Mr. Coaster
GAUTENG DEPARTMENT OF EDUCATION SENIOR SECONDARY INTERVENTION PROGRAMME
LIFE SCIENCES GRADE 12 SESSION 3 (LEARNER NOTES)
Page 1 of 10
TOPIC 1: MENDEL’S 1ST LAW, SEX AND BLOOD GROUP DETERMINATION
Learner Note: Mendel’s Laws are very important and you must understand the basic concepts of Genetics. You must understand the concepts of dominance and how this plays a role in monohybrid crosses (mono = one = one characteristic or trait). Be aware of confusing the word ‘cross/ crossing’ with ‘crossing over’ in Meiosis. You cross individuals and calculate the chances of a characteristic or trait being in the offspring. “Crossing over’ takes place in Meiosis during prophase where pieces of chromosomes cross over from the male chromosomes to the female chromosomes to ensure a mix of the characteristics in the offspring. You must be clear of the difference between these two terms. Questions on blood group inheritance and sex determination are often asked during examinations. The more examples of genetic crosses you do, the better you will be.
QUESTION 1: 6 minutes (Taken and adapted from Study & Master Biology Grade 11)
1. Blood typing can be used to identify a parent in that the blood type can prove that a person is not the parent of a child rather than determine without question who the parent is. A, B, AB and O blood groups are the result of three alleles. Allele A and B are co-dominant and O is recessive to both A and B. Should the discrepancy continue, tissue typing and DNA fingerprinting will be used. Read through the following information and answer the questions below:
In a maternity ward of a hospital, two newly born babies were mixed up. One baby is blood type O and the other is type A. Both mothers believe the baby with blood type O is their baby. Can you sort it out? On testing the parents’ blood it was found that:
1. Mr. Xhosa is blood group AB and his wife is blood group B
2. Mr. Mbundwini is type A.
Who owns baby ‘O’ and who owns baby ‘A’? Explain /
LIFE SCIENCES GRADE 12 SESSION 3 (LEARNER NOTES)
Page 1 of 10
TOPIC 1: MENDEL’S 1ST LAW, SEX AND BLOOD GROUP DETERMINATION
Learner Note: Mendel’s Laws are very important and you must understand the basic concepts of Genetics. You must understand the concepts of dominance and how this plays a role in monohybrid crosses (mono = one = one characteristic or trait). Be aware of confusing the word ‘cross/ crossing’ with ‘crossing over’ in Meiosis. You cross individuals and calculate the chances of a characteristic or trait being in the offspring. “Crossing over’ takes place in Meiosis during prophase where pieces of chromosomes cross over from the male chromosomes to the female chromosomes to ensure a mix of the characteristics in the offspring. You must be clear of the difference between these two terms. Questions on blood group inheritance and sex determination are often asked during examinations. The more examples of genetic crosses you do, the better you will be.
QUESTION 1: 6 minutes (Taken and adapted from Study & Master Biology Grade 11)
1. Blood typing can be used to identify a parent in that the blood type can prove that a person is not the parent of a child rather than determine without question who the parent is. A, B, AB and O blood groups are the result of three alleles. Allele A and B are co-dominant and O is recessive to both A and B. Should the discrepancy continue, tissue typing and DNA fingerprinting will be used. Read through the following information and answer the questions below:
In a maternity ward of a hospital, two newly born babies were mixed up. One baby is blood type O and the other is type A. Both mothers believe the baby with blood type O is their baby. Can you sort it out? On testing the parents’ blood it was found that:
1. Mr. Xhosa is blood group AB and his wife is blood group B
2. Mr. Mbundwini is type A.
Who owns baby ‘O’ and who owns baby ‘A’? Explain /