Answer:
Proteins and lipids exist as separate but loosely attached molecules that can move around
Explanation:
Cell membranes are mainly composed of lipids, proteins, and also carbohydrates. Phospholipids are the most abundant type of lipid and the main constituent of the cell membranes. Membrane proteins are divided into two types according to their interactions with the cell membrane: 1-integral (intrinsic) and peripheral (extrinsic) proteins. These peripheral proteins are loosely attached by ionic bonds or calcium bridges with the phosphate heads of the phospholipids; whereas integral membrane proteins contain side chains that interact with fatty acyl groups of the phospholipids. Cell membrane fluidity indicates how easily lipids (e.g., phospholipids and cholesterol) and proteins (e.g., intrinsic proteins) diffuse laterally in the cell membrane. This fluidity is affected by the amount of cholesterol, temperature, and the ratio of unsaturated to saturated fatty acids. Saturated fatty acids have no double bonds in the hydrocarbon chain, whereas unsaturated fatty acids have at least one double bond (these double bonds increase fluidity). Moreover, higher temperatures increase membrane fluidity, whereas cholesterol molecules function to regulate membrane fluidity: at high temperatures cholesterol molecules stabilize the membrane, whereas at low temperatures intercalate between phospholipids, thereby preventing them from clustering together.
Answer: c. proteasome
Explanation:
Proteasomes are extremely important multi-catalytic proteases and are involved in various cellular functions. The proteasome is an essential component of eukaryotic cells and is responsible for the ATP-dependent proteolytic degradation of most cellular proteins. They are present in the nucleus and cytosol and can represent up to 1% of total cell proteins. Proteasomes generally degrade proteins to small peptides, most of which are rapidly hydrolyzed by cytoplasmic exopeptidases. It catalyzes the rapid degradation of many enzymes, regulatory proteins, and eliminates abnormal proteins resulting from mutation or damaged proteins. The inability of this cellular organelle can lead to neurodegenerative diseases, such as Parkinson´s disease.
Answer:
Nucleotides are the smaller parts of the nucleic acids
Explanation:
That would be B. From energy in photons.
Photons(from sunlight) give energy to electrons and “excite” them(sending them to a higher energy level). Electrons can then release this energy and excite other electrons in other chlorophyll molecules.
