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Cell Division. Mitosis & Meiosis . 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 . Liver Cell. Liver Cell. 46

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Cell division

Cell Division





  • The form of cell divisionby 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.

Mitosis each human body cell has 46 chromosomes

Liver Cell

Liver Cell











Liver Cell

Mitosiseachhuman body cell has 46 chromosomes

(Parent cell)

What is a chromosome


What Is A Chromosome?

DNA double helix

  • A chromosome is a very long, continuous piece of DNA.

  • Chromosomes contain many genes.

  • Genesare the units of heredity in organisms.


  • 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.

Genes heredity

Genes & Heredity

Why Do I Look Like My Parents???


Why Don’t You Look Like a rhinoceros?


Because _______.

Heredity is the passing of traits from parents to offspring.

Traits and characteristics pass from parents to offspring through genes.

Genetics terms
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.

Homozygous vs heterozygous
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.

Homologous chromosomes what the
Homologous Chromosomes? What the …

Each set of chromosome is a homologous pair

Homologouschromosomes – 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.

Genotype phenotype
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.

Dominant recessive traits
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.

Genotype phenotype1
Genotype & Phenotype

Both mother and father are heterozygous for tongue rolling.

Genotype: heterozygous alleles (one dominant & one recessive)


Ability to roll tongue

Cell division

Attached earlobe vs. free

(or detached) earlobe

Attached is a recessive trait

Cell division

Dark Hair

Curly Hair

Mid-finger Hair

Tongue Rolling

Widow’s Peak

Black Eyes

Some Dominant Traits

Punnett square
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)

Punnett square1
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? ______

Practice with punnett square
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?

Questions page 19l
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.

Cell division

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.