Homework questions Flashcards
If prokaryotes did not exist, what would change in the nitrogen cycle?
The rate of movement of nitrogen atoms through ecosystems would be much slower
This is because prokaryotes facilitates many steps of the nitrogen cycle
What is the electron acceptor for humans in the electron transport chain?
Oxygen
Autotrophs
Create their own nutrients and energy
Heterotrophs
cannot synthesize organic molecules from inorganic sources and must obtain organic material by consuming other organisms.
Chemoautotrophs
need only carbon dioxide as a carbon source and obtain energy by oxidizing inorganic substances.
Photoheterotrophs
use light to generate ATP but must obtain carbon in organic form.
Chemoheterotrophs
must consume organic molecules for both energy and carbon.
Phototrophs
The general term for organisms that obtain energy from light
Chemotrophs
The general term for organisms that obtain energy from chemicals
Metagenomic analysis
Technique to isolate, observe, and study microbial DNA present in any environment or biological sample
What has metagenomic analysis allowed researchers to do for the first time?
study organisms that cannot be cultured (grown in the lab)
The important primary producers in marine ecosystems with cellulose cell walls are _____.
dinoflagellates
dinoflagellate
a single-celled aquatic organism with two flagella.
endosymbiosis theory for the origin of the mitochondrion
holds that mitochondria, plastids such as chloroplasts, and possibly other organelles of eukaryotic cells are descended from formerly free-living prokaryotes
What advantage do organisms that reproduce sexually have over organisms that reproduce asexually?
Their offspring may be more adaptable to changes in the environment.
Which structure mediates the attachment of spores to a surface on which to grow?
Holdfast as it attaches spores to surfaces which it can grow
Where are the microsporangium found in a tulip?
stamen
Where are the megasporangium found in a tulip?
ovule
Describe how green plants affect the abiotic environment in ways that are advantageous to humans.
Plants release oxygen that we breathe.
Plants increase water supplies that humans can use for drinking, irrigation, or industrial use.
Plants build soils required for human agriculture and forestry.
Plants hold soils required for human agriculture and forestry.
Angiosperms are most closely related to _____.
gymnosperms
_____ are an example of seedless vascular plants.
Ferns
The living plants that are most similar to the first plants to bear gametangia are the _____.
bryophytes
charophyceans
class of green algae commonly found in fresh water
Related to land plants the most
Byrophytes
nonvascular plants that reproduce by spores and do not have flowers or seeds
In moss, _____ produce sperm.
antheridia
archegonia
produce eggs
Archegonium
organ of the gametophyte phase of certain plants, producing and containing the ovum or female gamete.
In mosses gametes are produced by _____; in ferns gametes are produced by _____.
mitosis … mitosis
Antheridia
An organ in certain organisms that produces male gametes
Where do fern antheridia develop?
on the underside of the gametophyte
In the pine, microsporangia form _____ microspores by _____.
haploid … meiosis
microspores
land plant spores that develop into male gametophytes, whereas megaspores develop into female gametophytes
Megaspores
One of the two types of plants spores
Larger than microspore
Germinates into a female gametophyte
What structure do moss sperm use for motility, and how does that reflect the evolution of land plants from green algae?
Moss sperm and green algae sperm both have flagella
hyphae
The fine, branching tubes which make up the body (or mycelium) of a multicellular fungus
Why are ectomycorrhizal fungi, or EMF, aptly named?
Their hyphae form dense mats that envelop roots but do not penetrate the cell walls.
If the trees in that woodlot are associated with EMF, what effect might the excess nitrate have on the fungi and/or trees?
The trees may take up the nitrate directly into their roots and rely less on the fungi.
hyphae of arbuscular mycorrhizal fungi (AMF) form bushy structures after making contact with the plasma membrane of a root cell. What are the function of the structures
They increase the surface area available for the transfer of nutrients.
What are asci?
sac-like structures that produce eight spores
Which term describes the fusion of cytoplasm from two individuals?
Plasmogamy
Basidia produce spores by a process known as _____.
meiosis
mycelium
network of filaments that forms the body of a fungus
Has a high surface-area-volume ratio which allows for the growing mushroom to nourish itself
Process of fertilization in fungi
two-step process consisting of the fusion of cells and then the fusion of nuclei in the fused cells.
Basida
specialized cells in the gills of a mushroom in which haploid nuclei fuse in preparation for meiosis.
Which of the following events occurs first in the development of a spore into a mature mushroom?
A heterokaryotic mycelium forms.
Why is it logical that most fungi don’t have lignin or cellulose in their cell walls?
Fungi produce enzymes that degrade cellulose and lignin.
Why does iron fertilization of open oceans increase phytoplankton densities? See Section 27.2 (Page) .
The growth of phytoplankton is often limited by iron availability in the open oceans.
Which evidence is consistent with the endosymbiotic hypothesis for the origin of the mitochondrion?
Mitochondria have their own ribosomes and manufacture their own proteins.
endosymbiotic hypothesis for the origin of the mitochondrion
posits that mitochondria are the direct descendants of a bacterial endosymbiont that became established at an early stage in a nucleus-containing (but amitochondriate) host cell.
What evidence supports the hypothesis that the nuclear envelope of eukaryotes arose from infolding of the plasma membrane?
The nuclear membrane and endoplasmic reticulum (ER) of modern eukaryotes are continuous.
How do humans benefit from the gut microbiome?
The gut microbiome also helps create essential amino acids and break down complex carbohydrates.
The transfer of genetic information by way of a virus is called____________.
Transduction
During transduction a virus injects donor DNA into a host bacteria, which can recombine with the host chromosome.
Which current global health concern is caused by a protist?
Malaria is caused by a protist, Plasmodium.
Which of the following is a fundamental difference between bacteria and yeast?
Yeast undergo meiosis and mitosis while bacteria do not.
Mold on a single piece of fruit can easily spread to a nearby piece of fruit because ________.
molds produce many, many asexual spores that can be dispersed by air currents
Mushrooms, brackets, and puffballs are examples of structures used for _____.
reproduction
Which is the longest living part of the fungal life cycle?
Mycelium
The fundamental reproductive cell produced by fungi is the
spore
What is the symbiotic relationship that characterizes arbuscular mycorrhizal fungi
AMF provide key nutrients to tree, grass, and shrub roots in exchange for sugar.
What is a pollen grain?
It is the male gametophyte of a seed plant surrounded by a tough coat of sporopollenin.
What is the symbiotic relationship that characterizes ectomycorrhizal fungi (EMF)
EMF are ecologically important because they decompose biomass to make it more available to the roots of the host plant..
