Reference no: EM132347207
Part I - Human ABO Blood Type
"But I already know all this stuff! I'll do well on the test tomorrow, I promise," begged Kevin. He really wanted to go
out that night with his friend, but his mother had other ideas.
"No, absolutely not. You're going to stay home and study; tomorrow's test is very important," his mother replied.
Kevin ended up staying home that night, reluctantly.
The next day Kevin met his best friend Peter. "How's it going?" asked Peter.
"Not so good. We had a test today. I guess it went all right," said Kevin.
"How's your stomach doing? Is it still sore?" Peter asked.
"Oh, it's better now. You know, there's something weird going on. Last time I was in the hospital, neither of my parents could donate blood to me. The doc said they aren't a match for my blood type."
"They don't match? What do you mean?" Peter asked.
"Well, the doc said I'm type O positive, my mom is type A positive, and my dad is type B negative. We're all different, and I don't get it. They're my parents-I mean, I should inherit my blood type from at least one of them, if not both, right?"
"That's a good point," Peter agreed. "Well, I've got a very cool science teacher, Ms. B. She would know better than us.
Let's ask her. She has a class tomorrow. We can meet her afterward. What do you say?"
The next day, Kevein and Peter met Ms. B. and explained Kevin's puzzle about his family's blood types.
"Ah, good question," replied Ms. B. "Let me explain how blood types work so that it will help you to understand why your parents couldn't donate blood to you and how you can all have different blood types in one and the same family."
"The ABO blood group system is one of the most important systems that hospitals use to identify individuals for blood transfusion. ABO stands for the type of carbohydrate that sits on the surface of red blood cells; it's this carbohydrate that allows cells to recognize themselves. They are also called surface markers. Positive (+) refers to the presence of Rhesus (Rh) factor. Some individuals lack Rh factor, and they are negative (-). Rh factor is a predominant protein surface marker on red blood cells."
"Interesting. What is carbohydrate exactly? The stuff we eat, like bread and sugar?" Peter asked.
"Yes. Sugar is a carbohydrate and bread is made of lots of different carbohydrates. Red blood cells may have carbohydrate A on the cell surface, which results in type A blood; but if they have carbohydrate B, then they become type B blood. Some red blood cells have both carbohydrate A and B, which makes them have type AB blood. When neither carbohydrate A nor B is present on the red blood cell surface, the blood type is considered to be type O."
That made sense to Peter, who then asked "How do red blood cells get those carbohydrates?"
The Genetics of ABO Blood Types
NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE
"Why Is He Different from Both Parents?" by Liang and Rice Page 2
"That's a great question. The types of carbohydrate on the red blood cell surface are controlled by genes. In this case, the gene that controls carbohydrate types presented on red blood cell surface encodes enzymes. Enzymes are proteins that catalyze chemical reactions," Ms. B. continued. "There are two types of such enzymes: enzyme A and enzyme B, which deposit carbohydrate A and carbohydrate B respectively on the red blood cell surface. The three different versions of the gene are called alleles. Allele A codes for enzyme A; Allele B codes for enzyme B; Allele O doesn't code for a functional protein."
"Oh, then I must have O alleles since I'm type O!" Kevin was excited to figure out the alleles he had in his body.
Questions
1. What is the human ABO blood group system?
2. What types of biochemicals are surface markers on red blood cells?
3. How many blood phenotypes are there in the ABO blood group system?
Attachment:- The Genetics of ABO Blood Types.rar