1. 2d. Know new combinations of alleles may be generated in a zygote through the fusion of male & female gametes (fertilization)‏ 1

2. _____ + _____ = New Organism
Once gametes are formed, the second half of sexual reproduction can take place.
During ______________ a diploid organism is formed by 2 haploid parts.
When a sperm is united w/ an egg, a __________ (fertilized egg) is formed which contains the combined genotypes of the parents to produce a new allele composition. 2

3. Fertilization
The uniting of male and female ___________. 3

4. Zygote
When a sperm fertilizes an egg
Now a _________ cell 4

5. 5

6. 2e. Know why approximately half of an individual’s DNA sequence comes from each parent.6

7. 2f. Know the role of chromosomes in determining an individual’s sex.7

8. Copyright Pearson Prentice Hall
Human Chromosomes
Two of the ____ human chromosomes are known as _________ chromosomes, because they determine an individual's sex.
Females have two copies of an ___ chromosome.
Males have one __ chromosome and one ___ chromosome.
The remaining ___ chromosomes are known as autosomal chromosomes, or ________________.
Copyright Pearson Prentice Hall 8

9. Copyright Pearson Prentice Hall
Human Chromosomes
How is sex determined?
All human _____ cells carry a single X chromosome (23,X).
Half of all __________ cells carry an X chromosome (23,X) and half carry a Y chromosome (23,Y).
About half of the _____________ will be 46,XX (female) and half will be 46,XY (male).
Copyright Pearson Prentice Hall 9

10. 10

11. What are you? Females carry two X chromosomes ____.
Males carry one X & one Y chromosome  _____. 11

12. How many chromosomes are in the cell?
A normal human ___________ cell (every cell in the body except for the reproductive cells) contains 46 chromosomes.
44 chromosomes are homologous chromosomes (___________)
2 chromosomes are _______ chromosomes 12

13. Human Chromosomes
Males and females are born in a roughly ___ : ____ ratio because of the way in which sex chromosomes segregate during _________.
In humans, egg cells contain a single X chromosome. Sperm cells contain either one X chromosome or one Y chromosome. In a population, approximately half of the zygotes are XX (female) and half are XY (male). 13