1. Cell Division
Mitosis
&
Meiosis

2. Mitosis
The form of cell division by which a eukaryotic somatic cell (body cell) duplicates.
Mitosis is asexual reproduction.
Cell division is the continuation of life based on the reproduction of cells.

3. Mitosis each human body cell has 46 chromosomes
two
identical
daughter
cells
Liver Cell 46
chromosomes
Liver Cell
(Parent cell)

4. A chromosome is a very long, continuous piece of DNA.
What Is A Chromosome?
A chromosome is a very long, continuous piece of DNA.
Chromosomes contain many genes.
Genes are the units of heredity in organisms.
DNA double helix
chromosome

5. Meiosis
Meiosis is the process of cell division that only occurs in gametes or sex cells(egg & sperm).
During meiosis, a cell produces 4 gametes with half the number of chromosomes in each gamete.
The traits are distributed randomly in the newly formed gametes.

6. Number of Chromosomes in some Species of Animals#
Fruit fly 8
Guinea Pig 16
Dove
Snail 24
Earthworm 36
Tibetan fox
Cat 38
Pig
Mouse 40
Rat 42
Rabbit 44
Syrian hamster
Hare 46
Human
Gorilla 48
Sheep 54
Elephant 56
Cow 60
Donkey 62
Horse 64
Dog 78
Chicken
Carp
104
Butterflies
380

7. 23 pairs (46) of chromosomes in human
Female
Male

8. Why Do I Look Like My Parents???
Genes & Heredity
Why Do I Look Like My Parents???

9. Question:
Why Don’t You Look Like a rhinoceros?

10. Answer: Because _______.
Heredity is the passing of traits from parents to offspring.
Traits and characteristics pass from parents to offspring through genes.

11. Genetics Terms
Alleles: the different forms of a gene.
Dominant allele: an allele whose trait always shows up when it is present.
Recessive allele: an allele that is masked when a dominant allele is present.

12. Homozygous vs. Heterozygous
If both the alleles inherited by the zygote(fertilized egg) for a particular characteristic are the same they are called homozygous.
If they are different from each other they are called heterozygous.

13. Homologous Chromosomes? What the …
Each set of chromosome is a homologous pair
Homologous chromosomes – chromosomes which contain the same genes, one from each parent
Homologous chromosomes look alike with similar information stored on them
One member of each homologous pair is inherited from each parent through egg or sperm.

14. Homologous Chromosomes
=(Location)

16. Dominant Allele vs. Recessive Allele

17. Genotype & Phenotype
A set of alleles inherited by an individual is called a genotype.
The way the genes express themselves in the individual's appearance is their phenotype.

18. Dominant & Recessive Traits
Some traits show more often than other traits.
The traits that show often are called dominant traits.
Those traits that don’t show often are recessive traits.

19. Both mother and father are heterozygous for tongue rolling.
Genotype & Phenotype
Both mother and father are heterozygous for tongue rolling.
Genotype: heterozygous alleles (one dominant & one recessive)
Phenotype:
Ability to roll tongue

20. Albino snake, a recessive trait of not having colors

21. Attached earlobe vs. free Attached is a recessive trait
(or detached) earlobe
Attached is a recessive trait

22. Some Dominant Traits Curly Hair Dark Hair Mid-finger Hair Widow’s Peak
Tongue Rolling
Widow’s Peak
Black Eyes
Some Dominant Traits

23. Punnett square
Punnett Squares are diagrams used to help us to figure out how inherited traits (characteristics) will be distributed
Dominant trait is written by capital letter (A)
Recessive trait is written by lower case letter (a)

24. Punnett square
Both parents birds are homozygous, with the red bird having 2 dominant alleles, and the blue bird having 2 recessive alleles.
There is only one possible genotype for all the offspring, and that is heterozygous.
What is the phenotype of the offspring? ______

25. Practice with Punnett Square
In rabbits, black fur is dominant to white fur. A male rabbit with BB genotype and a female with a Bb genotype are crossed.
What is their phenotype?
What are the possible genotypes and phenotypes of the offspring? (Show using a Punnett square)
What is the percent chance for each type?

26. Questions- page 19L Copy & answer What is heredity? What is genetics?
Who was Gregor Mendel?
What type of organism did he work on?
What does true-breed mean?
What does self-pollinate mean?
What is offspring?
In genetics, what is P, F1, F2?
What does cross-pollination mean?
Define dominant & recessive.

27. Inside the nucleus of a cell long strings of DNA are coiled up and spooled onto chromosomes, and on each chromosome there are several thousand genes - shorter sections of DNA which act as a code for a particular characteristic. Since we inherit particular chromosomes through the egg and sperm, we also inherit the particular characteristics coded for by the genes on those chromosomes.