Podcast
Questions and Answers
What are the components of a nucleotide?
What are the components of a nucleotide?
How is DNA structurally characterized in comparison to RNA?
How is DNA structurally characterized in comparison to RNA?
What is the correct way to name a purine nucleotide?
What is the correct way to name a purine nucleotide?
What forms the backbone of the DNA structure?
What forms the backbone of the DNA structure?
Signup and view all the answers
Which base pairing is correct in the DNA structure as described?
Which base pairing is correct in the DNA structure as described?
Signup and view all the answers
What is the role of hydrogen bonding in the structure of DNA?
What is the role of hydrogen bonding in the structure of DNA?
Signup and view all the answers
How many hydrogen bonds are formed between a guanine (G) and a cytosine (C) base pair?
How many hydrogen bonds are formed between a guanine (G) and a cytosine (C) base pair?
Signup and view all the answers
Which component of the DNA structure is located on the outside of the helix?
Which component of the DNA structure is located on the outside of the helix?
Signup and view all the answers
What distinguishes the major groove from the minor groove in the DNA double helix?
What distinguishes the major groove from the minor groove in the DNA double helix?
Signup and view all the answers
In writing a DNA sequence, what does the notation '5' end indicate?
In writing a DNA sequence, what does the notation '5' end indicate?
Signup and view all the answers
Which sequence represents the complementary base sequence for the DNA section A-G-T-C-C-A-A-T-G-C?
Which sequence represents the complementary base sequence for the DNA section A-G-T-C-C-A-A-T-G-C?
Signup and view all the answers
What types of organisms typically have a single circular chromosome?
What types of organisms typically have a single circular chromosome?
Signup and view all the answers
What feature characterizes the nucleoid in prokaryotes?
What feature characterizes the nucleoid in prokaryotes?
Signup and view all the answers
What is the primary function of tropoisomerases in DNA replication?
What is the primary function of tropoisomerases in DNA replication?
Signup and view all the answers
How do helicases contribute to DNA replication?
How do helicases contribute to DNA replication?
Signup and view all the answers
What role do primers play in DNA synthesis?
What role do primers play in DNA synthesis?
Signup and view all the answers
What characteristic of DNA polymerases allows for efficient DNA synthesis?
What characteristic of DNA polymerases allows for efficient DNA synthesis?
Signup and view all the answers
What are Okazaki fragments and where are they formed?
What are Okazaki fragments and where are they formed?
Signup and view all the answers
How are mutations classified?
How are mutations classified?
Signup and view all the answers
What is the consequence of failing to repair UV-induced pyrimidine dimers?
What is the consequence of failing to repair UV-induced pyrimidine dimers?
Signup and view all the answers
What feature distinguishes primases from other DNA enzymes?
What feature distinguishes primases from other DNA enzymes?
Signup and view all the answers
What is the primary role of transfer RNA (tRNA) in protein synthesis?
What is the primary role of transfer RNA (tRNA) in protein synthesis?
Signup and view all the answers
Which DNA repair mechanism is characterized by the removal of damaged bases and replacement with correct nucleotides?
Which DNA repair mechanism is characterized by the removal of damaged bases and replacement with correct nucleotides?
Signup and view all the answers
During transcription, what happens to the double helix of DNA?
During transcription, what happens to the double helix of DNA?
Signup and view all the answers
Which class of RNA is primarily responsible for forming ribosomes?
Which class of RNA is primarily responsible for forming ribosomes?
Signup and view all the answers
What happens at the AP site during base excision repair?
What happens at the AP site during base excision repair?
Signup and view all the answers
What structural feature is characteristic of tRNA?
What structural feature is characteristic of tRNA?
Signup and view all the answers
Which of the following describes a primary function of messenger RNA (mRNA)?
Which of the following describes a primary function of messenger RNA (mRNA)?
Signup and view all the answers
What is a key characteristic of nucleotide excision repair (NER)?
