-Hemoglobin is the protein molecule in red blood cells that carries oxygen from the lungs to the body's tissues and returns carbon dioxide from the tissues back to the lungs.
-Hemoglobin is made up of four protein molecules (globulin chains) that are connected together.
- Hemoglobin also plays an important role in maintaining the shape of the red blood cells. In their natural shape, red blood cells are round with narrow centers resembling a donut without a hole in the middle. Abnormal hemoglobin structure can, therefore, disrupt the shape of red blood cells and impede their function and flow through blood vessels.
"The energy contained in the food we eat is used to synthesize the energy that directly powers all of our cellular activities".
Explanation:
The food we eat undoubtedly contains energy. This energy is stored in the bonds of the molecules that make up the food. However, the food undergoes the process of digestion to yield glucose (a sugar). This glucose sugar is used in the process of CELLULAR RESPIRATION to synthesize a form of chemical energy usable by cells called ATP.
ATP or Adenosine triphosphate is a molecule that stores chemical energy in living cells. It is the molecule that directly powers all of our cellular activities. Hence, the statement in this question is FALSE. The correct statement should be "The energy contained in the food we eat is used to synthesize the energy that directly powers all of our cellular activities".
The voltage-gated potassium channels associated with an action potential provide an example of what type of membrane transport?
A. Simple diffusion.
B.<u> Facilitated diffusion.
</u>
C. Coupled transport.
D. Active transport.
You are studying the entry of a small molecule into red blood cells. You determine the rate of movement across the membrane under a variety of conditions and make the following observations:
i. The molecules can move across the membrane in either direction.
ii. The molecules always move down their concentration gradient.
iii. No energy source is required for the molecules to move across the membrane.
iv. As the difference in concentration across the membrane increases, the rate of transport reaches a maximum.
The mechanism used to get this molecule across the membrane is most likely:
A. simple diffusion.
<u>B. facilitated diffusion.
</u>
C. active transport.
D. There is not enough information to determine a mechanism.
Carrier proteins - exist in two conformations, altered by high affinity binding of the transported molecule. Moves material in either direction, down concentration gradient (facilitated diffusion). EXAMPLE: GluT1 erythrocyte glucose transporter.
Channel proteins - primarily for ion transport. Form an aqueous pore through the lipid bilayer. May be gated. Moves material in either direction, down concentration gradient (facilitated diffusion). EXAMPLES: Voltage-gated sodium channel, erytrhocyte bicarbonate exchange protein.
This might be helpful... because I don't know anything about facilitated diffusion.
Macroevolution occurs due to the genetic differences accumulates in the population of the same species which gets reproductively isolated from the older population and got different environments and resources to live.
Macroevolution leads to the creation of a new species over a long period of time because of the genetic difference that occurs due to mutation in the gene in the population who got reproductively isolated. So the new species evolved from the macroevolution.
