Microbiology Study Guide: Biomolecules, Genetics, and Viruses

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Q1. Describe the four main groups of biomolecules (structure and function). Fill out the chart for each biomolecule.

Background

Topic: Biomolecules in Microbiology

This question tests your understanding of the basic building blocks of life: carbohydrates, lipids, nucleic acids, and proteins. You need to know their structure, function, and examples.

Key Terms:

Carbohydrates: Sugars and polysaccharides, energy storage and structure.
Lipids: Fats, oils, phospholipids, membranes, energy storage.
Nucleic Acids: DNA and RNA, genetic information storage and transfer.
Proteins: Amino acid polymers, enzymes, structure, signaling.

Step-by-Step Guidance

Identify the building blocks for each biomolecule (e.g., monosaccharides for carbohydrates, fatty acids for lipids, nucleotides for nucleic acids, amino acids for proteins).
Describe the general structure of each biomolecule (e.g., ring structure for carbohydrates, long hydrocarbon chains for lipids, double helix for DNA).
Explain the main function of each biomolecule in cells (e.g., energy storage, genetic information, catalysis).
Provide examples for each biomolecule (e.g., glucose for carbohydrates, triglycerides for lipids, DNA for nucleic acids, hemoglobin for proteins).

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Q2. What are the FOUR structural levels of proteins?

Background

Topic: Protein Structure

This question is about the hierarchy of protein structure: primary, secondary, tertiary, and quaternary levels.

Key Terms:

Primary structure: Sequence of amino acids.
Secondary structure: Local folding (alpha helices, beta sheets).
Tertiary structure: 3D folding of a single polypeptide.
Quaternary structure: Association of multiple polypeptides.

Step-by-Step Guidance

List the four structural levels and define each one.
Describe how each level contributes to the overall protein shape and function.
Give examples of structural features (e.g., hydrogen bonds in secondary structure).
Explain why quaternary structure is only present in proteins with multiple subunits.

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Q3. How can proteins be denatured?

Background

Topic: Protein Denaturation

This question tests your understanding of how protein structure can be disrupted by environmental factors.

Key Terms:

Denaturation: Loss of protein structure and function.
Factors: Heat, pH, chemicals, mechanical agitation.

Step-by-Step Guidance

List common causes of protein denaturation (e.g., high temperature, extreme pH).
Explain how these factors disrupt bonds (e.g., hydrogen bonds, ionic bonds).
Describe the consequences for protein function.

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Q4. Define genotype and phenotype and discuss their relationship.

Background

Topic: Genetics

This question is about the basic concepts of genetics: genotype (genetic makeup) and phenotype (observable traits).

Key Terms:

Genotype: The set of genes in an organism.
Phenotype: The physical expression of those genes.

Step-by-Step Guidance

Define genotype and phenotype clearly.
Explain how genotype determines phenotype (e.g., gene expression).
Discuss examples where environment can influence phenotype.

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Q5. Explain the difference between genomes and genes.

Background

Topic: Genetic Organization

This question tests your understanding of the hierarchy of genetic material.

Key Terms:

Genome: The entire set of genetic material in an organism.
Gene: A segment of DNA that codes for a specific protein or function.

Step-by-Step Guidance

Define genome and gene.
Explain how genes are part of the genome.
Discuss the relationship between the two.

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Q6. Compare and contrast how genetic material is organized in eukaryotic and prokaryotic cells.

Background

Topic: Cell Biology

This question is about the differences in DNA organization between eukaryotes and prokaryotes.

Key Terms:

Eukaryotes: DNA in nucleus, linear chromosomes.
Prokaryotes: DNA in nucleoid, circular chromosomes, plasmids.

Step-by-Step Guidance

Describe where DNA is located in each cell type.
Explain the form of chromosomes (linear vs circular).
Discuss the presence of plasmids in prokaryotes.

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Q7. What is a plasmid and explain the function of plasmids.

Background

Topic: Plasmids in Microbiology

This question is about extra-chromosomal DNA elements in prokaryotes.

Key Terms:

Plasmid: Small, circular DNA molecule.
Function: Antibiotic resistance, gene transfer.

Step-by-Step Guidance

Define plasmid.
Explain how plasmids can carry genes for special functions.
Discuss their role in horizontal gene transfer.

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Q8. Describe the structure of DNA and RNA nucleotides.

