Exam 2 Flashcards
What are some of the advantages of doing independent research, internships, etc., during your years as an undergraduate student?
(1) Hands on research experience
(2) Field specific problem solving and exposure to the research process
(3) Ability to explore and experience your future interests
(4) Connecting with other students with similar research
(5) Professional networking and connection building
(6) You get paid!
What is the significance of the science behind inserting a mouse eye gene into a fruit fly and it producing a healthy, compound insect eye?
The significance of this study was the finding of two explanations for genetic similarities.
(1) homology: were they passed down from the common ancestor of all these different organisms
(2) analogy: did they all evolve independently through convergent evolution
Are viruses alive?
No, they do not fulfill requirements for a living organism, they are not capable of growth and development, they can’t pass on their DNA (the host cell does that for them) and they are not made up of cells
Why do vaccines (and many other scientific/medical advances) get pushback rom segments of society?
Skepticism of today is rooted in the social movements of the postwar era, which prompted a new generation of parents (and their children) to question environmental contaminants, drugs, doctors, and authority in general.
What are the advantages of vaccines?
he most effective way to prevent the spread of infectious diseases.
Why do vaccines work?
Help your immune system fight infections faster and more effectively.
Define bacteriophage
A virus that infects bacteria; also called a phage.
Describe the significance of the tobacco mosaic virus
The first virus to be discovered ever, leading to research into the many other viruses and the ability to see them (via electron microscope).`
Who was Adolf Mayer?
Discovered the he could transmit TMD from plant to plant by rubbing sap extracted from diseased leaves onto healthy plants.
Who was Dmitri Ivanowsky?
A Russian biologist who passed sap from infected tobacco leaves through a filter designed to remove bacteria.
Who was Wendell Stanley?
An American scientist who crystallized the infectious particle, now known as tobacco mosaic virus (TMV)
Define Capsid
The protein shell that encloses a viral genome. It may be rod-shaped, polyhedral, or more complex in shape.
Describe Lytic cycle vs. lysogenic cycle
A type of phage replicative cycle resulting in the release of new phages by lysis (and death) of the host cell
VERSUS
A type of phage replicative cycle in which the viral genome becomes incorporated into the bacterial host chromosome as a prophage, is replicated along with the chromosome, and does not kill the host.
Define Prophage
A phage genome that has been inserted into a specific site on a bacterial chromosome.
Define Retrovirus
An RNA virus that replicates by transcribing its RNA into DNA and then inserting the DNA into a cellular chromosome; an important class of cancer-causing viruses.
Define Reverse transcriptase
An enzyme encoded by certain viruses (retroviruses) that uses RNA as a template for DNA synthesis.
Define Provirus
A viral genome that is permanently inserted into a host genome.
Define vaccine
A harmless variant or derivative of a pathogen that stimulates a host’s immune system to mount defenses against the pathogen.
Describe the life-history of a typical virus.
Attachment, penetration, uncoating, gene expression and replication, assembly and release.
Provide some examples of mobile transposable elements.
Proviruses and endogenous retroviruses
Describe the Spanish Influenza outbreak of 1918. Why was it so deadly?
An exceptionally deadly global influenza pandemic caused by the H1N1 influenza A virus. Because the virus was new, very few people, if any, had some immunity to the disease.
Describe the structure of a typical flagellum.
A supramolecular structure composed of about 20 protein components and divided into three substructures:
(1) the filament (the filament is a helix, which takes on several distinct forms under various conditions)
(2) the hook
(3) the basal body.
Does the flagellum structure represent an example of irreducible complexity?
Yes!
What are the 3 Domains of life?
Bacteria, Archaea, and Eukarya
Define Biosphere
The entire portion of Earth inhabited by life; the sum of all the planet’s ecosystems.
Give the types of prokaryotes (common shapes)
Spheres, rods, or spirals
Define Peptidoglycan
A type of polymer in bacterial cell walls consisting of modified sugars cross-linked by short polypeptides.
Define Gram Stain
A staining method that distinguishes between two different kinds of bacterial cell walls; may be used to help determine medical response to an infection.
Define Capsule
A dense and well-defined layer of polysaccharide or protein that surrounds the cell wall and is sticky, protecting the cell and enabling it to adhere to substrates or other cells.
Define Fimbria
A short, hairlike appendage of a prokaryotic cell that helps it adhere to the substrate or to other cells.
Define Pilus
A structure that links one cell to another at the start of conjugation; also called a sex or conjugation _____.
