Answer:
limiting factors
Explanation:
The ecological optimum represents the value of the factors within the ecological valence at which the life processes of a species take place best. The upper and lower limits of an ecological valence are its maximum and minimum. Beyond these limits, physiological processes are interrupted and death occurs.
Answer:
Transpiration is the evaporation of water from the surface of leaf cells in actively growing plants. ... If water loss is greater than water uptake, air bubbles can form in the xylem. Plants reduce water loss by closing their stomata, developing thick cuticles, or by possessing leaf hairs to increase the boundary layer.
Their main difference is how they form the daughter cells during cytokinesis. During that stage, animal cells form furrow or cleavage that gives way to formation of daughter cells. Due to the existence of the rigid cell wall, plant cells don't form furrows.
Hope this helps, if not let me know. Also, do you have multiple choice answers? If this isn't one let me know the options and I'm sure I can help.
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.
