Do Now Define the word “energy” How does your body get energy? Can your body function if all of the ingredients (reactants) need to produce energy are not present?

Do Now 02/22-25 What unlocks the binding sites on actin? A myofibril is made up of repeating sections called _________________. When all of these units shorten the muscle will ________________. Have your assignment from last class out on your desk for collection.

Let’s Review You owe me a roadmap of the mitochondria and twenty questions. Absent last class? See the makeup folder. We are going to review the 20 questions about ATP and Cellular Respiration together as a class. Expectations: Everyone is listening Students participation Correct/Modify your answers as we move along

New Vocabulary Antagonists- Working against each other Atrophy- partial or complete wasting away of a body part Extensor- A muscle that increases the angle in a joint Flexor-A muscle that decreases the angle in a joint Myoglobin- special blood found in our muscles Synergists- When things work together (sum is greater than its parts) Words you should already have defined: Fasicle Muscle Fiber Myofibril Myosin Actin Sarcomere Neurotransmitter Motor neuron Motor unit

Using Muscles Requires Energy Chemical energy used by the body is called ATP Which process makes this molecule? What is the chemical formula for this reaction? Where does it occur? ATP stores energy like a glow stick- in order to access that energy you have to BREAK it.

ATP-ADP Cycle The release of energy

Check your recall What reactants do you need to make energy? Glucose Oxygen

Getting Oxygen to your Muscles A special type of blood called myoglobin which only works in muscles and makes it so more oxygen is available to the muscles.

Strengthening Muscle How to strengthen a muscle depends on how you want to improve it: Building Stamina If you do weight-bearing exercises like running or cardio, then you will work on slow fibers. These fibers are in change of sustained activities and will get better are working a long time and less prone to fatigue, but will not get stronger. Strength Training If you lift weights or do short-term, high-stress exercise, then you will work on fast fibers. These fibers are in charge of strength and power and will get stronger and be able to do more

What happens when you build muscle? When you build up muscles, you muscles are adding more Actin and Myosin. You don’t gain more muscles or more muscle fibers, you gain more protein fibers which makes the muscles bigger and stronger.

Let’s Build Some Muscle We are going to do 10 lunges Anyone struggle a little? What do you feel? WHY?????

Anaerobic Cellular Respiration Occurs when you do not have enough oxygen to support energy production When your mitochondria run out of oxygen, they switch to anaerobic metabolism. This makes less energy and produces lactic acid. As the lactic acid builds up, your muscles are not able to work as well and get tired. BURNS