A cell is the smallest life unit
Answer:
<h2>
Protein exists in different forms- primary, secondary, tertiary and quaternary structure.</h2>
Explanation:
Primary structure of protein consists of amino acids joined by a peptide bonds. Peptide bond exists as covalent bond. Secondary structure of protein is stabilized by hydrogen bonds. Tertiary structure is stabilized by hydrophobic interaction, electrostatic interaction and disulphide bonds. Similarly, quaternary structure is stabilized by non-covalent interactions and disulphide bonds. So, each structure of protein is stabilized by different types of bonds.
Cell membranes do not make nutrients (or energy) for the cells. This is the function of the mitochondria by the electron transport chain, tricarboxylic acid cycle, and beta oxidation. The cell membrane is responsible in holding the cytoplasmic components of the cells. The cell membrane is also involved in substance regulation by acting as a semi-permeable membrane for simple diffusion as well as the site where carrier proteins are embedded for facilitated diffusion (not ATP requiring) and active transport (ATP requiring). The cell membrane is also involved in cell to cell recognition because receptors are also embedded in the cell membrane.
Bacteria and archaea are classified as prokaryotes pro means before and Kary means nucleus . Animals plants fungi and protist are all eukaryotes
