What molecule is pictured? What are genes? Why should I care?

DNA Genes are sections of DNA that code for heritable traits and proteins. B/C some traits are beneficial, but some are harmful (deadly).

1860s—Mendel is considered the father of genetics DNA Revolution 1860s—Mendel is considered the father of genetics was the first to scientifically prove parents pass some of their DNA/genes/traits to their offspring.

What does DNA do? Carries the code (instructions) for all genes/traits/proteins in every cell in every living organism.

What does DNA (nucleic acid) do? An organism’s DNA/genes determine which proteins an organism (bacteria, plant, animal, fungi, protist) can produce.

Proteins, like enzymes, perform much of the work in a cell. What does DNA do? Proteins, like enzymes, perform much of the work in a cell.

How is DNA put together? DNA is made up of nucleotides Each nucleotide is made up of a 1. sugar 2. phosphate group 3. nitrogen base

How is DNA put together? DNA is a Ladder: 1. Sugar (deoxyribose) and phosphate groups are the sides of the ladder 2. Nitrogen bases make up the rungs

Sugar-phosphate backbone Nucleotide Hydrogen bonds Sugar-phosphate backbone Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

Eukaryote Chromosomes DNA double helix Chromosome Supercoils Coils Nucleosome Histones Our cells have about 6 billion base pairs—enough to fill about 900 thick textbooks! Errors in copying? Only about one per every billion nucleotides.

DNA Nitrogen bases Adenine (A) Thymine (T) Guanine (G) Cytosine (C) A bonds (pairs) with T / G bonds (pairs) with C

DNA Replication DNA opens or “unzips” at the hydrogen bonds with the help of the enzyme (proteins), helicase, and copies in both directions. 2. Other enzymes (proteins) add free nucleotides (About 50 per second in humans!)

DNA Replication 3. Base pairs are bonded until entire chain is copied. IMPORTANT: Since the DNA is being copied in both directions, 2 copies of DNA are made.

DNA replicates before Mitosis and Meiosis Growth DNA polymerase Growth Replication fork Replication fork

What would the complementary DNA strand for ATCGGTACATTC be? TAGCCATGTAAG What would the complementary DNA strand for CGTAATGGCTAT be? GCATTACCGATA What would the complementary DNA strand for ATCGTTAGGCTC be? TAGCAATCCGAG

Importance of DNA sequence Used to determine evolutionary relationships Paternity relationships Crime scene matches Disease identification and therapy

Structure of RNA (a nucleic acid) RNA is a molecule also made up of nucleotides: 1. sugar 2. phosphate 3. nitrogen base

Differences between DNA &RNA 1.The nitrogen base Uracil replaces Thymine. 2. Ribose is the sugar. 3. RNA is single stranded.

The function (job) of RNAs is Protein Synthesis 2 Steps: Transcription – takes place in the nucleus of the cell Translation- takes place in the cytoplasm of the cell

Protein Synthesis Step 1. Transcription Transcription takes place in the nucleus - mRNA gets the code from DNA for a specific protein.

Step 1. Transcription mRNA – Messenger RNA - gets code from DNA.

cytoplasm and meets up with rRNA at the ribosome. Protein Synthesis 2. Translation Then, mRNA carries this code into the cytoplasm and meets up with rRNA at the ribosome.

Step 2. Translation rRNA – Ribosomal RNA – translates the coded instruction for the specific protein.

Protein Synthesis 2. Translation Once mRNA and rRNA join up in the cytoplasm, they take the code and translate it into instructions for making proteins for the cell.

Translation Continued… mRNA uses codons – a set of 3 nitrogen bases- to represent different amino acids…

What do RNA’s do? 3. tRNA – Transfer RNA – transport and attaches the amino acids to make the specific protein.

Step 2. Translation Next, tRNAs bring the specific amino acids to mRNA/rRNA and add the A.A.s together to make the particular protein.

What would the complementary mRNA strand for ATCGGTACATTC be? UAGCCAUGUAAG What would the complementary mRNA strand for CGTAATGGCTAT be? GCAUUACCGAUA What would the complementary mRNA strand for ATCGTTAGGCTC be? UAGCAAUCCGAG

http://www.abpischools.org.uk/page/modules/hormones/horm6.cfm http://www.lpscience.fatcow.com/jwanamaker/animations/Protein%20Synthesis%20-%20long.html http://www.littletree.com.au/dna.htm