Answer the following question given this paragraph: 10.3 Muscle Fiber Contraction and Relaxation A sarcomere is the smallest contractile portion of a muscle. Myofibrils are composed of thick and thin filaments. Thick filaments are composed of the protein myosin; thin filaments are composed of the protein actin. Troponin and tropomyosin are regulatory proteins. Muscle contraction is described by the sliding filament model of contraction. ACh is the neurotransmitter that binds at the neuromuscular junction (NMJ) to trigger depolarization, and an action potential travels along the sarcolemma to trigger calcium release from SR. The actin sites are exposed after Ca++ enters the sarcoplasm from its SR storage to activate the troponin-tropomyosin complex so that the tropomyosin shifts away from the sites. The cross-bridging of myposin heads docking into actin-binding sites is followed by the "power stroke"the sliding of the thin filaments by thick filaments. The power strokes are powered by ATP. Ultimately, the sarcomeres, myofibrils, and muscle fibers shorten to produce movement. Q: What is the smallest contractile portion of a muscle? Choices: - filaments - cell - capillary - sarcomere A:
sarcomere
(Question)
Answer the following question given this paragraph: Chlorine is the active ingredient in household bleach. It removes stains from clothes. It can also be used to disinfect countertops and other surfaces. Q: What is the active ingredient in household bleach? Choices: - magnesium - oxygen - iodine - chlorine A:
(Answer)
chlorine
Ques: Answer the following question given this paragraph: Q: Did the the open circulatory systems of molluscs and arthropods arise dependently or independently of each other? Choices: - dependently - together - separately - independently A:
Ans: independently
(Q).
Answer the following question given this paragraph: Chromoplasts make and store pigments that give petals and fruit their orange and yellow colors. Q: What makes and stores pigments that give petals and fruit their orange and yellow colors? Choices: - sporozoans - protozoa - pores - chromoplasts A:
(A).
chromoplasts
Ques:Answer the following question given this paragraph: 9.3 Transcription In prokaryotes, mRNA synthesis is initiated at a promoter sequence on the DNA template. Elongation synthesizes new mRNA. Termination liberates the mRNA and occurs by mechanisms that stall the RNA polymerase and cause it to fall off the DNA template. Newly transcribed eukaryotic mRNAs are modified with a cap and a poly-A tail. These structures protect the mature mRNA from degradation and help export it from the nucleus. Eukaryotic mRNAs also undergo splicing, in which introns are removed and exons are reconnected with single-nucleotide accuracy. Only finished mRNAs are exported from the nucleus to the cytoplasm. Q: Only finished mrnas are exported from the nucleus to what? Choices: - amino acids - cerebellum - electron - cytoplasm A:

Ans:cytoplasm
Answer the following question given this paragraph: Nearly all fish reproduce sexually, and most species have separate sexes. Those without separate sexes avoid self-fertilization by producing sperm and eggs at different times. Each fish typically produces a large number of gametes. In most fish species, fertilization takes place externally. These fish are oviparous. Eggs are laid and embryos develop outside the mother's body. In a minority of fish, including sharks, eggs develop inside the mother's body but without nourishment from the mother. These fish are ovoviviparous. Q: In ovoviviparous fish like shark, what develops inside the mother's body but without nourishment from the mother? Choices: - genes - spores - molecules - eggs A:
eggs