Background

Topic: Nucleic Acid Structure

This question is about the basic building blocks of DNA and RNA.

Key Terms:

Nucleotide: Sugar, phosphate, nitrogenous base.
DNA: Deoxyribose sugar, bases A, T, C, G.
RNA: Ribose sugar, bases A, U, C, G.

Step-by-Step Guidance

Draw and label the three parts of a nucleotide.
Describe the differences between DNA and RNA nucleotides.
Explain how nucleotides link to form strands.

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Q9. Explain the “ladder structure” of DNA.

Background

Topic: DNA Structure

This question is about the double helix and base pairing in DNA.

Key Terms:

Double helix: Two strands twisted together.
Base pairs: A-T, C-G.

Step-by-Step Guidance

Describe how the sugar-phosphate backbone forms the sides of the ladder.
Explain how base pairs form the rungs.
Discuss the importance of complementary base pairing.

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Q10. Explain why DNA strands are complementary and antiparallel.

Background

Topic: DNA Structure

This question is about the orientation and pairing of DNA strands.

Key Terms:

Complementary: A pairs with T, C pairs with G.
Antiparallel: Strands run in opposite directions (5' to 3' and 3' to 5').

Step-by-Step Guidance

Explain what complementary means in terms of base pairing.
Describe what antiparallel means for strand directionality.
Discuss why this arrangement is important for replication.

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Q11. Explain why DNA is arranged 5’ to 3’.

Background

Topic: DNA Directionality

This question is about the chemical structure of DNA and how nucleotides are linked.

Key Terms:

5’ and 3’: Refers to carbon positions in the sugar molecule.
Phosphodiester bond: Links 5’ phosphate to 3’ hydroxyl.

Step-by-Step Guidance

Describe the numbering of carbons in the sugar.
Explain how nucleotides are linked from 5’ to 3’.
Discuss why this directionality is important for replication and transcription.

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Q12. Detail the steps of DNA replication in prokaryotes.

Background

Topic: DNA Replication

This question is about the process of copying DNA in prokaryotic cells.

Key Terms:

Origin of replication, helicase, primase, DNA polymerase, ligase.

Step-by-Step Guidance

Identify the origin of replication.
Describe the role of helicase in unwinding DNA.
Explain how primase lays down RNA primers.
Discuss how DNA polymerase synthesizes new DNA strands.

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Q13. Complete the table by describing the function of each enzyme: Helicase, Primase, DNA polymerase III, DNA polymerase I, Ligase, Single-stranded binding proteins.

Background

Topic: DNA Replication Enzymes

This question is about the specific roles of enzymes in DNA replication.

Key Terms:

Helicase: Unwinds DNA.
Primase: Synthesizes RNA primer.
DNA polymerase III: Main enzyme for DNA synthesis.
DNA polymerase I: Removes RNA primer, replaces with DNA.
Ligase: Joins DNA fragments.
Single-stranded binding proteins: Stabilize unwound DNA.

Step-by-Step Guidance

List each enzyme and its function.
Explain how the enzymes work together during replication.
Discuss the importance of each enzyme for accurate DNA synthesis.

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Q14. Explain why DNA replication is continuous on the leading strand and discontinuous on the lagging strand.

Background

Topic: DNA Replication Mechanism

This question is about the directionality of DNA synthesis and the formation of Okazaki fragments.

Key Terms:

Leading strand: Synthesized continuously.
Lagging strand: Synthesized in fragments (Okazaki fragments).

Step-by-Step Guidance

Describe the direction of DNA synthesis (5’ to 3’).
Explain why the leading strand can be synthesized continuously.
Discuss why the lagging strand must be synthesized in fragments.

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Q15. What is the general flow of genetic information?

Background

Topic: Central Dogma of Molecular Biology

This question is about the pathway from DNA to RNA to protein.

Key Terms and Formula:

Central Dogma: DNA → RNA → Protein

Step-by-Step Guidance

Describe the process of transcription (DNA to RNA).
Explain translation (RNA to protein).
Discuss the importance of this flow for cell function.

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Q16. Explain the three main steps of transcription.

Background

Topic: Transcription

This question is about the process of making RNA from DNA.

Key Terms:

Initiation, elongation, termination.

Step-by-Step Guidance

Describe what happens during initiation (RNA polymerase binds to promoter).
Explain elongation (RNA strand is synthesized).
Discuss termination (RNA polymerase releases the completed RNA).

