Copy of 10.02.20 (Sync + Async) - Sliding Filament Model (5/28/2026)

Last updated about 1 month ago

22 Nsɛmmisa

Part 1: Skeletal Muscle Structure

The Sliding Filament Model is our current understanding of how the skeletal muscles of the body contract. While there are some differences between skeletal muscle and cardiac muscle contraction, cardiac muscle contraction is similar.

Part 3: The Art of Muscle Contraction

Ok- you know the structures. Now let's focus on HOW they work together to contract skeletal muscles.

Part 4: Putting it All Together

Think about parts 1, 2, and 3 as you answer questions 16-20.

Copy of 10.02.20 (Sync + Async) - Sliding Filament Model (5/28/2026)

Last updated about 1 month ago

22 Nsɛmmisa

Sliding Filament Model

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Objectives: Students will...

differentiate between the proteins, enzymes, and other biochemicals important in the Sliding Filament Model of muscle contraction
differentiate between the steps involved in the Sliding Filament Model of muscle contraction
write a love letter or story about various proteins involved in muscle contraction

Put the following muscle structures in order from largest to smallest.

Muscle fiber (muscle cell)
Myofibril
Muscle
Fascicle

Categorize the following substances as proteins or ions.

Ca²⁺
Tropomyosin
Actin
Myosin
Troponin
Na⁺
Titin

Protein
Ion

Part 1: Skeletal Muscle Structure

First, identify the following as true or false:
Myofibrils are smaller than sarcomeres.
Then, draw a picture justifying your answer.

Nokorɛ

Ɛnyɛ ampa

The picture below displays a simplified version of a single sarcomere.
Match the terms with the correct letter on the diagram.

Draggable item		Corresponding Item
G		A band
C		Z line
A		H zone
H		Sarcomere
D		Thin filaments
B		Thick filaments
E		I band
F		Myosin heads

Which of the following best describes the difference between the A band and the I band?

The A band is the same length as the thin filament. The A band does not change in length during muscle contraction.

The I band is the distance between the Z-lines of a sarcomere. The I band gets shorter during muscle contraction.

The A band is the same length as the thick filament. The A band does not change in length during muscle contraction.

The I band is the distance between the end of one thick filament and the beginning of another thick filament in a neighboring sarcomere. The I band gets shorter during muscle contraction.

The A band is the same length as the thin filament. The A is the same length as the thin filament.

The I band is the distance between the Z-lines of a sarcomere. The I band does not change in length during muscle contraction

The A band is the same length as the thick filament. The A band gets shorter during muscle contraction

The I band is the distance between the end of one thick filament and the beginning of another thick filament in a neighboring sarcomere. The I band does not change in length during muscle contraction.

Now let's talk about thick and thin filament in a little more detail. Examine the picture of thick and thin filaments below while answering questions 6-9.

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Match the following proteins with the structure they are on

Tropomyosin
Actin
Myosin
Troponin

Thick filaments
Thin filaments

Which of the following best describes thick filaments?

They have a "hinge" region, which is flexible (like a hinge on a door) and myosin heads.

The myosin heads contain binding sites where they attach to troponin

The myosin heads contain binding sites where they attach to actin.

Thick filaments have ATP, ADP, and P binding sites.

Thick filaments are made of a protein called myosin.

Thick filaments are made of a protein called tropomyosin.

What binds at each of these sites on myosin?

Draggable item		Corresponding Item
B		Actin
A		ATP

Compare and contrast troponin and tropomyosin.

What questions do you still have about Part 1: Skeletal Muscle Structure?

Part 2: The Neuromuscular Junction

Skeletal muscle only contracts when it is activated by the nervous system. Nervous system cells, like muscle cells, are excitable - this means that they can send messages within their cells using electrical signal. If not for the electrical signals of your nervous and muscle cells, we would not exist as we do today.

Communication between the nervous cells and muscle cells requires another form of communication: chemical communication. Neurotransmitters are the chemicals used to relay messages from a nervous cell to a muscle cell. While we will learn more about neurotransmitters when we get to the nervous system next semester, a basic understanding of this signaling is important in understanding how muscles contract.

Watch the following video about the neuromuscular junction. Remember that we have not yet talked about the nervous system and that we will learn more about neuron structure and action potentials next semester. For now, focus on the terms provided below.

Draggable item		Corresponding Item
Acetylcholine (ACh)		Space between neuron and muscle cell
ACh Receptors		Neurotransmitter released from neuron
Ca²⁺		Proteins on the membrane of the muscle cell that bind to ACh
Synaptic cleft		Ions that enter the muscle cell when enough ACh has attached to the muscle cell receptros
Na⁺		Ions that enter the neuron and trigger the release of ACh

Compare and contrast the roles of Na⁺ and Ca²⁺ in muscle contraction.

What questions do you still have about Part 2: The Neuromuscular Junction?

Part 3: The Art of Muscle Contraction

Ok- you know the structures. Now let's focus on HOW they work together to contract skeletal muscles.

Watch the following video on muscle contraction.
(Note: You may watch the whole thing, but the beginning is review. He'll start talking about skeletal muscle contraction at 1:45)
As you watch, match the terms below with the best description.

Draggable item		Corresponding Item
Tropomyosin		Protein
Titin		Long, "strink-like" protein blocking the binding sites on actin
Troponin		Binds to the protein troponin in order to expose myosin binding site on actin
Myosin		Small protein attached to tropomyosin when muscle is at rest; binds to Ca²⁺during muscle contraction
Ca²⁺		Protein holding the thick filaments in place

Describe the relationship between tropomyosin, troponin, myosin, and actin

Ok - Let's talk more about ATP. Examine the picture below, focusing on Adenosine Triphosphate (ATP), Adenosine Diphosphate (ADP), and Phosphate (P).
Which of the following statements about the role of ATP, P, and ADP in muscle contraction are accurate?

ADP and P detach from the myosin head when the myosin head attaches to actin

ATP turns into ADP and P when the myosin head moves back to its "ready" position

ATP attaches to the myosin head when the myosin head detaches from actin binding sites.

ATP turns into ADP and P when the myosin head pulls the thin filaments 'in'

ATP detaches from the myosin head when the myosin head detaches from actin binding sites.

ATP --> ADP + P

ADP + P --> ATP

ADP and P attach to the myosin head when the myosin head attaches to actin

Think back to this simplified description of ATP hydrolysis that we saw the other day (left) and compare it to the more complex, accurate description on the right.
Which of the following best describes ATP hydrolysis?

ATP --> ADP + P Reaction is exothermic: more energy is released than used up

There is a net gain of energy when ATP --> ADP + P

ATP --> ADP + P Reaction is endothermic: more energy is used up than is released

ATP releases water when it forms ADP and Phsophate

There is a net loss of energy when ATP --> ADP + P

ATP reacts with water to form ADP and Phosphate.

What questions do you still have about Part 3: The Art of Muscle Contraction

Part 4: Putting it All Together

Think about parts 1, 2, and 3 as you answer questions 16-20.

WITHOUT LOOKING AT YOUR NOTES: Put the following steps of muscle contraction in the correct order. The order should go from before a contraction --> contraction

Acetylcholine crosses the synaptic cleft and binds to receptors on the muscle fiber
ATP reacts with water, forming ADP and phosphate. The energy created is used to move the myosin head back to its original position.
Calcium ons (Ca²⁺) bind to troponin molecules
The myosin heads of the thick filaments attach to the actin binding sites on the thin filaments, forming a cross bridge
ATP binds to myosin, disconnecting the crossbridge
ADP and phosphate are released fom their binding sites on the myosin heads
Myosin heads rotate towards the center of the sarcomere, bringing the Z-lines closer together
The shape of troponin is altered, causing tropomyosin to move and expose the actin binding sites on the thin filaments
Sodium ions (Na⁺) enter the plasma membrane of the muscle cell. Potassium ions (K⁺) exit the plasma membrane of the muscle cell
Calcium ions (Ca²⁺) are released from the sarcoplasmic reticulum of the muscle cell

What is still confusing about the Sliding Filament Model?

