Electron transport chain (ETC) refers to a series of complexes involved in the transfer of electrons from electron donors to electron acceptors through the reduction and oxidation reactions.
The similarities between the ETC in mitochondria and chloroplasts are as follows-
1. Both involve the electron transport chains on their inner membranes.
2. The energy produced pumps the protons against their concentration gradient across a membrane.
3. ATP synthase is used.
4. Two protons provide energy for the production of three molecules of ATP.
The differences between the ETC in mitochondria and chloroplasts are as follows-
Mitochondria- It uses the process of oxidative phosphorylation and chemical energy from the reduction-oxidation reactions. The electron transport chain occurs in the cristae. The coenzymes involved include the NAD and FAD. ATP synthase is located in the cristae. The protons are pumped out of the matrix. The final electron acceptor is the oxygen.
Chloroplast- It uses the process of photophosphorylation and the light energy. The electron transport chain occurs in the thylakoid membrane. The coenzyme involved is the NADP. ATP synthase is located in the thylakoid membrane. The protons are pumped into the thylakoids. The final electron acceptor is the chlorophyll in cyclic photophosphorylation and NADPH+ in the non-cyclic photophosphorylation.
Answer:
1- Test tube with DNA sample is placed in machine
2- DNA sample is heated
3- DNA denatures
4- Taq polymerase initiates DNA synthesis
5- Double-stranded DNA is produced
Explanation:
The Polymerase Chain Reaction (PCR) is a technique widely used in molecular biology laboratories in order to produce many copies of a specific DNA sample. Thermocyclers are machines designed for a cyclic temperature change of the PCR. First, an initial denaturation step where DNA sample is heated to separate the double-stranded DNA into two single strands. Subsequently, 20-40 PCR cycles are repeated to produce millions of copies of a specific DNA sequence. There are three steps in each PCR cycle: 1-Denaturation to 94–98 °C (DNA strands are separated), 2-Annealing to 50–67 °C (primers bind to each DNA strand on the opposite ends of the DNA strands to be copied) and 3-Extension to 75–80 °C (Taq polymerase initiates the synthesis of complementary DNA strands).
Nitrifying bacteria convert ammonia to nitrites or nitrates. Ammonia, nitrites, and nitrates are all fixed nitrogen and can be absorbed by plants. Denitrifying bacteria converts nitrates back to nitrogen gas.