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Q17. Describe the function of the three RNA types: mRNA, tRNA, rRNA.

Background

Topic: Types of RNA

This question is about the roles of messenger, transfer, and ribosomal RNA in protein synthesis.

Key Terms:

mRNA: Carries genetic code from DNA to ribosome.
tRNA: Brings amino acids to ribosome.
rRNA: Forms the core of the ribosome.

Step-by-Step Guidance

Define each type of RNA.
Explain the function of each in translation.
Discuss how they work together to build proteins.

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Q18. Eukaryotic mRNA has Introns and Exons. Define Introns and Exons and explain their purpose.

Background

Topic: RNA Processing

This question is about the structure of eukaryotic genes and mRNA splicing.

Key Terms:

Introns: Non-coding sequences.
Exons: Coding sequences.

Step-by-Step Guidance

Define introns and exons.
Explain why introns are removed during splicing.
Discuss the purpose of exons in coding for proteins.

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Q19. What is mRNA splicing?

Background

Topic: RNA Processing

This question is about the removal of introns from pre-mRNA.

Key Terms:

Splicing: Removal of introns, joining of exons.

Step-by-Step Guidance

Describe the process of splicing.
Explain the role of the spliceosome.
Discuss the importance for mature mRNA.

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Q20. Where does transcription occur in Eukaryotes vs prokaryotes, and why?

Background

Topic: Cell Biology

This question is about the location of transcription in different cell types.

Key Terms:

Eukaryotes: Nucleus.
Prokaryotes: Cytoplasm.

Step-by-Step Guidance

Describe where transcription occurs in each cell type.
Explain why eukaryotes have a nucleus and prokaryotes do not.
Discuss the implications for gene expression.

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Q21. What is a codon? Provide an example.

Background

Topic: Genetic Code

This question is about the triplet code in mRNA.

Key Terms:

Codon: Three-nucleotide sequence in mRNA.

Step-by-Step Guidance

Define codon.
Explain how codons specify amino acids.
Provide an example (e.g., AUG codes for methionine).

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Q22. What is an anticodon?

Background

Topic: Translation

This question is about the complementary sequence on tRNA.

Key Terms:

Anticodon: Three-nucleotide sequence on tRNA.

Step-by-Step Guidance

Define anticodon.
Explain how anticodons pair with codons during translation.
Discuss the importance for accurate protein synthesis.

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Q23. Explain the steps of Translation.

Background

Topic: Protein Synthesis

This question is about the process of translating mRNA into protein.

Key Terms:

Initiation, elongation, termination.

Step-by-Step Guidance

Describe initiation (ribosome assembly, first tRNA binds).
Explain elongation (tRNA brings amino acids, peptide bonds form).
Discuss termination (stop codon, release of protein).

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Q24. What is the difference between horizontal and vertical gene transfer?

Background

Topic: Genetic Variation

This question is about how genes are transferred between organisms.

Key Terms:

Horizontal gene transfer: Between organisms, not parent to offspring.
Vertical gene transfer: From parent to offspring.

Step-by-Step Guidance

Define horizontal and vertical gene transfer.
Explain the significance for genetic diversity.
Discuss examples (e.g., antibiotic resistance).

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Q25. Explain the processes of horizontal gene transfer (HGT): Conjugation, Transformation, Transduction, Transposons.

Background

Topic: Microbial Genetics

This question is about the mechanisms by which bacteria acquire new genes.

Key Terms:

Conjugation: Direct transfer via pilus.
Transformation: Uptake of free DNA.
Transduction: Transfer by bacteriophage.
Transposons: Mobile genetic elements.

Step-by-Step Guidance

Describe each process briefly.
Explain how each contributes to genetic variation.
Discuss the importance for evolution and adaptation.

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Q26. Explain how genetic variation occurs without sexual reproduction.

Background

Topic: Microbial Genetics

This question is about mechanisms of genetic diversity in microbes.

Key Terms:

Mutation, horizontal gene transfer, recombination.

Step-by-Step Guidance

List mechanisms for genetic variation (e.g., mutation, HGT).
Explain how these processes work.
Discuss their impact on microbial populations.

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Q27. Explain why viruses are classified as nonliving microbes.

Background

Topic: Virology

This question is about the characteristics that distinguish viruses from living organisms.

Key Terms:

Nonliving: Lack metabolism, cannot reproduce independently.

Step-by-Step Guidance

List criteria for life (e.g., metabolism, cellular structure).
Explain which criteria viruses do not meet.
Discuss why viruses are considered nonliving.

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Q28. Fill out the table: Compare viruses, prokaryotes, and eukaryotes (cells, alive, structure, replication, metabolism, genome composition).

Background

Topic: Microbial Classification

This question is about the differences between viruses, prokaryotes, and eukaryotes.

Key Terms:

Cellular structure, metabolism, genome type.

Step-by-Step Guidance

List characteristics for each group.
Compare and contrast their features.
Discuss implications for classification.

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Q29. Describe features and functions of viral structures, including capsids, envelopes, and spikes.

Background

Topic: Virology

This question is about the structural components of viruses and their roles.

Key Terms:

Capsid: Protein shell.
Envelope: Lipid membrane.
Spikes: Glycoproteins for attachment.

Step-by-Step Guidance

Describe each structure and its function.
Draw and label a virus with these features.
Explain how these structures affect infectivity.

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Q30. Explain how viral envelopes develop, which types of viruses would contain a viral envelope, and the pros and cons of having an envelope.

Background

Topic: Virology

This question is about the origin and significance of viral envelopes.

Key Terms:

Envelope: Derived from host cell membrane.
Enveloped vs non-enveloped viruses.

Step-by-Step Guidance

Explain how envelopes are acquired during viral release.
List types of viruses with envelopes.
Discuss advantages and disadvantages of envelopes.

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Q31. Explain the importance of viral spikes regarding tropism and host immune responses. Relate this knowledge to the influenza virus and explain the consequences of mutations in the spikes.

Background

Topic: Virology

This question is about how viral spikes determine host specificity and immune evasion.

Key Terms:

Tropism: Specificity for host cells.
Immune response: Recognition by antibodies.

Step-by-Step Guidance

Describe the role of spikes in host cell attachment.
Explain how spikes affect tropism.
Discuss how mutations in spikes can lead to immune evasion (e.g., influenza antigenic drift).

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Q32. What type of genetic material can a virus contain (DNA vs RNA, single or double stranded, chromosome type)?

Background

Topic: Viral Genomes

This question is about the diversity of viral genetic material.

Key Terms:

DNA or RNA, single or double stranded, linear or circular.

Step-by-Step Guidance

List possible types of viral genomes.
Explain how genome type affects replication.
Discuss examples of viruses with different genome types.

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Q33. What do viral genomes encode for?

Background

Topic: Viral Genetics

This question is about the functions encoded by viral genes.

Key Terms:

Structural proteins, enzymes, regulatory proteins.

Step-by-Step Guidance

List types of proteins encoded by viral genomes.
Explain their roles in viral replication and assembly.
Discuss why viruses rely on host machinery.

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Q34. Explain why viruses exhibit a fast rate of genomic change.

Background

Topic: Viral Evolution

This question is about mutation rates and genetic variation in viruses.

Key Terms:

Mutation, recombination, reassortment.

Step-by-Step Guidance

Explain why viral polymerases are error-prone.
Discuss the role of recombination and reassortment.
Describe the consequences for viral evolution.

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Q35. Explain the process of genetic re-assortment.

Background

Topic: Viral Genetics

This question is about how viruses exchange genetic material.

Key Terms:

Reassortment: Exchange of genome segments.

Step-by-Step Guidance

Describe how reassortment occurs in segmented viruses.
Explain the impact on viral diversity.
Discuss examples (e.g., influenza virus).

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Q36. Explain antigenic shift vs antigenic drift (relate to influenza virus).

Background

Topic: Viral Evolution

This question is about mechanisms of genetic change in viruses.

Key Terms:

Antigenic drift: Small mutations.
Antigenic shift: Major changes via reassortment.

Step-by-Step Guidance

Define antigenic drift and shift.
Explain how each affects influenza virus.
Discuss consequences for immunity and outbreaks.

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Q37. What is an attenuated strain?

Background

Topic: Vaccines and Virology

This question is about weakened forms of viruses used in vaccines.

Key Terms:

Attenuated: Weakened, non-pathogenic.

Step-by-Step Guidance

Define attenuated strain.
Explain how attenuation is achieved.
Discuss the use in vaccines.

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Q38. Explain how viruses are grouped (which four properties).