Refer back to Section 10.2 or Section 10.3 of your textbook and fill in your confusion.
How did the textbook help? What are you still confused about?

Before you move on, go back to #19 and try to re-sequence the steps. You can use your notes this time!

Then, re-watch the Crash Course:

Do you need to resequence again? What things make sense now that didn't make sense before?

Role: Some type of protein involved in muscle contraction (Acton, Myosin, Tropomyosin, Troponin)
Format: Love Letter
Topic: Your feelings towards another protein (or proteins) involved in muscle contraction. You should discuss / refer to the following in your letter:
actin
myosin
tropomyosin
troponin
ATP
ADP and P
water
Ca²⁺
thick filaments
thin filaments
sarcomeres
myofibril
Z-lines
mitochondria

Copy of 10.02.20 (Sync + Async) - Sliding Filament Model (5/28/2026)

Part 1: Skeletal Muscle Structure

Part 3: The Art of Muscle Contraction

Part 4: Putting it All Together

Copy of 10.02.20 (Sync + Async) - Sliding Filament Model (5/28/2026)

Sliding Filament Model

Put the following muscle structures in order from largest to smallest.

Categorize the following substances as proteins or ions.

Part 1: Skeletal Muscle Structure

First, identify the following as true or false: Myofibrils are smaller than sarcomeres.Then, draw a picture justifying your answer.

The picture below displays a simplified version of a single sarcomere. Match the terms with the correct letter on the diagram.

Which of the following best describes the difference between the A band and the I band?

Match the following proteins with the structure they are on

Which of the following best describes thick filaments?

What binds at each of these sites on myosin?

Compare and contrast troponin and tropomyosin.

What questions do you still have about Part 1: Skeletal Muscle Structure?

Part 2: The Neuromuscular Junction

Watch the following video about the neuromuscular junction. Remember that we have not yet talked about the nervous system and that we will learn more about neuron structure and action potentials next semester. For now, focus on the terms provided below.

Compare and contrast the roles of Na+ and Ca2+ in muscle contraction.

What questions do you still have about Part 2: The Neuromuscular Junction?

Part 3: The Art of Muscle Contraction

Watch the following video on muscle contraction. (Note: You may watch the whole thing, but the beginning is review. He'll start talking about skeletal muscle contraction at 1:45)As you watch, match the terms below with the best description.

Describe the relationship between tropomyosin, troponin, myosin, and actin

Ok - Let's talk more about ATP. Examine the picture below, focusing on Adenosine Triphosphate (ATP), Adenosine Diphosphate (ADP), and Phosphate (P).Which of the following statements about the role of ATP, P, and ADP in muscle contraction are accurate?

Think back to this simplified description of ATP hydrolysis that we saw the other day (left) and compare it to the more complex, accurate description on the right. Which of the following best describes ATP hydrolysis?

What questions do you still have about Part 3: The Art of Muscle Contraction

Part 4: Putting it All Together

WITHOUT LOOKING AT YOUR NOTES: Put the following steps of muscle contraction in the correct order. The order should go from before a contraction --> contraction

What is still confusing about the Sliding Filament Model?

Refer back to Section 10.2 or Section 10.3 of your textbook and fill in your confusion. How did the textbook help? What are you still confused about?

Sliding Filament Model

Put the following muscle structures in order from largest to smallest.

Categorize the following substances as proteins or ions.

First, identify the following as true or false: Myofibrils are smaller than sarcomeres.Then, draw a picture justifying your answer.

