PLTW BIOMEDICAL SCIENCE LEVEL 1 REVISED EXAM
2025/2026 Q&A
Medical Interventions - A medical intervention is any measure whose purpose is to improve health or
alter the course of a disease.
Pathogens - Pathogens are biological agents that cause disease (typically bacteria and viruses, but
may also be fungi, protozoans, helminths, or prions).
Bioinformatics - The collection, classification, storage, and analysis of biochemical and genetic
information using computers
(think "big data" in relation to genetic information)
Outbreak - An outbreak is when cases of a disease occur in numbers greater than expected in a
specific area or among a specific group of people.
How can Bioinformatics be used to identify disease pathogens. - 1. **Genomic Sequencing**:
Bioinformatics tools analyse the genetic material of pathogens. By sequencing the DNA or RNA of a
pathogen, researchers can identify its unique genetic markers.
2. **Comparative Genomics**: By comparing the genomic sequences of known pathogens with
those of unknown samples, scientists can identify similarities that indicate the presence of a specific
pathogen.
3. **Phylogenetic Analysis**: This involves constructing a phylogenetic tree to understand the
evolutionary relationships between different pathogens. It helps in tracking the source and spread of
infectious diseases.
4. **Protein Analysis**: Bioinformatics can also analyse proteins expressed by pathogens, helping to
identify their function and potential vulnerabilities.
5. **Data Integration**: By integrating data from various sources, such as clinical records,
environmental factors, and genetic information, bioinformatics provides a comprehensive view of
disease outbreaks and pathogen characteristics.
Overall, bioinformatics plays a crucial role in modern microbiology and epidemiology, enhancing our
ability to detect and respond to infectious diseases.
What is the purpose of PCR - PCR, or Polymerase Chain Reaction, used to amplify small segments of
DNA. It allows scientists to make millions of copies of a specific DNA sequence,
1. **Denaturation**: The double-stranded DNA is heated to separate it into two single strands.
, 2. **Annealing**: Short DNA primers attach to the specific target sequences on the single-stranded
DNA.
3. **Extension**: A DNA polymerase enzyme synthesizes new DNA strands by adding nucleotides to
the primers, effectively doubling the amount of DNA.
Primers - Short segments of DNA that are complimentary to the template strands of a copy so when
they attach it provides a double stranded segment to which DNA Polymerase can attach and begin
adding nucleotides.
What region of DNA is used to identify primers that can be used to separate the pathogen's DNA
from the patients? And why? - Ribosomes - Pathogens have ribosomes that are unique to every
other organism.
Reactants in PCR reaction - 1. Primers
2. DNA Polymerase
3. Nucleotides (dNTPs)
4. Fluorescently labeled ddNTPs
How are ddNTPs different from dNTPs? - Deoxyribose (Sugar) is missing an oxygen, and each base
has a different colored fluorescent tag added.
What happens when ddNTP is added to a DNA strand during replication? Why is this Useful? - It
stops the replication because the ddNTP is missing an oxygen therefore it cannot complete
Dehydration synthesis.
Useful because it creates DNA fragments of different lengths.
What is the purpose of Gel Electrophoresis in DNA sequencing? - To separate different sized DNA
fragments.
What is a Molecular Database? - A molecular database is a collection of molecular information that
stores data about various biological molecules, such as proteins, nucleic acids, and small molecules.
These databases can include sequences, structures, functions, and interactions of molecules.
What molecular database did we use to identify unkown pathogens? - Basic Local Alignment Search
Tool, often called "BLAST"
2025/2026 Q&A
Medical Interventions - A medical intervention is any measure whose purpose is to improve health or
alter the course of a disease.
Pathogens - Pathogens are biological agents that cause disease (typically bacteria and viruses, but
may also be fungi, protozoans, helminths, or prions).
Bioinformatics - The collection, classification, storage, and analysis of biochemical and genetic
information using computers
(think "big data" in relation to genetic information)
Outbreak - An outbreak is when cases of a disease occur in numbers greater than expected in a
specific area or among a specific group of people.
How can Bioinformatics be used to identify disease pathogens. - 1. **Genomic Sequencing**:
Bioinformatics tools analyse the genetic material of pathogens. By sequencing the DNA or RNA of a
pathogen, researchers can identify its unique genetic markers.
2. **Comparative Genomics**: By comparing the genomic sequences of known pathogens with
those of unknown samples, scientists can identify similarities that indicate the presence of a specific
pathogen.
3. **Phylogenetic Analysis**: This involves constructing a phylogenetic tree to understand the
evolutionary relationships between different pathogens. It helps in tracking the source and spread of
infectious diseases.
4. **Protein Analysis**: Bioinformatics can also analyse proteins expressed by pathogens, helping to
identify their function and potential vulnerabilities.
5. **Data Integration**: By integrating data from various sources, such as clinical records,
environmental factors, and genetic information, bioinformatics provides a comprehensive view of
disease outbreaks and pathogen characteristics.
Overall, bioinformatics plays a crucial role in modern microbiology and epidemiology, enhancing our
ability to detect and respond to infectious diseases.
What is the purpose of PCR - PCR, or Polymerase Chain Reaction, used to amplify small segments of
DNA. It allows scientists to make millions of copies of a specific DNA sequence,
1. **Denaturation**: The double-stranded DNA is heated to separate it into two single strands.
, 2. **Annealing**: Short DNA primers attach to the specific target sequences on the single-stranded
DNA.
3. **Extension**: A DNA polymerase enzyme synthesizes new DNA strands by adding nucleotides to
the primers, effectively doubling the amount of DNA.
Primers - Short segments of DNA that are complimentary to the template strands of a copy so when
they attach it provides a double stranded segment to which DNA Polymerase can attach and begin
adding nucleotides.
What region of DNA is used to identify primers that can be used to separate the pathogen's DNA
from the patients? And why? - Ribosomes - Pathogens have ribosomes that are unique to every
other organism.
Reactants in PCR reaction - 1. Primers
2. DNA Polymerase
3. Nucleotides (dNTPs)
4. Fluorescently labeled ddNTPs
How are ddNTPs different from dNTPs? - Deoxyribose (Sugar) is missing an oxygen, and each base
has a different colored fluorescent tag added.
What happens when ddNTP is added to a DNA strand during replication? Why is this Useful? - It
stops the replication because the ddNTP is missing an oxygen therefore it cannot complete
Dehydration synthesis.
Useful because it creates DNA fragments of different lengths.
What is the purpose of Gel Electrophoresis in DNA sequencing? - To separate different sized DNA
fragments.
What is a Molecular Database? - A molecular database is a collection of molecular information that
stores data about various biological molecules, such as proteins, nucleic acids, and small molecules.
These databases can include sequences, structures, functions, and interactions of molecules.
What molecular database did we use to identify unkown pathogens? - Basic Local Alignment Search
Tool, often called "BLAST"