Background

Topic: Viral Classification

This question is about the criteria used to classify viruses.

Key Terms:

Genome type, capsid shape, envelope presence, host range.

Step-by-Step Guidance

List the four properties used for classification.
Explain each property briefly.
Discuss examples of virus groups.

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Q39. Define host range.

Background

Topic: Virology

This question is about the spectrum of hosts a virus can infect.

Key Terms:

Host range: Number of species or cell types a virus can infect.

Step-by-Step Guidance

Define host range.
Explain factors that determine host range.
Discuss examples of broad and narrow host range.

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Q40. Explain the difference between broad and narrow host range (give examples).

Background

Topic: Virology

This question is about the specificity of viruses for different hosts.

Key Terms:

Broad host range: Infects many species.
Narrow host range: Infects few species.

Step-by-Step Guidance

Define broad and narrow host range.
Provide examples (e.g., rabies virus vs HIV).
Discuss implications for disease spread.

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Q41. Define tropism.

Background

Topic: Virology

This question is about the specificity of viruses for certain cell types.

Key Terms:

Tropism: Preference for specific cell types.

Step-by-Step Guidance

Define tropism.
Explain how viral spikes determine tropism.
Discuss examples of broad and narrow tropism.

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Q42. Explain the difference between broad and narrow tropism (give examples).

Background

Topic: Virology

This question is about the range of cell types a virus can infect.

Key Terms:

Broad tropism: Infects many cell types.
Narrow tropism: Infects specific cell types.

Step-by-Step Guidance

Define broad and narrow tropism.
Provide examples (e.g., cytomegalovirus vs hepatitis B).
Discuss implications for disease severity.

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Q43. What is a bacteriophage?

Background

Topic: Virology

This question is about viruses that infect bacteria.

Key Terms:

Bacteriophage: Virus that infects bacteria.

Step-by-Step Guidance

Define bacteriophage.
Describe its structure.
Discuss its role in gene transfer.

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Q44. DRAW and Explain the lytic pathway.

Background

Topic: Bacteriophage Replication

This question is about the process by which bacteriophages destroy their host.

Key Terms:

Lytic cycle: Infection, replication, lysis.

Step-by-Step Guidance

Draw the steps of the lytic cycle.
Explain each step (attachment, entry, replication, assembly, lysis).
Discuss the outcome for the host cell.

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Q45. DRAW and Explain lysogenic replication.

Background

Topic: Bacteriophage Replication

This question is about the process by which bacteriophages integrate into the host genome.

Key Terms:

Lysogenic cycle: Integration, dormancy, induction.

Step-by-Step Guidance

Draw the steps of the lysogenic cycle.
Explain each step (integration, replication with host, induction).
Discuss the potential for switching to lytic cycle.

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Q46. What is a temperate virus?

Background

Topic: Virology

This question is about viruses that can undergo both lytic and lysogenic cycles.

Key Terms:

Temperate virus: Can integrate into host genome.

Step-by-Step Guidance

Define temperate virus.
Explain its ability to switch between cycles.
Discuss implications for host cell.

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Q47. Explain the six steps of generalized replication in animal viruses.

Background

Topic: Animal Virus Replication

This question is about the stages of viral infection in animal cells.

Key Terms:

Attachment, entry, uncoating, replication, assembly, release.

Step-by-Step Guidance

List the six steps.
Describe what happens at each stage.
Discuss differences between enveloped and non-enveloped viruses.

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Q48. Explain the difference between fusion and endocytosis during the penetration phase and the difference between budding and lysing during the release phase.

Background

Topic: Viral Entry and Exit

This question is about mechanisms of viral entry and release from host cells.

Key Terms:

Fusion: Viral envelope merges with cell membrane.
Endocytosis: Cell engulfs virus.
Budding: Virus exits via membrane.
Lysing: Cell bursts to release virus.

Step-by-Step Guidance

Describe fusion and endocytosis mechanisms.
Explain budding and lysing during viral release.
Discuss implications for cell survival.

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Q49. Explain the difference between acute, latent and chronic infections.

Background

Topic: Viral Pathogenesis

This question is about types of viral infections and their outcomes.

Key Terms:

Acute: Rapid onset, short duration.
Latent: Dormant, can reactivate.
Chronic: Persistent, long-term.

Step-by-Step Guidance

Define each type of infection.
Explain how they differ in symptoms and duration.
Discuss examples of each type.