Biology DMD Test Flashcards

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Questions and Answers

What are muscles made of?

Proteins, Actin, and Myosin

What did we learn about the muscles of people with DMD?

They cannot repair and grow, which is known as dystrophy.

How does the analogy help us understand the structure and function of dystrophin?

The boat (Actin) and Anchor (Dystrophin) analogy and the bottom of the lake (Membrane).

Describe the function of dystrophin in a normal muscle.

It prevents membrane damage, keeps the sarcomere intact, and keeps the proteins in place. Signup and view all the answers

What happens to the production of dystrophin in DMD?

It is too short to connect to the cell membrane, causing membrane damage. Signup and view all the answers

What is the function of Actin and Myosin proteins in our muscle cells?

They contract our muscles. Signup and view all the answers

In DMD, how does the defective dystrophin protein affect muscle cells/sarcomeres during contraction?

It causes tears in the membrane. Signup and view all the answers

Describe the role of Ca2+ ions in the deterioration of muscles in DMD patients.

The Ca2+ ions flow into the inside myocyte through the membrane and destroy healthy cells. Signup and view all the answers

What does Creatine Kinase do for our muscles?

An enzyme that stores energy. Signup and view all the answers

How is Creatine Kinase used for the diagnosis of DMD?

It leaves the membrane and flows into the blood, creating elevated levels. Signup and view all the answers

What does the DMD protein have to do with boys?

It is on the X chromosome, and boys only have one X. Signup and view all the answers

What are the 3 types of muscles in our body?

Smooth (involuntary), Cardiac (involuntary), and Skeletal (voluntary). Signup and view all the answers

What is the relationship between muscle, fascicles, muscle fiber, myofibrils, sarcomeres, and microfilaments?

Muscle (organ), Fascicles (tissue), Muscle Fiber (cell), Myofibril (protein organelle), Sarcomeres (units of contraction), Microfilaments (proteins). Signup and view all the answers

How do we grow our muscles?

We contract our muscles which tears them and they repair themselves. Signup and view all the answers

What would be possible symptoms for someone with DMD?

Frequent falling, waddling gait, big calves, Gower's sign, curved posture. Signup and view all the answers

List some possible treatments for those with DMD.

Physical therapy, steroids, surgery, gene therapy. Signup and view all the answers

Describe what a virus vector is.

Incorporates a modified gene into the muscle cell. Signup and view all the answers

Study Notes

Muscle Structure and Function

Muscles are primarily composed of proteins, specifically Actin and Myosin, which are essential for contraction.
Dystrophin plays a crucial role in maintaining muscle integrity, preventing membrane damage, and securing proteins in place.

Duchenne Muscular Dystrophy (DMD)

DMD results in muscle degeneration due to an inability to repair and grow, a condition known as dystrophy.
The defective dystrophin in DMD is too short to anchor to the cell membrane, causing tears during muscle contraction.
Symptoms of DMD include frequent falling, waddling gait, enlarged calves, Gower's sign, and weakened abdominal muscles.

Muscle Contraction Dynamics

Dystrophin can be understood through the analogy of a boat (Actin) connected to an anchor (Dystrophin), where the membrane acts as the lake's bottom.
In normal muscle contractions, the presence of dystrophin is vital for preventing membrane damage and maintaining sarcomere structure.

Role of Ions and Enzymes

Calcium ions (Ca2+) enter myocytes through damaged membranes, leading to the destruction of both healthy and dead muscle cells.
Creatine Kinase serves as an enzyme that stores energy in muscles and becomes a diagnostic marker for DMD when it leaks into the bloodstream.

Genetic Factors

DMD predominantly affects boys since the gene responsible is located on the X chromosome; boys have only one X chromosome.
Muscles are organized into a hierarchy: Muscle → Fascicles → Muscle Fiber → Myofibrils → Sarcomeres → Microfilaments (Actin, Myosin, Dystrophin, Titin, Creatine Kinase).

Muscle Growth and Repair

Muscle growth occurs through the process of contraction, which causes micro-tears; these are repaired, resulting in stronger muscles.
Treatment options for DMD include physical therapy, steroids, surgery, and emerging gene therapies.

Viral Vectors

Viral vectors are modified viruses designed to deliver genetic material into muscle cells, facilitating potential gene therapies for conditions like DMD.

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Description

This quiz focuses on key concepts related to Muscular Dystrophy (DMD) and muscle composition. It covers the roles of proteins such as Actin and Myosin, and the implications of dystrophy on muscle repair and growth. Understand analogies used to explain muscular structures and their functions.