Name: ___________________
WHAT SHOULD I KNOW FOR THE Mini-Test?
Chapter 11- Introduction to Genetics
Mini-Test Date: ________
1. Who is considered to be the “Father of Genetics”?
Gregor Mendel
2. What was Gregor Mendel’s contribution to our understanding of genetics?
He research and determined how “factors” (now called genes) are passed from parent to offspring.
3. What is the relationship between the P, F1, and F2 generations?
P generation produces the F1 generation which produces F2 generation.
4. What 2 laws did Mendel propose to explain how traits are inherited?
Law of Segregation (1st set of experiments – 1 trait: Monohybrid), Law of Independent Assortment (2 nd
set of experiments – 2 traits: Dihybrid)
5. When do segregation and independent assortment happen?
Segregation – Anaphase 1, Independent Assortment – Metaphase 1
6. How are these related to the events that happen during meiosis?
Homologous chromosomes are separated during Anaphase 1. Homologous chromosomes line up randomly at
the metaphase plate.
7. Be able to explain the difference between complete, incomplete, and codominance
and give examples of each.
Complete dominance (Dominant/Recessive) – T= tall, t= short. TT=tall, Tt=tall, tt=short
8. What is the law of segregation?
Separation of alleles during meiosis.
9. What is the probability that a human couple will have a boy?
50% or 1/2
10. What are the chemical factors in chromosomes that determine traits called?
genes! (segments of DNA that code for a trait in an organism)
11. Why did Mendel remove the male parts from flowers of some plants?
To be able to manipulate plants with two different traits. He cross-fertilized two different parent
plants to form offspring.
12. Why did Mendel choose pea plants to study the inheritance of traits?
Because he could manipulate them by removing the male sex organs and transfer them to the female sex
organs.
13. What is the difference between homozygous/heterozygous? _homozygous – TT or tt, heterozygous –
Tt
14. Dominant/recessive? Dominant – Capital letter, masks the recessive trait. Recessive – lower case
letter, is masked by the dominant trait.
15. Pure/hybrid? Pure = Homozygous (TT or tt), Hybrid = Heterozygous (Tt)
16. allele/trait? Allele = options within a gene. Trait = the expressed phenotype of a gene.
For example, if you inherit 2 blue eye alleles on your eye color gene, you will express the trait of blue
eyes.
17. genetics/heredity? Genetics – study of traits being passed on from parent to offspring. Heredity –
the lineage or inheritance of traits from your parents.
18. Genotype/phenotype? Genotype = what alleles are in your DNA (what we cannot see by simply looking
at someone). You write this as letters (like TT or Tt). Phenotype = the expression of the alleles in your
DNA. By expression I mean, what you can physically see but looking at someone’s appearance.
For example: Genotype of a person with blue eyes = bb
Phenotype of a person with blue eyes = BLUE eyes!
19. What is the difference between a MONOHYBRID and a DIHYBRID cross?
Monohybrid = 1 trait (4 square punnett)
Dihybrid = 2 traits (16 square punnett)
20. Which type of Punnett square is used for each of these?
see above
21. What phenotypic inheritance patterns are seen in different kinds of crosses?
Monohybrid cross of 2 heterozygotes: 3:1
22. What are test crosses used for?
To determine an unknown genotype of an organisms.
23. What genotype is used to make a test cross?
pure recessive
MONOHYBRID CROSSES – 4 Square Punnett
HOMOZYGOUS DOMINANT X HOMOZYGOUS RECESSIVE =
100% heterozygous dominant
HETEROZYGOUS X HETEROZYGOUS
¾ Dominant; ¼ recessive
DIHYBRID CROSSES- 16 Square Punnett
HOMOZYGOUS DOMINANT (for 2 traits) X HOMOZYGOUS RECESSIVE (for 2 traits)
100% heterozygous dominant for BOTH traits
HETEROZYGOUS (for 2 traits)
X
HETEROZYGOUS (for 2 traits)
9/16 – Dominant for BOTH traits
3/16 – Dominant for trait 1; Recessive for trait 2
3/16 – Recessive for trait 1; Dominant for trait 2
1/16 – Recessive for BOTH traits
INCOMPLETE DOMINANCE
Heterozygous individuals show a blended intermediate phenotype (Ex: Rr = pink flowers not red)
CODOMINANCE
Both traits show together side by side (Ex: AB blood type)
If given traits and parents, be able to use a Punnett square or patterns to predict the probability of
offspring for a given cross and express it as a fraction, percent, or ratio.
Multiple Alleles
For every gene, there are multiple alleles (options) present in the population.
Polygenic
In this type of trait, many genes contribute to the expression of the trait.