KEY
Asexual Reproduction
Prokaryotes reproduce using the following process? ____binary fission/asexual reproduction
_________________________
Do some eukaryotes reproduce asexually? __yes________
How many parents does an asexual organism have? __1 parent_________
An asexual organism’s offspring is a ___clone_____ of the parent which means the
offspring is genetically ___identical______ to its parent.
Sexual Reproduction
5.
How many parents do sexually reproducing organisms have? __2 parents_______
6.
Offspring of a sexually reproducing organism have _____different_____ genetic code as
their parents.
Meiosis
7.
Meiosis results in cells with ___half__________ the number of chromosomes as the parent
cell.
8.
In what kind of cells will a change in the genetic code be passed on? ___germ/sex cells_
9.
What are the two types of animal gamete cells? Sperm and egg
10. In animals, what two organs have specialized cells that perform meiosis?
____ovaries_________ ___testes________
11. Spermatogenesis results in how many functional sperm? ___4________
12. Oogenesis results in how many functional eggs? _1 egg only____
13. What is another name for egg? Singular ____ovum_________ Plural
___ova___________
14. In order to give 1 ovum a lot of nutrients, oogenesis results in 3 ___polar bodies______.
15. Meiosis results in four haploid _sex cells/gametes___. Plural for nucleus nuclei
16. How many chromosomes are in human haploid nuclei? __23____
17. What is crossing over? __crossing over recombines genetic information
between two homologous chromosomes DURING prophase I of meiosis.__________
18. When does crossing over happen? __Prophase I of Meiosis______
19. Crossing over of homologous chromosomes increases ____genetic variation______
within a species.
20. Draw the stages of crossing over using the two homologous chromosomes. See below
Label the two processes below with sperm, ovum, polar bodies, spermatogenesis, oogenesis, and
crossing over.
Spermatogenesis
Oogenesis
Crossing over 
Sperm (4)
Crossing over 
1 Ovum^
^ Polar bodies (3)
Fertilization and n Value
22. n equals how many sets of chromosomes? ___1 set_________
23. 2n equals how many sets of chromosomes? ___2 sets_________
24. When a sperm fuses with an egg, what is created? ____Zygote_______________
25. Write in the n value for the following equation. __1n_ sperm + _1n_ egg = _2n_ zygote 26.
Why is the fusion of egg and sperm random? _____Because any given sperm with its
own genetic combination must find the ovum to fertilize. With millions of sperm at once,
this provides many different genetic possibilities_________________
Karyotypes
27. Using the karyotype, circle the gender of this individual and write the gender next to it.
Perform nondisjunction by drawing in a 3rd chromosome to create Down syndrome.
(extra is at Chromosome 21 “Trisomy 21”)
Increasing Genetic Variation
28. What is genetic variation? ___a measure of genetic differences within a population
29. A change in the genetic code is called a __mutation____.
30. ____Fertilization___ is the random fusion of egg and sperm to create
unique gene combinations.
31. The exchange of segments by homologous chromosomes is called _crossing over__.
32. The random distribution of chromosomes during meiosis is called _independent
assortment (how the chromosomes line up on the equator during metaphase I determines
genetic variety)__.