Search results
Results from the WOW.Com Content Network
Ribosomes (/ ˈ r aɪ b ə z oʊ m,-s oʊ m /) are macromolecular machines, found within all cells, that perform biological protein synthesis (messenger RNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA molecules to form polypeptide chains. Ribosomes consist of two major components: the ...
Cell walls perform many essential functions. They provide shape to form the tissue and organs of the plant, and play an important role in intercellular communication and plant-microbe interactions. [1] The cell wall is flexible during growth and has small pores called plasmodesmata that allow the exchange of nutrients and hormones between cells ...
Some eukaryotic cells (plant cells and fungal cells) also have a cell wall. Inside the cell is the cytoplasmic region that contains the genome (DNA), ribosomes and various sorts of inclusions. [2] The genetic material is freely found in the cytoplasm. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular.
To exert their functions in the cell newly synthesized proteins must be targeted to the appropriate location in the cell, which is achieved by protein targeting and translocation systems. [37] The growing polypeptide leaves the ribosome through a narrow tunnel in the large subunit.
Organelles (literally "little organs") are usually membrane-bound structures inside the cell that have specific functions. Some major organelles that are suspended in the cytosol are the mitochondria, the endoplasmic reticulum, the Golgi apparatus, vacuoles, lysosomes, and in plant cells, chloroplasts.
In muscle cells, it regulates calcium ion concentration. Smooth endoplasmic reticulum is found in a variety of cell types (both animal and plant), and it serves different functions in each. The smooth endoplasmic reticulum also contains the enzyme glucose-6-phosphatase, which converts glucose-6-phosphate to glucose, a step in gluconeogenesis.
All of the cellular functions of a sieve-tube element are carried out by the (much smaller) companion cell, a typical nucleate plant cell except the companion cell usually has a larger number of ribosomes and mitochondria. The dense cytoplasm of a companion cell is connected to the sieve-tube element by plasmodesmata. [10]
The ribosomal DNA includes all genes coding for the non-coding structural ribosomal RNA molecules. Across all domains of life, these are the structural sequences of the small subunit (16S or 18S rRNA) and the large subunit (23S or 28S rRNA).