Term
Where is the protein called actin located in the body?
a. ATP molecules c. myosin filaments
b. thin filaments d. acetylcholine neurotransmitters |
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In addition to myosin, what other protein is involved in skeletal muscle contraction?
a. collagen c. ATP
b. actin d. chitin |
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Definition
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What happens when the thin filaments in a muscle fiber slide over the thick filaments?
a. A muscle contracts.
b. A muscle relaxes.
c. A muscle both contracts and relaxes.
d. A muscle neither contracts nor relaxes. |
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Myosin and actin make up
a. osteoblasts. c. myofibrils.
b. collagen. d. red marrow. |
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Definition
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According to the sliding-filament model, which of the following steps does NOT occur in muscle contraction?
a. Myosin and actin filaments come near each other.
b. Myosin filaments form cross-bridges with actin filaments.
c. Cross-bridges pull the two filaments past each other.
d. Actin filaments return to their original positions. |
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Definition
| Actin filaments return to their original positions. |
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Term
What tough connective tissues join skeletal muscles to bones?
a. joints c. periosteum
b. ligaments d. tendons |
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Term
Which of the following types of muscle generally remains in a state of partial contraction when your legs are straight?
a. skeletal muscle c. smooth muscle
b. cardiac muscle d. all of the above |
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Which of the following is NOT true about muscle tone?
a. It is responsible for keeping the back and legs straight when you’re relaxed.
b. It is increased through regular exercise.
c. It describes the tightening of some muscles.
d. It increases with age. |
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The elbow joint bends when the
a. triceps muscle contracts. c. biceps muscle contracts.
b. triceps muscle relaxes. d. biceps muscle relaxes. |
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Definition
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Which of the following is NOT true about the effects of exercise on muscles?
a. It increases muscle tone.
b. It adds material to the outside of the muscle cells.
c. It increases the efficiency of the heart.
d. It can cause muscles to visibly increase in size. |
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Definition
| It adds material to the outside of the muscle cells |
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Term
The most important function of the skin is
a. protection. c. sweating.
b. storing fat. d. insulation. |
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Definition
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Term
What two layers make up skin?
a. keratin and dermis c. epidermis and dermis
b. epidermis and melanin d. melanin and keratin |
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Definition
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Term
The top layer of the epidermis is made of
a. flat, dead cells. c. collagen.
b. melanin. d. healthy, living cells. |
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Definition
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Term
Which of the following is NOT a function of skin?
a. helps regulate body temperature c. contracts and relaxes muscles
b. removes body wastes d. helps prevent infection |
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Definition
| contracts and relaxes muscles |
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Term
What happens when the keratin-producing cells of the skin die?
a. Melanin and keratin are produced. c. A waterproof coating is formed.
b. An additional dermis layer is formed. d. Melanin is produced. |
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Definition
| A waterproof coating is formed. |
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