GED Science : Homeostasis
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Example Question #11 : Homeostasis
The cell membrane is composed of a phospholipid bilayer. The structure and chemistry of phospholipids helps to maintain the integrity of the membrane.
The "water-loving" heads of phospholipids are said to be __________, while their "water-fearing" tails are __________.
acidic . . . basic
basic . . . acidic
saturated . . . unsaturated
hydrophobic . . . hydrophilic
hydrophilic . . . hydrophobic
hydrophilic . . . hydrophobic
The "water-loving" hydrophilic heads of phospholipids orient themselves outwards towards the watery cytoplasm inside the cell and interstitial fluid outside the cell. Meanwhile, the "water-fearing" hydrophobic tails of phospholipids orient themselves inwards toward one another.
Example Question #12 : Homeostasis
What is the substance surrounding living tissue cells referred to?
Cerebrospinal fluid
Blood
Plasma
Water
Interstitial fluid
Interstitial fluid
Interstitial fluid is the substance surrounding living tissue cells, its solute concentration is critical to the maintenance of homeostasis for the cells. Cells may have to spend valuable energy to keep unwanted materials from passing through their semi-permeable membranes in some conditions.
Example Question #13 : Homeostasis
Materials can be transported across the cell membrane in a variety of ways.
Which of the following is/are examples of passive transport?
Osmosis only
Active transport only
Facilitated diffusion and osmosis
Diffusion, facilitated diffusion, and osmosis
Diffusion only
Diffusion, facilitated diffusion, and osmosis
Diffusion, facilitated diffusion, and osmosis are all examples of passive transport because no energy is required to move molecules across the cell membrane. The driving force is the concentration gradient of the substance.
Example Question #14 : Homeostasis
What is true about active transport?
Molecules always move from high to low concentrations.
Energy is required.
Only fat-soluble molecules can undergo active transport.
It includes diffusion and osmosis.
Energy is required.
Active transport always requires energy since molecules are being pumped against their concentration gradients by being transported from areas of low concentration to areas of high concentration. Osmosis and diffusion are examples of passive transport and do not require energy.
Example Question #15 : Homeostasis
If a cell is placed in a hypertonic solution, water will move __________.
into the cell
out of the cell
in and out of the cell at the same rate
nowhere, the water will not move at all
into the cell membrane
out of the cell
In a hypertonic solution, the cell has a greater concentration of water molecules inside it than the solution does. Because of this, the water will move out of the cell in an effort to balance the concentration of water molecules both inside and outside of the cell.
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