Midterm 2 review

Question 1

An organism displays the following characteristics:
- a bilayer of phospholipids
- is an extremophile
- a circular chromosome
- contains histone proteins
- a cell wall
- absence of organelles
It is:

Answer 1

An archaea

Question 2

The growth of a bacterial population in the log-phase displayed on a log-scale is:

Answer 2

Linear

Question 3

In the Long Term Evolutionary Experiment (LTEE) conducted by Dr. Richard Lenski, which of the following is (or are) important to show that the population has adapted to low-glucose utilization through the accumulation of beneficial mutations?

Answer 3

1) The measure of population growth (in the log-phase) in the presence of glucose
The comparison of growth rate to the ancestral population
2) The daily transfer of the population into a fresh glucose medium
3) The sequencing of the ancestral and the evolved populations

Question 4

Concentration of a nutrient becomes a limiting factor:

Answer 4

When the graph begins to plateau

Question 5

What characteristic makes the F factor a selfish-element?

Answer 5

The genes it contains code for the formation of a sex pilus, which facilitates its own transmission.

Question 6

You wish to create and isolate a recombinant bacteria that carries an ampicillin-resistance gene. How would you proceed?

Answer 6

You perform a transformation of the bacteria with a plasmid containing the ampicillin-resistance gene, treat the transformed cells with ampicillin before picking a colony that survives.

Question 7

Why is treating the transformed cells with ampicillin the right course of action?

Answer 7

d

Question 8

What is one of the roles of the outer membrane in Gram (-) bacteria?

Answer 8

It protects against the entry of water-soluble antibiotics

Question 9

Humans are:

Answer 9

Chemoheterotrophs

Question 10

What are chemoheterotrophs?

Answer 10

Organisms that get their energy source and carbon source from organic sources. Chemoheterotrophs must consume organic building blocks that they are unable to make themselves. Most get their energy from organic molecules such as sugars.

Question 11

What are phototrophs?

Answer 11

Organisms that capture light energy from the sun and convert it into chemical energy inside their cells.

Question 12

What are chemotrophs?

Answer 12

Organisms that break down either organic or inorganic molecules to supply energy for the cell

Question 13

What are photoheterotrophs?

Answer 13

Organisms that capture light energy to convert to chemical energy in the cells, but they get carbon from organic sources (other organisms).

Question 14

What are photoautotrophs?

Answer 14

cells that capture light energy, and use carbon dioxide as their carbon source

Question 15

What are chemoautotrophs?

Answer 15

cells that break down inorganic molecules to supply energy for the cell, and use carbon dioxide as a carbon source

Question 16

The presence of bacteria in the gut of mammals is a good example of:

Answer 16

Commensalism

Question 17

Bacteria living in their host gut provide their host with:

Answer 17

Vitamins

Question 18

Sort the following steps of the origin of life in the correct chronological order
1) synthesis of organic monomers
2) transmission of self-replicating molecules (inheritance)
3) formation of protocells
4) synthesis of organic polymers

Answer 18

1 4 3 2

Question 19

Which of the following is not a living organism?
One that is able to multiply
One that uses DNA as genetic material
One that needs a host to perform all of its metabolic reaction
One that does not react to a change in temperature
One whose number of cells does not increase over time

Answer 19

One that needs a host to perform all of its metabolic reaction

Question 20

Which domain is thought to be responsible for the increase in atmospheric oxygen in the early history of life?

Answer 20

Domain bacteria

Question 21

What are consequences of horizontal gene transfers?

Answer 21

The low resolution in the root of the Tree of Life
The acquisition of new metabolic pathways (metabolic flexibility)

Question 22

True or False? The genetic code is identical in all living organisms without exception.

Answer 22

False

Question 23

What is adaptive radiation?

Answer 23

A process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available

Question 24

What is an isotopic half-life?

Answer 24

The amount of time it takes for 50% of a radioactive isotope to decay

Question 25

Which came first during the history of organisms on earth?

Answer 25

The increase of atmospheric oxygen

Question 26

What is the result/consequence of bilateral symmetry?

Answer 26

Development of a complex nervous system

Question 27

What is the result/consequence of an exoskeleton?

Answer 27

New ecological relationships

Question 28

What is the result/consequence of mitochondria?

Answer 28

Aerobic respiration in eukaryotes

Question 29

What is the result/consequence of vascularization?

Answer 29

Colonization on land

Question 30

What is the result/consequence of multicellularity?

Answer 30

Increase in size

Question 31

What is convergent evolution?

Answer 31

Organisms in similar biomes evolve similar adaptations.

Question 32

Why does convergent evolution occur?

Answer 32

Organisms converge in appearance and function since they are adapting to similar environments

Question 33

What is important to remember about convergent evolution?

Answer 33

Organisms may look similar, but have different evolutionary history and mechanisms

Question 34

Desert biomes experience ___ precipitation and ___ evapotranspiration.

Answer 34

Low, high

Question 35

What is evapotranspiration?

Answer 35

the amount of water plants lose due to climate

Question 36

Rain forests experience ___ precipitation and ___ evapotranspiration

Answer 36

High, high

Question 37

List weaknesses of the biological species concept:

Answer 37

1) It cannot easily be applied to fossils
2) Quantifying reproductive barriers is hard when populations are allopatric
3) It is unclear/subjective how strong reproductive barriers must be
4) It doesn’t apply to asexual organisms

Question 38

Explain how the biological species concept defines species

Answer 38

The biological species concept defines species as groups that actually or potentially interbreed and produce FERTILE offspring, and do not form offspring with members of other groups