Answer:
Organelles in a cell are essentially the same as organs in an organism. The mitochondria is the powerhouse of the cell, as we all know. It creates ATP, which is what gives the cell energy. This is similar to how we consume food and create energy from it. Cell membranes are similar to skin, as they keep needed things in, and unwanted things out. Our cells need water too, as it helps create the cytoplasm. We need water to keep us alive and well, as it helps to create many of our needed bodily fluids, and rid us of toxins.
Chordates are animals that possess certain characteristics including a notochord. Humans fall into this category along with many vertebrates such as whales, falcons etc; therefore, all of the answers apply.
Food, research, therapy, entertainment affection.
A, cells with a thick cuticle
Answer:
The correct answers are option A. "tethering proteins to the cell cortex", B. "using barriers such as tight junctions", C. "tethering proteins to the extracellular matrix", D. "forming a covalent linkage with membrane lipids", E. "tethering proteins to the surface of another cell"
Explanation:
According to the fluid-mosaic model, the components of cell membranes are in constant movement forming a barrier to avoid unwanted exterior component internalization and to avoid the loss of precious internal components. This constant movement could cause that proteins move across the plasma membrane. But, this is avoided by several mechanisms including:
A. Tethering proteins to the cell cortex. The cell cortex is a rigid structure made of actin and actomyosin. Proteins found in the plasma membrane are tethered to this structure to restrict their movement.
B. Using barriers such as tight junctions. Tight junctions are barriers found in epithelia made of claudin and occludin proteins. These barriers are impenetrable, which avoid the movement of proteins in the cell membrane.
C. Tethering proteins to the extracellular matrix. The extracellular matrix is made of several proteins and macromolecules that provide a structural and biochemical support to cells that are nearby. Proteins could be tethered to this rigid structure as well.
D. Forming a covalent linkage with membrane lipids. The proteins in the cell membrane that form a covalent linkage with membrane lipids are known as lipid-anchored proteins, or lipid-linked proteins.
E. Tethering proteins to the surface of another cell. When cell-cell communication take place it is possible that proteins in the cell membrane got tethered to the surface of the other cell.
