Question

1. According to the paper, what does lactate dehydrogenase (LDH) do and what does it allow to happen within the myofiber? (5 points)

2. According to the paper, what is the major disadvantage of relying on glycolysis during high-intensity exercise? (5 points)

3. Using Figure 1 in the paper, briefly describe the different sources of ATP production at 50% versus 90% AND explain whether you believe this depiction of ATP production applies to a Type IIX myofiber in a human. (5 points)

4. Briefly describe the differences between aerobic and anaerobic metabolism (10 points).

Answer all questions please

EXPERIMENTAL CELL RESEARCH 316(2016) 303-30 available at www.sciencedirect.com C RESEARCH ScienceDirect ELSEVIER ate/yexer Review Skeletal muscle: Energy metabolism, fiber types, fatigue and adaptability Håkan Westerblad". Joseph D. Bruton, Abram Katz Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden ARTICLE INFORMATION ABSTRACT Article Chronology: Received 10 March 2010 Revised version received 17 May 2010 Accepted 17 May 2010 Available online 24 May 2010 Keywords: Skeletal muscle Energy metabolism Muscle fatigue Endurance training Calcium Reactive oxygen species Skeletal muscles cope with a large range of activities, from being able to support the body weight during long periods of upright standing to perform explosive movements in response to an unexpected threat. This requires systems for energy metabolism that can provide energy during long periods of moderately increased energy consumption as well as being able to rapidly increasing the rate of energy production more than 100-fold in response to explosive contractions. In this short review we discuss how muces can deal with these divergent demands. We first outline the major energy metabolism pathways in skeletal muscle. Next we describe metabolic differences between different muscle libertypes. Contractile performance declines during intense activation, Le fatigue develops, and we discuss likely underlying mechanisms. Finally, we discuss the ability of muscle fibers to adapt to altered demands, and mechanisms behind these adaptations. The accumulated experimental evidence forces us to conclude that most aspects of energy metabolism involve multiple and overlapping signaling pathways, which indicates that the control of energy metabolism is too important to depend on one single molecule or mechanism 2010 Elsevier Inc. All rights reserved Contents Introduction Energy metabolism Anaerobic metabolism Aerobic metabolism Muscle fiber types Fatigue. Adaptation Perspective. Acknowledgments References 3094 3094 3094 3094 3095 3095 3097 3097 3098 3098 * Corresponding author. Fac +46 8 32 70 25. E-mail address: hakan.westerbladokise (HL Westerblad). Abbreviations AMPK, AMP-dependent protein kinase: Chytosolic free a concentration: C. creatine: MAPK mitogen-activated protein kinase MHC, myosin heavy chain: Orphosphocreatine: IGC-1, peroxisome proliferator-activated receptor gamma coactivator Tocinorganic phosphate ions: ROS, reactive oxygen species: SERCA. Sarcoplasmic reticulum Cae* pump: SR, sarcoplasmic reticulum 0014-4827/5 - see front matter o 2010 Elsevier Inc. All rights reserved doi:10.1016/jyexcr 2010.05.019

Answer 1

Name:1.According to the paper, what does lactate dehydrogenase (LDH) do and what does it allow to happen within the myofiber?

a.LDH converts NADH + (H+) + pyruvate to lactate + (NAD+). More lactate is produced during heavy intense exercise because the rate at which ATP is used is high. This is done so that glycolysis could be maintained and regenerate

2.According to the paper, what is the major disadvantage of relying on glycolysis during high-intensity exercise

a.It yields much less ATP per glucosyl unit as compared to aerobic breakdown (theoretically 3 vs. 38 ATP/glucosyl unit). This is a problem because during long exercise, muscle performance can be limited due to the depletion of glycogen.3.Using Figure 1 in the paper, briefly describe the different sources of ATP production at 50% versus 90% AND explain whether you believe this depiction of ATP production applies to a Type IIX myofiber in a human.