DNA Vocabulary Draw a word from the bucket Complete a 4 Corners mini poster about your word! Remember to make your poster neat and colorful!! Vocabulary Word Picture Definition (in English!) Word used in a sentence

DNA Structure DNA – deoxyribonucleic acid Found in the nucleus of eukaryotic cells!

DNA Structure Made of nucleotides with 3 parts: Phosphate Sugar (deoxyribose) Nitrogenous Base Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

I’ll be impressed if you remember these… Nucleic acid was one of our 4… The name for a long molecule made of MANY building blocks?

I’ll be impressed if you remember these… Good job! MACRO MOLECULES! POLYMER!

DNA Structure You tell me… what pairs with what?

DNA Structure – Base Pairing Rules 1949: Erwin Chargaff concluded that nucleotides in DNA are in pairs (2s!) Adenine (A) ALWAYS paired with Thymine (T) Cytosine (C) ALWAYS paired with Guanine (G) They fit together like puzzle pieces!

Pyrimidines and Purines Pyrimidines: Cytosine Uracil (RNA) Thymine “ CUT the pyramid.” Purines: Adenine Guanine “ AGriculture”

DNA Structure - Shape 1952: Rosalind Franklin took an X-ray diffraction photograph of DNA

DNA Structure - Shape 1953: James Watson and Francis Crick used Franklin and Chargaff’s work to discover the shape of DNA

DNA Structure - Shape DNA is shaped like a double helix (twisted ladder)

DNA Structure - Shape The sides of the ladder is the sugar- phosphate backbone (held by bonds) The rungs (steps) of the ladder are the nitrogenous bases The nitrogenous bases are held together with hydrogen bonds (just like water!)

DNA Structure - Model Let’s label this together!

DNA is “Antiparallel” Each side of DNA faces in the OPPOSITE direction – they’re “upside down” from each other. 5’ end is the end with the Phosphate group. 3’ end is the end with the Deoxyribose sugar.

DNA vs. RNA DNARNA Deoxyribo Nucleic Acid Ribo Nucleic Acid Holds the genetic information Holds genetic info to make proteins Double strandedSingle stranded Nitrogen Bases: Adenine Thymine Cytosine Guanine Nitrogen Bases: Adenine Uracil Cytosine Guanine

DNA Function The function of DNA is to store genetic information + use it to make proteins. This information is stored in the sequence of nitrogenous bases (A, T, C, G)

Base Pairing Rules Practice We’ve learned about the Base-Pairing rules. This says that the nitrogenous bases in a nucleotide will always pair up the same way.

Base Pairing Rules Adenine (A) always pairs with Thymine (T). Cytosine (C) always pairs with Guanine (G). A-T G-C

Base-Pairing Rules This is very important for DNA Replication. Replication is when DNA makes a copy of itself. This must happen before the cell divides.

Base Pairing Rules Remember that the instructions to make you who you are can be found in the sequence or order of nitrogenous bases (A, T, C, G). The order of the letters is very important – if we change one letter, we might change who you are!

Base Pairing Rules Let’s say we have this sequence of nitrogenous bases. We need to use our base-pairing rules to find the complementary strand of DNA. This means we need to make the strand that would match this one! A – T – C – G – G – C – A – A – T – C – G – T

Base Pairing Rules We used the base-pairing rules to find the complementary strand of DNA. Let’s try another one…find the complementary strand of DNA. T – A – C – C – A – T – G – G – G – T – A – G

Base Pairing Rules Getting the hang of it? Let’s do one more. T – A – G – G – T – A – C – C – T – A – G - A

Base Pairing Rules It’s as easy as that! Always remember your base-pairing rules for DNA when making a complementary strand of DNA.