Enhance your knowledge with our comprehensive guide and curated study materials.
RNA is a single-stranded polynucleotide composed of ribose sugar, phosphate, and nitrogenous bases.
Nitrogenous bases: Adenine, Guanine, Cytosine, Uracil (uracil replaces thymine).
Sugar is β-D-ribose with a free 2′-OH group, making RNA chemically less stable than DNA.
RNA synthesis occurs in the 5′ → 3′ direction.
Types of RNA:
mRNA → codes for proteins.
tRNA → transports amino acids.
rRNA → structural and catalytic component of ribosome.
snRNA, snoRNA → involved in RNA processing.
mRNA carries genetic information from DNA to ribosome.
In eukaryotes, initially synthesized as heterogeneous nuclear RNA (hnRNA).
Structural components of eukaryotic mRNA:
5′ cap (7-methyl guanosine) → prevents degradation and helps ribosome binding.
Coding region (exons) → translated into protein.
3′ poly-A tail (200–250 A residues) → stability and nuclear export.
Prokaryotic mRNA:
Usually polycistronic.
Lacks 5′ cap and poly-A tail.
RNA polymerase catalyzes synthesis of RNA using DNA as template.
Forms phosphodiester bonds between ribonucleotides.
Does not require a primer.
Types of RNA polymerase in eukaryotes:
RNA polymerase I → rRNA (28S, 18S, 5.8S).
RNA polymerase II → mRNA and snRNA.
RNA polymerase III → tRNA and 5S rRNA.
Prokaryotes possess a single RNA polymerase; specificity provided by sigma (σ) factor.
Transcription is the synthesis of RNA from DNA template.
Occurs in:
Nucleus → eukaryotes.
Cytoplasm → prokaryotes.
Template strand is the antisense strand.
Base pairing rules:
A pairs with U.
G pairs with C.
Three stages:
Initiation
Elongation
Termination
DNA sequences that regulate transcription.
Promoter:
Located upstream of transcription start site.
Contains TATA box (Pribnow box in prokaryotes).
Enhancers:
Increase transcription efficiency.
Can act at a distance and in either orientation.
Terminator sequences:
Signal the end of transcription.
RNA polymerase binds to promoter region.
Prokaryotes:
Sigma factor recognizes promoter.
RNA polymerase holoenzyme initiates transcription.
Eukaryotes:
Requires general transcription factors (TFIIA, TFIIB, TFIID).
TFIID contains TATA-binding protein (TBP).
DNA strands unwind forming transcription bubble.
First ribonucleotide is added without primer.
RNA polymerase moves along template strand.
RNA chain grows in 5′ → 3′ direction.
Energy derived from hydrolysis of NTPs.
DNA unwinds ahead and rewinds behind the enzyme.
Newly synthesized RNA remains temporarily hybridized with DNA.
Termination marks the end of RNA synthesis.
Prokaryotes:
Rho-dependent termination → rho protein required.
Rho-independent termination → GC-rich hairpin loop followed by poly-U.
Eukaryotes:
Termination occurs after poly-A signal (AAUAAA).
RNA is cleaved downstream of signal.
Occurs only in eukaryotes.
Converts hnRNA into mature mRNA.
Steps:
5′ capping → protection and ribosome recognition.
3′ polyadenylation → stability and transport.
Splicing → removal of introns.
Essential for proper gene expression.
Large ribonucleoprotein complexes.
Composed of snRNA (U1, U2, U4, U5, U6) and associated proteins.
Recognize conserved splice sites:
5′ splice site → GU.
Branch point → Adenine.
3′ splice site → AG.
Functions:
Excise introns.
Join exons precisely.
Alternative splicing:
Allows multiple proteins from a single gene.
Major contributor to protein diversity.
Ribozymes are RNA molecules with catalytic activity.
They can catalyze biochemical reactions without proteins.
Prove that RNA can act as both genetic material and enzyme.
