Answer:
Option (1), (2) and (3).
Explanation:
DNA is the genetic material of all the living organisms present on earth. The DNA contains the nitrogenous bases, pentose sugar and the phosphate group. DNA strands runs in the opposite direction and shows polarity.
Watson and Crick explain the structure of DNA based on the X ray diffraction produced by Rosalind. According to the structure, chromosomes are present in the nucleus and contains the DNA and wrapped around the proteins. The genes is considered as the functional segment of DNA.
Thus, the correct answer is option (1), (2) and (3).
Answer:
When a muscle cell contracts, the myosin heads each produce a single power stroke.
Explanation:
In rest, attraction strengths between myosin and actin filaments are inhibited by the tropomyosin. When the muscle fiber membrane depolarizes, the action potential caused by this depolarization enters the t-tubules depolarizing the inner portion of the muscle fiber. This activates calcium channels in the T tubules membrane and releases calcium into the sarcolemma. At this point, <em>tropomyosin is obstructing binding sites for myosin on the thin filament</em>. When calcium binds to the troponin C, the troponin T alters the tropomyosin by moving it and then unblocks the binding sites. Myosin heads bind to the uncovered actin-binding sites forming cross-bridges, and while doing it ATP is transformed into ADP and inorganic phosphate which is liberated. Myofilaments slide impulsed by chemical energy collected in myosin heads, <u>producing a power stroke</u>. The power stroke initiates when the myosin cross-bridge binds to actin. As they slide, ADP molecules are released. A new ATP links to myosin heads and breaks the bindings to the actin filament. Then ATP splits into ADP and phosphate, and the energy produced is accumulated in the myosin heads, which starts a new binding cycle to actin. Z-bands are then pulled toward each other, thus shortening the sarcomere and the I-band, and producing muscle fiber contraction.
I think that correct answers are:
<span>Some of them lose their leaves in winter. (i.e. <span><em>Larix</em></span>)</span>
<span>They include the tallest plants (i.e<em>.Sequoia)
</em>I don't think they are the oldest type of seed plants, since in the past the classes like progymnosperms and seed ferns existed prior to the gymnosperms. But question isn't absolutely clear to me and I can't be 100% sure.
All of the gymnosperms have seeds unless human grows some seedless variant.
Gymnosperms don't have flowers like angiosperms do, but some people think that cone is kind of flower.
Male cones produce pollen, not female.
Hope I helped :)
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Answer:
Two patterns of complex inheritance are a color-blind male and flowers and when there is a color-blind male and a normal female.
Explanation: One of the Mendelian laws states that there is a dominant and a recessive gene. If these are together and form heterozygote only the dominant allele will be shown.
racoons
Explanation:
they are nocturnal animals
hope that helps
