HORTICULTURE SCIENCE
PLANT BIOLOGY
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
Plant cells only contain 70S ribosomes
|
|
|
Plant cells only contain 80S ribosomes
|
|
|
Plant cells use 70S ribosomes but their mitochondria and chloroplasts contain 80S ribosomes
|
|
|
Plant cells use 80S ribosomes but their mitochondria and chloroplasts contain 70S ribosomes
|
Detailed explanation-1: -Therefore, bacterial cells, mitochondria, and chloroplast all contain the 70S ribosome. So, the correct answer is ‘70 S type’. Note: 70S ribosomes are present in prokaryotic cells and all eukaryotic cells only contain 80S ribosomes.
Detailed explanation-2: -Plant cells have three distinct ribosome species; 80 S ribosomes in their cytosol, 70 S-like ribosomes in their chloroplasts, and mitochondrial ribosomes.
Detailed explanation-3: -Chloroplast ribosomes are 70S like those of higher plants but are very unstable.
Detailed explanation-4: -Chloroplast ribosomes are similar to those found in prokaryotes i.e., of 70S type. Eukaryotic ribosomes which are found in cytoplasm are of 80S type. S stands for Svedberg unit, and is indicative of density and size. Thus, ribosomes found in chloroplast are smaller than those found in the cytoplasm.
Detailed explanation-5: -The protein biosynthesis in chloroplasts is catalysed by a bacterial‐type 70S ribosome (Tiller & Bock, 2014), called chloroplast ribosome, composed of a 50S large subunit and a 30S small subunit.