Examples:
RNase P → removes leader sequence from tRNA.
Self-splicing introns.
Hammerhead ribozyme.
Clinical importance:
Supports RNA world hypothesis.
Target for gene therapy research.
Genes are composed of:
Exons → coding sequences.
Introns → non-coding intervening sequences.
During transcription, both introns and exons are copied into hnRNA.
Introns are removed during splicing.
Exons are joined to form mature mRNA.
Alternative splicing:
Different exon combinations.
Produces multiple proteins from a single gene.
Introns are common in eukaryotes, rare in prokaryotes.
Reverse transcriptase is an RNA-dependent DNA polymerase.
Synthesizes DNA from RNA template.
Found in retroviruses (e.g., HIV).
Functions:
RNA → DNA conversion.
DNA integrates into host genome as provirus.
Clinical importance:
Target of antiretroviral drugs (AZT, nevirapine).
Used in molecular biology for cDNA synthesis.
tRNA transports amino acids to ribosome.
Smallest RNA (~75–90 nucleotides).
Cloverleaf structure with:
Anticodon loop → recognizes codon on mRNA.
Acceptor arm (3′ CCA) → amino acid attachment site.
Each amino acid has a specific tRNA.
Charging of tRNA:
Catalyzed by aminoacyl-tRNA synthetase.
Requires ATP.
Wobble hypothesis:
One tRNA can recognize multiple codons.
rRNA forms the structural and catalytic core of ribosome.
Most abundant RNA (~80%).
Prokaryotes:
16S rRNA (30S subunit).
23S + 5S rRNA (50S subunit).
Eukaryotes:
18S rRNA (40S).
28S + 5.8S + 5S (60S).
rRNA acts as a ribozyme during peptide bond formation.
Ribosomes are ribonucleoprotein complexes.
Site of protein synthesis.
Types:
70S ribosome → prokaryotes (30S + 50S).
80S ribosome → eukaryotes (40S + 60S).
Functional sites:
A site → aminoacyl-tRNA binding.
P site → peptide bond formation.
E site → exit of tRNA.
Ribosomes may be:
Free → cytosolic proteins.
Bound to RER → secretory proteins.
snRNA are small RNA molecules found in nucleus.
Combined with proteins form spliceosomes.
Types:
U1, U2, U4, U5, U6.
Function:
Recognition of splice sites.
Removal of introns from hnRNA.
Essential for accurate mRNA maturation.
Translation is synthesis of protein from mRNA.
Occurs on ribosomes in cytoplasm.
Requires:
mRNA, tRNA, ribosomes.
ATP and GTP.
Steps:
Initiation → formation of initiation complex.
Elongation → peptide chain growth.
Termination → release of completed protein.
Direction:
mRNA read 5′ → 3′.
Protein synthesized N-terminal → C-terminal.
Genetic code is the language converting nucleotide sequence into amino acids.
Triplet code → 3 nucleotides = 1 codon.
Total codons: 64.
Start codon:
AUG → methionine.
Stop codons:
UAA, UAG, UGA.
Properties:
Universal (with few exceptions).
Degenerate → multiple codons for same amino acid.
Non-overlapping and comma-less.
Mutations affecting genetic code can lead to genetic disorders.
Translation is the process by which mRNA directs synthesis of protein.
Occurs on ribosomes in the cytoplasm.
Requires:
mRNA (template)
tRNA (adaptor molecule)
Ribosomes (site of synthesis)
ATP and GTP (energy)
Direction:
mRNA read 5′ → 3′
Polypeptide synthesized N-terminal → C-terminal
Multiple ribosomes translating a single mRNA form a polysome.
Initiation begins with formation of initiation complex.
Key components:
Small ribosomal subunit
Initiator tRNA
mRNA
Initiation factors (IFs/eIFs)
Initiator tRNA carries N-formyl methionine (fMet).
mRNA binds to ribosome via Shine–Dalgarno sequence.
