Section 3.1- 3.2- 3.3 Notes Visuals and Notes

3.1 Focusing Questions What is the difference between DNA, Genes, and Chromosomes? How many chromosomes do humans have in their body cells?

DNA: Deoxyribonucleic acid All together, it is the genetic material found in the nucleus of every cell in your body. It is the “blueprint” for who you are as the coded sequence of chemicals, inherited from your parents, stores the information about the specific traits that you have.

4 chemicals that make up DNA

A look at the pairs of chromosomes in body cells…

Genes segment (piece) of DNA on a chromosome that codes (has a specific combination of chemicals) for a specific trait (characteristic)

Relationship between DNA, Genes, and Chromosomes In the nucleus of body cells, humans have 23 pairs of chromosomes (46 in total)

3.2 Focusing Questions (3) What's so special about gametes? What is the process called that forms them? (4) What is each stage in sexual reproduction called and how many chromosomes does each stage have?

“Cell division” is a silly name “Cell division” is a silly name. We are making more…shouldn’t it be called “cell addition”?? To make more body cells, all human cells go through mitosis To make more gametes, human cells go through meiosis

Mi-“toe”-sis Original Body Cell – In humans, 46 chromosomes What other process does this remind you of? Mi-“toe”-sis DNA then splits DNA doubles itself Original Body Cell – In humans, 46 chromosomes or 23 pairs New Cell: with 46 chromosomes or 23 pairs

Mei-“ovary”-sis Careful: this process creates gametes !! Start with 46 chromosomes at the beginning of meiosis, or 23 pairs Finish with 23 individual chromosomes at the end of meiosis

So how do I answer that weird chart question in the booklet….. This number would be the same as a body cell because mitosis is the process that creates new body cells Meiosis is the process that splits the number of chromosomes in half, so a gamete would have half the number of a body cell Zygote is just the first body cell

What is each stage in sexual reproduction called?

3.3 Focusing Questions (5) How did my 2 black cats just produce a white cat?

Important Definitions Parents: two organisms passing along their traits to offspring Offspring: an organism created from the genetic combination of two organisms through reproduction Traits: Characteristics passed down from parents to an offspring (Ex: eye color, ear lobes)

Punnett Squares: Chart used to predict the outcome of two parents reproducing Allele: Spot on a chromosome where a gene is located. We use a letter used to describe genetic information for a trait. Typically two alleles per trait. (Example; “A” for not albino, “a” for albino)

Purebred / Homozygous: is a term used to describe two of the same allele (Example; AA or aa). Hybrid / Heterozygous: is a term to describe two different alleles for the same trait. (Example; Aa).

Dominant: Allele that masks or hides the recessive allele when the combination is heterozygous. (Example; the ‘A’ in Aa). Recessive: Allele that is hidden or masked by a dominant allele, unless both alleles are recessive. (Example; the ‘a’ in Aa).

Incomplete Dominance: when neither allele is dominant and instead of one being expressed, they both combine and create a mixture of the two. Example: When you mate a homozygous red rose with a homozygous white rose, you end up with a heterozygous pink rose.