1. All Living Things reproduce!!! All Living Things Have DNA!!!
CHARACTERISTICS OF LIFE
All Living Things reproduce!!!
All Living Things Have DNA!!!

2. WHY ARE WE ALL DIFFERENT?
We all inherited different genes from our parents which determines our traits.
Heredity – Passing on of genes which
determine your traits from parents
to offspring.
23 chromosomes from
each parent.

3. Genes – Pieces of DNA that carry hereditary
instructions and are passed from parents.
Traits – A distinguishing characteristic that is
passed from parents to offspring.
Genetics – Study of heredity (passing
on of genes)

4. Johann Gregor Mendel was born July 22, 1822
Johann Gregor Mendel was born July 22, Mendel became a friar at the Augustinian monastery in Brno, Czechoslovakia. From 1868 until his death, Mendel was the abbot of the monastery.
Mendel was experimenting with flowers in the monastery's gardens. He wondered how traits were passed from parent to offspring. He studied the relations between parents and offspring with mathematical symbols. His favorite plants to experiment with were peas.
FATHER Of
genetics

5. MENDEL’S EXPERIMENT PART 1
He bred a tall pea plant with a pure short pea plant. But ALL the offspring were TALL.
How could that be?
Maybe a mistake was made?
PART 2
He crossed 2 of the
offspring from the above
cross.
Results – 75% Tall
25% Short
Now wait a minute!! He crossed two tall and go a short? What’s going on?????

6. GENETIC RULES
Every organism has TWO forms of a gene for each trait. One from each parent. Each form is called an ALLELE.
You can receive a dominant or recessive gene
From your parent.

7. GREGOR MENDEL Father of Genetics. He realized in the first cross, one
trait appeared and the other seemed to be masked.
* The trait that masks or is stronger than the other trait is called the dominant trait.
* The trait that is covered up is called the recessive trait.
For these reasons, Mendel is called the
Father of Genetics.

8. GENETICS RULES GENETIC SYMBOLS
Scientists use symbols to represent different forms of a gene.
Capital Letters – Represents dominant
trait. Dominant traits are the stronger traits.
Lower Case Letters – Represents recessive trait. Recessive traits are the weaker traits that are often masked by dominant traits.
Examples-BB – brown eyes bb - blue
Bb – brown eyes

9. Example Dominant Traits
Brown Eyes- B
Widow’s Peak- W
Unattached Earlobes- E
Freckles- F
Example Recessive Traits
Blue eyes- b
Straight hairline- w
Attached earlobes- e
No Freckles- f

10. Examples – aa , AA , LL , ll , TT , tt
If the inherited genes (alleles) are the same, then they are called HOMOZYGOUS or purebred. Letters are the same size.
Examples – aa , AA , LL , ll , TT , tt
If the inherited genes are different, then they are called HETEROZYGOUS or hybrid. Letters are different sizes.
Examples – Aa , Ll , Tt, Bb

11. Used to predict – the results of genetics crosses.
GENETIC PROBABILITY
Mendal crossed yellow and green pea plants
and discovered that 1 out of 4 were green.
He was using probability.
Probability – The possibility or likelihood that
a particular event will occur.
Used to predict – the results of genetics
crosses.

12. PUNNETT SQUARES A Punnett square is a special chart used to
show the possible gene combinations in a
cross between 2 organisms.
Developed by an English geneticist by the
name of Reginald Punnett.

13. PARTS OF A PUNNETT SQUARE
Male Genes
Female
Genes
Offspring
Combinations

14. How does a Punnett Square Work?
Draw a square and divide
it into 4 sections.
Write the gene pairs across the top of the box, then the
other down the side.
In each box, place the correct gene to see the possible combinations.
Each square
represents a 25%
possibility of getting
that trait.

15. Tt Tt Tt Tt Cross between homozygous
dominant curly tail (TT) and a homozygous
recessive straight tail (tt). Tt Tt Tt Tt

16. Tt Tt Tt Tt
What are the percent of the offspring?
What are the genotypes?
What are the phenotypes?

17. What are the percentages of offspring? What are the genotypes?
Cross between
two heterozygous curly tailed parents (Tt). TT Tt tt Tt
What are the percentages of offspring?
What are the genotypes?
What are the phenotypes?

18. Mathematical Computations
In a Punnett Square where both parents are
hybrids the percents are listed below:
25% purebred (homozygous) curly – TT
50% hybrid (heterozygous) curly - Tt
25% purebred (homozygous) straight - tt
% of same genotype as parents -
50 %
% of same phenotype as parents -
75%

19. The squares contain the gene combinations
that could occur in the cross.
The genotype is the letter combination or
gene combinations in the squares.
Example – Tt, Aa, bb,or Ll
The phenotype is the actual appearance of
the organism.
Example – tall, brown hair, blue eyes, long
toes

20. INCOMPLETE DOMINANCE Sometimes, you may notice that traits can blend
together. The blending of two traits is call incomplete
dominance. Two capital letters are used. For example, from baby marsmellow RY = orange nose, RR = red nose, and RY = yellow nose
Examples – roan color in horses and cows, pink color in flowers are red and white combined.

21. http://www. world-builders. org/lessons/less/les4/inherit

22. Bellringer #9
The process in which DNA makes more copies of itself for all new cells is:
a. Reproduction
b. Replication
c. Copying
d. Cloning
The three part unit of DNA that is in a repeating pattern is called:
a. Nitrogen base
b. Hydrogen bonds
c. Nucleotide
d. Deoxyribose
The nitrogen bases will always connect to a:
a. Sugar
b. Phosphate
d. They do not connect