1. Structure and Function of Cellulose Molecule:
- Cellulose is a polysaccharide composed of repeating glucose units linked together by β-1,4 glycosidic bonds.
- Its structure consists of long, linear chains with hydrogen bonds forming between adjacent chains, creating a strong and rigid structure.
- Cellulose molecules are arranged in parallel bundles, forming microfibrils, which further aggregate into macrofibrils, providing structural support to plant cell walls.
- The structural arrangement of cellulose molecules makes them insoluble in water and resistant to enzymatic degradation by most organisms.
- Functionally, cellulose provides rigidity and strength to plant cell walls, allowing plants to maintain their shape and withstand mechanical stress.
2. Impact of Nucleotide Sequence on Protein Function:
- The sequence of nucleotides in DNA determines the sequence of amino acids in a protein through the process of transcription and translation.
- Any change in the DNA sequence, such as a substitution, insertion, or deletion of nucleotides, can result in a change in the corresponding amino acid sequence in the protein.
- This alteration in the amino acid sequence can lead to changes in the protein's structure and function, potentially causing it to malfunction.
- For example, a single nucleotide substitution (point mutation) in the DNA sequence may result in the substitution of one amino acid for another in the protein sequence, affecting its folding and therefore its function.
- Additionally, frameshift mutations, caused by insertions or deletions of nucleotides not in multiples of three, can lead to a shift in the reading frame during translation, resulting in a completely different amino acid sequence and potentially nonfunctional protein.
3. Role of ATP in Energy Provision:
- Adenosine triphosphate (ATP) is a molecule that stores and transfers energy within cells.
- ATP consists of an adenine molecule, a ribose sugar, and three phosphate groups.
- When ATP is hydrolyzed by the enzyme ATPase, the terminal phosphate group is cleaved off, releasing energy and forming adenosine diphosphate (ADP) and inorganic phosphate (Pi).
- This release of energy can be used to drive various cellular processes, including muscle contraction, active transport of molecules across cell membranes, and biosynthesis of macromolecules.
- ATP acts as an energy currency in cells, providing readily available energy for cellular work whenever and wherever it is needed.
- Through a cycle of ATP hydrolysis and synthesis (reformation of ATP), cells can continually replenish their ATP pool to maintain energy homeostasis and support essential cellular functions.