Glycolysis / LA system

Question 1

glyconeolysis

Answer 1

The energy pathway responsible for the initial catabolism of glucose that begins with glucose or glycogen
- end w pyruvate (aerobic/slow)
- end w lactate (anaerobic/fast)

Question 2

glycogenesis

Answer 2

production of glycogen in the muscle and liver

Question 3

Glyconeogenesis

Answer 3

The creation of glucose (in the liver) from noncarbohydrate sources, primarily glycerol, lactate, pyruvate and alanine

Question 4

Embden-Meyerhof pathway

Answer 4

glycolytic/lactic acid system
- glucose or glycogen substrate
- catabolic pathway
- peak 15-30sec, last 45-120sec

Question 5

GLUT-1

Answer 5

transporter in sarcolemma to bring glucose diffuse into cell
- cannot bring in glucose fast enough so need help of GLUT 4

Question 6

GLUT-4

Answer 6

internal vesicle to help GLUT1 bring glucose into cell with high-blood glucose levels
- beta cells make insulin and tell GLUT 4 to move from internal to cell membrane

Question 7

insulin independent method

Answer 7

Ca high from muscle contraction tell glut4 to go to cell membrane (get more glucose into cell since exercising)

Question 8

Phosphorylase

Answer 8

enzyme to turn glycogen into glucose 1-Phosphate
- increase w more Ca, P and epinephrine

Question 9

hexokinase

Answer 9

enzyme turns glucose into glucose 6-phosphate
- ATP + glucose = ADP + G6P

Question 10

phosphofructokinase

Answer 10

enzymes turn to fructose-6-P to fructose-1,6-P
- F6P + ATP = F1,6P + ADP
- glycolysis rate limiting factor
- affected by low ATP, high H+ and P and ADP/AMP

Question 11

glycolysis facts

Answer 11

• in sarcoplasm
• breakdown glucose/glycogen for ATP
• aerobic/slow = pyruvate
• anaerobic/fast = lactate and H
• energy to activate pathway (HK and PFK)
• 2 net ATP (glucose) or 3 (glycogen)

Question 12

Lactate Dehyrogenase

Answer 12

enzyme turn pyruvate = lactate by oxidizing NAD
- LDH1 = cardiac muscle, MI marker
- LDH5 = skeletal muscles

Question 13

G3P dehydrogenase

Answer 13

G3P to 1,3-bisphosphoglycerate

Question 14

resting lactate levels

Answer 14

Remain relatively unchanged with long-term cardiovascular training. As a result of proper cardiovascular training, less lactic acid will be produced at submaximal workloads during exercise.

1-2mmol/L

Question 15

glycolysis influenced by

Answer 15

• NAD/NADH ratio: high NAD = faster glycolysis
• ADP/ATP ratio: high ATP = faster glycolysis
• substrate avaliability: low glucose = slow glycolysis (fasting, disease, malnutrition, prior exercise)

Question 16

LA system summary

Answer 16

• substrates are glucose (blood) and glycogen (muscle)
• sarcoplasm
• fast glycolysis (more H = discomfort)
• peak at 15-30 sec
  mod-high power; mod-low capacity (45-120 sec)

Question 17

pH of blood and muscles

Answer 17

• resting blood: 7.4-7.45pH
• resting muscle: 6.9-7pH
• after exercise in muscle: 6.4pH

Question 18

where is H from in heavy exercise

Answer 18

modern view is H is made from steps 1, 3, 6 of glycolysis and fast rates of ATP hydrolysis

Question 19

consequences of H in fast glycolysis

Answer 19

• more H accumulation = pain
• inhibit PFK and phosphroylase activity and Ca bind to troponin and O2 to Hb
• decrease ATPase (less Na/K transport, less mATPase, contractions)

Question 20

consequences of La in fast glycolysis

Answer 20

more La:
- accumulate in muscle
- more oxidation of La- in muscle
- more efflux to blood and muscles (lead to excretion, gluconeogenesis, oxidation of La)

Question 21

Lactate in Recovery

Answer 21

• 50-75% used as fuel (oxidized into pyruvate to be used for kreb and ECT)
• 10-25% for gluconeogenesis (liver)
• 5-10% as provide C for Amino acids in transamination

Question 22

Lactate Clearance

Answer 22

• oxidation (turn to pyruvate, oxidize ATP, CO2, H2O for Krebs – using intracellular and extracellular shuttles)
• reconverted to glucose (liver prefers to make glycogen) via gluconeogenesis
• oxidative and glycolytic fibers turn La into alanine via transamination
• some La leaves via circulate in blood (heart loves it in exercise!) or via sweat

Question 23

lactate production

Answer 23

• muscle contractions
• enzyme activity
• muscle fiber type
• sympathetic neurohormonal activity
• insufficient oxygen

Question 24

intracellular lactate shuttle

Answer 24

transport lactate from cytoplasm to mitochondria where it is turned back into pyruvate by LDH1 and use for Krebs Cycle stages 2, 3, 4
These lactate cant be measured in blood lactate levels

Question 25

extracellular lactate shuttle

Answer 25

transport lactate between tissues. lactate is cleared into slow-oxidative fibers by oxidation and transamination ; into circulation/skin/liver by gluconeogenesis and transamination
Transports out due to MCT4
Transports in due to MCT1

Question 26

Gluconeogenesis importance

Answer 26

• glucose is essential for brain and CNS
• GNG important for starvation, prolong exercise (low blood sugar)
• precursors are pyruvate, lactate, glycerol, alanine, FFA,
• occur in liver

Question 26

Improving Buffering Capacity

Answer 26

-Better buffering capacity = more glycolytic capacity = higher post exercise blood lactate
-Not good at buffering = use H back into glycolysis = slow it down

Question 27

buffering capacity

Answer 27

HCO3, Pi, histidine, and Hb in RBC
- maintain muscle pH
- extend anaerobic power production
- reduces power drop off
- trainable in sprint trained athletes and breath holding mammals

Question 28

bicarbonate (baking soda) loading

Answer 28

↑ in blood pH (not muscle pH) ingest 5-6mmol/L 1 - 3 hours prior to exercise

↑ buffering potential, therefore improving anaerobic performance
↑ rate of H efflux due to ↑ gradient

• has fewer bad side effects

Question 29

B-alanine supplementation

Answer 29

B-alanine + L-histidine = Carnosine
- Carnosine = important intramuscular buffer
- Decrease 800m running times

Question 30

lactic system and training

Answer 30

• ↑ activity of PFK, HK, phosphorylase and LDH5, which ↑ power of system
• ↑ skeletal muscle buffering capacity (resist pH change), which ↑ capacity of system
• ↑ glycogen stores in muscle, important for ↑ capacity and power of system