Aim How is DNA coded for traits?

What is Genetics? The branch of biology that studies genes, heredity and variation of organisms

Heredity For offspring to resemble their parents, there must be a reliable way to transfer information from one generation to the next. Heredity is that passage of these instructions from one generation to another

Traits Physical Attributes or characteristic Example: hair color, eye color, height

What is DNA? Every organism requires a set of coded instructions for specifying its traits. DNA Contains coded instructions for inherited traits Contains code for making proteins

Genes A set of DNA strands that are responsible for traits. One or more genes determine a trait Genes

Chromosomes There are 46 chromosomes in the nucleus. Chromosomes are x shaped and contain thousands of genes.

Largest to smallest Cell Nucleus Chromosome Gene

Where do organism receive their heredity in sexual reproduction? You will receive half the code from your mother and half the code from your father. Leads to variety 23 23

Double stranded-looks like a latter (Sides & Rungs) Phosphoric Acid Sugar Rungs(steps) A-T G-C Base Pairs Connect two sides

The molecular bases 5 The most common molecular bases are Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

The bases always pair up in the same way Bonding 1 10 The bases always pair up in the same way Adenine forms a bond with Thymine A-T Adenine Thymine and Cytosine bonds with Guanine C-G Cytosine Guanine

Base sequence is important Base sequence determines kind of gene an organism possesses If the base sequence changes, trait also changes The gene expression changes Hair color gene -Brown

1. If Strand I in the diagram represents a segment of a replicating DNA molecule with bases A-T-C-C-G-A, the complementary DNA strand would contain the bases T-A-G-G-C-T T-U-G-G-C-T U-A-G-G-C-U A-T-G-G-C-T

2. The type of molecule represented above is found in organisms. Which statement correctly describes the sequence of bases found in this type of molecule? It changes every time it replicates. It determines the characteristics that will be inherited. It is exactly the same in all organisms. It directly controls the synthesis of starch within a cell

3. Which statements best describe the relationship between the terms chromosomes, genes, and nuclei? 1.Chromosomes are found on genes. Genes are found in nuclei. 2.Chromosomes are found in nuclei. Nuclei are found in genes. 3.Genes are found on chromosomes. Chromosomes are found in nuclei. 4.Genes are found in nuclei. Nuclei are found in chromosomes

4. The diagram below represents the banding pattern for human chromosome 11, with some of the bands labeled. The bands represent proteins genes starches enzymes

5. What determines the kind of genes an organism possesses? 1.type of amino acids in the cells of the organism 2.sequence of the subunits A, T, C, and G in the DNA of the organism 3.size of simple sugar molecules in the organs of the organism 4.shape of the protein molecules in the organelles of the organism

What is replication? DNA must copy before cells divide. This is called replication Nucleus can then divide. This is called mitosis

Steps for DNA replication: DNA untwists and separate DNA copies (replication)using each strand as a template 2 strands twist into helix

Step 1- DNA separates Separation occurs at base pairs Separation occurs at the molecular base pairs. It is indicated by the arrow in the picture to the left

Two templates are created These templates will now determine the order of the new base pairs created 2 templates

Step 2- Two new DNA molecules are created Replication produces two identical strands of DNA

When does DNA need to copy? For cell division to occur Mitosis Meiosis