DNA Structure and Technology By: Amber Tharpe

DNA Structure Monomers are nucleotides Monomers are nucleotides 3 parts of a nucleotide 3 parts of a nucleotide Phosphate group Phosphate group Deoxyribose sugar Deoxyribose sugar Nitrogen base Nitrogen base 4 different bases 4 different bases Cytosine (C)- thymine (T) Cytosine (C)- thymine (T) Adenine (A)- Guanine (G) Adenine (A)- Guanine (G)

DNA Structure Double helix- shape of 2 chains of DNA in a twisted spiral Double helix- shape of 2 chains of DNA in a twisted spiral 2 chains held together by H- bonds between the bases 2 chains held together by H- bonds between the bases

DNA Nucleic acid that serves as the “blueprints of life” Nucleic acid that serves as the “blueprints of life” Housed in the nucleus Housed in the nucleus Determines what traits are inherited from one generation to the next Determines what traits are inherited from one generation to the next Leads to the variation in all living things Leads to the variation in all living things

Base Pairing Rules A always bonds with T A always bonds with T C always bonds with G C always bonds with G

Base Pairing Practice If one strand of DNA is ACACAC, what is the other strand? If one strand of DNA is ACACAC, what is the other strand? If one strand of DNA is TGAC, what is the other strand? If one strand of DNA is TGAC, what is the other strand? If one strand of DNA is CTGCTA, what is the other strand? If one strand of DNA is CTGCTA, what is the other strand?

Replication DNA has the ability copy itself DNA has the ability copy itself An enzyme “unzips” the 2 strands An enzyme “unzips” the 2 strands A single DNA strand serves a template or pattern for making a new strand A single DNA strand serves a template or pattern for making a new strand Free bases bind based on the base pairing rules Free bases bind based on the base pairing rules 2 identical strands are formed 2 identical strands are formed

Replication Terms Template strand Template strand DNA strand that is being copied DNA strand that is being copied Complimentary strand Complimentary strand New DNA strand that is formed by pairing nucleotides to the template strand New DNA strand that is formed by pairing nucleotides to the template strand DNA polymerases DNA polymerases Enzymes that bond nucleotides together to form complimentary strands Enzymes that bond nucleotides together to form complimentary strands

Central Dogma DNA→ RNA→ Protein DNA→ RNA→ Protein DNA- RNA is transcription DNA- RNA is transcription RNA- Protein is translation RNA- Protein is translation In eukaryotes, replication and transcription occurs in the nucleus, while translation occurs in the cytoplasm In eukaryotes, replication and transcription occurs in the nucleus, while translation occurs in the cytoplasm

RNA Single-stranded nucleotides with U’s bonding to A’s Single-stranded nucleotides with U’s bonding to A’s DNARNA sugardeoxyriboseribose bases T bonds with A U bonds with A strands Double- stranded Single- stranded

Transcription Process of using a strand of template DNA to make a complimentary strand of RNA Process of using a strand of template DNA to make a complimentary strand of RNA RNA polymerases RNA polymerases Enzymes that bond nucleotides together to make a new RNA molecule Enzymes that bond nucleotides together to make a new RNA molecule

Transcription Practice Transcribe a strand of DNA that is ACACAC. Transcribe a strand of DNA that is ACACAC. If a strand of DNA is TGAC, what strand of RNA will it make? If a strand of DNA is TGAC, what strand of RNA will it make? Convert a strand of DNA that is CTGCTA to RNA. Convert a strand of DNA that is CTGCTA to RNA.

3 Types of RNA Messenger RNA (mRNA) Messenger RNA (mRNA) Code translated to form a protein Code translated to form a protein Ribosomal RNA (rRNA) Ribosomal RNA (rRNA) Forms part of ribosomes to make protiens Forms part of ribosomes to make protiens Transfer RNA (tRNA) Transfer RNA (tRNA) Brings amino acids from the cytoplasm to make proteins Brings amino acids from the cytoplasm to make proteins Has an anticodon on one end Has an anticodon on one end

Transcription Does not transcribe the whole DNA molecule Does not transcribe the whole DNA molecule Only transcribes the portions of DNA (gene) needed for cell function at that specific time Only transcribes the portions of DNA (gene) needed for cell function at that specific time

Translation The process that converts mRNA into a polypeptide (or protein) The process that converts mRNA into a polypeptide (or protein) The code for nucleic acids is 4 nucleotides: The code for nucleic acids is 4 nucleotides: A,G,C, and T or U A,G,C, and T or U The code for proteins 20 different amino acids The code for proteins 20 different amino acids Nucleotides are like letters, while amino acids are like words Nucleotides are like letters, while amino acids are like words

