Answer:
A. S phase
Explanation:
The cell cycle involves all the series of division events that occurs to an organism. Cell division, which can be meiosis or mitosis, involves two main stages viz: Interphase and M phase.
Interphase describes the resting stage of the cell i.e. when the cell is not dividing. The cell uses this time to prepare itself for the next round of division. Interphase stage further consists of three main phases viz: G1, S and G2 phases.
In the S phase or synthesis phase of Interphase, the cell duplicates its genetic material (DNA). Hence, an onion cell observed by a student to have loosely coiled chromatin depicting DNA duplication is in the S-PHASE.
Answer:
Enzymes are one kind of protein which functioning as catalyst that speed up reactions by lowering activation energy.Enzyme accelerate a reaction without altering its chemical equilibrium.
Explanation:
Energy which is required for start a biochemical reaction is called activation energy.Activation Energy helps to jump and start a thermodynamically favorable reactions.
Enzymes can many way to its activation energy.
1. The enzyme may hold the substrates in such a way as to distort the substrate bonds closer to their form in the transition state. This reduces the amount of energy needed to complete the transition.
2.Enzyme create a charge distributor which opposite of transition state his lowers the energy of the transition state and decreases the activation energy.
3.The enzyme may reduce the reaction entropy by bringing substrates together in the correct orientation to react.
4. The enzyme may provide a completely different chemical pathway for the reaction. It may form new bonds in the ES complex that would be difficult to form without the enzyme.
Answer:
Refer to the attached image for correct labeling.
Explanation:
- The diagram is of a plant cell and its organelles.
- The nucleus houses the genetic material and controls all life processes.
- A plant cell contains one large vacuole in the center that stores water and nutrients.
- Chloroplast is the site for photosynthesis. It captures light and utilizes it and carbondioxide to produce glucose.
- Mitochondria are called the power house of the cell. Through a process called cellular respiration, they break down the glucose produced in photosynthesis into energy compounds such as ATP as well as oxygen and water.
- The endoplasmic reticulum is the site for protein sysnthesis. It contains two parts: the rough endoplasmic reticulum (RER) which contains ribosomes that synthesize proteins and the smooth endoplasmic reticulum (SER) which packages the proteins into transport vesicles.
- The nucleus contains the nucleolus that is the site for ribosome assembly.
- The cell membrane is a semi-permeable membrane that covers the cell and controls cellular transport.
- The cell wall is a hard, outer covering that protects the cell and maintains its structure and shape.
The theory of evolution is a shortened form of the term “theory of evolution by natural selection,” which was proposed by Charles Darwin and Alfred Russel Wallace in the nineteenth century
