Chapter 7 - Protein Flashcards

Question

# internal absorption factors stomach acid

Answer 1

stomach acid also affects protein digestion and absorption ## Footnote individuals with less stomach acid often absorb less of the protein they consume

Answer 2

the efficiency of digestion and absorption decreases as the volume and amount of protein increases ## Footnote **For example, if someone consumes ~10 grams of protein, they will absorb a higher percentage of those 10 grams than they would if they were to consume ~100 grams of protein**

Answer 3

The digestive and absorptive properties of various proteins can have important impacts on athletes For example, the digestive properties of proteins can influence the anabolic response to protein both during exercise and at rest. These proteins are often classified as fast or slow based on digestion and absorption The majority of research into fast and slow protein compares whey, casein, and soy (the most commonly consumed isolated protein). Whey and soy are considered to be fast proteins, whereas casein is slow. Another factor to consider when choosing the type of protein to consume is the amino acid content, specifically leucine. This amino acid acts as a signaling molecule that stimulates protein synthetic pathways such as mTOR. Whey protein contains more leucine than casein or soy; however, supplementation can often contain additional leucine, which promotes anabolic response post-exercise

Answer 4

plant-based diets tend to consume less protein overall, and because plant-based protein sources are incomplete, they can increase the risk of amino acid deficiencies Plant-based diets are often found to be lower in leucine, lysine, methionine, isoleucine, threonine, and tryptophan

Answer 5

A culmination of proteins that, on their own, are missing some essential amino acids, **but when combined have a complete amino acid profile**

Answer 6

The amino acids present in this pool are then transported around the body, used where required, and are constantly incorporated into protein structures and broken back down to amino acids ## Footnote the body contributes 400 g daily to this pool

Answer 7

The balance of protein synthesis and protein degradation ## Footnote the half-life of proteins can range from minutes to weeks, depending upon the function of the specific protein

Answer 8

process of making protein ## Footnote Synthesis is the creation of larger protein structures from individual amino acids

Answer 9

breaking down protein

Answer 10

the enlargement of a tissue or organ ## Footnote in the context of fitness, it is often used to describe the enlargement of skeletal muscle

Answer 11

The wasting away or decrease in size of body tissue

Answer 12

A measure of nitrogen input versus nitrogen output ## Footnote Historically, one of the ways to assess protein balance (ratio of protein synthesis to protein breakdown) was using a method known as nitrogen balance. This method examined the rate at which dietary nitrogen was entering the body through protein consumption and the rate at which it was leaving the body through urine. This method was used for several decades, but recent methodologies have been developed that are much more accurate, such as indicator amino acid oxidation tests

Answer 13

Carbohydrates and fats serve as the primary fuel sources in the human body; however, during periods of low energy availability or low nutrient availability, protein—specifically amino acids—can be utilized to provide energy

Answer 14

1. First, some amino acids can be converted into **pyruvate**, which eventually becomes Acetyl-CoA that then enters into the Krebs cycle 2. amino acids can be converted into α-ketoglutarate or **fumarate**, which are intermediaries in the Krebs cycle 3. amino acids are used as substrates for creating more **glucose** through the process of gluconeogenesis, which requires lactate, glycerol, and amino acids

Answer 15

more protein will elicit a greater muscle protein synthesis response | 20 - 40 g is good ## Footnote there are diminishing returns as the amount of protein synthesis goes up

Answer 16

based on the current literature, it appears that consuming protein post-workout is important, but the window may be as long as 4-6 hours, and that daily protein intake is likely the most important factor

Answer 17

dietary protein DOES NOT cause kidney damange ## Footnote **does not extend to those with established kidney disease

Answer 18

1. tissue remodeling (protein synthesis and degradation) 2. enzymes + cellular transporters 3. cell signaling 4. fluid balance 5. hormones and neurotransmitters 6. immune system function

Answer 19

they DO NOT increase muscle protein synthesis and DO NOT increase weight loss ## Footnote valine is an important BCAA

Answer 20

protein DOES NOT cause weak and brittle bones ## Footnote A series of studies demonstrated that low protein intake results in less calcium absorption than high-protein diets, and that higher protein intake is associated with greater bone mineral density than lower protein intake

Answer 21

because soy is lower in the essential amino acid leucine, it DOES NOT produce as great of muscle protein synthesis response as whey protein (which has more leucine)

Answer 22

Athletes who adopt a plant-based diet often consume less protein than their omnivorous counterparts it has been estimated that athletes who follow a plant-based diet have an increased protein requirement of 20 or more grams per day than athletes who follow an omnivorous diet

Answer 23

mTOR, which is known as the mammalian target of rapamycin, is an enzyme that is involved in the cell signaling processes that **increase muscle protein synthesis** ## Footnote **leucine** provides one of the most potent signals for activating it.

Answer 24

proteins are an important component of other bodily tissues Protein is important for bone tissue, connective tissue (e.g., tendons and ligaments), and organ tissue

Answer 25

critical in biochemical reactions through their roles as enzymes and cellular transporters, moving nutrients, hormones, electrolytes, and other molecules throughout the body

Answer 26

Proteins are critical in these cellular signaling processes in that most of the nodes in these signals are made of proteins

Answer 27

Protein plays an important role in ensuring that fluids are correctly distributed across these three compartments. When proteins are located within circulation, they exert what is known as **colloid-osmotic pressure**, which means that they attract water, allowing the body to hold an adequate amount of fluid within circulation

Answer 28

hormones and neurotransmitters are made of amino acids

Answer 29

produced by the hypothalamus and secreted by the pituitary gland that acts as a neurotransmitter and is **involved in childbirth and breast-feeding.**

Answer 30

A broad category of molecules, often proteins, involved in cell signaling.

Answer 31

A class of proteins that stimulate the directional movement of other cells (leukocytes, epithelial cells, etc).

Answer 32

adult: 0.8 g/kg athlete: 1.6-2.2 g/kg

Answer 33

training-induced adaptations such as mitochondrial recovery and tendon and ligament remodeling **1.6 - 1.7 g/kg represents the minimal threshold of protein intake to prevent degredation of muscle mas**s (it's not necessarily the optimal amount)

Answer 34

1.6 - 2.0 g/kg

Answer 35

1.4 g/kg daily soccer, rugby, basketball, etc.

Answer 36

as training volume increases, tissue turnover increases, which requires more protein

Answer 37

It has been proposed that 1.6–2.0 g per kg body weight per day should be recommended to optimize muscle protein synthesis in older athletes, especially as training and competition cause damage to contractile and connective tissue there is a phenomenon known as anabolic resistance present among older individuals, in which the anabolic response to amino acids is impaired among older adults (~65 years of age and older)

Answer 38

there are similar protein requirements between sexes

Answer 39

dipeptides

Answer 40

glycine and proline