Start codon: AUG.
Initiator tRNA carries methionine.
Small subunit binds to 5′ cap and scans for AUG.
Start site surrounded by Kozak sequence.
Initiator tRNA binds directly to P site.
Repeating cycle of amino acid addition.
Occurs at A, P, and E sites of ribosome.
Steps:
Aminoacyl-tRNA binding to A site (requires GTP).
Peptide bond formation (peptidyl transferase activity of rRNA).
Translocation of ribosome along mRNA.
Elongation factors:
Prokaryotes → EF-Tu, EF-Ts, EF-G
Eukaryotes → eEF-1, eEF-2
Energy requirement:
1 ATP for tRNA charging.
2 GTP per peptide bond.
Occurs when ribosome encounters a stop codon.
Stop codons:
UAA, UAG, UGA
No tRNA corresponds to stop codons.
Release factors bind to A site.
Polypeptide chain released from tRNA.
Ribosomal subunits dissociate from mRNA.
Newly synthesized proteins must reach correct cellular location.
Signal peptide:
Short hydrophobic amino-terminal sequence.
Cytosolic proteins:
Synthesized on free ribosomes.
Secretory and membrane proteins:
Targeted to rough endoplasmic reticulum (RER).
Signal recognition particle (SRP):
Recognizes signal peptide.
Directs ribosome to RER membrane.
Mitochondrial and nuclear proteins have specific targeting signals.
Modifications occurring after protein synthesis.
Types:
Proteolytic cleavage (e.g., proinsulin → insulin).
Phosphorylation (serine, threonine, tyrosine).
Glycosylation.
Hydroxylation (collagen).
Acetylation, methylation.
Essential for:
Functional activity.
Stability.
Proper localization.
Newly synthesized polypeptides fold into native 3-D structure.
Driven by:
Hydrogen bonds
Ionic interactions
Hydrophobic interactions
Disulfide bonds
Proper folding is essential for biological function.
Misfolding may lead to:
Loss of function.
Protein aggregation diseases.
Chaperones are proteins that assist in proper folding of other proteins.
Prevent aggregation of nascent polypeptides.
Do not become part of final structure.
Examples:
Hsp60 (GroEL–GroES system).
Hsp70.
Require ATP for activity.
Synthesized in response to cellular stress (heat, toxins, hypoxia).
Act as molecular chaperones.
Common types:
Hsp70 → early folding.
Hsp60 → folding in mitochondria.
Hsp90 → stabilizes signaling proteins.
Clinical relevance:
Involved in cancer, neurodegenerative diseases.
Protect cells from stress-induced damage.
Protein synthesis can be inhibited at initiation, elongation, or termination.
Most inhibitors act at the ribosomal level.
Selectivity is due to structural differences between:
Prokaryotic (70S)
Eukaryotic (80S) ribosomes
Clinical importance:
Basis of action of many antibiotics.
Useful in cancer chemotherapy and research.
Act mainly on prokaryotic ribosomes.
Aminoglycosides → misreading of mRNA.
Tetracyclines → block aminoacyl-tRNA binding.
Chloramphenicol → inhibits peptidyl transferase.
Macrolides (erythromycin) → block translocation.
Clindamycin → inhibits peptide bond formation.
Linezolid → inhibits initiation complex.
Mitochondria possess their own DNA and RNA.
mtDNA is:
Circular
Double-stranded
Maternally inherited
Encodes:
13 proteins (ETC components)
22 tRNAs
2 rRNAs
Mitochondrial ribosomes resemble prokaryotic ribosomes.
Sensitive to antibiotics affecting bacterial translation.
Caused by mutations in mitochondrial or nuclear genes.
Lead to defective ATP production.
Common features:
Myopathy
Neurological deficits
Lactic acidosis
Examples:
Leber hereditary optic neuropathy
MELAS syndrome
MERRF syndrome
Inheritance is typically maternal.
Genomics:
Study of entire genome.
