ICAR AICE-JRF/SRF Advanced Dairy Microbiology: practice questions

1 · Genomics of lactic acid bacteria · medium

The first complete genome of a lactic acid bacterium, published in 2001, was that of:

1. Lactococcus lactis IL1403
2. Lactobacillus acidophilus NCFM, which was the first probiotic genome sequenced in the 1990s
3. Escherichia coli K-12
4. Streptococcus thermophilus LMD-9, sequenced before any lactococcus

2 · CRISPR systems and phage resistance · medium

Cas9 belongs to which CRISPR–Cas class and type?

1. Class 1, type I, using a multi-protein Cascade complex
2. Class 2, type II
3. Class 1, type III
4. Class 2, type VI

3 · CRISPR systems and phage resistance · medium

Phages escape CRISPR immunity most commonly by:

1. Mutating the protospacer or PAM
2. Acquiring their own CRISPR arrays from the host
3. Becoming lysogenic in every case
4. Increasing their burst size

4 · Microbiome of raw milk, cheese and the gut · medium

The proposal that a resident microbiome exists inside the healthy udder is:

1. Proven beyond doubt by culture of every milk sample worldwide
2. Rejected because milk never contains bacterial DNA
3. Debated because low-biomass samples are easily contaminated
4. Accepted only for goats

5 · Microbiome of raw milk, cheese and the gut · medium

Non-starter lactic acid bacteria in ripened cheddar-type cheese are mainly:

1. Streptococcus thermophilus added at the start of manufacture
2. Heterofermentative lactobacilli such as L. paracasei
3. Gram-negative coliforms
4. Bifidobacteria

6 · Metagenomics and amplicon sequencing · medium

Amplicon sequence variants (ASVs) differ from traditional OTUs in that ASVs are:

1. Clusters at 97% similarity defined differently in each study
2. Only fungal sequences
3. Counts of live cells
4. Exact denoised sequences

7 · Metagenomics and amplicon sequencing · medium

Metatranscriptomics adds to metagenomics by showing:

1. Which DNA is from dead cells only
2. The fat content of cheese
3. Which genes are actively expressed
4. Taxonomy at kingdom level only

8 · Stress responses and injured cells · medium

Which systems help Listeria tolerate acid by consuming protons?

1. Catalase and superoxide dismutase
2. Glutamate decarboxylase
3. Cold shock proteins
4. Lipoprotein lipase

9 · Predictive microbiology · medium

A bias factor above 1 for a pathogen growth model means it predicts:

1. Slower growth than observed
2. Faster growth than observed
3. Exactly the observed growth
4. No growth

10 · Predictive microbiology · medium

The gamma concept assumes that environmental factors affect growth rate:

1. Additively in every case
2. Only through temperature
3. Not at all
4. Multiplicatively and independently