Introduction to Genetics and Reproduction

Genetics is the study of heredity and the different types of inherited traits. There are different types of genes in different organisms. Those types of genes are called Alleles. The alleles determine the traits of an organism. When the number of genes on a chromosome is determined, it makes the trait polygenic. In meiosis, organisms reproduce sexually. In meiosis gametes are produced which are cells used in sexual reproduction.

Essential Questions

What is the outcome of meiosis?
How are DNA, genes, alleles, and chromosomes related in regards to inheritance?
Explain the functional relationships between DNA, genes, alleles, and chromosomes and their roles in inheritance

Key Terms

Allele-

A version/type of a gene

DNA-

Carries the genetic instructions for growth

Gametes-

A mature male or female germ cell that goes together with another reproductive cell to form a zygote (ex- Sperm or Egg)

Meiosis-

a type of cell division that results in four cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores.

Zygote-

A fertilized ovum or egg from a female. It is the earliest developmental stage.

Chromosomes-

threadlike, gene-carrying particles in a nucleus

Polygenic-

genes that are too small to observe, but when put together, can be observed

Genotype-

A combination of alleles

Phenotype-

The appearance of a gene

Dominant allele-

Is a trait that is noticeable if there is one copy of this trait

Recessive allele-

A trait that is noticeable if there are 2 copies of this trait.

Objectives- What do you gain

-Understanding the basic types of genes

-Understanding DNA and chromosomes

-Understanding meiosis

Key Facts

Meiosis and Genes

Humans can only reproduce with other humans because of our chromosome number.
Genes have different versions or types called alleles
When mammals reproduce, they’re sex is determined by x and y chromosomes.
There are different types of Genes called Alleles
Punnett Squares - Help determine the probability of a child having a certain trait or mutation.
Pedigree charts- Used to go back and look to where a certain trait comes out

Representation of DNA and Meiosis

Punnett Square and pedigree chart

Review Questions

A zygote is the earliest developmental stage

True B.False

2. A human can make babies with a dog

True B.False

3. How many chromosomes does a human zygote have?

15 C.23
30 D.46

4.What is the purpose of Punnett Squares?

______________________________________________________________________________________________________

5. What are some examples of gametes

_____________________________________________________________________________________________________

Answer Key

A zygote is the earliest developmental stage

True

The first stage of 2 gametes becoming one is called a zygote

2. A human can make babies with a dog

B.False

Meiosis can only occur with the same species

3. How many chromosomes does a human zygote have?

D.46

The male gamete has 26 chromosomes and the female gamete has 26 chromosomes. When they come together, that makes 46 chromosomes

4. What is the purpose of Punnett Squares?

________Determining dominant or recessive traits in a child ______________________________________________________________________________________________

5. What are some examples of gametes

___________Egg and Sperm __________________________________________________________________________________________