LIFESCI 7C CERTIFICATION PAPER 2026
FULL SOLUTION GRADED A+
● Explain how and when the human microbiome is formed. Answer:
Babies inherit their microbiota from their mother
-> at birth, have immature microbiota
-> mother's milk helps the microbiota develop (Milk Oriented
Microbiota, aka MOM)
Infancy:
Breast milk contains lactose, lipids and Human Milk Oligosaccharides
(HMO)
Host cells can NOT digest HMOs, only bacteria/microbes can
-bifidobacteria-
Post-Infancy:
still dependent on bacteria to digest some complex polysaccharides,
fibers
-bacteroides-
● Describe how major life events influence the microbiome. Answer:
Birth:
- intro to microbes, womb is "sterile" environment
, - natural birth gets mother's internal microbes, C-section gets mother's
skin microbes
Toddler (2-3 y/o)
- maturation of microbiome
- presence of most microbes present in adults
● Identify selective pressures present in the developing and adult
microbiome. Answer:
● Explain in general terms how 16S sequencing data is collected.
Answer: -> DNA isolation from sample
-> PCR amplification of bacterial 16S rRNA gene
-> high-throughtput sequencing of amplified 16S rRNA genes
-> data processing, quality control, analysis
-> identify microbes and relative abundance
● Differentiate between alpha diversity and beta diversity. Answer:
Alpha:
a quantitative measure of different microbes present in a sample
Beta:
FULL SOLUTION GRADED A+
● Explain how and when the human microbiome is formed. Answer:
Babies inherit their microbiota from their mother
-> at birth, have immature microbiota
-> mother's milk helps the microbiota develop (Milk Oriented
Microbiota, aka MOM)
Infancy:
Breast milk contains lactose, lipids and Human Milk Oligosaccharides
(HMO)
Host cells can NOT digest HMOs, only bacteria/microbes can
-bifidobacteria-
Post-Infancy:
still dependent on bacteria to digest some complex polysaccharides,
fibers
-bacteroides-
● Describe how major life events influence the microbiome. Answer:
Birth:
- intro to microbes, womb is "sterile" environment
, - natural birth gets mother's internal microbes, C-section gets mother's
skin microbes
Toddler (2-3 y/o)
- maturation of microbiome
- presence of most microbes present in adults
● Identify selective pressures present in the developing and adult
microbiome. Answer:
● Explain in general terms how 16S sequencing data is collected.
Answer: -> DNA isolation from sample
-> PCR amplification of bacterial 16S rRNA gene
-> high-throughtput sequencing of amplified 16S rRNA genes
-> data processing, quality control, analysis
-> identify microbes and relative abundance
● Differentiate between alpha diversity and beta diversity. Answer:
Alpha:
a quantitative measure of different microbes present in a sample
Beta:
