Catalyst 1. SpongeBob is known for his round eyes (R), which is dominant over an oval eye shape (r). If he is heterozygous for his round eye shape and marries a woman with oval eye shape, what type of eyes might the kids have? Use a Punnett square to show the possibilities that would result. 2. What are the chances of a child with a round eye shape? ____% 3. What are the chances of a child with an oval eye shape? ____%

Genes, DNA, and Proteins Genetics Week 4

I Can… I CAN describe the relationship between DNA and traits (the genetic code).

Can you crack the code? 1. Use the morse code in the chart to decode the message. The letters are separated by / 2. Write your answer in morse code.

What do genes do exactly? PROTEINS The main function of GENES is to control the production of PROTEINS in cells.

What are proteins? PROTEINS are molecules that help determine the size, shape, color, and other traits of an organism.

What are proteins? Proteins are made up of building blocks called AMINO ACIDS.

Protein Synthesis The production of proteins in cells is called PROTEIN SYNTHESIS. During protein synthesis, the cell uses information from a GENE on a CHROMOSOME to produce a specific PROTEIN.

What is a gene? A gene is a section of a DNA molecule that contains the information to “code” for one specific protein.

What is a gene? SO… a gene is made up of a series of DNA bases in a row. The bases in a gene are arranged in a specific order--for example ATGACTTA.

Why does the order matter? The order of nitrogen bases (A, T, G, C) in a gene forms a GENETIC CODE that tells the body’s cells what type of protein to produce.

What is the genetic code? In the genetic code, every 3 DNA bases in a row codes for one amino acid. For example, the base sequence CGT always codes for the amino acid: alanine.

What is the genetic code? The order of the three- base code units decides the order of the amino acids in the protein.

Think-Pair-Share: 2 min 1. What are proteins made of? 2. How are DNA bases and proteins related? 3. Why does the order of DNA bases matter?

Quick Quiz 1. Amino acids 2. Proteins 3. Genes 4. Chromosomes 5. Protein synthesis A. Sections of DNA that contain information to code for one specific protein. B. Molecules that help determine the traits of an organism. C. The production of proteins in cells. D. Very long, coiled up DNA molecules. E. The building blocks of proteins.

RNA is very similar to DNA except… –It only has 1 side of the ladder –It has ribose instead of deoxyribose –It has URACIL instead of THYMINE. What is RNA?

Quick Quiz: DNA to RNA 1. Is the sequence of nitrogen bases to the right part of a DNA molecule or a RNA molecule? Why? 2. Turn the following DNA sequence into an RNA sequence: GATTACA

Messenger RNA Messenger RNA: copies coded message from the DNA and carries the message to the cytoplasm. mRNA

Transfer RNA Transfer RNA: carries amino acids to the ribosome and adds them to the growing protein. tRNA mRNA tRNA

How are proteins made? With a table partner, write a prediction about what is happening in each picture (1-4).

How are proteins made? 1. mRNA is produced from DNA 2. mRNA attaches to a ribosome 3. tRNA attaches to messenger RNA 4. Protein production occurs as the amino acids on the tRNA bond. 1. Nucleus: Change DNA code to RNA code. 2. Cytoplasm:Pass mRNA to the ribosome. 3. Ribosome: Attach matching tRNA’s to the mRNA 4. Chemical Reaction: Tie the amino acids together to make a protein. REAL LIFEDEMO

How are proteins made? 1. mRNA is produced from DNA

How are proteins made? 2. mRNA attaches to a ribosome

How are proteins made? 3. tRNA attaches to messenger RNA

How are proteins made? 4. Protein production occurs as the amino acids on the tRNA bond.

Exit Slip What are proteins? What are proteins made up of? What are genes? What is the main job of a gene? How (be specific) do genes direct the production of proteins?

Catalyst 1. What are chromosomes composed of? 2. What are genes? 3. What forms the “rungs” of the DNA ladder? 4. Why is the sequence of bases important? 5. How are nitrogen base of DNA like the letters of the alphabet?

I CAN… I CAN describe why the order of base pairs is important.

Mutation A mutation is any change in a gene or chromosome.

Mutations Mutations can cause a cell to produce an incorrect protein. As a result, the organism’s trait, or phenotype, may be different from what it would have normally been.

Inheriting Mutations If a mutation occurs in a body cell, such as a skin cell, the mutation will not be passed on to its offspring. If a mutation occurs in a sex cell, the mutation can be passed on to an offspring and can affect the offspring’s phenotype too!

Types of Mutations Mutations can occur both at the DNA base level and at the chromosome level. Sometimes a cell will end up with too many or too little chromosomes because the chromosomes didn’t separate properly during meiosis.

Types of Mutations Other times, there can be a mistake in the order or number of bases in a gene. –SUBSTITUTION: One base pair can be substituted for another. –DELETION: One base pair is removed –ADDITION: One base pair is added.

Effects of Mutations A mutation is harmful to an organism if it reduces an organism’s chance for survival.

Effects of Mutations A mutation is helpful if it improves an organism’s chance for survival and reproduction in its environment.

Effects of Mutations Whether a mutation is helpful or not depends in part on the organism’s environment.

Genetic Disorder A genetic disorder is an abnormal condition that a person inherits through genes or chromosomes. Some are caused by changes in the DNA of genes. Others are caused by the number or structure of the chromosomes.

Common Genetic Disorders Cystic Fibrosis Sickle-Cell Disease Hemophilia Down Syndrome

Catalyst Can mutations in DNA sequences ever be helpful? Why or why not?

Quick Write 1. Look around the room at the posted pictures. How many different skin colors do you see? 2. What do you believe is happening at a genetic level to produce the variety of skin color we see in the human species? Use your new understanding of genes and alleles to make an educated guess.

Patterns of Human Inheritance The inheritance of traits is rarely as simple as in Mendel’s experiments. Human traits rarely come in just two simple forms like pea plant flowers.

3 Patterns of Human Inheritance 1. Trait controlled by single gene with 2 alleles. 2. Trait controlled by single gene with multiple alleles. 3. Trait controlled by many genes that act together.

Single Gene with 2 Alleles Traits that are controlled by a single gene with just two alleles only have two possible phenotypes or physical appearances. Examples: Widow’s Peak or No Widow’s Peak

Single Gene with Multiple Alleles Multiple alleles: three or more forms of a gene that code for a single trait. Example: A gene that comes in three forms: purple, white, and blue.

Single Gene with Multiple Alleles Even though a gene may have multiple alleles, a person can ONLY carry 2 of those alleles because chromosomes exist in PAIRS (not triples, quadruples etc.) Each chromosome in a pair only carries one allele for the trait. Example: Human Blood Type –A, B, AB, or O.

Traits Controlled By Many Genes Some human traits show a large variety of phenotypes because the traits are controlled by many genes. The genes act together as a group to produce a single trait. Example: Height in humans (at least four genes), also skin, eye color, hair color.

Traits Controlled By Many Genes Gummy Bear Breeding Part 2