Codons 3 nucleotide sequence that codes for a particular amino acid 3 nucleotide sequence that codes for a particular amino acid Considered a triplet code, since 3 nucleotides are used to make each amino acid Considered a triplet code, since 3 nucleotides are used to make each amino acid Many amino acids are coded for by more than 1 codon Many amino acids are coded for by more than 1 codon Anticodon Anticodon Set of 3 nucleotides found on tRNA that is complimentary to an mRNA codon Set of 3 nucleotides found on tRNA that is complimentary to an mRNA codon

Translation Occurs in the cytoplasm Occurs in the cytoplasm 1. mRNA is pulled through the ribosome exposing one codon at a time to pair with the complimentary tRNA 2. The ribosome forms a peptide bond between the amino acids brought in by the tRNA 3. This process continues as the polypeptide grows and eventually a stop codon is reached

Translation Practice p. 244 If a strand of RNA is ACACAC, what amino acids does this make? If a strand of RNA is ACACAC, what amino acids does this make? Translate a strand of RNA is UGACUC. Translate a strand of RNA is UGACUC. If a strand of DNA is CUGCUA, what amino acids does this make? If a strand of DNA is CUGCUA, what amino acids does this make?

Mutation Change in an organism’s DNA Change in an organism’s DNA Can occur in DNA replication or in meiosis Can occur in DNA replication or in meiosis Substitution (point mutation) Substitution (point mutation) One nucleotide is substituted for an incorrect one One nucleotide is substituted for an incorrect one May alter an amino acid in a protein May alter an amino acid in a protein Ex: sickle cell anemia Ex: sickle cell anemia

Frameshift Mutation Frameshift mutation Frameshift mutation Insertion or deletion of a nucleotide in DNA Insertion or deletion of a nucleotide in DNA Makes an abnormal protein Makes an abnormal protein Reading frame is shifted because DNA is read in a triplet code Reading frame is shifted because DNA is read in a triplet code THE CAT ATE THE RAT THE CAT ATE THE RAT Remove the first E Remove the first E What does the sentence say? What does the sentence say?

Nondisjunction When chromosomes fail to separate properly in meiosis When chromosomes fail to separate properly in meiosis Ex. Down Syndrome- 3 copies of chromosome 21 Ex. Down Syndrome- 3 copies of chromosome 21

Mutagens Agents in the environment that can change DNA Agents in the environment that can change DNA Ex: UV light, radiation, chemicals in tobacco products Ex: UV light, radiation, chemicals in tobacco products Often lead to cancer Often lead to cancer

Biotechnology The use of organisms or their products to improve human health or food production The use of organisms or their products to improve human health or food production Types Types DNA Fingerprinting DNA Fingerprinting Genetic Engineering Genetic Engineering Genetic Screening Genetic Screening

DNA Fingerprinting Gel electrophoresis Gel electrophoresis Used for comparing DNA samples Used for comparing DNA samples DNA is cut and run through the gel based on electric charge DNA is cut and run through the gel based on electric charge Smaller fragments move farther than large fragments Smaller fragments move farther than large fragments The different size fragments make bands on the gel that can be compared The different size fragments make bands on the gel that can be compared

DNA Fingerprinting Uses Uses Paternity testing Paternity testing Forensics Forensics Identifying dead bodies Identifying dead bodies Solving crimes Solving crimes Compare DNA left at crime scene to suspects’ DNA Compare DNA left at crime scene to suspects’ DNA

Genetic Engineering Genes are transferred from 1 organism to another Genes are transferred from 1 organism to another Recombinant DNA Recombinant DNA When DNA from 2 different sources are combined When DNA from 2 different sources are combined Used in medicine (gene therapy) and agriculture Used in medicine (gene therapy) and agriculture Modify plants to grow larger, faster, and more disease resistant Modify plants to grow larger, faster, and more disease resistant Use the gene for making insulin to treat diabetes Use the gene for making insulin to treat diabetes

Cloning A normal cell is taken from the organism that is being cloned A normal cell is taken from the organism that is being cloned An egg cell from an organism of the same species is taken and the nucleus removed An egg cell from an organism of the same species is taken and the nucleus removed The 2 cells are fused and the embryo is placed in the uterus of a female to develop and be born The 2 cells are fused and the embryo is placed in the uterus of a female to develop and be born