Inheritance and Blood Typing, Study notes of Genetics

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Inheritance and Blood Typing

Vanderbilt Student Volunteers for Science

Training Presentation

2018-2019 VINSE/VSVS Rural

Important!!!

•^

Please make sure that the studentsunderstand that there is no real bloodin this lesson.

•^

All solutions are made from chemicals.

II. Red Blood Cell Demo

•^

Show the students the red styrofoam ballsand tell them that they represent red bloodcells.

-^

RBCs have proteins on their surface thatdetermine what blood type a person is—theseproteins are called

antigens

•^

The pipe cleaners are the antigens (pink isthe “A” antigen, blue is the “B” antigen).

-^

Jab a ball with a pink pipe cleaner. This redblood cell now has the “A” antigen and is an A blood cell

•^

Jab a blue pipe cleaner into another red ball.This RBC has a “B” antigen and is a

B blood

cell.

-^

Make an “AB” blood cell with both a pink andblue pipe cleaner.

-^

Ask the students what a RBC with NOantigens (no pipe cleaners) would be called?(“O”).

-^

Tell students to look at the handout to see acomparison of the different types of bloodcells and the relative representation of bloodtypes in the American population.

ANTIBODIES

-^

If a person’s RBC have one type of antigen (A or B), then their bloodcontains antibodies to the missing antigen.– eg. If the persons RBC has “A” antigens, then they will have

antibodies against the “B” antigen.

-^

Tell students to look at the Table in the handout.

-^

Antibodies help in removing unwanted things from the body.•^

Antibodies will attack and destroy any transfused or transplanted blood cells withthat antigen.

-^

People need to have their blood tested before receiving someone else’s blood.

-^

When blood is donated, the plasma and the RBCs are separated. This ensuresthat the antibodies (in the plasma) don’t get transferred during the transfusion.

ABO Blood Type

ContainsAntigen

A

ContainsAntigen

B

ContainsAntibodyanti-A

ContainsAntibodyanti-B

A^

yes

no^

no^

yes

B^

no^

yes

yes

no

AB

yes

yes

no^

no

O^

no^

no^

yes

yes

http://anthro.palomar.edu/blood/ABO_system.htm

III. The Kidney Problem

-^

Read the kidney scenario in the manual.

-^

Remind the students that the blood samples are notreally blood.

-^

Students will test the presence of antibodies by

adding

Anti-A and Anti-B serum

to each person’s blood

sample.

-^

A sample is positive for an antigen by observing whetheragglutination (

clumping

) occurs.

• If the blood clumps for the anti-A serum and not the anti-B

serum, then the blood type is A.

• If it clumps for the anti-B and not for the anti-A, then the blood

type is B.

• If it clumps for both, the blood type is AB.– If there is no clumping, then the blood type is O.

Learning Goals: Students understand the relationship between antigens and antibodies,and identify which blood types are compatible as donors and receivers. With support,students identify a method for determining blood type.

III. The Kidney Problem (cont.)

•^

Divide the students into pairs. Pass outsafety goggles to each student and oneset of materials to each pair ofstudents.

-^

Have students add a squirt of

Mrs.

Sanderson’s

samples to the first two wells

in column 1.

Add a 2-3 drops of

anti-A

(blue) to

the first well in

1A.

Observe whether a precipitate (orcloudiness) occurs - record a “+” if itdoes, or a “-” if it does not.Add a 2-3 drops of

anti-B

(yellow) to

the 2

nd

well in

column 1 (1B)

and

record the results.

•^

Repeat with

Mr. Sanderson’s

samples to

the first two wells in

column 2,

with

Jill’s

samples to the first two rows in

column 3

and with

Jack’s

samples to the first two

rows in

column 4

•^

Tell the students to determine the bloodtype of each person.

V. Blood Genetics and Punnett

Squares -Optional

-^

Antigens and thus,

blood type

, are determined by the

genes

that get passed on from someone’s parents.

• Explain that each parent (and each person) has two blood type

alleles. This is what’s known as a

genotype

, or what genes are

in someone’s body. Each parent will pass on one of thesegenes to their child.

-^

These genes are for the

A antigen

,^

B antigen or no

antigen (O)

.

• The combination of two of these genes will result in

blood type

-^

Punnett squares

can be used to help figure out the

possible inherited genetic trait combinations, like bloodtype (see example on next slide).

-^

Learning Goals: Students use Punnett squares and basic genetics toconstruct an explanation for why people have certain blood types. Review the terms dominant, recessive and co-dominant

Punnett Square (Optional)

•^

Filling in the

Punnett Square

-^

The mother’s genes(AA) areplaced on top of the Punnettsquare with each gene situatedover one column.

-^

The father’s genes (AB) areplaced to the side with each genenext to its own row.

-^

One of the mother’s A genes iswritten in each square below it;similarly, the other A gene isplaced in the squares below it.

-^

The father’s A gene is written inboth squares to the right of it, as isthe B gene.

•^

This process is a

simulation of

genotypes their children

could

inherit.–

In other words, there is a 50%chance a child will be AA and a50% chance a child will be AB.

A

mother

A

mother

A

father

AA

AA

B

father

AB

AB

Possible Genotypes

-^

Ask students what each family member’s possiblegenotype is. Write these answers on the board and/orshare with the class.

Column 1

Column 2

Column 3

Column 4

Mrs. Sanderson

Mr. Sanderson

Jill

Jack

Row A Anti-A serum

(+ / -)

Yes

No

Yes

No

Row B Anti-B serum

(+ / -)

No

Yes

Yes

No

Blood Type(A, B, or O)

A^

B^

AB

O

Possible Genotype

AA or AO

BB or BO

AB

OO

Dominant and Recessive Genes

cont.

Ask students: If Jack has type O blood, what are the genotypes forhis mother and father?Have the students fill out their Punnett square using all the possiblegenotypes for Mr. and Mrs. Sanderson.