What is a key characteristic of nucleotide excision repair (NER)?
Signup and view all the answers
Which enzyme is responsible for mRNA formation during transcription?
Which enzyme is responsible for mRNA formation during transcription?
Signup and view all the answers
What is the function of the promoter in a eukaryotic gene?
What is the function of the promoter in a eukaryotic gene?
Signup and view all the answers
Which process occurs after transcription initiation?
Which process occurs after transcription initiation?
Signup and view all the answers
What modification occurs at the 5’ end of the transcribed mRNA?
What modification occurs at the 5’ end of the transcribed mRNA?
Signup and view all the answers
Which statement about RNA polymerase II is true after transcription termination?
Which statement about RNA polymerase II is true after transcription termination?
Signup and view all the answers
What characteristic of the genetic code ensures that multiple codons can code for the same amino acid?
What characteristic of the genetic code ensures that multiple codons can code for the same amino acid?
Signup and view all the answers
What role do transcription factors play in the transcription process?
What role do transcription factors play in the transcription process?
Signup and view all the answers
How are introns treated in mRNA after transcription?
How are introns treated in mRNA after transcription?
Signup and view all the answers
What characteristic defines the genetic code as nonoverlapping and commaless?
What characteristic defines the genetic code as nonoverlapping and commaless?
Signup and view all the answers
Which of the following is NOT a component of transcription regulation in eukaryotes?
Which of the following is NOT a component of transcription regulation in eukaryotes?
Signup and view all the answers
What role do enhancers play in gene regulation?
What role do enhancers play in gene regulation?
Signup and view all the answers
How do transcription factors locate their targeted sites on promoters?
How do transcription factors locate their targeted sites on promoters?
Signup and view all the answers
Which statement about the genetic code is true?
Which statement about the genetic code is true?
Signup and view all the answers
What is a response element in gene regulation?
What is a response element in gene regulation?
Signup and view all the answers
What is a characteristic of transcription factors?
What is a characteristic of transcription factors?
Signup and view all the answers
Which of the following sequences reflects the direction in which codons are written?
Which of the following sequences reflects the direction in which codons are written?
Signup and view all the answers
Study Notes
Nucleic Acids
- Nucleic acids are biopolymers composed of nucleotides, aldopentoses (either ribose or deoxyribose), and a purine or pyrimidine base linked to a phosphate
- DNA and RNA are chemical carriers of genetic information
- A nucleotide consists of a nitrogen-containing heterocyclic base, a ribose or deoxyribose sugar ring, and a phosphoric acid unit
Structure of the Nucleotide
- DNA and RNA are polymers
- The monomer units are called nucleotides
- Nucleotides are made up of a nitrogen containing heterocyclic base, a pentose (five-carbon) sugar and a phosphate group
DNA and RNA
- Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA) are the chemical carriers of genetic information
- Nucleic acids are biopolymers made of nucleotides and aldopentoses linked to a purine or pyrimidine and a phosphate
Sugars in DNA and RNA
- RNA is derived from ribose
- DNA is derived from 2'-deoxyribose
- The prime symbol (') is used to refer to positions on the sugar portion of a nucleotide
Major Purine Bases
- Adenine (A)
- Guanine (G)
- These are found in both DNA and RNA
Major Pyrimidine Bases
- Cytosine (C)
- Thymine (T)
- Uracil (U)
- Cytosine is found in both DNA and RNA
- Thymine is found in DNA
- Uracil is found in RNA
Nucleotides
- Nucleotides are the repeating units of DNA or RNA polymers
- In DNA and RNA, the base is bonded to the 1' carbon of the sugar; the phosphate bonds to the 5' carbon (connected to the 3' of the next unit)