Includes gene mapping, sequencing, and function.
Proteomics:
Study of entire protein complement of a cell.
Includes structure, function, interactions.
Proteome is more complex than genome due to:
Alternative splicing.
Post-translational modifications.
Clinical applications:
Personalized medicine.
Disease biomarkers.
Small non-coding RNA (~22 nucleotides).
Regulates gene expression post-transcriptionally.
Binds to complementary mRNA sequences.
Leads to:
Translational repression.
mRNA degradation.
Important in development, cancer, and apoptosis.
RNA interference (RNAi) is sequence-specific gene silencing.
Mediated by:
siRNA
miRNA
Mechanism:
dsRNA cleaved by Dicer.
siRNA incorporated into RISC.
Target mRNA degraded.
Used in research and therapy.
Uses short synthetic DNA or RNA sequences.
Complementary to specific mRNA.
Binding leads to:
Blocked translation.
mRNA degradation.
Applications:
Genetic disorders.
Cancer.
Viral infections.
Example:
Antisense therapy in spinal muscular atrophy.
Fusion proteins are created by joining two genes.
Expressed as a single polypeptide.
Advantages:
Improved stability.
Targeted action.
Examples:
Insulin fusion analogs.
Monoclonal antibody fusion proteins.
Used in:
Biotechnology.
Targeted cancer therapy.
Research tagging (e.g., GFP fusion).
Transcription is the process by which RNA is synthesized from a DNA template using RNA polymerase.
The antisense (template) strand acts as template; the sense strand has the same sequence as RNA (except T replaced by U).
RNA synthesis occurs in the 5′ → 3′ direction.
RNA polymerase catalyzes transcription.
Three:
RNA polymerase I → rRNA
RNA polymerase II → mRNA
RNA polymerase III → tRNA and 5S rRNA
Sigma factor helps RNA polymerase recognize promoter sequences in prokaryotes.
A promoter sequence rich in thymine and adenine that helps initiate transcription in eukaryotes.
Proteins required for binding of RNA polymerase II to DNA in eukaryotes.
Heterogeneous nuclear RNA is the primary transcript that undergoes post-transcriptional processing to form mRNA.
Introns → non-coding sequences removed during splicing
Exons → coding sequences retained in mature mRNA
Removal of introns and joining of exons to form functional mRNA.
A ribonucleoprotein complex composed of snRNA and proteins that mediates splicing.
U1, U2, U4, U5, and U6.
Process by which different proteins are produced from the same gene by varying exon combinations.
RNA molecules with enzymatic activity, capable of catalyzing reactions.
RNase P, which processes tRNA.
An RNA-dependent DNA polymerase that synthesizes DNA from RNA.
In retroviruses such as HIV.
Translation is the process of protein synthesis from mRNA on ribosomes.
On ribosomes in the cytoplasm.
mRNA, tRNA, ribosomes, amino acids, ATP, and GTP.
From N-terminal to C-terminal end.
AUG, coding for methionine.
UAA, UAG, and UGA.
Prokaryotes → fMet-tRNA
Eukaryotes → Met-tRNA
A ribosomal binding site on prokaryotic mRNA.
A consensus sequence around the start codon in eukaryotic mRNA.
A site → aminoacyl-tRNA binding
P site → peptide bond formation
E site → exit of tRNA
Peptidyl transferase, an rRNA-based ribozyme.
Proteins that recognize stop codons and terminate translation.
Multiple ribosomes translating a single mRNA simultaneously.
Proteins that assist in proper folding of newly synthesized polypeptides.
Stress-induced chaperone proteins that protect cells during heat, hypoxia, and toxins.
Chemical modification of proteins after synthesis, such as phosphorylation or glycosylation.
Correct folding is essential for biological activity and stability of proteins.
Process by which proteins are directed to their correct cellular location.
A short hydrophobic sequence that directs proteins to RER or specific organelles.
