DNA Structure and Technology
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Transcript of DNA Structure and Technology
DNA Structure and Technology
By: Amber Tharpe
DNA Structure Monomers are nucleotides 3 parts of a nucleotide
Phosphate group Deoxyribose sugar Nitrogen base
4 different bases Cytosine (C) - thymine (T) Adenine (A) - Guanine (G)
DNA Structure
Double helix- shape of 2 chains of DNA in a twisted spiral
2 chains held together by H-bonds between the bases
DNA Nucleic acid that serves as
the “blueprints of life”Housed in the nucleusDetermines what traits are
inherited from one generation to the next
Leads to the variation in all living things
Base Pairing Rules
A always bonds with T
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 TGAC, what is the other strand?
If one strand of DNA is CTGCTA, what is the other strand?
ReplicationDNA has the ability copy
itselfAn enzyme “unzips” the 2
strandsA single DNA strand serves a
template or pattern for making a new strand
Free bases bind based on the base pairing rules
2 identical strands are formed
Replication Terms Template strand
DNA strand that is being copied Complimentary strand
New DNA strand that is formed by pairing nucleotides to the template strand
DNA polymerases Enzymes that bond nucleotides
together to form complimentary strands
Central DogmaDNA→ RNA→ ProteinDNA- RNA is transcription
RNA- Protein is translationIn eukaryotes, replication and transcription occurs in the nucleus, while translation occurs in the cytoplasm
RNASingle-stranded nucleotides with U’s bonding to A’sDNA RNA
sugar deoxyribose
ribose
bases T bonds with A
U bonds with A
strands
Double-stranded
Single-stranded
TranscriptionProcess of using a strand of template DNA to make a complimentary strand of RNA
RNA polymerasesEnzymes that bond nucleotides together to make a new RNA molecule
Transcription PracticeTranscribe a strand of DNA
that is ACACAC. If a strand of DNA is TGAC,
what strand of RNA will it make?
Convert a strand of DNA that is CTGCTA to RNA.
3 Types of RNA Messenger RNA (mRNA)
Code translated to form a protein Ribosomal RNA (rRNA)
Forms part of ribosomes to make protiens
Transfer RNA (tRNA) Brings amino acids from the
cytoplasm to make proteins Has an anticodon on one end
Transcription
Does not transcribe the whole DNA molecule
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 code for nucleic acids is 4
nucleotides: A,G,C, and T or U
The code for proteins 20 different amino acids
Nucleotides are like letters, while amino acids are like words
Codons 3 nucleotide sequence that codes for
a particular 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
Anticodon Set of 3 nucleotides found on tRNA that
is complimentary to an mRNA codon
Translation Occurs in the cytoplasm1. 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?
Translate a strand of RNA is UGACUC.
If a strand of DNA is CUGCUA, what amino acids does this make?
MutationChange in an organism’s
DNACan occur in DNA replication
or in meiosisSubstitution (point mutation)
One nucleotide is substituted for an incorrect one
May alter an amino acid in a protein
Ex: sickle cell anemia
Frameshift Mutation Frameshift mutation
Insertion or deletion of a nucleotide in DNA
Makes an abnormal protein Reading frame is shifted because
DNA is read in a triplet code THE CAT ATE THE RAT Remove the first E What does the sentence say?
Nondisjunction
When chromosomes fail to separate properly in meiosis
Ex. Down Syndrome- 3 copies of chromosome 21
Mutagens
Agents in the environment that can change DNA
Ex: UV light, radiation, chemicals in tobacco products
Often lead to cancer
BiotechnologyThe use of organisms or their
products to improve human health or food production
Types DNA FingerprintingGenetic EngineeringGenetic Screening
DNA FingerprintingGel electrophoresis
Used for comparing DNA samples
DNA is cut and run through the gel based on electric charge
Smaller fragments move farther than large fragments
The different size fragments make bands on the gel that can be compared
DNA FingerprintingUses
Paternity testingForensics
Identifying dead bodiesSolving crimes
Compare DNA left at crime scene to suspects’ DNA
Genetic Engineering Genes are transferred from 1
organism to another Recombinant DNA
When DNA from 2 different sources are combined
Used in medicine (gene therapy) and agriculture Modify plants to grow larger,
faster, and more disease resistant Use the gene for making insulin to
treat diabetes
CloningA 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
The 2 cells are fused and the embryo is placed in the uterus of a female to develop and be born