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BIO 1220 > Exam 2 > Flashcards

Exam 2 Flashcards

1
Q

what are the 3 branches on the tree of life

A

bacteria and archaea are the 2 largest, 3 major branch is Eukarya

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2
Q

what is a microbiome

A

community of microbes that naturally inhabit a particular area, encompasses all the genetic material contained within in, includes prokaryotes that live on the body

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3
Q

how abundant are bacteria and archaea

A

dominant life forms, marine archae have over 10,000 individuals per mL of seawater, bacteria and archaea living under the ocean may make up 10% of worlds total mass of living material

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4
Q

what are extremophiles

A

live in extreme habitats like hydrothermal vents, ph < 1.0, 0C under antarctic ice, water 5-10 times saltier than seawater

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5
Q

what kind of polymerase is heat resistant to do PCR tests

A

7AC

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6
Q

why are extremophiles a hot area of research

A

origin of life, may help explain how life on Earth began, astrobiologists use extremophiles as model organisms to search for extraterrestrial life; commercial applications - enzymes that function at extreme temperatures and pressures used in industrial processes

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7
Q

what does infectious mean

A

diseases that are spread in 3 main ways,
1. passed from person to person
2. transmitted by bites from insects or animals
3. acquired by ingesting contaminated food or water, or exposure to microbes in surrounding environment

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8
Q

what did koch’s experimental results lead to

A

first test of germ theory of disease, pattern component is that some diseases are infectious and process responsible for pattern is transmission and growth of certain bacteria and viruses

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9
Q

what is virulence

A

ability to cause disease, heritable, variable trait

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10
Q

what are endospores

A

tough, thick walled, dormant structures formed during times of environmental stress

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11
Q

what is bioremediation

A

use of bacteria and archaea to clean up sites polluted with organic solvents, water pollutants are toxic to eukaryotes, don’t dissolve in water, and accumulate in sediments, naturally existing populations of bacteria and archaea can grow in spills and degrade toxins

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12
Q

what are the 2 complementary strategies of bioremediation

A
  1. fertilizing contaminated sites to encourage growth of existing bacteria and archaea
  2. seeding or adding specific species of bacteria and archaea to contaminated sites
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13
Q

how do biologists study bacteria and archaea

A

using enrichment cultures, using metagenomics, investigated human microbiome, molecular phylogenetics

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14
Q

what are enrichment cultures

A

isolate large populations of cells that grow under specific conditions, led to discovery of thermophiles

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15
Q

what is metagenomics sequencing

A

also environmental sequencing, identify species and biochemical pathways by comparing DNA sequences with those of known genes, rapidly identify and characterize organisms never seen, used in combination with direct sequencing (isolating and sequencing a specific gene from organisms found in a particular habitat) to understand prokaryotic diversity

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16
Q

what RNA molecules were found in a small subunit of ribosomes

A

16S and 18S

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17
Q

what is lateral gene transfer

A

allows for acquisition of traits not otherwise available via binary fission (asexual reproduction)

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18
Q

what is transformation

A

when bacteria or archaea naturally take up DNA from environment released by cell lysis or secreted

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19
Q

what is transduction

A

viruses pick up DNA from one prokaryotic cell and transfer it to another cell

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20
Q

what is conjugation

A

genetic information transferred by direct cell to cell contact includes event called plasmid transfer

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21
Q

how is the diversity of bacterial and archaea

A

size - 0.15 num^3 - 200 x 10^6 num^3
shape - filaments, spheres, rods, and chains to spirals
motility - flagella and gliding

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22
Q

what is a gram stain, what does gram positive and negative mean

A

gram stain - dyeing system to examine cell walls
gram positive - positive cells look purples under a microscope cell, well has extensive amount of carbohydrate peptidoglycan
gram negative - looks pink, cell wall has thin layer containing peptidoglycan and outer phospholipid bilayer

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23
Q

all organisms must

A

acquire chemical energy that is used to make ATP, obtain carbon compounds that can serve as building blocks for synthesis of cellular components