Naming Nucleotides
- Begin with the base name
- Remove -ine ending and replace with -osine (for pyrimidines) or -idine (for purines). Uracil: replace -acil with -idine
- Add ribose or deoxyribose to denote the sugar
- Add prefix based on the number of phosphoryl groups (e.g., mono-, di-, triphosphate)
The Deoxyribonucleotides
- 2'-Deoxyadenosine 5'-phosphate
- 2'-Deoxythymidine 5'-phosphate
- 2'-Deoxyguanosine 5'-phosphate
- 2'-Deoxycytidine 5'-phosphate
The Ribonucleotides
- Adenosine 5'-phosphate
- Guanosine 5'-phosphate
- Cytidine 5'-phosphate
- Uridine 5'-phosphate
Generalized Structure of DNA
- DNA is a double helix with a sugar-phosphate backbone on the outside and base pairs in the middle
- Nucleotides are linked in a 5' to 3' direction
DNA-Secondary Structure
- The most common form of DNA is the B form
- The DNA structure was determined by Watson and Crick in 1953
- This structure is a right-handed double helix
- The strands run antiparallel
- Complementary base pairs are held together by hydrogen bonds: A=T, G=C
H-bonding in DNA Structure
- Hydrogen bonding between complementary base pairs holds the two DNA strands together
- A-T base pairs have two hydrogen bonds
- G-C base pairs have three hydrogen bonds
H-Bonds in DNA
- G-C base pairs have three hydrogen bonds
A-T Base Pairing
- A-T base pairs have two hydrogen bonds
B DNA segment
- Sugar-phosphate backbone outside the helix
- Hydrogen bonded base pairs inside the core of the helix
Grooves in DNA
- Two continuous grooves (major and minor).
- The sugar-phosphate backbone runs outside the helix
- Hydrogen bonds between base pairs inside
B DNA Structure
- Outside diameter; 2 nm
- Interior diameter; 1.1 nm
- Length of one turn of a helix is 3.4 nm and contains 10 base pairs
Nucleic Acid Sequences
- Differences arise from the sequence of bases
- A nucleic acid is a polymer made of nucleotides linked together
Describing a Sequence
- A typical sequence is written from the 5' end
- Using abbreviations (A for adenosine, G for guanosine, C for cytidine, T for thymine, U for uracil in RNA)
Learning Check NA1
- Complementary base sequence for -A-G-T-C-C-A-A-T-G-C-: -T-C-A-G-G-T-T-A-C-G-
Chromosomes
- Chromosomes are pieces of DNA that contain genetic instructions (genes)
- Prokaryotes have a single, circular, supercoiled chromosome in a region called the nucleoid
- Eukaryotes have multiple linear chromosomes within a nucleus, with membrane-bound organelles
RNA Structure
- Sugar-phosphate backbone for ribonucleotides (linked by 3' to 5' phosphodiester bonds)
- RNA molecules are usually single-stranded
- Ribose replaces deoxyribose in RNA
- Uracil replaces thymine in RNA
- Base pairing between U and A, and G and C, can form double-stranded portions in RNA
Nucleic Acids and Heredity
- Processes transferring genetic information:
- Replication: produces identical copies of DNA
- Transcription: reads genetic messages and carries them to ribosomes for protein synthesis
- Translation: genetic messages are decoded to make proteins
DNA Replication
- DNA replicates itself every cell division to maintain correct genetic information
- Two strands of DNA unwind, each strand acts as a template for a new strand, and new bases pair with their complementary base
- Two double helixes form, which are copies of the original DNA
DNA Unwinds
- G-C, A-T, C-G, T-A
DNA Copied With Base Pairs
- Two copies of the original DNA strand
DNA Replication (part 2: Replication Initiation)
- DNA replication is semi-conservative
- Each parental strand acts as a template for a new, complementary strand
DNA Replication (part 2: Replication Initiation)
- DNA unwinds, and hydrogen bonds between the two strands are broken
DNA Replication (part 2: Replication Initiation)
- This process is aided by the enzyme helicase
- Single-strand binding proteins (SSBs) prevent the separated strands from rejoining
DNA Replication (part 2: Replication Initiation)
- This creates a replication bubble
- Replication bubbles form at multiple sites along the DNA molecule to speed up replication
DNA Replication (part 3: Replication of the Leading Strand)
