Download BSG_Genetics_Notes

Name: Brendan G
Date: 1/5/11
The Study of Genetics: The Basics
Use the internet to research the following questions. Once everyone on your team has completed
each answer, compare and contrast your answers. After your team has compared and contrasted
your answers, we will discuss this as a class.
1. Heredity explains a lot about who we are. What is heredity?
Heredity is the study of traits getting passed from the parents to the offspring
2. Traits are passed on from parent to offspring. What are traits? Give three examples. How are
they passed on? How many genes for a trait do we get from each parent?
Traits are a certain characteristic, feature, or quality distinguishing an individual. Traits can be
eye color, hair color, and build. They are passed on by each parent giving one gene to the
offspring for a certain trait, passed through reproduction. You get 23 chromosomes from each
parent, those make up a gene. The combination then determines how the trait will show.
3. Some traits are dominant and some traits are recessive. What does this mean? How are they
represented? Which are more likely to show in an organism? Give an example of three
dominant traits and three recessive traits in humans.
Dominant traits (require 1 allele to show) mask the presense of the other trait and the recessive
(requires two to shows) trait is masked by another trait, if there is a dominant. The dominant
traits are represented by capital letters and recessive traits are represented by lower case
letters. The dominant trait is more likely to show in an organism. Brown eyes dominant to blue
eyes. Normal sight dominant to color blindness. Dark hair dominant to light hair.
4. Traits can be show as phenotypes and genotypes. What is the difference between these two?
Give an example of a phenotypes and its genotype.
Phenotypes is the way that the genes physically show up on a person, while genotype is the
code for the trait. A genotype could be bb and the phenotype would be blue eyes.
5. When we get genes from our parents we can get several different combinations. What is it
called when we get two dominant traits? two recessive traits? one dominant and one
recessive?
Two dominant traits is called homozyous dominant, two recessive traits is homozygous
recessive, and one dominant and one recessive is called heterozygous.
6. A Punnett Square is used when studying heredity. What does a Punnett Square allow us to
figure out about heredity?
A Punnett square can show us what the probability of a certain trait will be based on the traits
of the parents.
7. Gregor Mendel is known as the father of genetics. Why was he called this? How did he make
this discovery?
He is called the father of genetics because he discovered dominant and recessive traits. He
made this discovery by breeding peas and noticed how certain plants had certain traits more
than others and that some were hybrids and some were purebreds.