Signal recognition particle (SRP).
Aminoglycosides, tetracyclines, macrolides, chloramphenicol, linezolid.
Because bacterial ribosomes are 70S, different from eukaryotic 80S ribosomes.
Circular, double-stranded DNA present in mitochondria, inherited maternally.
They resemble bacterial ribosomes and are sensitive to certain antibiotics.
Disorders caused by defects in mitochondrial ATP production.
MELAS, MERRF, Leber hereditary optic neuropathy.
Study of the entire genome of an organism.
Study of the entire protein complement of a cell.
Small non-coding RNA that regulates gene expression post-transcriptionally.
Sequence-specific gene silencing mediated by siRNA and miRNA.
Use of complementary nucleic acid sequences to block mRNA translation.
Proteins created by combining two different genes into a single polypeptide.
Because defects in transcription, translation, folding, or targeting cause genetic disorders, cancer, infections, and metabolic diseases.
A. 3′ → 5′
B. 5′ → 3′
C. N → C
D. C → N
Answer: B
A. RNA polymerase I
B. RNA polymerase II
C. RNA polymerase III
D. RNA polymerase IV
Answer: B
A. Kozak sequence
B. TATA box
C. Pribnow box
D. Poly-A signal
Answer: C
A. Mature mRNA
B. tRNA
C. rRNA
D. hnRNA
Answer: D
A. Ribosomes
B. RNA polymerase
C. Spliceosome
D. Dicer
Answer: C
A. U1
B. U2
C. U4
D. U7
Answer: D
A. rRNA
B. tRNA
C. Ribozyme
D. miRNA
Answer: C
A. DNA-dependent DNA polymerase
B. RNA-dependent RNA polymerase
C. RNA-dependent DNA polymerase
D. DNA-dependent RNA polymerase
Answer: C
A. Adenovirus
B. Retrovirus
C. Herpesvirus
D. Poxvirus
Answer: B
A. mRNA
B. rRNA
C. tRNA
D. snRNA
Answer: C
A. Anticodon loop
B. TΨC loop
C. D loop
D. 3′ CCA end
Answer: D
A. Protein enzyme
B. DNA
C. rRNA
D. tRNA
Answer: C
A. A site
B. P site
C. E site
D. S site
Answer: B
A. UAA
B. UGA
C. AUG
D. UAG
Answer: C
A. Methionine
B. Formyl methionine
C. Valine
D. Glycine
Answer: B
A. Eukaryotic mRNA
B. Prokaryotic mRNA
C. tRNA
D. rRNA
Answer: B
A. Termination of transcription
B. Translation initiation in eukaryotes
C. Splicing
D. RNA degradation
Answer: B
A. UAA
B. UAG
C. UGA
D. AUG
Answer: D
A. Initiation factor
B. Elongation factor
C. Release factor
D. Sigma factor
Answer: C
A. Polycistron
B. Polysome
C. Operon
D. Spliceosome
Answer: B
A. Tetracycline
B. Aminoglycoside
C. Chloramphenicol
D. Penicillin
Answer: C
A. Blocking initiation
B. Blocking translocation
C. Preventing aminoacyl-tRNA binding
D. Causing premature termination
Answer: C
A. Higher ATP requirement
B. Presence of cell wall
C. Difference in ribosomal structure
D. Faster metabolism
Answer: C
A. Father
B. Mother
C. Both parents
D. Autosomes
Answer: B
A. Eukaryotic cytosolic ribosomes
B. Nuclear ribosomes
C. Prokaryotic ribosomes
D. Lysosomal ribosomes
Answer: C
A. Glycolysis
B. Translation initiation
C. Oxidative phosphorylation
D. DNA replication
Answer: C
A. Proteomics
B. Transcriptomics
C. Genomics
D. Metabolomics
Answer: C
A. rRNA
B. tRNA
C. miRNA
D. hnRNA
Answer: C
A. RISC
B. Dicer
C. Spliceosome
D. RNA polymerase
Answer: B
A. Increasing transcription
B. Enhancing translation
C. Binding complementary mRNA
D. Activating ribosomes
Answer: C
A. Post-translational modification
B. Joining two genes
C. Alternative splicing
D. RNA editing
Answer: B
A. Transcription factor
B. Chaperone
C. Release factor
D. Signal peptide
Answer: B
A. Starvation
B. Heat and cellular stress
C. Hypoxia alone
D. Vitamin deficiency
Answer: B
A. DNA replication
B. Protein folding
C. Protein targeting to RER
D. RNA splicing
Answer: C
A. Acetylation
B. Phosphorylation
C. Hydroxylation
D. Glycosylation
Answer: C
A 6-year-old child presents with delayed development and recurrent infections. Genetic analysis shows a defect in removal of introns from primary RNA transcripts.
