Topic 5 - Science as a Human Endeavour

Question 1

What are antibiotics?

Answer 1

Antibiotics are substances that target bacteria, either by killing them or inhibiting their growth. They are used to treat bacterial infections only — they do not affect viruses.

Question 2

What are the two main ways antibiotics target bacteria?

Answer 2

• Disrupting bacterial cell wall or membrane function, causing death (bactericidal).
• Inhibiting essential processes like protein or DNA synthesis, slowing growth (bacteriostatic).
• These mechanisms ensure bacteria can’t survive or multiply.

Question 3

What are narrow-spectrum antibiotics?

Answer 3

Narrow-spectrum antibiotics: Effective against specific types of bacteria (e.g., only Gram-positive).

Question 4

What are broad-spectrum antibiotics?

Answer 4

Broad-spectrum antibiotics: Act on a wide variety of bacteria, both Gram-positive and Gram-negative. Broad-spectrum is useful when the specific pathogen is unknown but may disrupt beneficial bacteria too.

Question 5

What are bactericidal antibiotics?

Answer 5

Kills basteria by changing the cell wall or disrupting the action of essential enzymes.

Question 6

What are bacteriostatic antibiotics?

Answer 6

Prevents reproduction of bacteria by disrupting protein synthesis.

Question 7

What is antibiotic resistance?

Answer 7

Antibiotic resistance occurs when bacteria mutate or acquire genes that protect them from antibiotics.

Question 8

How does antibiotic resistance occur?

Answer 8

• Overuse or misuse of antibiotics (not finishing prescriptions)
• Horizontal gene transfer between bacteria
• Selective pressure allowing resistant strains to multiply

This makes future infections harder to treat and can lead to superbugs.

Question 9

What are antivirals?

Answer 9

Antivirals are drugs that inhibit viral replication and spread within the body. They do not kill viruses but block parts of their life cycle to limit infection severity. Unlike antibiotics, antivirals are virus specific.

Question 10

Why is it difficult to develop antiviral drugs?

Answer 10

• Viruses replicate inside host cells, using the host’s machinery.
• This makes it hard to target viruses without damaging healthy cells.
• Viruses mutate rapidly, leading to drug resistance.
• Targeting the virus without harming host cells is a key challenge.

Question 11

How do antiviral drugs work to stop viral infections?

Answer 11

• Preventing viral attachment and/or entry into host cells
• Inactivating extracellular viral particles (before entering cells)
• Preventing replication of the viral genome
• Blocking transcription/translation of viral proteins
• Stopping assembly or release of new viruses

Question 12

What is the structure of DNA?

Answer 12

DNA is made up of two strands of nucleotides twisted into a double helix. Each nucleotide has a deoxyribose sugar, phosphate group, and a nitrogenous base (Adenine, Thymine, Cytosine, or Guanine). The bases pair specifically — A with T, and C with G.

Question 13

What is recombinant DNA technology?

Answer 13

The artificial manipulation of DNA by combining genes from different organisms to produce new combinations of alleles.

Question 14

What is artificial selection?

Answer 14

Choosing parent organisms with desirable traits to breed.

Question 15

What is genetic engineering?

Answer 15

The deliberate modification of an organism’s DNA using biotechnology.

Question 16

What is recombinant DNA?

Answer 16

DNA formed by combining DNA from different sources.

Question 17

What is GMO (Genetically Modified Organism)?

Answer 17

An organism whose DNA has been altered.

Question 18

What is a transgenic organism?

Answer 18

An organism that contains DNA from another species.

Question 19

What are restriction enzymes and how are they used?

Answer 19

Restriction enzymes cut DNA at specific recognition sites. They can create:

• Sticky ends: staggered cuts with overhanging bases
• Blunt ends: straight cuts with no overhangs

They’re used to cut both the gene of interest and the plasmid so they can be joined later in recombinant DNA processes.

Question 20

What is DNA ligase?

Answer 20

DNA ligase is an enzyme that joins DNA fragments together by sealing bonds between the sugar and phosphate backbone. This is found in E. Coli

Question 21

What is litigation?

