IB Biology SL 2.3.11 Crossing over and genetic variation Question Bank
Practise IB Biology SL 2.3.11 by describing crossing over and how meiosis creates genetic variation.
- Syllabus
- First assessment 2025
- Course
- Biology SL
- Level
- SL
Exam points
- State when crossing over occurs in meiosis.
- Explain how crossing over and independent assortment produce variation.
D2.1.11—Meiosis generates variation question 1
[Maximum number: 7]
Genetic information controls the production of all proteins needed by the body to carry out its functions, including proteins acting as enzymes and hormones as well as proteins for structures and transport.
Explain the stages and processes of meiosis leading to genetic variation.
a. meiosis divides a diploid nucleus to produce (4) haploid nuclei;
b. meiosis halves the chromosome number;
c. chromosomes consist of two sister chromatids at the start of meiosis;
d. homologous chromosomes are paired;
e. crossing over occurs between homologous chromosomes;
f. crossing over promotes genetic variation/new gene/allele combinations;
g. pairs of homologous chromosomes are randomly oriented/assorted in the first division of meiosis
OR sister chromatids are randomly assorted during the second division of meiosis;
h. in the first division of meiosis pairs of homologous chromosomes are separated;
i. random orientation promotes genetic variation/new gene/allele/chromosome combinations;
j. meiosis produces haploid gametes (to ensure offspring have complete set of chromosomes);
k. fusion of gametes from different parents promotes (genetic) variation;
Drawings which are annotated to explain are acceptable.
7 max
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