Protein Metabolism + Nutrition in Endurance Performance Flashcards Preview

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Flashcards in Protein Metabolism + Nutrition in Endurance Performance Deck (49)
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1
Q

Define protein

A

chains of amino acids, arranged into primary, secondary and tertiary structures which contain nitrogen.

2
Q

What are the 3 processes of protein production

A

transcription, translation (initiation, elongation and termination) and post-translation modification

3
Q

Give 3 functions of proteins

A
  • Provide structure
  • Hormones
  • Antibodies
  • Transporters
  • Enzymes
  • Movement
4
Q

Define Muscle) protein synthesis

A

o The creation of new proteins from amino acids (as a result of initial transcription of the DNA).

5
Q

Define Muscle) protein breakdown

A

o The degradation of whole proteins back to constituent amino acids.

6
Q

Define (Muscle) protein balance

A

o The net result of muscle protein synthesis and muscle protein breakdown (Synthesis-Breakdown).

7
Q

Define Amino acid oxidation

A

o The breakdown of intracellular amino acids for energy production.

8
Q

Define Amino acid uptake

A

o The rate of transport of amino acids from one pool (e.g. the plasma) to another (e.g. the muscle cell).

9
Q

Define Amino acid utilization

A

o The amount of dietary amino acids (obtained from dietary protein) that is used by the tissue and organs of the body for the above processes.

10
Q

What are the 3 possible classes of proteins

A

Essential
Non-essential
Conditionally essential

11
Q

Define primary structure of protein

A

Sequence of amino acids

12
Q

Define secondary structure of protein

A

Local folding of polypeptide chain

13
Q

Define tertiary structure of protein

A

three dimensional folding pattern of a protein- side chain interactions

14
Q

Define quaternary protein structure

A

protein consisting of more than one amino acid chain

15
Q

What is deamination

A

removal of amine group (NH3) in liver

16
Q

In the average person,how much protein is synthesised each day?

A

350g/day

17
Q

In the average person, what is the protein synthesis rate?

A

1-2% a day

18
Q

What is a stable isotope

A

Isotopes function identically, but can be marked, so act as a tracer to measure net nitrogen balance.

19
Q

give 3 factors affecting protein turnover

A
  • Habitual diet
  • Protein intake
  • Energy intake
  • Hormones
    o Insulin
    o Steroids e.g. testosterone
  • Exercise
20
Q

Give 3 potential roles of dietary protein in sport and exercise

A
	Muscle hypertrophy 
	Muscle strength 
	Immune function 
	Central fatigue
	Glycogen re-synthesis
	Additional energy during exercise 
	Specific function of individual amino acids 
	Effects on muscle damage
21
Q

Bowtell et al 1998 found that leucine oxidation increased most when after exercise

A

1 hour post-exercise

22
Q

Hulston et al 2011 found what sort of protein balance during exercise

A

negative net balance, but exercise increased both protein synthesis and breakdown

23
Q

Protein ingestion before, during or after exercise promotes what sort of balance

A

positive net balance

24
Q
Protein ingestion is associated with which synthesis rates?
A) increased myofibrillar
B) decreased myofibrillar
C) Increased mitochondrial
D) decreased mitochondrial
A

A) increased myofibrillar

25
Q

In the trans-alp challenge, which group improved their performance?
o 7.6% cho-e solution and cho bars (placebo)
o 7.2% cho-e, 1.8% wp solution and cho/protein bars.

A

o 7.2% cho-e, 1.8% wp solution and cho/protein bars.

26
Q

What is central fatigue theory

A

Fatigue may be associated with inadequate central nervous system “drive” to the working muscle e.g. by neurotransmitters

27
Q

What is the serotonin central fatigue theory

A

Increased brain 5-hydroxytryptamine (5-HT) (Serotonin) concentration causes a deterioration in performance

28
Q

Describe the central fatigue theory mechanism

A
the selective transporter poses competition with branched chain amino acids (increasing tryptophan and serotonin) so... 
•	reduced [BCAA] and increased [fTryp]
•	increased fTryp : BCAA
•	increased fTryp transport into brain
•	increased serotonin synthesis
•	impaired CNS function
29
Q

Did Blomstrand et al 1991 show BCAA supplementation to improve mental and physical performance

A
  • some evidence of improved mental performance

* slower runners (3.05 - 3.30 h) improved performance

30
Q

Did Van Hall et al 1995 show BCAA/tryptophan supplementation improved physical performance

A

• No difference in time to exhaustion despite increased fTryptophan:BCAA.

31
Q

True or false: A hypocaloric diet decreases body mass, lean body mass and fat mass

A

False, Lean body mass increased

32
Q

What is the recommended protein dose?

A

RDI = 1.2 – 2.0 g/kg

33
Q

What is the timing consideration for protein ingestion?

A

o Protein ingestion in close proximity to exercise may facilitate muscle reconditioning
o Protein feeding during exercise does not appear to enhance exercise performance assuming adequate CHO is consumed.

34
Q

True of False: Tarnopolsky et al 1992 suggested a RDA for sedentary subjects to be 0.89 g/kg/day and 1.76g/kg/day for strength trained subjects.

A

True

35
Q

What is the anabolic stimulus for muscle production in the diet?

A

Protein

36
Q

Why does exercise cause an immediate reduction in muscle protein synthesis?

A

the priority is ATP for muscular contraction at the time

37
Q

What is more important in Rex training: intensity or carrying it out to failure

A

carrying it out to failure

38
Q

What is more important in Rex training: eccentric or concentric exercise

A

eccentric

39
Q

Why do we see an increase in MPB following exercise

A

protein breakdown replaces protein fibres with stronger, faster fibres

40
Q

If protein turnover is around 300-600g per day.. what can this increase too post-exercise

A

around 600-900g per day

41
Q

True or false: there is a golden 30 mins post-exercise

A

False-
protein synthesis is increased for up to 2 hours post. Plus, the body is sensitive to protein for all meals within this 2 days

42
Q

What does net protein accretion result in

A

Hypertrophy

43
Q

When should whey protein be ingested

A

ingested and absorbed faster than casein- so post-exercise

44
Q

When should casein protein be ingested

A

pre-bed

45
Q

What is leucine better at than other amino acids?

A

Faster FSR

46
Q

True or false: CHO can improve MPS

A

There was an increase in MPB with CHO and exercise, but CHO reduced MPS with exercise

47
Q

What is the RDA for protein? Sedentary

A

0.89 g/kg/d

48
Q

What is the RDA for protein? ReX trained

A

1.76 g/kg/d

49
Q

How much protein post-exercise will induce an optimal anabolic response

A

20-30g