1. 6.1 Meiosis
Chapter 6 notes

2. General info
__________________– requires two parents and produces offspring that are genetically different from each other

3. General info
Sexual reproduction – requires two parents and produces offspring that are genetically different from each other

4. ______________– variation, or inherited genetic differences, in a species

5. Genetic diversity – variation, or inherited genetic differences, in a species

6. Genetic diversity – variation, or inherited genetic differences, in a species
In eukaryotic organisms, the chromosome number is referred to as the ______________(2n) since there are two sets of chromosomes

7. Genetic diversity – variation, or inherited genetic differences, in a species
In eukaryotic organisms, the chromosome number is referred to as the diploid number (2n) since there are two sets of chromosomes

8. Genetic diversity – variation, or inherited genetic differences, in a species
In eukaryotic organisms, the chromosome number is referred to as the diploid number (2n) since there are two sets of chromosomes
Humans inherit one set of chromosomes, the ______ _______(1n), from each parent

9. In eukaryotic organisms, the chromosome number is referred to as the diploid number (2n) since there are two sets of chromosomes
Humans inherit one set of chromosomes, the haploid number (1n), from each parent

10. More general info
Haploid chromosomes are carried in gametes (sex cells), specialized cells necessary for reproduction 
Male gametes are called _____ and female gametes are called _____ 

11. More general info
Haploid chromosomes are carried in gametes (sex cells), specialized cells necessary for reproduction 
Male gametes are called sperm and female gametes are called eggs 

12. During fertilization, an egg cell joins a sperm cell and the genetic information is combined, resulting in a diploid cell called a ______ 
The zygote undergoes mitosis and cell division and develops into an embryo

13. During fertilization, an egg cell joins a sperm cell and the genetic information is combined, resulting in a diploid cell called a zygote 
The zygote undergoes mitosis and cell division and develops into an embryo

14. Stages of meiosis
Process that produces four gametes with half the number of chromosomes

15. Meiosis I
Prophase I – homologous chromosomes pair up (one from each parent) and non sister chromatids exchange genetic material (called crossing over) 

16. Metaphase I – homologous chromosomes pair up at the equator

17. Anaphase I – homologous chromosomes separate and are pulled to opposite poles by the spindle fibres

18. Telophase I – one chromosomes from each homologous pair is at each pole of the cell

19. Interkinesis – 2 cells result and each cell grows and makes proteins but unlike mitosis, DNA does not replicate

20. Meiosis II
Prophase II – there is one chromosome of the homologous pair in each cell

21. Metaphase II – the X-shaped chromosomes form a single line across the middle of the cell

22. Anaphase II – sister chromatids move to opposite poles of the cell (each one is now considered a chromosome)

23. Telophase II – spindle fibres begin to disappear and a nuclear membrane forms around each set of chromosomes

24. Cytokinesis – the two daughter cells are separated

25. Crossing over
In crossing over, parts of non-sister chromatids exchange segments of DNA to create an infinite amount of genetic variation 

26. Independent assortment is when homologous pairs of chromosomes separate at the equator and move towards opposite ends... you never know which one will go which way 

27. In sperm cell, all four cells may develop into mature sperm but in egg cell there is an unequal division of cytoplasm and organelles so three cells disintegrate and only one large egg cell remains

28. Chromosome mutation
During meiosis, pieces of chromosomes can be lost, duplicated or moved within a chromosome or moved to another chromosome
Mutations occur when cells are exposed to mutagens 
Large chromosome errors are usually prevented from being passed along because the offspring will die before birth or fail to reach reproductive age 

29. A karyotype is a picture of all our chromosomes arranged in a particular order

30. Karyotypes are studied to help physicians diagnose and treat patients with genetic disorders (syndromes) like Down syndrome