Question:
Which molecular process is defective, and what structure is primarily involved?
Answer:
Defective process → RNA splicing
Structure involved → Spliceosome (snRNA + proteins)
Explanation:
Introns are removed from hnRNA by spliceosomes. Defects lead to abnormal mRNA and defective protein synthesis.
A patient on long-term chloramphenicol therapy develops bone marrow suppression.
Question:
Explain the biochemical basis of this adverse effect.
Answer:
Chloramphenicol inhibits peptidyl transferase activity.
Mitochondrial ribosomes resemble prokaryotic ribosomes.
Inhibition of mitochondrial protein synthesis → ↓ ATP production → marrow toxicity.
A newborn presents with muscle weakness, lactic acidosis, and neurological deficits. Family history shows maternal inheritance.
Question:
What is the most likely biochemical defect?
Answer:
Defect in mitochondrial oxidative phosphorylation
Due to mutation in mitochondrial DNA
Explanation:
Mitochondrial DNA is maternally inherited and encodes key components of the electron transport chain.
An HIV-positive patient is started on zidovudine (AZT).
Question:
Which enzyme is targeted and why is this effective?
Answer:
Target enzyme → Reverse transcriptase
Reason → HIV requires reverse transcriptase to convert RNA into DNA for integration into host genome.
A mutation alters the Kozak sequence of a gene but leaves the coding region intact.
Question:
What will be the effect on protein synthesis?
Answer:
Defective initiation of translation
Reduced or absent protein synthesis
Explanation:
Kozak sequence is essential for recognition of the start codon in eukaryotes.
A child has a genetic disorder where multiple proteins are missing despite normal gene count.
Question:
Which mechanism could explain this finding?
Answer:
Defective alternative splicing
Explanation:
Alternative splicing allows one gene to produce multiple proteins. Its failure reduces protein diversity.
A patient develops hearing loss after receiving an aminoglycoside antibiotic.
Question:
What is the mechanism of action of this drug?
Answer:
Aminoglycosides bind to 30S ribosomal subunit
Cause misreading of mRNA
Clinical correlation:
Ototoxicity occurs due to damage to mitochondrial ribosomes in inner ear cells.
A researcher observes that a synthetic RNA molecule suppresses expression of a specific gene.
Question:
What mechanism is responsible for this phenomenon?
Answer:
RNA interference (RNAi) mediated by siRNA or miRNA
Explanation:
Small RNAs guide RISC to complementary mRNA, leading to degradation or translational repression.
A child has cystic fibrosis due to a deletion mutation but mRNA is still synthesized.
Question:
At which level is gene expression primarily affected?
Answer:
Translation and protein folding
Explanation:
The mutation causes production of a misfolded CFTR protein, which is degraded despite normal transcription.
A drug blocks binding of aminoacyl-tRNA to ribosome.
Question:
Which class of antibiotic shows this action?
Answer:
Tetracyclines
A patient has a disease caused by accumulation of misfolded proteins in neurons.
Question:
Which protective cellular proteins normally prevent this?