Describe the different types of Taxis
phototaxis: response to light
aerotaxis: response to oxygen
osmotaxis: response to ionic strength
hydrotaxis: response to water
Define plasmid
A small, circular, double-stranded DNA molecule that carries accessory genes separate from those of a bacterial chromosome
Describe the Nucleoid Region
The region in a prokaryotic cell consisting of a concentrated mass of DNA.
Describe how prokaryotes reproduce using the words transformation, conjugation, transduction, horizontal gene transfer, mutation, endospores
In transformation, a bacterium takes up a piece of DNA floating in its environment.
In transduction, DNA is accidentally moved from one bacterium to another by a virus.
In conjugation, DNA is transferred between bacteria through a tube between cells.
Transposable elements are chunks of DNA that “jump” from one place to another. They can move bacterial genes that give bacteria antibiotic resistance or make them disease-causing.
Why do prokaryotes have high genetic variation?
Mutation, recombination and immigration of genes
What are the 4 categories prokaryotic nutrition and metabolism?
Photoautotrophs, chemoautotrophs, photoheterotrophs, or chemoheterotrophs.
Define and describe the protists as an informal taxonomic group (recall that this group is polyphyletic)
Apart of kingdom Protista
What are the 3 nutrition categories of protists
Photosynthetic, holozoic, and parasites
How does endosymbiosis fit into the evolutionary history of the protists?
The earliest protists evolved from prokaryotes (single-celled organisms)
Define Secondary endosymbiosis
A process in eukaryotic evolution in which a heterotrophiceukaryotic cell engulfed a photosynthetic eukaryotic cell, which survived in a symbiotic relationship inside the heterotrophic cell.
Define Euglenozoa
A member of a diverse clade of flagellated protists that includes predatory heterotrophs, photosynthetic autotrophs, and pathogenic parasites.
Define Dinoflagellates
A member of a group of mostly unicellular photosynthetic algae with two flagella situated in perpendicular grooves in cellulose plates covering the cell.
Define Apicomplexans
A group of alveolate protists, this clade includes many species that parasitize animals. Some can cause human disease.
Define Ciliates
A type of protist that moves by means of cilia.
Define Stramenopila
One of the three major subgroups for which the SAR eukaryotic supergroup is named. This clade arose by secondary endosymbiosis and includes diatoms and brown algae.
Define Diatoms
Photosynthetic protist in the stramenopile clade; contain a unique glass-like wall made of silicon dioxide embedded in an organic matrix.
Define Brown algae
A multicellular, photosynthetic protist with a characteristic brown or olive color that results from carotenoids in its plastids. Most are marine, and some have a plantlike body.
Describe Alternation of generations
A life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristic of plants and some algae.
Describe Red algae
A photosynthetic protist, named for its color, which results from a red pigment that masks the green of chlorophyll. Most are multicellular and marine.
Describe Green algae
A photosynthetic protist, named for green chloroplasts that are similar in structure and pigment composition to the chloroplasts of plants.
Define Unikonta
One of four supergroups of eukaryotes proposed in a current hypothesis of the evolutionary history of eukaryotes. This clade, which is supported by studies of myosin proteins and DNA, consists of amoebozoans and opisthokonts.
What are the 4 supergroups of eukaryotes?
- Excavata
- SAR clade
- Archaeplastida
- Unikonta
Describe the life-history cycle of malaria.
Sporozoite, liver-stage, blood-stage, and sexual-stage
What adaptations were necessary for plants to colonize land?
A water-repellent cuticle
Stomata to regulate water evaporation
Specialized cells to provide rigid support against gravity
Specialized structures to collect sunlight
Alternation of haploid and diploid generations
Sexual organs
What are the 3 key traits shared in common between land plants and charophytes?
(1) Rings of cellulose-synthesizing complexes
(2) Similarity in sperm structure
(3) The formation of a phragmoplast in cell division.
What are the four characteristics land plants have evolved that are NOT present in charophytes?
(1) Presence of stomata
(2) Presence of cuticles
(3) Spore walls
(4) Multicellular embryos
Define Gametophyte
The sexual phase in the alternation of generations of plants and a few algae
Define Sporophyte
Diploid, or spore-producing phase of a plant life cycle
Define Bryophyte
A plant that lacks xylem and phloem, a seedless nonvascular plant that includes mosses, liverworts, and hornworts
Define Pteridophyte
Includes ferns
Define Gymnosperm
Woody, vascular seed plant without fruit
Define Angiosperm
A flowering plant that produces seeds within a fruit
Describe Placental transfer cells
A plant cell that enhances the transfer of nutrients from parent to embryo
Define Sporopollenin
A durable polymer that covers exposed zygotes of charophyte algae and forms the walls of plant spores, preventing them from drying out.
