BIOC19H3 Lecture Notes - Lecture 3: Yolk Sac, Hbb, Globin

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redelephant995

18 Nov 2016

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Reptiles and amphibian, birds and fish round/oval have a dark, small nucleus condensed and not active for gene expression. Dogs, cats and human have mature red blood cells without a nucleus. During differentiation of the red blood cell the nucleus got lost: have a very high level of protein called hemoglobin. Erythrocyte is the term used to define a mature red blood cell. When you look at it, it is a very simple cell. Packed full of a particular protein called hemoglobin. We use rbc as a model system because the final cell is highly differentiated. )t has no nucleus and doesn"t have any org anelles on the inside either packed full of a rbc specific protein. Very specific cytoskeleton that keeps the rbc in this shape. Compared to other cells in the human body this cell is relatively small. Why is it small: lost its nucleus which makes it smaller, they are also very flexible.

Related Questions

A human gene called the Î²-globin gene encodes a polypeptide that functions as a subunit of the protein known as hemoglobin. Hemoglobin is found within red blood cells; it carries oxygen. In human populations the Î²-globin gene can be found as the common allele known as Hb^A, and it can also be as the Hb^S allele. Individuals who have two copies of the Hb^S allele have the disease called sickle cell disease. Are the following examples descriptions of genetics at the molecular, cellular, organism, or population level?

A. The Hb^Sallele encodes a polypeptide that functions slightly differently from the polypeptide encoded by the Hb^Aallele.

B. If an individual has two copies of the Hb^Sallele, that persons red blood cells take on a sickle cell shape.

C. Individuals who have two copies of the Hb^Aallele do not have sickle cell disease, but are not resistant to malaria. People who have one Hb^Aallele and one Hb^S allele do not have sickle cell disease but are resistant to malaria. People who have two copies of the Hb^Sallele have sickle cell disease, and this disease may significantly shorten their lives.

D. Individuals with sickle cell disease have anemia because their red blood cells are easily destroyed by the body.

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1. In lecture, we described a simple osmotic pressure gradient when discussing osmosis. For question #1, describe the simple osmotic pressure gradient, in terms of osmotic pressure, that exists across the red blood cell plasma membrane when red blood cells are suspended in a severely hypotonic solution, such as a 0.2% NaCl solution. Use scientific terminology.

2. We mentioned in class that biological systems are always in a state of osmotic equilibrium due to a combination of solute diffusion in some cases and osmosis in others. In this experiment, when you add the red blood cells to a severely hypotonic solution, what substances are moving across the red blood cell plasma membrane to achieve osmotic equilibrium, Na+ and Cl- or water? Explain why based on your understanding of the permeability characteristics of biological membrane. Always use scientific language.

CAN QUESTIONS 1 AND 2 BE ANSWERED DIRECTLY AND ADEQUATLEY PLEASE.

HERE IS AN INTRO TO THE LAB EXPERIMENT

Intro:

We have known for a very long time that the mammalian red blood cell plasma membrane is very permeable to water. Even the introductory biology student understands that if you put mammalian red blood cells in water, they will rapidly swell and break open (hemolyze) due to the rapid osmosis of water into the cell. The experimental question we are asking in today's lab experiment is "Is the high water permability of mammalian red blood cell plasma membrane due solely to the lipid bilayer, or are there water channels present in the membrane?"

Experimental Design:

It has been shown by several investigators that water movement through water channels can be blocked by the known K+ channel blocker, tetraethylammonium chloride (TEAC). Brooks, Regan and Yool (2000) showed that TEAC reduces the water permeability of human water channels expressed in the plasma membranes of frog ocytes. After preincubation of the oocytes for 15 min with 100 microM TEAC, the water permeability of frog oocyte plasma membrane containing human water channels was reduced 20 to 40%. The investigators concluded that treatment of cells with TEAC can be useful in determining the presence of aquaporins in membranes.The specific objective of today's experiment is to uncover the presence of water channels in mammalian red blood cell plasma membrane by determining the effect of tetraethylammonium chloride on the water permeability of mammalian RBC plasma membrane.

We mentioned in class that biological systems are ... We mentioned in class that biological systems are always in a state of osmotic equilibrium due to a combination of solute diffusion in some cases and osmosis in others. In this experiment, what substance is moving across the red blood cell plasma membrane to achieve osmotic equilibrium, Na+ and Cl- or water? Explain why based on your understanding of the permeability characteristics of biological membrane. Always use scientific language. HERE IS AN INTRO TO THE LAB EXPERIMENT Intro: We have known for a very long time that the mammalian red blood cell plasma membrane is very permeable to water. Even the introductory biology student understands that if you put mammalian red blood cells in water, they will rapidly swell and break open (hemolyze) due to the rapid osmosis of water into the cell. The experimental question we are asking in today's lab experiment is "Is the high water permability of mammalian red blood cell plasma membrane due solely to the lipid bilayer, or are there water channels present in the membrane?" Experimental Design: It has been shown by several investigators that water movement through water channels can be blocked by the known K+ channel blocker, tetraethylammonium chloride (TEAC). Brooks, Regan and Yool (2000) showed that TEAC reduces the water permeability of human water channels expressed in the plasma membranes of frog ocytes. After preincubation of the oocytes for 15 min with 100 microM TEAC, the water permeability of frog oocyte plasma membrane containing human water channels was reduced 20 to 40%. The investigators concluded that treatment of cells with TEAC can be useful in determining the presence of aquaporins in membranes.The specific objective of today's experiment is to uncover the presence of water channels in mammalian red blood cell plasma membrane by determining the effect of tetraethylammonium chloride on the water permeability of mammalian RBC plasma membran

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BIOC19H3 Lecture Notes - Lecture 3: Yolk Sac, Hbb, Globin

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