- Once strands are unwound and separated, DNA polymerase begins building a new strand
DNA Replication (part 3: Replication of the Leading Strand)
- DNA polymerase builds the new strand in a 5' to 3' direction
DNA Replication (part 3: Replication of the Leading Strand)
- DNA polymerase can't build a new strand from scratch; it can only build onto a pre-existing strand
DNA Replication (part 3: Replication of the Leading Strand)
- RNA primase synthesizes the first nucleotides of the new strand
DNA Replication (part 3: Replication of the Leading Strand)
- The RNA primer provides a free 3' end to bind to
DNA Replication (part 3: Replication of the Leading Strand)
- DNA polymerase can now assemble complementary nucleotides as it moves along the parent strand
DNA Replication (part 3: Replication of the Leading Strand)
- DNA polymerase reads the parent strand in a 3' to 5' direction while building the new strand in a 5' to 3' direction
DNA Replication (part 3: Replication of the Leading Strand)
- The helix continues to unwind and open, allowing the leading strand to grow continuously towards the replication fork
DNA Replication (part 3: Replication of the Leading Strand)
- Later a different kind of DNA polymerase replaces the RNA primer with DNA
DNA Replication (part 3: Replication of the Leading Strand)
- How the new DNA strand is formed
DNA Replication (part 4: Replication of the Lagging Strand)
- The lagging strand is built in the opposite direction that the helix unwinds
DNA Replication (part 4: Replication of the Lagging Strand)
- First, RNA primase adds a section of RNA primer
DNA Replication (part 4: Replication of the Lagging Strand)
- Next, DNA polymerase begins to synthesize the new strand of DNA
DNA Replication (part 4: Replication of the Lagging Strand)
- Before more lagging strand can be built, the helix must continue to unwind
DNA Replication (part 4: Replication of the Lagging Strand)
- Thus, the lagging strand is built discontinuously
- Discontinuous sections are called Okazaki fragments
DNA Replication (part 4: Replication of the Lagging Strand)
- As in the leading strand, a different DNA polymerase changes the RNA primer into DNA
DNA Replication (part 4: Replication of the Lagging Strand)
- Then, ligase joins the segments of DNA together
DNA Replication (part 4: Replication of the Lagging Strand)
- Replication continues in this manner along the lagging strand, building in sections as the helix unwinds
DNA Replication (part 5: Bringing It All Together)
- Now let's look at the entire replication bubble
DNA Replication (part 5: Bringing It All Together)
- Leading and lagging strands begin to replicate, working in opposite directions
DNA Replication (part 5: Bringing It All Together)
- Meanwhile, another leading strand is replicating on the other strand of the bubble
DNA Replication (part 5: Bringing It All Together)
- There is a second lagging strand at the opposite end
DNA Replication (part 5: Bringing It All Together)
- Next, a second DNA polymerase adds deoxyribose, changing the sections of RNA into DNA
DNA Replication (part 5: Bringing It All Together)
- Finally, ligase joins the loose segments of DNA together
DNA Replication (part 5: Bringing It All Together)
- Now, let's see the entire replication bubble in action
DNA Replication (part 5: Bringing It All Together)
- There are multiple replication bubbles along the DNA molecule
DNA Replication (part 5: Bringing It All Together)
- They continue to grow until they join together
DNA Replication (part 5: Bringing It All Together)
- Now there are two complete molecules of DNA
DNA Replication (part 5: Bringing It All Together)
- Each new DNA molecule will be able to replicate and start the process all over again
Summary: DNA Replication (part 1: Opening up the Superstructure)
- During replication, the very condensed superstructure of chromosomes is opened
Summary: DNA Replication (part 1: Opening up the Superstructure)
- One step of this mechanism involves acetylation and deacetylation of key lysine residues
Summary: DNA Replication (part 2: Relaxation of Higher Structures of DNA)
- Tropoisomerases help relax supercoiled DNA by introducing single- or double-strand breaks