The picture below displays a simplified version of a single sarcomere. Match the terms with the correct letter on the diagram.

Which of the following best describes the difference between the A band and the I band?

Match the following proteins with the structure they are on

Which of the following best describes thick filaments?

What binds at each of these sites on myosin?

Compare and contrast troponin and tropomyosin.

What questions do you still have about Part 1: Skeletal Muscle Structure?

Part 2: The Neuromuscular Junction

Watch the following video about the neuromuscular junction. Remember that we have not yet talked about the nervous system and that we will learn more about neuron structure and action potentials next semester. For now, focus on the terms provided below.

Compare and contrast the roles of Na+ and Ca2+ in muscle contraction.

What questions do you still have about Part 2: The Neuromuscular Junction?

Watch the following video on muscle contraction. (Note: You may watch the whole thing, but the beginning is review. He'll start talking about skeletal muscle contraction at 1:45)As you watch, match the terms below with the best description.

Describe the relationship between tropomyosin, troponin, myosin, and actin

Ok - Let's talk more about ATP. Examine the picture below, focusing on Adenosine Triphosphate (ATP), Adenosine Diphosphate (ADP), and Phosphate (P).Which of the following statements about the role of ATP, P, and ADP in muscle contraction are accurate?

Think back to this simplified description of ATP hydrolysis that we saw the other day (left) and compare it to the more complex, accurate description on the right. Which of the following best describes ATP hydrolysis?

What questions do you still have about Part 3: The Art of Muscle Contraction

WITHOUT LOOKING AT YOUR NOTES: Put the following steps of muscle contraction in the correct order. The order should go from before a contraction --> contraction

What is still confusing about the Sliding Filament Model?

Refer back to Section 10.2 or Section 10.3 of your textbook and fill in your confusion. How did the textbook help? What are you still confused about?

First, identify the following as true or false:
Myofibrils are smaller than sarcomeres.
Then, draw a picture justifying your answer.

The picture below displays a simplified version of a single sarcomere.
Match the terms with the correct letter on the diagram.

Compare and contrast the roles of Na⁺ and Ca²⁺ in muscle contraction.

Watch the following video on muscle contraction.
(Note: You may watch the whole thing, but the beginning is review. He'll start talking about skeletal muscle contraction at 1:45)
As you watch, match the terms below with the best description.

Ok - Let's talk more about ATP. Examine the picture below, focusing on Adenosine Triphosphate (ATP), Adenosine Diphosphate (ADP), and Phosphate (P).
Which of the following statements about the role of ATP, P, and ADP in muscle contraction are accurate?

Think back to this simplified description of ATP hydrolysis that we saw the other day (left) and compare it to the more complex, accurate description on the right.
Which of the following best describes ATP hydrolysis?

Refer back to Section 10.2 or Section 10.3 of your textbook and fill in your confusion.
How did the textbook help? What are you still confused about?

First, identify the following as true or false:
Myofibrils are smaller than sarcomeres.
Then, draw a picture justifying your answer.

The picture below displays a simplified version of a single sarcomere.
Match the terms with the correct letter on the diagram.

Compare and contrast the roles of Na⁺ and Ca²⁺ in muscle contraction.

Watch the following video on muscle contraction.
(Note: You may watch the whole thing, but the beginning is review. He'll start talking about skeletal muscle contraction at 1:45)
As you watch, match the terms below with the best description.

Ok - Let's talk more about ATP. Examine the picture below, focusing on Adenosine Triphosphate (ATP), Adenosine Diphosphate (ADP), and Phosphate (P).
Which of the following statements about the role of ATP, P, and ADP in muscle contraction are accurate?

Think back to this simplified description of ATP hydrolysis that we saw the other day (left) and compare it to the more complex, accurate description on the right.
Which of the following best describes ATP hydrolysis?

Refer back to Section 10.2 or Section 10.3 of your textbook and fill in your confusion.
How did the textbook help? What are you still confused about?