1. Genetics and Heredity

2. DNA in the Nucleus
All the genetic information is organized in chromosomes
DNA is a chemical with information for an organisms growth
DNA is shaped like a twisted ladder

3. DNA
DNA is wrapped around proteins like thread around a spool and compacted into chromosomes
During cell division DNA duplicates
Humans have 46 chromosomes in 23 pairs,
FYI: Fruit flies have 8 chromosomes, Corn plants have 20.

4. Cell Division
In unicellular(single celled)organisms the function of cell division is for reproduction
In multicellular organisms the function of cell division includes growth, development and repair.

5. Cell Division Produces 2 genetically identical cells
Occurs in both sexual and asexual reproduction
Asexual– only one parent
Budding
Regeneration
Cloning
Sexual– two parents
How the organism grows

6. Replication Before a cell divides, all its DNA is copied Step 1
DNA “unzips”
Step 2
Bases in the area fill in
Now 2 strands where it was once 1

7. Type of cell division Mitosis – how your body cells divide
Meiosis – how sex cells divide

9. DNA & inheritance What characteristics might be inherited?
1 min--- make a list of characteristics you can observe about the girl
Are those characteristics inherited or learned?

10. DNA & Inheritance Living things inherit traits in patterns
Parents and offspring are similar
Genes are on chromosome pairs
A gene is a piece of information in a specific location on a chromosome & codes for a particular thing.
Various forms of the same gene are called alleles.

11. DNA & inheritance (cont)
Heredity
When traits are passed from parent to offspring
Genetics
The study of how traits are passed from parent to offspring
eandgenetics/genetics/

12. Dna & Inheritance
Gregor Mendel made some important discoveries about heredity
A monk
Experimented with Pea plants
Called the Father of Modern Genetics
Since the mid 1800’s Mendel’s experiments and conclusions have been the basis for the most of our ideas about heredity

13. Dna & Inheritance Alleles interact to produce traits
We discuss alleles in genotype and phenotype
Genotype
Can be dominant or recessive
The genes present (AA, Aa, aa)
Phenotype
How the trait looks (Tall, short)

15. Dominant and Recessive alleles
Combination of alleles determines the trait
Pea plants can have purple or white flowers
Pea Plant

16. Dominant and Recessive alleles
Purple allele is dominant
Dominant is an upper case letter
White allele is recessive
Recessive is a lower case letter p P

17. Dominant and Recessive alleles
If a baby plant gets a Purple allele from one parent and a Purple allele from the other parent what color will the flowers be? P P

18. Dominant and Recessive alleles
If a baby plant gets a Purple allele from one parent and a White allele from the other parent what color will the flowers be? p P

19. Dominant and Recessive alleles
If a baby plant gets a white allele from one parent and a white allele from the other parent what color will the flowers be? p p

20. VAriation
Different ways a trait appears
Can be small or large

21. Tool used to predict or identify hereditary results
Punnett Square
Tool used to predict or identify hereditary results

22. Alleles Each cell has 2 for each trait Can be the same– AA, aa
called homozygous
Can be different – Aa
called heterozygous

23. Genotype Vs. Phenotype Genotype – a description of the alleles.
* the actual genes ---- RR, Rr. rr
Phenotype – describes what the trait looks like
*the way it looks---- Red, Red, white

24. How to make a punnett Square
Decide which letters to use to represent the trait
Ie. Trait is flower color we will use the letter R
Trait is height we could use the letter T
Hair type we could use the letter W

25. How to make a punnett Square
2. Determine the parent is heterozygous or homozygous for that trait
Homozygous could be RR, or rr
Heterozygous would be Rr

26. How to make a punnett Square
3. Know if the traits are dominant or recessive
Capital letters represent dominant
Lower case letters represent recessive
The only time you see the recessive trait is when you have two lower case letters (rr)

27. How to make a punnett Square
4. Draw the box

28. How to make a punnett Square
Fill in the letters for each parent
R r R

29. How to make a punnett Square
6. Fill in the grid
R r R RR Rr

30. Let’s Practice Tall is dominant (T) Mom is heterozygous
Dad is heterozygous
Lets draw the punnett square for them.
TT Tt
Tt tt

31. Ratio’s the percentage of each thing occurring out of 100
Genotypes:
TT %
Tt %
tt %
Phenotypes
Tall %
Short %

33. Fertilization
When the male and female reproductive cells combine
Sea Biscuit’s life

34. Mutation A change in a gene or chromosome
What might cause this kind of change to happen?
Can be good
Can be neutral
Can be bad

35. Mutations Lab activity

36. Cell Division Meiosis is a special form of cell division
In sexual reproduction two cells join (egg and sperm)
In order to maintain the proper # of chromosomes in body cells, sex cells must contain ½ the chromosomes of body cells.
Meiosis allows for a 2nd cell division to cut the amount of genetic material in half.

37. Making proteins DNA does not directly make proteins
It needs the help of RNA (its like a code breaker)
RNA transcribes DNA
Then RNA translates into protein our body needs
Ribosomes move along the strand of RNA building the amino acids which build the proteins