Chapter 4: Human Microbiome

Question 1

biome

Answer 1

a naturally occurring community of plants or animals occupying a particular habitat

Question 2

microbiome

Answer 2

a collection of microorganisms residing within distinct communities on and in the human body

Question 3

the human microbiome

Answer 3

• essential for human life
• an organized system of microbes within every healthy adult
• consists of over 100 trillion organisms
• discovered by “The Human Microbiome Project”
• the human body contains more microbes than human cells

Question 4

importance of the microbiome

Answer 4

essential for normal body function:
- digest food
- absorb nutrients
- prime immune system
- produce vitamins
- play a role in energy production
- guard against disease
- influence mental health

Question 5

microbial communities

Answer 5

• nostrils
• teeth
• mouth
• gastrointestinal tract
• vagina

Question 6

genetic implications

Answer 6

• 22,000 human genes vs. 8,000,000 microbial genes
• humans share 99.9% of the same DNA
• no two individuals have the same microbiome
• microbiome often referred to as our “second genome”

Question 7

dysbiosis

Answer 7

imbalances of the microbiome

Question 8

communication

Answer 8

• there is two way communication between the microbiome and body systems
• members of the microbiota release hormones and chemicals into the bloodstream
• hormones secreted elsewhere influence members of the microbiota

Question 9

building a microbiome

Answer 9

• birth process (most significant)
  
  • placenta contains its own microbiome and most likely inoculates the fetus with microbes
  • when a newborn passes through the birth canal, bacteria from a woman’s vagina coat the newborn, forming the bulk of the newborn’s microbiome
• trees
• skin contact
• other people
• breastfeeding
• furniture
• pets

Question 10

immune system and microbes

Answer 10

greater microbial diversity = a stronger immune system
- low diversity microbiomes have been linked to multiple
disorders
- obesity, arthritis, IBS, osteoporosis, psychiatric disorders,
cancer

Question 11

breastfeeding

Answer 11

• breast milk contains more than 700 species of bacteria and sugars the infants cannot digest
• the sugar nourishes the beneficial gut bacteria
• 30% of beneficial bacteria in baby’s intestinal tract come from breast milk
• another 10% comes from the skin on the mother’s breast

Question 12

cesarean section

Answer 12

• infants delivered by c-section lack man microbes routinely passed from mother to child
• have significantly increased risk of developing asthma, systematic connective tissue disorders, juvenile arthritis, IBS, immune deficiencies, leukemia, and Crohn’s disease

Question 13

bacterial link to obesity

Question 14

stages of microbiome development

Answer 14

• in utero: from placenta
• birth: passage through the birth canal
• first year: breastfeeding
• second year: solid food
• ages 2 to 5: resembles that of an adult
• adulthood: altered by food, environment, antibiotics
• old age: decreased diversity

Question 15

boosting the microbiome

Answer 15

• consumption of a high-fiber, plant based diet
• eating foods rich in polyphenols
• taking probiotics
• consuming prebiotics
• eating fermented foods
• exercising
• spending time outdoors
• avoiding unnecessary antibiotics

Question 16

threats to the microbiome

Answer 16

• antibiotic
• a high fat, high sugar diet
• stress
• smoking
• air pollution
• sedentary lifestyle
• overuse of sanitizing products
• invasion by disease-causing bacteria

Question 17

stress

Answer 17

stress makes the gut more accessible to unwanted bacteria. these bacteria then trigger an immune response that depletes the microbiome of beneficial bacteria

Question 18

components of the microbiome

Answer 18

• bacteria
• viruses
• fungi
• archaea

Question 18

components of the microbiome

Answer 18

• bacteria
• viruses
• fungi
• archaea

Question 19

bacteria

Answer 19

• the chief inhabitant of the microbiome
• single-cell microscopic organisms
• components:

Question 20

cocci

Answer 20

round or spherical

Question 21

bacilli

Answer 21

rod-shaped

Question 22

spirilla

Answer 22

spiral-shaped

Question 23

diplococci

Answer 23

cocci that exist in sets of two, whereas monococci live singly

Question 24

staphylococci

Answer 24

cocci that occur in clusters

Question 25

streptococci

Answer 25

cocci that exist in chain form

Question 26

gram-positive bacteria

Answer 26

• have a thick layer of peptidoglycan in cell wall
• retain dye
• stain purple

Question 27

gram-negative bacteria

Answer 27

• have a thin layer of peptidoglycan in cell wall
• lose dye when rinsed
• appear red or pink after counterstain is applied

Question 28

viruses

Answer 28

• extremely small infectious agents
• cannot be seen under light microscope
• unlike bacteria, viruses are NOT cells
• can’t metabolize nutrients, produce or excrete waste, or move around independently
• cannot reproduce on their own (must be inside a host cell)

Question 29

viral shapes

Answer 29

• helical capsid
• polyhedral capsid
• complex capsid

Question 30

bacteriophages

Question 31

viral replication

Answer 31

• viruses must invade a host cell and hijack the cell’s metabolic chemicals and ribosomes
  1.

Question 32

fungi

Answer 32

• include molds and yeasts
• live in the soil, on plants, and in the air
• millions of fungal species reside in the human microbiome
• can overgrow and cause illness when immune system is compromised
• many fungal infections begin on the skin or in the lungs