Answer:
Chaperones and heat shock proteins (HSPs)
Explanation:
They assist in correct folding and prevent aggregation of nascent proteins.
A protein synthesized in cytosol fails to reach the rough endoplasmic reticulum.
Question:
Which component is likely defective?
Answer:
Signal recognition particle (SRP) or signal peptide
A mutation changes a codon but still codes for the same amino acid.
Question:
What property of genetic code explains this?
Answer:
Degeneracy of genetic code
A premature stop codon appears in the middle of a gene.
Question:
What is the result at protein level?
Answer:
Truncated, non-functional protein
Translation terminates early due to release factor binding.
A novel cancer therapy uses a molecule that binds specifically to mRNA and blocks its translation.
Question:
What type of therapy is this?
Answer:
Antisense therapy
A biotechnology lab joins two genes to create a protein with dual function.
Question:
What is this protein called?
Answer:
Fusion protein
A bacterial strain becomes resistant to macrolide antibiotics.
Question:
Which step of translation is normally inhibited by macrolides?
Answer:
Translocation step on 50S ribosomal subunit
A child presents with optic neuropathy and mitochondrial DNA mutation.
Question:
Name the likely disorder.
Answer:
Leber hereditary optic neuropathy
A mutation affects peptidyl transferase activity.
Question:
Which molecule is directly involved?
Answer:
rRNA
A stress-exposed cell increases synthesis of protective proteins.
Question:
Which proteins are upregulated?
Answer:
Heat shock proteins (HSPs)
Synthesis of RNA from a DNA template using RNA polymerase.
The antisense (template) strand.
5′ → 3′ direction.
RNA polymerase.
Three.
RNA polymerase II.
Recognition of promoter in prokaryotes.
A promoter sequence that helps initiate transcription.
Primary transcript containing introns and exons.
Non-coding sequences removed during RNA processing.
Coding sequences retained in mature mRNA.
Removal of introns and joining of exons.
Spliceosome.
U1, U2, U4, U5, U6.
Production of multiple proteins from a single gene.
RNA molecules with enzymatic activity.
RNase P.
RNA-dependent DNA polymerase.
Retroviruses (e.g., HIV).
Protein synthesis from mRNA.
On ribosomes in cytoplasm.
N-terminal → C-terminal.
AUG.
Methionine.
UAA, UAG, UGA.
fMet-tRNA.
Met-tRNA.
Ribosome-binding site in prokaryotic mRNA.
Sequence around start codon in eukaryotes.
A site, P site, E site.
P site.
A site.
E site.
rRNA (peptidyl transferase).
Proteins assisting elongation of polypeptide chain.
Proteins that recognize stop codons.
Multiple ribosomes translating one mRNA.
Proteins assisting proper folding of polypeptides.
No.
Stress-induced chaperone proteins.
Hsp70, Hsp60, Hsp90.
Directing proteins to correct cellular location.
Short hydrophobic sequence guiding protein targeting.
Directs ribosome-protein complex to RER.
Chemical modification after protein synthesis.
Phosphorylation, glycosylation, hydroxylation.
Essential for collagen stability.
Tetracyclines, aminoglycosides, macrolides, chloramphenicol.
Difference between 70S and 80S ribosomes.
Chloramphenicol.
Aminoglycosides, tetracyclines.
Circular, maternally inherited DNA in mitochondria.
Mitochondrial ribosomes resemble bacterial ribosomes.
Diseases due to defective mitochondrial ATP synthesis.
MELAS, MERRF, Leber optic neuropathy.
Study of the entire genome.
Study of the entire protein complement.
Small non-coding RNA regulating gene expression.
Sequence-specific gene silencing.
Dicer and RISC.
Blocking mRNA using complementary nucleic acid.
Proteins formed by joining two different genes.
Explains genetic disorders, antibiotic action, mitochondrial diseases, cancer, and modern gene therapies.
Get the full PDF version of this chapter.
Continue with Google
