Viruses/ Prokaryotes/Archea/Protists Flashcards
What is a virus?
Obligate intracellular parasite
Properties of viruses
cannot multiple unless they invade a specific host cell and instruct its genetic and metabolic machinery to make and release new viruses, infect any cell – plant, algae, protozoa, animals
Describe the structures of viruses and their genomes
Regular repeating subunits- External coating, core containing one or more nucleic acid strains of DNA or RNA, sometimes one or two enzymes
Describe the differences between DNA and RNA viruses
RNA are single stranded, replicate in host cell’s cytoplasm, and transcribe to double stranded DNA with reverse transcriptase – DNA are double stranded and are replication in nucleus of a eukaryotic host cell
Describe the components viruses may contain(4)
Capsid, Envelope, Spikes, Genome
Capsid
protein shell that surrounds the nucleic acid made of capsomeres - protein subunits
Envelope
external covering of nucleocapsid, usually modified piece of the hosts cell membrane
Spikes
Allow viruses to dock with host cells, found on naked and enveloped viruses, project from nucleocapsid or envelope
Genome
the sum total of the genetic information carried by an organism
obligate cellular parasites
Cannot reproduce outside of their host
bacteriophage
Bacteria eating – They infect bacteria
Lytic Cycle
Attachment, Injection, Synthesis, Assembly, Release
Lysogenic Cycle
Attachment, Injection, Integration into the host cell genome, Replication with host’s DNA
Describe how viruses can contribute DNA to their hosts. How can this contribute to an increase in virulence of otherwise harmless organisms.
They incorperate themselves into the genome and reproduce with host DNA
Organelles or structures in prokaryotes
Cell envelope, cytoplasm, appendages - No membrane bound organelles – Outer cell wall, sometimes flagella and plasmids
Bianary Fission
Asexual reproduction by a separation of the body into two new bodies
Conjugation
forms between two cells – donor to recipient through the plius
Transformation
picks up free DNA from other prokaryotes and incorporates them into the genome
Transduction
bacteriophages carry portions of bacterial DNA from one cell to other
3 ways of Genetic Recombination
Transduction, Transformation, Conjagation
- What are the differences between gram-positive and gram-negative bacteria?
Gram-negative has a second plasma membrane and makes infections more difficult to treat
Obligate aerobes
unable to grow without oxygen
Obligate anaerobes
unable to grow with oxygen
Facultative anaerobes
can grow with or without oxygen
Aerotolerant anaerobes
doesn’t need it but can grow with it
endospore
A dormant and highly resistant cell to preserve the genetic materal in times of stress
Describe two ways antibacterial compounds work
Compound inhibits protein biosynthesis – compound inhibits cell wall biosynthesis
biofilm
Microorganisms all together on a surface - teeth
Characteristics of Archaea
No peptidoglycan in cell walls, tend to live in harsh conditions
halophile
Need high salt – salty lakes
thermoacidophile
Need extreme temperatures – hot sulfur springs
Methanogen
Need methane – Anaerobic marshes
Compare prokaryotes to eukaryotic.
Eukaryotes have distinct nucleus and organelles - Prokaryotes have no membrane bound organelles
Autotrophic
Make own food – plant like
Heterotrophic
Eat food – animal like
Phagotrophs.
engulfing food to eat it - hetero
Mixotrophs
can use a mix of different sources of energy
Saprotrophs
decomposers – fungus like
What are the characteristics of animal like protist? List some examples of these protist
Protozoans – cilia and cytoplasmic streaming- pseudopod , paramecium, amoeba, recycles organic materials, food for other organisms
- What are the characteristics of plant like protist? List some examples of these protist
flagella- euglena, algae, recycles organic materials
What are the characteristics of Fungus like protist? List some examples of these protist.
Slime mold, water mold – recycles organic materials
Are fungus unicellular or multicellular? Give examples
Can be both - yeast is uni - molds are multi
How does fungus obtain nutrients?
grows through food source (substratum) excretes digestive enzymes, and absorbs dissolved food
Hyphae
Branching filaments to make up the mycelium of fungi - Tubular, hard wall of chitin, full of cytoplasm
mycelium
Mass of branching interconnected hyphae that forms sex organs
mycorrhizal
Fungal roots.- mutualistic releationship between fugus and plant roots – carbohydrates for fungi/ nutrient and water for plant
lichen
composite organisms of fungi & algae; resilient – can colonize harsh environments & begin succession by breaking down rock
Why are fungal infections difficult to treat in humans?
The cells are eukaryotic and harder to distinguish from the hosts regular cells
Characteristics of animals
No cell wall, heterotrophic, aerobic, diploid, motile, eukaryotic
Two tissues unique to animals
muscle and nervous
What group lacks true tissues
Parazoas
gastrulation
When the blastula turns into the three layered embryo known as the gastrula - creates germ layers
- How is the primitive gut(archenteron) formed?
gastrulation
blastopore
The opening to the primitive gut - archenteron
What are the possible 3 tissue layers?
Mesoderm, ectoderm, Endoderm
endoderm
Organs of the digestive system
ectoderm
Outer layer of tissue and nervous system
Mesoderm
Tissue and organ systems like muscle and skeletal
diploblastic
two germ layers
triploblastic
three germ layers
asymmetrical symmetry
Cut anywhere and its not symmetrical - sponge
radial symmetry
Cut anywhere and its symmetrical - sea anemone
Bilateral symmetry
cut down the middle and its symmetrical - elephant
cephalization
Presence of a head - not all animals have
What are body cavities
Open spaces for organs
Coelom
A body cavity surrounded by mesoderm
Acoelomate
no body cavity
psuedocoelemate
body cavity but not surrounded by mesoderm
coelomate
has a coelom
protostomes
blastula turns into mouth first
dueterostome
blastula turns into anus first
chitin
A carbohydrate that tends to make up exoskeletons
What are the advantages of having an exoskeleton
no desiccation, protections, cite for muscle attachment
What are the disadvantages of having an exoskeleton
molting, heavy and restrictive
