This document provides an overview of basic genetics concepts. It defines traits and alleles, and explains dominant and recessive genes. A Punnett square is used to show the probability of different genotypes in offspring. Genetic concepts like homozygous, heterozygous, phenotype, genotype, and DNA are defined. Mendelian inheritance patterns are demonstrated through examples of dominant and recessive traits.

1. Genetics Review

2. •Physical characteristics studied in
genetics are called ?

3. Traits
•For example: height, color, dimples, etc.

4. •The different forms of a gene are
called?

5. Alleles
•You get one from each parent.
•Maybe a dominant from Mom and
recessive from Dad

6. •A hidden or masked trait in a
gene combination is called?

7. recessive
•You only ‘see’ the recessive trait if there
are two of them
•Homozygous recessive, ee

8. •Show a heterozygous gene
combination using the letter G

9. Gg
•Heterozygous gene combinations have two
different genes, one dominant and one
recessive

10. •How many genes for each trait
does an offspring receive from
each parent?

11. One
•You get one gene from each parent.

12. •What does a Punnett square
show?

13. Probability of Genotypes
•The probability of the genotypes of the
offspring.
•75% chance of being tall
•25% chance of being short

14. •In genetics a capital letter
represents a __________
trait.

15. Dominant
•All dominant traits are
represented with a capital letter.

16. •In genetics a lower case letter
represents a ___________ trait.

17. recessive
•Recessive traits are represented
with a lower case letter, you must
have two of them in order to ‘see’
that trait.

18. If G=green and g= blue
What would be the
probability of the
offspring being blue?

19. 25%

20. If G=green and g=blue
What word describes
the genotypes of the
parents?

21. Heterozygous or Hybrid

22. If G=green and g=blue
What words
describe the
genotype of the
blue offspring?

23. homozygous recessive or
purebred recessive

24. •An organism’s expressed physical
trait, such as seed color or shape,
is called its ______________.

25. Phenotype
•A phenotype is an organism’s
physical appearance.

26. •If purple flowers are dominant to white
flowers, what would be the phenotypes
of the offspring of a purple homozygous
flower with a white homozygous flower?

27. Purple
PP x pp means all
offspring will be Pp,
so they will all be
purple.
Pp Pp
Pp Pp

28. •Which nitrogen pairs bond
with each other?
•(hint: A,C,G,T)

29. A – T and C – G
•Adenine always bonds with Thymine
•Cytosine always bonds with Guanine

30. •What word describes an organism
that has two identical alleles for a
trait?

31. Homozygous
•The prefix ‘homo’ means ‘same’

32. List the levels of organization
from largest to smallest.
•Use these terms:
•DNA, chromosome, gene, nucleus, cell

33. Cell – nucleus – chromosome- gene- DNA

34. •What is the function of DNA?

35. DNA carries all of the genetic
information of the organism.
•DNA is the code for how to build and
maintain and organism (like you).

36. •How do you get a genetic
disorder?

37. Passed from the genes of a parent
•A genetic disorder is passed from
parent to child through the genes,
it cannot be ‘caught’ like the flu or
the measles.

38. •If an offspring has two parents
and is a unique individual is it a
product of asexual or sexual
reproduction?

39. Sexual Reproduction

40. G = green and g = blue
•Genotype of homozygous
dominant

41. GG

42. G = green and g = blue
•Genotype for hybrid

43. Gg

44. G = green and g = blue
•Phenotype of homozygous
recessive

45. blue

46. G = green and g = blue
•Phenotype of heterozygous

47. Green

48. G = green and g = blue
•Phenotype of homozygous
dominant

49. Green

50. G = green and g = blue
•Show the genotypic cross
between a purebred blue
and a hybrid

51. gg x Gg

52. G = green and g = blue
•Show a Punnett square for
a cross between two
heterozygous parents

53. G g
GG Gg
gg