Consider statements about human digestion: 1. Saliva contains the enzyme ptyalin. 2. The stomach secretes hydrochloric acid. 3. Bile is produced by the gall bladder. Which are correct? MCQ with Answer and Explanation

Explanation:
RNA polymerase recognizes and binds to the promoter region of DNA, which is located upstream of the coding sequence. This initiates transcription. The terminator signals the end of transcription. Start codon (AUG) is on mRNA where translation begins. Enhancers are regulatory DNA sequences that increase transcription but are not the primary binding site for polymerase.

Explanation:
Chloroplasts are the sites of photosynthesis in plant cells, converting solar energy into chemical energy (food). Hence they are called the kitchen of the cell. Mitochondria are the powerhouse, generating ATP; ribosomes are protein factories; Golgi apparatus is the packaging center.

Explanation:
In C4 plants, the initial fixation of CO2 occurs in the mesophyll cells. The primary CO2 acceptor is a 3-carbon compound, phosphoenolpyruvate (PEP). The enzyme PEP carboxylase catalyzes the reaction, forming a 4-carbon compound, oxaloacetate (OAA). In C3 plants, the primary acceptor is RuBP, a 5-carbon compound, and the enzyme is RuBisCO.