Define Archegonia
Female gametangia
Define Antheridia
Male gametangia
Define Apical meristem
A localized region at a growing tip of a plant body where one or more cells divide repeatedly. The dividing cells enable the plant to grow in length.
Define Xylem
Vascular plant tissue consisting mainly of tubular dead cells that conduct most of the water and minerals upward from the roots to the rest of the plant.
Define Phloem
Vascular plant tissue consisting of living cells arranged into elongated tubes that transport sugar and other organic nutrients throughout the plant.
Define Lignin
A strong polymer embedded in the cellulose matrix of the secondary cell walls of vascular plants that provides structural support in terrestrial species.
Define Tracheid’s
A long, tapered water-conducting cell found in the xylem of nearly all vascular plants. No longer living.
Define Microphylls
A small, usually spine-shaped leaf supported by a single strand of vascular tissue, found only in lycophytes.
Define Macrophylls
A leaf with a highly branched vascular system, found in almost all vascular plants other than lycophytes.
Describe the Life-history cycle of Ferns and Mosses
Consists of two different stages: sporophyte, which releases spores, and gametophyte, which releases gametes.
What are the 5 key traits common to all seed plants?
(1) Seeds
(2) Reduced gametophytes
(3) Heterospory
(4) Ovules
(5) Pollen
Describe the Life-history cycle of gymnosperms and angiosperms.
It is dominated by the sporophyte stage (the plant structure that you see is the sporophyte), with the gametophyte remaining attached to and dependent on the sporophyte (reverse of bryophytes).
Define Monocot
A member of a clade consisting of flowering plants that have one embryonic seed leaf, or cotyledon.
Define Dicot
A term traditionally used to refer to flowering plants that have two embryonic seed leaves, or cotyledons.
Define Cotyledon
A seed leaf of an angiosperm embryo. Some species have one, others two.
Describe Double fertilization
A mechanism of fertilization in angiosperms, in which two sperm cells unite with two cells in the embryo sac to form the zygote and endosperm.
Define Micropyle
A pore in the integuments of an ovule.
Define Simple fruit
A fruit derived from a single carpel or several fused carpels.
Define Aggregate fruit
fruits derived from multiple ovaries of a single flower.
Define Multiple fruit
A fruit derived from an entire inflorescence.
Describe some mechanisms to ensure cross-pollination.
The factors which favour cross pollination are unisexuality, dichogamy, self sterility, mechanical and structural barrier and heterostyly.
Define Co-evolution
Process by which two species evolve in response to changes in each other
Why are flowers adaptive?
Flowers protect the female gametophyte from herbivory & other harm
Flowers may attract pollinators
Flowers allow pollination via visiting pollinators moving its’ pollen
What are the three major adaptations of seed plants?
Seed, microscopic gametophytes, ovules and pollen, vascular tissue - xylem and phloem
Why was the advent of pollen so important?
It was essential for sexual reproduction of flowering plants and plants that produce cones.
Is pollen haploid or diploid?
Haploid
What is meant by the following statement? “Dispersal in plants occurs in two separate ways”
(1) Natal dispersal, which is movement and subsequent breeding away from the birth territory or area
(2) Breeding dispersal, which is movement from one area to another after the first breeding season.
What is fruit?
A mature ovary of a flower. The fruit protects dormant seeds and often functions in their dispersal.
What are the three forms fruits exhibit?
(1) Simple fruit.
(2) Aggregate fruit.
(3) Multiple fruit.
What advantage does fruit confer (e.g. why would fruit have evolved)?
They help to protect the developing seeds and aid dispersal once they are mature.
What are the key differences between the monocots and dicots?
Develop a fibrous root system where no single root serves as the origin for all of the other roots.
VERSUS
Develop a taproot system where a single root descends from the embryo (seed) and branches out into a network of smaller roots and finally root hairs that absorb water and nutrients.
What are the three basic tissue systems and their corresponding primary meristems?
(1) Dermal
(2) Vascular
(3) Ground tissue
Where is vascular, ground, and dermal tissue each located on a growing plant?
These tissues are located deep to superficial, respectively.
Why is a root cap important?
It protects the root from environmental stress and functions in gravity perception
What is the function of the endosymbiotic fungi (mycorrhiza)?
Increase water and nutrient absorption capabilities
What is the function of root hairs?
Increase the surface area of the root
