BIOL Topic 2

Question 1

When did the first prokaryote form

Answer 1

3.5 bya

Question 2

The first organisms were likely

Answer 2

prokaryotes

Question 3

Domains Archaea and Bacteria form distinct branches but inherited simple prokaryotic cell organization from _____

Answer 3

a common ancestor

Question 4

Why do prokaryotic cells differ from eukaryotic cells

Answer 4

Prokaryote cells are small (0.5 - 5 µm) and unicellular, diffusion limits the size in prokaryotic cells, have circular genomes (lack a nucleus), and lack membrane-bound organelles

Question 5

Structural and functional adaptations that contribute to the prokaryotic success

Answer 5

cell surface structures, endospores, mobility, simple internal organization and DNA, and reproduction

Question 6

Cell wall

Answer 6

maintains cell shape, protects the cell, and prevents it from bursting in a hypotonic environment (lower solute concentrations than cell contents)

Question 7

Peptidoglycan

Answer 7

a network of sugar polymers cross-linked by polypeptides

Question 8

Bacterial cell walls contain

Answer 8

peptidoglycan

Question 9

Archea cell walls contain polysaccharides and proteins but lack _____

Answer 9

peptidoglycan

Question 10

peptidoglycan

Answer 10

a network of sugar polymers cross-linked by polypeptides

Question 11

Gram Stain

Answer 11

Can be used to classify bacteria by cell wall composition

Question 12

Gram-positive bacteria

Answer 12

have simpler walls with large amount of external-facing peptidoglycan

Question 13

Gram-negative bacteria

Answer 13

have less peptidoglycan and an outer lipopolysaccharide membrane

Question 14

Lipopolysaccharide outer membrane

can contain toxins that _____

Answer 14

resist antibiotics

Question 15

Capsule

Answer 15

a sticky polysaccharide/protein layer that surrounds prokaryotes

Question 16

Capsules adhere to

Answer 16

cells and other surfaces

Question 17

Biofilms

Answer 17

communities of cells in a slimy extracellular

matrix

Question 18

Capsules retain ___ protecting the cells against desiccation

Answer 18

water

Question 19

fimbriae

Answer 19

hair like appendages that help cells adhere to a substrate or other individuals in a colony

Question 20

Pili

Answer 20

are longer than fimbrae and allow prokaryotes to exchange DNA

Question 21

Endospores

Answer 21

Endospores are small, rounded, resting
cells that form inside some prokaryotes
when conditions become unfavorable

Question 22

Endospores have a tough coat that is:

Answer 22

resistant to UV light, chemicals, heat, high salt, and extreme pH

Question 23

Endospore formation is induced by
_______, such as an increase
in heat or lack of nutrients. Endospores remain dormant until environmental conditions are suitable for ____

Answer 23

environmental stress, growth

Question 24

About ____ of known prokaryotes are motile

Answer 24

half

Question 25

Most motile prokaryotes propel | themselves by:

Answer 25

flagella

Question 26

Taxes

Answer 26

The ability to move toward or away from a stimulus, e.g. positive phototaxis is the movement towards light (most prokaryotes exhibit this

Question 27

Prokaryotic cells usually lack:

Answer 27

complex compartmentalization, membrane-bound organelles (nucleus, mitochondria, chloroplast)

Question 28

Example of a prokaryote that have specialized membranes that perform metabolic functions:

Answer 28

Thylakoid membranes in cyanobacteria

Question 29

Prokaryotes have small genomes consisting of:

Answer 29

single circular chromosomes that are enclosed in the nucleoid region

Question 30

Plasmids

Answer 30

small rings of DNA containing a few extra genes (some species of bacteria also have these)

Question 31

Prokaryotes reproduce by

Answer 31

binary fission (asexual reproduction)

Question 32

Binary fission process:

Answer 32

1. DNA replicates 2. Cell elongates itself 3. cell splits into two (daughter cells are identical)

Question 33

Factors contributing to prokaryote genetic diversity

Answer 33

rapid reproduction, mutations, genetic recombination

Question 34

Genetic recombination

Answer 34

combining DNA from two sources and contributes to genetic diversity

Question 35

Horizontal gene transfer

Answer 35

movement of genes among individuals from different species

Question 36

Genetic recombination of prokaryotic DNA from different individuals can occur by

Answer 36

transformation, transduction, and conjugation

Question 37

Transformation

Answer 37

uptake and incorporation of foreign DNA | from the surrounding environment

Question 38

Transduction

Answer 38

the transfer of a portion of DNA between bacteria by bacteriophages (viruses that infect bacteria)

Question 39

Conjugation

Answer 39

occurs when genetic material is transferred between prokaryotic cells through direct contact (a donor cells transfers DNA to a recipient cell) which can recombine with the bacterial chromosome of the recipient cell

Question 40

____ are often trasferred during conjugation

Answer 40

plasmids

Question 41

Plasmids ofte carry _____ resistance ans is why horizontal gene transfer is one reason why antibiotic resistance spreads so quickly

Answer 41

antibiotic

Question 42

Types of sources of energy for prokaryotes

Answer 42

1. light (phototrophs) | 2. from chemicals (chemotrophs)

Question 43

Two types of sources of carbon for prokaryotes

Answer 43

1. inorganic molecules such as CO2 (autotrophs) | 2. organic substrates (heterotrophs)

Question 44

Obligate aerobes

Answer 44

require O2 for cellular respiration

Question 45

Obligate anaerobics

Answer 45

are poisoned by O2 and use termination or anaerobic respiration

Question 46

Facultative anaerobic

Answer 46

can survive with or without O2

Question 47

biological nitrogen fixation

Answer 47

some bacteria and methanogens use this process to convert atmospheric nitrogen to ammonia

Question 48

Nitrogen is needed for

Answer 48

production of amino acids and nucleic acids, obtain N from a limited range of N-containing compound

Question 49

two lineages of prokaryotes

Answer 49

domain bacteria and domain eukaria

Question 50

______ include the vast majority of familiar prokaryotic species

Answer 50

bacteria

Question 51

5 types of bacteria

Answer 51

alpha, beta, gamma, delta, and Epsilon

Question 52

Proteobacteria

Answer 52

a large and metabolically diverse group of Gram-negative bacteria with 5 sub-lineages (alpha to epsilon)

Question 53

Alpha

Answer 53

(proterobacteria) many are closely associated with aeukaryotic cells

Question 54

hypothesized that mitochondria of eukaryotes evolved from:

Answer 54

aerobic alpha proteobacteria through endosymbiosis

Question 55

Gamma and epsilon proteobacteria | include

Answer 55

pathogens

Question 56

Chlamydias

Answer 56

parasites that live within animal cells. They lack peptidoglycan in their cell walls

Question 57

Cyanobacteria

Answer 57

produce O2 through phototrophy

Question 58

Domain Archea shares ____ with bacteria

Answer 58

simple prokaryotic cell organization inherited from a common ancestor

Question 59

Archea thrives where:

Answer 59

energy availabe for growth is too limited to support bacteria or Eukariotes

Question 60

Subdomain Bacteria is divided into 5 clades:

Answer 60

Euryarchaeotes, Thaumarchaeotes, Aigarchaeotes, Crenarchaeotes, and Korarchaeotes

Question 61

Methanogens

Answer 61

archea that lives in anoxic habitats like marshes and swamps and produces methane as a waste product

Question 62

Extreme Halophiles

Answer 62

live in highly saline environments

Question 63

Extreme thermophiles

Answer 63

archea that thrives in very hot environments

Question 64

Prokaryotes often form ____ relationships with larger organisms

Answer 64

symbiotic