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24
Q

bacteria and archaea may use one of three sources of energy for ATP production

A

light, organic molecules, inorganic molecules

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25
phototrophs
light used to excite electrons, ATP made by photophosphorylation
26
chemoorganotrophs
oxidize organic molecules with high potential energy, ATP made by cellular respiration or fermentation pathways
27
chemolithotrophs
oxidize inorganic molecules with high potential energy, ATP made by cellular respiration
28
autotrophs
synthesize building block compounds from simple starting materials
29
heterotrophs
absorbing building block compounds from their environmeent
30
methanotrophs
use methane as their carbon source
31
methanogen
produce methane as a by product of cellular respiration
32
oxygen revolution
no free molecular oxygen existed for first 2.3 billion years of earth's history, cyanobacteria lineage of photosynthetic bacteria, were first to perform oxygenic photosynthesis, were responsible for changing Earth's atmosphere to one with a high concentration of oxygen, once oxygen is common in oceans, cells carry out aeorbic respiration, before that anaerobic respiration was possible so cells had to use other compounds
33
nitrogen cycle
34
nitrogen runoff
1. ammonia NH3 is introduced as fertilizer 2. corn uses some of NH3 to build protein soil dwelling bacteria and archaea use NH3 as an electron donor 3. nitrate NO3- a byproduct of respiration enters groundwater and washes into rivers 4. NO3- from runoff stimulates blooms of marine algae and cyanobacteria 5. when cells that bloomed eventually die, decomposers such as bacteria and archaea grow rapidly, using up oxygen O2 6. anoxic dead zone
35
nitrogen fixation
molecular nitrogen is abundant but most organisms cant use it directly, must obtain from ammonia or nitrate, nitrogen fixation - certain bacteria and archaea are only organisms capable of converting N2 to NH3, nitrogen fixing bacteria live in close association with plants eg in nodules
36
virus
obligate, intracellular parasite, enters a host cell and uses the host's machinery to replicate, depend on host cell
37
virion
a virus outside of the host
38
why do we study viruses
contribute genetic material to organisms, about 5-8% of human genome is from remnants of viral genomes
39
what is an epidemic
disease that rapidly infects many individuals over a widening area
40
pandemic
worldwide epidemic,
41
2 categories of viruses
1. enclosed only by a protein shell called a capsid 2. enclosed by both a capsid and one or more phospholipid membranous envelopes
42
what are the 6 phases common to replicative growth of viruses
1. attachment to a host cell and entry into the cytosol 2. viral genome transcription and viral protein production 3. viral genome replication 4. assembly of a new generation of virions 5. exit from the infected cell 6. transmission to a new host
43
what are the 3 hypotheses to explain the origin of viruses
1. origin in plasmids and transposable elements 2. origin in symbiotic bacteria 3. origin at the origin of life
44
origin of viruses in symbiotic bacteria
DNA viruses descend from bacteria that live inside eukaryotic cells bacteria degenerated into viruses and slowly lost genes needed to synthesize ribosomes, ATP, nucleotides, amino acids and other compounds
45
origin of viruses at the origin of life
viruses descended from the first RNA based life forms on Earth, evolving since life began, several proteins expressed in viruses not expressed in any known cell, gene coding come from RNA world pool of genes instead of a cell
46
origin of viruses in plasmid and transposable elements
simple viruses are escaped gene sets, mobile genetic elements from genes of prokaryotic and eukaryotic chromosomes, escaped genes encode information needed to replicated themselves and include information on how to make a capsid
47
emerging disease
new illnesses that suddenly affect significant numbers of individuals in a host population
48
emerging viruses
causative agents for emerging diseases
49
virus strain
populations that have similar characteristics
50
a virus outbreak is indicated by certain factors
patients have identical and unusual disease symptoms, in same geographic area, and affected over a short period of time
51
physicians report the cases to the officials that ______
identify the agent that caused the disease and the origin
52
what fundamental features of eukaryotes distinguish them from bacteria and archaea
most are large, have more organelles, and more extensive cytoskeleton, nuclear envelope, multicellularity evolved multiple times, asexual and sexual reproduction
53
protists environment
open ocean, shallow coastal waters, intertidal habitats
54
endosymbiosis theory
