Are cell membranes more permeable to lipid-soluble or water-soluble substances?

Lipid-soluble substances

large protein responsible for passive elasticity (two names for it)

Titin (also known as connectin)

what is the largest sinle polypeptide?

Titin/connectin

Band within sarcomere that is dark and does not move during contraction

A band

Band within sarcomere that is light and moves during muscle contraction

I band

which parts interdigitate to make a muscle contract

actin and myosin

covers active sites and prevents interaction with myosin

Troponin I binds what? Troponin T binds? and Troponin C binds?

Actin, tropomyosin, calcium

Which Troponin subunit binds to create a conformational change to allow myosin to bind to actin

Troponin-C (calcium binds)

How many binding sites does myosin have and what are they

two- ATP and actin

How many heads does one myosin molecule have

two

How many light and heavy chains does myosin have

two heavy and four light

What does calcium bind to in the muscle cell

troponin

Explain the four stages of the "Walk-Along Theory"

1. myosin head binds to actin (new ATP comes in and causes) 2. Myosin head to release from actin (ATP hydrolysis which causes) 3. Myosin head to become cocked/active (ADP and Pi) 4. Myosin head attaches to actin and pulls =power stroke (ADP bound)

Explain Rigor Mortis

less O2 available after death, so decrease in ATP, no more ATP cant cause conformational change to pull myosin off actin so stuck in rigor state

AT= TT-PT Explain this equation

active tension cannot be measured directly. but passive and total tension can. so this equation calculate

T or F: active tension falls away linearly with increasing length (as well as with decreasing length)

True

Isotonic vs isometric

Isotonic: muscle changes length to contract heavy object Isometric: object to heavy muscle cannot change length when contracts

Define motor unit

it is the motor neuron and all of the muscle fibers that it innervates

What type of skeletal muscle: slow, oxidative, red muscle, low glycolytic enzyme content, lots of mitochondria, small diameter, lots of myoglobin

Type I

What type of skeletal muscle: glycolytic, fast, larg diameter, white muscle, few mitochondria,