Lecture 4 Microbes 1

Question 1

Why care about microbes (5)

Answer 1

They make us sick or not sick (gut, train immune system, protect against pathogens)
They evolve for billions of years,
They are present everywhere
They are essential for all global nutrient cycles (C, N, P)
They are models for evolution

Question 2

Louis Pasteur proved that (microbes)

Answer 2

invisible microbes are responsible for fermentation, sepsis and disease.

Question 3

Koch’s Postulates (to define infectious microbes) (4)

Answer 3

Found in abundance in all organisms with disease, none in healthy individuals.
Isolated from diseased and grown in pure culture
Cause disease when introduced to healthy organism
Identical to the original after infection

Question 4

Symbiosis is

Answer 4

organism living together

Question 5

Microbiome is

Answer 5

microbes living in and on plants/animals

Question 6

Human have __% bacteria by mass, __ common species.

Answer 6

2%; 100

Question 7

An example of mutually beneficial relationship

Answer 7

Vibrio fischeri on squid provide camouflage

Question 8

An example of pathogenesis

Answer 8

vibrio cholerae causes diarrheal illness

Question 9

Balance between bacterial and human cells: : by cells, : by genes

Answer 9

1:1; 100:1

Question 10

An example of bacterial fossils studies that is living today

Answer 10

Stromatolites are layered sedimentary formations (microbialite) that are created mainly by photosynthetic microorganisms such as cyanobacteria, sulfate-reducing bacteria, and Pseudomonadota (formerly proteobacteria). These microorganisms produce adhesive compounds that cement sand and other rocky materials to form mineral “microbial mats”. In turn, these mats build up layer by layer, growing gradually over time. A stromatolite may grow to a meter or more.

Question 11

Cyanobacteria through oxygenic photosynthesis can oxidize what

Answer 11

ferrous iron (2+) to ferric iron (3+) in flint and iron oxide

Question 12

Characteristics of bacteria evolution (2)

Answer 12

infinite adaptation (no fitness plateau), very rapid

Question 13

3 levels of biological organisation, their mechanism, and major processes

Answer 13

Question 14

Boundary for cells and its function (1+3)

Answer 14

plasma membrane of phospholipid bilayer (use: transport, signals, adhesion)

Question 15

Dual system of cells

Answer 15

Metabolism: harvest energy to form biomass
Information: store info to synthesize

Question 16

Importance of cell membrane in terms of dual system

Answer 16

Without a membrane the products of metabolism would rapidly diffuse away from one another.
Without a membrane the information system could not be permanently linked to the metabolic system.

Question 17

Why are large cells inefficient

Answer 17

SA/V is small. So cell reproduction happens instead of infinite growth.

Question 18

Two steps of evolution of natural selection

Answer 18

Reproduction includes division of biomass and replication of info
Efficient metabolism leads to rapid growth and production, and is inheritable

Question 19

Bacterial genomes store info in which two structures

Answer 19

nucleoid, plasmids (small DNA molecules not essential for function)

Question 20

Three characteristics of plasmids in cell reproduction (3)

Answer 20

Numbers received may vary in daughter cells
Plasmids encode conjugation results in transfer to a recipient via a pilus.
Could benefit bacteria or be parasites.

Question 21

Common process for eukaryotes and prokaryotes DNA replication? (7)

Answer 21

There are some occasional errors

Question 22

The process of chromosome replication and cell division (6)

Answer 22

Differential reproduction leads to evolution by natural selection.

Question 23

What does trophic links between different metabolisms of organisms mean

Answer 23

Product of one is reactant of another