Answer:
because plants faces and gets sunlight to grow
The two main processes by which plant cells absorb, release, and use
energy are photosynthesis and respiration. The
process of photosynthesis is present in the chloroplasts of a pant cell.
Photosynthesis uses the sun’s rays in the form of electromagnetic energy to
convert it into chemical energy to be used for the plants. It needs proteins
that are present in the plants to perform a series of necessary conversions.
Moreover, the energy from the sun is the main catalyst to convert the
carbohydrates in the plant into simpler sugars. And then a series of complex
reaction takes place that their end product is oxygen. The oxygen produced is
the cellular respiration.
DNA replication occurs in the 5 prime (5') to 3 prime (3') direction.
I'm sure you've heard this many times. I tutor in genetics, and all of my students can rattle that off. Less understand what it means.
First, understanding what 5' and 3' mean is important. DNA is composed of a ribose sugar, a phosphate group, and a base (A,T,G,C). The sugar has a phosphate group attached to its fifth carbon, and a hydroxyl group on its 3rd carbon. Nucleotides (separate components of DNA) are linked by the phosphate group and the hydroxyl group. So, every nucleotide is linked at the phosphate group and the hydroxyl group besides two - the two nucleotides at either end of the strand of DNA. The one that leaves a phosphate group exposed is called the 5' end of DNA, and the one that leaves a hydroxyl group exposed is called the 3' end of DNA.
<span>A problem with many students just memorizing that replication occurs in the 5' to 3' direction is that there are two strands of DNA involved in replication. DNA polymerase (the major enzyme responsible for replication) reads the already existing strand of DNA in the 3' to 5' direction, and creates the new strand of DNA in the 5' to 3' direction (meaning that it adds nucleotides to the 3' end of the new strand).</span>
This is true, all polysaccharides (or Macromolecules) are required to be chemically formed by subunits or monosaccharides....
Carbohydrates are made of the monsaccharies, some examples of monosaccharides are Glucose, Fructose, and Galactose
Answer:
C The sarcomere is contracted, and the actin and myosin filaments are completely overlapped.
Explanation:
In rest, the tropomyosin inhibits the attraction strengths between myosin and actin filaments. Contraction initiates when an action potential depolarizes the inner portion of the muscle fiber. Calcium channels activate in the T tubules membrane, releasing calcium into the sarcolemma. At this point, tropomyosin is obstructing binding sites for myosin on the thin filament. When calcium binds to troponin C, troponin T alters the tropomyosin position by moving it and unblocking the binding sites. Myosin heads join the uncovered actin-binding points forming cross-bridges, and while doing so, ATP turns into ADP and inorganic phosphate, which is released. Myofilaments slide impulsed by chemical energy collected in myosin heads, producing a power stroke. 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. Finally, Z-bands are pulled toward each other, shortening the sarcomere and the I-band, producing muscle fiber contraction.
In the sarcomere, which is the contractile unit of skeletal muscles, there are
- Thick myosin myofilaments in the central region belonging to the A band.
- Thin filaments united to the Z lines, extending in the interior of the A band until they reach the border of the H band.
- Thin actin filaments composing the I band, which belong to two sarcomeres adjacent to a Z line.
When the muscle contracts, the muscular fiber gets shorter and thicker due to the reduction in the length of the sarcomere. The H line and the I band get shorter. The Z lines get closer to the A band, meaning that they get closer to each other. A band keeps constant in length. This change is produced by movement mechanisms that involve a change in the relative position of actin and myosin filaments.
