Answer:
The answer is C) They appear to be the molecular carriers of coded hereditary information.
Explanation:
Why NOT C) They appear to be the molecular carriers of coded hereditary information?
This is the job of the nucleic acids. It is composed of nucleotides which are the basic units of DNA and RNA. They carry genetic information about a certain organism.
<h3 /><h3>True of proteins:</h3>
A) They may be denatured or coagulated by heat or acidity.
<u>Denaturation</u> is the <u>destruction of the protein's secondary and/or tertiary structures</u>. The <u>primary structure is not disrupted due to the tough peptide bonds</u> and can only be broken down by acid. For heat denaturation, hydrogen bonds are destroyed, as in cooking of egg whites and medical equipment sterilization.
B) They have both functional and structural roles in the body.
There are many kinds of proteins that have functional and structural roles like hormones <u>(FSH, LH)</u>, antibodies <u>(IgA, IgM),</u> enzymes <u>(lipase, amylase),</u> for storage/transport <u>(hemoglobin, ferritin)</u>, and locomotion <u>(actin, troponin).</u>
D) Their function depends on their three-dimensional shape.
Just like <u>hemoglobin</u>, it's <u>quaternary structure</u> can carry <u>4 molecules of iron</u> in one go. <u>Enzymes</u> are shaped accordingly to fit a<u> specific substrate</u> <em>(lock-and-key model)</em>
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.
Amobeo is very bigger then 2 and yeha j think