mitochondria originated when a bacterial cell took up residence inside another cell about 2 billion years ago
55
leading hypothesis for the origination of the nuclear envelope
infoldings of the plasma membrane
56
what is the purpose for presence and nature of structures
provide support and protection
57
multicellularity
refers to organisms with more than one cell
58
how doo pseudopodia eat
engulf it
59
how do ciliary currents eat
sweep food into gullet
60
viridiplantae
green plants, consist of green algae (freshwater) and land plants (terrestrial) both photosynthesizers
61
why do we study green algae along with land plants
1. closest living relatives to land plants 2. transition from aquatic to terrestrial life occurred when land plants evolved from green algage
62
what were the first organisms that could thrive with tissues completely exposed to the air
land plants
63
before land plants evolved, terrestrial life was limited to what
bacteria, archaea, and protists
64
ecosystem services
ex: produce oxygen, build soil, hold soil, hold water in soil, moderate climate
65
how are land plants the primary producers in terrestrial ecosystems
convert energy in sunlight into chemical energy, sugars made support all other organisms
66
how are land plants key to the carbon cycle
take CO2 from the atmosphere and reduce it to make sugars, fix much more CO2 than they release
67
how do biologists understand diversification
compare morphological traits, analyze the fossil record, estimate phylogenetic trees
68
with the morphological traits, green algae include species that are
unicellular, colonial, or multicellular; live in marine, freshwater, or moist terrestrial habitats
69
vast majority of green algae are
aquatic
70
vast majority of land plants are
terrestrial
71
nonvascular plants
lack vascular tissue - specialized groups of cells that conduct water or dissolved nutrients throughout the plant body, use spores not seeds for reproduction and dispersal (moss)
72
seedless vascular plants
have well developed vascular tissue, does not make seeds, uses sprores for reproduction (ferns)
73
seed plants
have vascular tissue, make seeds that consist of an embryo and a store of nutritive tissue surrounded by a tough protective layer, include angiosperms (encased seeds) or flowering plants and gymnosperms (naked seeds)
74
5 major events in diversification of land plants
1. origin of land plants (first evidence of land plants, cuticle, spores, sporangia) 2. silurian-Devonian explosion (most major morphological innovations, stomata, vascular tissue, roots leaves) 3. Carboniferous:club mosses and horsetails abundant (extensive coal forming swamps) 4. gymnosperms abundant (both wet and dry environments blanketed with green plants for the first time) 5. angiosperms abundant (diversification of flowering plants)
75
cuticle
waxy material that is a watertight barrier that coats the above ground parts of plants and helps prevent drying
76
sporopollen
waxy substance that surrounds spore and pollen and helps prevent drying
77
the phylogenetic tree of green plants show that
green and land plants are monophyletic, nonvascular plants are paraphyletic
78
natural selection favored early land plants with 3 main adaptations that solved the drying problem by
1. preventing water loss, which kept cells from drying out and drying 2. provide protection from harmful UV radiation 3. move water from tissues with direct access to water to tissues without direct access
79
stomata
have pores that allow gas exchange
80
flavonoids
pigment that protects DNA from UV damage
81
tracheids
thickened lignin contained secondary cell wall in addition to a cellulose based primary cell wall, pits in the sides and ends of the cell which lets water flow efficiently
82
vessel elements
shorter and wider than tracheids
83
innovations for plant reproduction in dry environment
1. spores that resist drying because they are encased in a tough coat of sporopollen 2. gametes that were produced in complex multicellular structures 3. embryos that were retained on and nourished by the plant parent
84
gametophyte
multicellular haploid phase
85
sporophyte
multicellular diploid phase
86
gametophyte dominant
in nonvascular plants, sporophyte is small and short lives and is largely dependent on gametophyte for nutrition
87
sporophyte dominant
ferns and other vascular plants, sporophyte is larger and longer lived
88
microsporangia
microspores (pollen) that develop into male gametophytes, which produce small gametes called sperm
89
megasporangia
produce megaspores that develop into female gametophytes, which produce large gametes called eggs
90
pollen grain
allow plants living in dry habitats to reproduce efficiently
91
seed
structure that includes embryo and store of nutrients provided by mother

BIO 1220 (6 decks)

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