55% fructose and __ glucose.

45%

Excessive fructose consumption can contribute to __ liver disease.

non-alcoholic fatty

Normal blood glucose (BG) levels, known as __, range from 70 to 100 mg·dl⁻¹.

euglycemia

A blood glucose level less than 70 mg·dl⁻¹ is classified as __.

hypoglycemia

A fasting blood glucose level greater than 126 mg·dl⁻¹ indicates __.

hyperglycemia

The __ is a measure of the increase in blood glucose over two hours after consuming 50 g of a CHO-containing food.

glycemic index (GI)

Foods with a glycemic index of less than 55 are considered __ CHO.

low GI / slow

The hormone __ is released from the beta cells of the pancreas and helps lower blood glucose levels.

insulin

The synthesis of glycogen from glucose is called __.

glycogenesis

Skeletal muscle accounts for approximately __ of glucose uptake from the blood.

90%

When insulin binds to its receptor on a muscle cell, it triggers the translocation of the __ protein, allowing glucose to enter the cell.

GLUT4

The hormone __ is released from the alpha cells of the pancreas and helps raise blood glucose levels.

glucagon

__ is the breakdown of glycogen into glucose.

Glycogenolysis

The synthesis of glucose from non-carbohydrate sources like pyruvate or lactate is known as __.

gluconeogenesis

Only __ glycogen can be broken down and released into the blood to raise blood glucose levels.

liver

Skeletal muscle glycogen cannot be used to raise blood glucose because it lacks the enzyme __.

glucose-6-phosphatase

__ (adrenaline) stimulates liver glycogenolysis, helping to increase blood glucose levels, especially during higher exercise intensity.

Epinephrine

The hormone __ stimulates muscle protein breakdown, providing amino acids for gluconeogenesis.

cortisol

Maintaining normal blood glucose levels can reduce __ secretion, demonstrating a "protein-sparing" effect.

cortisol

Daily carbohydrate recommendations for athletes range from __ g/kg of body weight.

3-12

For athletes with low-intensity or skill-based activities (

3-5

Pre-workout carbohydrate recommendations are typically __ g·kg⁻¹, consumed 1 to 4 hours before competition.

1 to 4

Pre-workout meals should consist of easily digested, low-fiber, mostly __ carbohydrates for optimal performance.

complex

During competition, suitable carbohydrate sources include glucose, sucrose, maltodextrin, and small amounts of __.

fructose

It takes approximately __ hours to restore muscle glycogen after glycogen-depleting exercise.

24

For rapid glycogen repletion post-exercise, athletes should consume approximately __ g·kg⁻¹·hr⁻¹ of carbohydrates each hour for up to 4 hours.

1.0

Post-workout carbohydrate intake for rapid glycogen repletion should include multiple-transportable CHO, such as a 2:1 ratio of __ and fructose.

maltodextrin/glucose/starch

Carbohydrate loading is also known as glycogen __.

supercompensation

Carbohydrate loading is appropriate for endurance athletes and those in intermittent high-intensity exercise sports to increase muscle and liver __.

glycogen