Week 12

Question 1

human microbiome

Answer 1

the functional collection of different microbes that inhabit the human body
Different in different areas

Question 2

microorganisms abundant in

Answer 2

mouth, nasal cavity, throat, stomach, intestines, urogenital tract and skin

Question 3

symbiosis

Answer 3

beneficial to at least one organism

Question 4

commensalism

Answer 4

where one organism benefits while the other remains unaffected

Question 5

mutualism

Answer 5

where both organisms benefit from the association

Question 6

parasitism

Answer 6

where one organism benefits at the expense of the other

Question 7

type of microbe determined by

Answer 7

chemistry in the area where it is located

Question 8

enterotype

Answer 8

type and number of flora we have
unrelated to gender, BMI, nationality
related to long term dietary patterns

Question 9

Ileum (anoxic)

Answer 9

Fusiform anaerobic bacteria attached to intestinal wall at one end; compete with host for rapid uptake of small carbs

Question 10

colon

Answer 10

obligate anaerobes like Clostridium and Bacteroides spp (complex carbs)

Question 11

gut bacteria composition determined early in life by:

Answer 11

delivery method

infant nutrition

Question 12

delivery method

Answer 12

Vaginally: similar bacterial distributions to mum’s gut (Escherichia, Bifidobacterium and Enterococcus spp.)
C-section: have bacteria normally found in skin nd oral cavity; due to mum’s antibiotics which impact microbe colonisation and diversity; also lower likelihood of breastfeeding

Question 13

Infant nutrition

Answer 13

Breastfeeding: high probiotics (Lactobacillus spp., Bifidobacterium longum); metabolise unusual complex sugars in breastmilk
Formula fed: do not have a predominant gut bacteria; populations of potentially harmful microbes like C.difficile
Interestingly, in babies that are breastfed, the shift in the gut microbiota to an adult-like species distribution occurs at the cessation of breastfeeding, rather than the introduction of solid foods, suggesting breast milk plays a significant role in determining the gut’s microbial composition.

Question 14

Gut-brain axis

Answer 14

Gut bacteria can produce tryptamine, a tryptophan metabolite thought to function as a biogenic neurotransmitter that signals to the enteric nervous system.

Question 15

people with depression

Answer 15

lack Coprococcus and Dialister

Question 16

Algae obtained by coral in two ways

Answer 16

The algal symbiont is present in the egg that is released from the coral parent OR
Free living algae are ingested by the coral. The coral then digests all of them except the most suitable one for the relationship

Question 17

coral may change its symbiont via two methods

Answer 17

symbiont swapping

symbiont switching

Question 18

symbiont swapping

Answer 18

the coral has more than one algal genetic variant present. After a traumatic event, the dominant algal variant changes

Question 19

symbiont switching

Answer 19

a new algae is taken up from a free-living water column population