Summary: DNA Replication (part 3: Unwinding the DNA Double Helix)
- Replication of DNA starts with unwinding
Summary: DNA Replication (part 3: Primer/Primases)
- Primers are short oligonucleotides (4-15 nucleotides long)
Summary: DNA Replication (part 4: DNA Polymerases)
- DNA polymerases are key enzymes in replication
Summary: DNA Replication (part 4: DNA Polymerases)
- In the absence of DNA polymerase, alignment is slow
Summary: DNA Replication (part 4: DNA Polymerases)
- Along the lagging strand (3' to 5'), polymerases can synthesize only short fragments
Summary: DNA Replication (part 4: DNA Polymerases)
- These short fragments are called Okazaki fragments
Summary: Mutation and Repair
- Mutations are mistakes introduced into the DNA sequence
- Mutations can be classified as point mutations, deletions, or insertions
- Mutagens cause base changes
Summary: UV Damage and DNA Repair
- UV light causes pyrimidine dimer formation on DNA strands
- Failure to repair these dimers can result in xeroderma pigmentosum, a genetic skin disorder
Summary: DNA Repair
- Cell viability depends on DNA repair enzymes
Summary: DNA Repair (Base Excision Repair)
- A DNA glycosylase recognizes the damaged base
Summary: DNA Repair (Base Excision Repair)
- It catalyzes the hydrolysis of the ẞ-N-glycosidic bond
Summary: DNA Repair (Base Excision Repair)
- The damaged base is flipped out and removed—the sugar-phosphate backbone remains intact
Summary: DNA Repair (BER cont'd)
- At the AP site, an endonuclease catalyzes hydrolysis of the backbone
- An exonuclease removes the damaged site
- DNA polymerase inserts the correct nucleotide
- DNA ligase seals the backbone
Summary: DNA Repair (NER—Nucleotide Excision Repair)
- NER removes and repairs 24-32 units through a similar mechanism involving a number of repair enzymes
The Central Dogma
- Replication, transcription, translation are the main processes in gene expression in a typical, single-celled organism
Classes of RNA Structure
- Transfer RNA (tRNA): transfers amino acids
- Ribosomal RNA (rRNA): forms ribosomes
- Messenger RNA (mRNA): directs the amino acid sequence of proteins
tRNA
- There is at least one tRNA for each amino acid
tRNA
- Intrachain hydrogen bonding creates stems and loops within the molecule, forming a cloverleaf structure
tRNA
- Amino acid attaches to the 3' end
Transcription
- Transcription is the process wherein a messenger RNA (mRNA) is synthesized along a template strand of DNA, specifically near a gene
Transcription
- Transcription happens in the nucleolus of a eukaryotic cell
Transcription (Initiation)
- The promoter signals where transcription begins
Transcription (Initiation)
- RNA polymerase locates and binds to the promoter
Transcription (Initiation)
- A group of proteins called transcription factors locate and bind to the TATA box
Transcription (Initiation)
- RNA polymerase II binds to the promoter
Transcription (Initiation)
- Aided by transcription factors, RNA polymerase II locates the start point and begins to unwind the DNA helix
Transcription (Elongation)
- RNA polymerase II assembles the RNA nucleotides that complement the template strand
Transcription (Elongation)
- RNA polymerase reads the template strand in a 3' to 5' direction, building the new RNA strand in a 5' to 3' direction
Transcription (Elongation)
- RNA contains the nitrogenous base uracil (U) instead of thymine (T)
Transcription (Elongation)
- RNA polymerase continues along the template as the DNA strands rejoin
Transcription (Termination)
- As the RNA transcript nears completion, the enzyme encounters a terminator sequence
Transcription (Termination)
- The RNA polymerase transcribes the terminator sequence and then continues about 10–15 nucleotides before releasing the pre-mRNA strand
Summary: Transcription
- Transcription starts with DNA unwinding near the gene
- Only one DNA strand is transcribed
- Ribonucleotides assemble along the strand in a sequence complementary to the template strand
- Enzymes called polymerases catalyze the process
Summary: Transcription
- Eukaryotic genes have two parts: structural genes and regulatory genes
Summary: Transcription
- Structural genes are made of exons and introns
- Regulatory genes have control elements, one of which is the promoter
Summary: Transcription
- Promoters are unique to each gene and have initiation signals
Summary: Transcription
- Promoters contain consensus sequences
Summary: Transcription
- A TATA box lies approximately 25 base pairs upstream
Summary: Transcription
- RNA polymerases interact with their promoter regions through transcription factors, which are binding proteins
Summary: Transcription
- After initiation, RNA polymerases zip up complementary bases in a process called elongation
Summary: Transcription
- Elongation is in the 5' -> 3' direction
Summary: Transcription
- Termination is present at the end of each gene
Summary: Transcription
- Poly II has two forms—unphosphorylated for initiation and phosphorylated for elongation—and is recycled between those roles
Summary: Transcription
- RNA products of transcription may not be functional RNA immediately
Summary: Transcription
- RNA products of transcription become functional through post-transcription modification
RNA Processing
- mRNA is capped at both ends, the 5' end acquires a methylated guanine, and the 3' end acquires a poly-A tail (100-200 adenines)
RNA Processing
- Introns are spliced out
RNA Processing
- tRNA is trimmed, capped, and methylated
RNA Processing
- Functional rRNA undergoes post-transcription modification
Translation
- Translation is the synthesis of a polypeptide strand using genetic information present in the mRNA molecule
Translation (Initiation)
- Initiation begins when the mRNA transcript comes together with the smaller of two ribosomal subunits and a tRNA molecule
Translation (Initiation)
- The tRNA molecule carries the first amino acid of the polypeptide
Translation (Initiation)
- The tRNA molecule attaches to the start codon (AUG)
Translation (Initiation)
- Now the larger ribosomal subunit arrives
Translation (Initiation)
- This ribosomal subunit has 3 tRNA binding sites (E, P, A)
Translation (Elongation)
- The mRNA transcript continues across the ribosome with the amino acids bonded by peptide bonds
Translation (Elongation)
- Codons are recognized: each codon codes for a particular amino acid
Translation (Elongation)
- The incoming tRNA contains an anticodon which complements the codon in the A site
Translation (Elongation)
- Hydrogen bonds hold the tRNA in place
Translation (Elongation)
- The tRNA carries the next amino acid in the chain
Translation (Elongation).
- Now the large ribosomal subunit joins the two amino acids together with a peptide bond.
Translation (Elongation)
- The tRNAs, together with the mRNA template, move down one site
Translation (Elongation)
- The used tRNA is released from the E site
Translation (Elongation)
- The entire process repeats
Translation (Termination)
- Translation is terminated when a stop codon is reached
Translation (Termination)
- The release factor is a protein that recognizes and binds to the stop codon
Translation (Termination)
- The release factor adds a water molecule, or hydrolyzes the chain, releasing the polypeptide.
Translation (Termination)
- Once the polypeptide is released, the ribosomal subunits and other factors break apart
Translation (Overview)
- Multiple ribosomes travel along the mRNA strand simultaneously translating copies of the polypeptide
Gene Regulation
- Gene regulation by various methods controls which genes are expressed and when
- Some regulations operate at the transcriptional level (DNA - > RNA)
- Other regulations operate at the translational level (mRNA - > Protein)
Gene Regulation: Transcriptional Level (Promoters)
- Promoters are located adjacent to the transcription site
- Defined by an initiator and conserved sequences such as TATA or GC boxes
- Transcription factors bind to different modules of the promoter
- Transcription factors allow the rate of mRNA synthesis to vary significantly
Gene Regulation: Transcriptional Level (Promoters)
- Transcription factors find their targeted sites by twisting their protein chains so that a certain amino acid sequence is present at the surface.