Answer 21

Ligation is the process of binding these fragments into a single, continuous DNA strand — essential in forming recombinant DNA.

Question 22

What is a vector?

Answer 22

A vector is a DNA molecule used to carry the gene of interest into a host cell.

Question 23

How are vectors used?

Answer 23

1) Isolate the gene using restriction enzymes
2) Isolate the vector with the same restriction enzyme

3) Insert the gene into the vector
- Bacterial plasmids and phage viruses are used
- Plasmids are circular double-stranded capable
of replicating in a cell

4) Use DNA ligase to seal it
5) Introduce the vector into a host cell

Question 24

What are bacterial plasmids?

Answer 24

Small, circular DNA molecules that replicate independently.

Question 25

What are bacteriophages?

Answer 25

Viruses that infect bacteria, also used to deliver DNA. They are used in genetic engineering to deliver foreign genes into host cells where they can be expressed.

Question 26

What are examples of how recombinant DNA technology is used in the modern day.

Answer 26

- Producing synthetic hormones: Insulin, Thyroxine, Growth Hormone, FSH, Factor VIII - Creating vaccines: Hepatitis B, HPV - Gene therapy for diseases like cystic fibrosis - Diagnosis of genetic disorders - Research into gene function and disease

Question 27

How is recombinant DNA used in research and vaccines?

Answer 27

Recombinant DNA allows scientists to insert viral genes into cells (yeast), which then produce viral proteins. These proteins are used in recombinant protein subunit vaccines, such as the Hepatitis B and HPV vaccines.

Question 28

What are synthetic hormones?

Answer 28

Synthetic hormones are hormones made in the lab to mimic natural hormones. They're used to treat conditions such as diabetes and thyroid disorders, replacing hormones that the body cannot produce in sufficient quantities.

Question 29

How is recombinant DNA technology used to produce synthetic hormones?

Answer 29

1) Identify and isolate the gene that codes for the human hormone (e.g. insulin). 2) Insert the gene into a plasmid (a circular DNA molecule). 3) Introduce the plasmid into a bacterial or yeast cell (commonly E. coli for insulin). 4) Bacteria reproduce, making many copies of the gene and producing the hormone. 5) Harvest and purify the hormone from the culture. 6) Use the hormone for medical purposes, such as treating diabetes.

Question 30

What is gene therapy?

Answer 30

Gene therapy is a technique for treating or curing genetic disorders by inserting, correcting, or replacing faulty genes with healthy ones in a patient’s cells. It often uses recombinant DNA technology and viral vectors to deliver the correct gene into target cells.

Question 31

What is Cell Replacement Therapy?

Answer 31

This therapy involves replacing damaged or dead cells with healthy, functioning ones — especially useful in neurodegenerative diseases like Alzheimer’s and Parkinson’s. - Often uses stem cells (embryonic stem cells or induced pluripotent stem cells). - Aim is to regenerate or restore lost tissue and function.

Question 32

What is Tissue Engineering?

Answer 32

Tissue engineering aims to grow healthy tissues in the lab using a patient’s own disease-free cells. - Cells are seeded onto a biodegradable scaffold that supports 3D growth. - Once the tissue grows, it’s implanted into the body and the scaffold naturally degrades. - Used in skin grafts, cartilage repair, and experimental organ regeneration.

Question 33

What is Alzheimers Disease?

Answer 33

A condition that affectes the memory centre of the brain, affecting, memory, language and thinking.

Question 34

What are symptoms of Alzheimers?

Answer 34

- Short term memory loss - Difficulty thinking - Language and speech difficulties

Question 35

What are causes of Alzheimers?

Answer 35

- Proteins called plaques and tangles accumulate in the brain which overtime results in cell death. - Reduction in acetylcholine results in speech difficulty and memory loss.

Question 36

What is Parkinsons Disease?

Answer 36

A condition that affects the part of the brain responsible for movement (basal ganglia).

Question 37

What are symptoms for Parkinsons Disease?

Answer 37

- Tremors - Slower movement - Muscle stiffness and rigidity

Question 38

What are causes for Parkinsons Disease?

Answer 38

Reduction in dopamine producing cells in the brain which causes tremors and loss of fine motor skills.