Gene Regulation: Transcriptional Level (Promoters)
- One such conformational twist is provided by metallic binding fingers (next screen).
- Two other prominent transcription factor conformations are: the helix-turn-helix and the leucine zipper.
Gene Regulation: Transcriptional Level (Promoters)
- Transcription factors also possess repressors that reduce the rate of transcription.
Gene Regulation: Transcriptional Level (Enhancers)
- Enhancers speed up transcription.
Gene Regulation: Transcriptional Level (Enhancers)
- Enhancers can be thousands of nucleotides away from the transcription site.
- DNA loops bring the enhancer to the initiation site.
Gene Regulation: Transcriptional Level (Response Elements)
- Response elements are activated by their transcription factors in response to an outside stimulus. This stimulus could be heat shock, heavy metal toxicity or hormonal signals.
Translation Level (AARS Control)
- Each amino acid must bond to the correct tRNA.
Translation Level (AARS Control)
- Enzymes called aminoacyl-tRNA synthetases (AARS) catalyze this bonding.
Translation Level (AARS Control)
- Each AARS recognizes its tRNA by specific nucleotide sequences
Translation Level (AARS Control)
- The active site of each AARS has two sieving sites
Translation Level (Termination Control)
- The stop codons must be recognized by release factors
Translation Level (Termination Control)
- The release factor combines with GTP
Translation Level (Post-translational Control)
- In most proteins, the Methionine (Met) at the N-terminal end is removed by Met-aminopeptidase.
Translation Level (Post-translational Control)
- Proteins called chaperones help newly synthesized proteins fold into their proper conformation
Translation Level (Post-translational Control)
- If rescue by chaperones fails, proteasomes may degrade the misfolded protein
Recombinant DNA
- Restriction enzymes cut the DNA backbone at specific sequences
Recombinant DNA
- Donor and plasmid DNA are cleaved by the same restriction enzyme
Recombinant DNA
- Donor DNA fragments join to complimentary plasmid fragments through hydrogen bonding
Recombinant DNA
- Plasmid ring is restored using DNA ligase
Recombinant DNA
- Engineered plasmid is introduced into a bacterium to be reproduced
Polymerase Chain Reaction (PCR)
- DNA is mixed with Taq polymerase, a primer sequence for a specific gene and nucleotide triphosphates
Polymerase Chain Reaction (PCR)
- A thermocycler raises and lowers the temperature to separate and anneal DNA strands, and to allow for DNA strand elongation
Polymerase Chain Reaction (PCR)
- Repeating the cycle doubles the new DNA strands
PCR: Heating and Reaction
- The subject DNA is heated with Taq polymerase and Mg2+ to separate strands
PCR: Heating and Reaction
- Deoxynucleotide triphosphates are also added, along with primers to aid in DNA strand elongation.
PCR: Annealing and Growing
- Temperature is reduced to 37-50 C to allow primers to hybridize to the complementary sequences
PCR: Annealing and Growing
- Primers are added to create complementary sequences
PCR: Taq Polymerase
- Taq polymerase raises temperature to 72°C to add nucleotides to the two primed DNA strands
PCR: Growing More Chains
- Repeating the denature, anneal, and synthesize cycles doubles the new DNA strands exponentially.
PCR: Growing More Chains
- PCR is now automated and can be carried out in a similar amount of time as it takes to make a cup of tea
PCR: Growing More Chains (data given)
- The table contains data for oligo sequence, primer and type. Each sequence with a given type is listed.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the key elements of DNA structure, including nucleotide composition, base pairing, and the function of enzymes in DNA replication. This quiz will test your understanding of the differences between DNA and RNA, alongside essential molecular biology concepts.
