Test 2 study guide Flashcards
1
Q
Characterize the features common to viruses
A
- small
- infectious
- non-living
- consists of protein and nucleic acid
2
Q
Describe the structures of viruses and the function of each of the parts
A
- composed of nucleic acid, proteins, and sometimes, a membranous envelope
- capsid: protective protein coat made of capsomeres around the nucleic acid
- other proteins besides the capsid; like glycoproteins or viral enzymes
3
Q
Describe bacteriophages strutures and their functions
A
- are viruses that infect bacteria
* bacteriopages have a complex capsid consisting of an icosahedral head and a tail apparatus
4
Q
Compare and contrast the two types of bacteriophage reproductive cycles
A
- lytic cycle: phage reproduces killing the host cells; lytic bacteriophages attach to the cell wall of a bacterial cell (attachment/absorption); inject viral DNA into the cell (penetration); phage takes over the cell’s metabolic machinery, degrades the cell’s DNA, and makes copies of its own genome and proteins. (replication); virus components assemble into new phage particles (assembly); the viruses lyse, or burst open the cell, resulting in death to the bacterial host (release)
- lysogenic cycle: phage reproduces without killing the host; phage attaches to the cell wall of a bacterial cell (attachment); virus genome enters the cell (penetration); phage circularized DNA will become inserted into a host cell chromosome and referred to a prophage (integration); DNA essentially “hidden” in the host cell’s DNA; prophage is replicated along with the bacterial host chromosome during cell (replication); A switch from lysogenic to a lytic cycle can be triggered; usually occurs as a result of an environmental factor, such as radiation or certain chemicals; the prophage is released from the host chromosome and returns to an active replication cycle that will lyse the host cell
5
Q
Understand how viruses infect a host and what determines their ability to infect a host
A
- They have to fit the proteins (specific)
* “host range”
6
Q
Contrast viroids and prions and the host range for each. Which targets plants? Animals?
A
- viroids: a plant pathogen consisting of molecule of naked, circular RNA
- prions: infectious agent consisting of a misfolded protein of a normal cellular protein; slow-acting, virtually indestructible infectious proteins that cause brain diseases in mammals by slowly converting correctly folded versions of the protein to more prions
7
Q
Understand retrovirues and their reproductive cycle
A
- retroviruses us reverse transcriptase to copy their RNA genome into DNA
- reverse transcriptase: an enzyme encoded by retroviruses that uses RNA as a template for DNA synthesis
- replicative cycle: the viral DNA that is integrated into the host genome is called a provirus; the host’s RNA polymerase transcribes the proviral DNA into RNA molecules; the RNA molecules function both as mRNA for synthesis of viral proteins and as genomes for new virus particles released from the cell
8
Q
Understand how humans prevent and treat viruses
A
- good hygiene: avoid contact with contaminated food, water, fecal material or body fluids; wash hands frequently
- vaccines: stimulate natural defenses in the body; contain a component of or a weakened or killed virus particles; developed for many once common illnesses such as smallpox, polio, mumps, chicken pox; not available for all viruses
- anti-viral drugs (but not antibiotics): available for some viruses; inhibit some virus development and/or relieve symptoms.
9
Q
Describe how new viruses emerge
A
- through mutation and evolution
- by spreading from one species to a new host species
- by spreading from an isolated location to more widespread locations
10
Q
Characterize the features common to prokaryotes
A
- single-celled
- most have distinctive cell walls
- lack membrane-bound organelles
- both anaerobic and aerobic
- genetic material is single circular bacterial chromosome and sometimes plasmids
- cell division is mostly asexual reproduction via binary fission also budding
11
Q
Compare and contrast features of prokaryotes and eukaryotes
A
- similar - they are both living; have DNA; plasma membrane; cytoplasm, and ribosomes
- prokaryotes - nucleoid region; very small; not very complex; only single-celled;
- eukaryotes - nucleus and other membrane bound organelles; large cells; complex; most multicelled but also some single-celled;linear chromosmes
12
Q
Describe three types of shapes that are used to classify bacteria
A
- bacilli (singular - bacillus): rod-shaped; usually solitary but in some forms the rods are arranged in chains
- cocci (singular - coccus): shperical shaped; occur singly, in pairs, in chains of many cells, and in clusters resembling bunches of grapes
- spiral (singular - spirillum): spirilla - comma shaped and loose coild; spirochetes - corkscrew shaped
13
Q
Explain how and where bacteria are able to carry out the functions of chlorophasts and mitochondira, which they lack
A
- the plasma membrane
- infoldings of plasma membrane functions in cellular respiration in some aerobic prokaryotes
- photosynthetic prokaryotes called cyanobacteria have thlakoid membranes much like those in choloroplast
14
Q
Describe the structures and their functions of a typical bacteria cell
A
- DNA loose in the cytoplasm, located in the nucleoid region. may also have small rings of DNA called plasmids
- ribosomes in the cytoplasm
- plasma membrane
- cell wall
- outer surface coating called a glycocalyx (capsule or slime layer)
- some have appendages (pili, fimbriae, endospore, flagella)
15
Q
Compare and contrast the cell walls of Archaea and Eubacteria
A
- gives them shape; protects them; prevents lyse
- eubacteria has peptidoglycan cell wall
- archaeabacteria cell wall is not made of peptidoglycan
16
Q
Explain how gram staining is used to classify bacteria as gram positive or gram negative
A
- gram positive is thick and simple and stains purple and is made of mostly peptidoglycan
- gram negative is thin and more complex stains pink and have less peptidoglycan
17
Q
Understand how rapid reproduction, mutation, and genetic recombination promote genetic diversity in prokaryotes
A
- binary fission which happens in short generation time of 1-3 hours
- mutation doesn’t happen often however high •generation time is so high allows for to accumulate rapidly
- genetic recombination - horizontal gene transfer; transformation (picking up dead cell DNA); transduction; conjugation
18
Q
Describe the ways in which bacteria move
A
- flagella
* taxis:chemotaxis (chemical stimuli; phototaxis (light stimuli)
19
Q
Contrast bacterial chromosomes with plasmids
A
- Plasmids has DNA and just a few genes and is not needed for life
- chromosomes is needed for normal metabolic processes
20
Q
Distinguish between transduction, transfromation, and conjugation
A
- transformation is a genotype and phenotype due to assimilation of external DNA by a cell (forgein DNA)
- transduction the movement of genes between bacteria by bacteriophages
- conjugation hollow bridge between two bacterial cells, genetic material moves from one cell to the other.
21
Q
Identify the structure that some bacteria form during harsh environmental conditions
A
•Endospores - thick internal wall that encloses the DNA and a portion of the cytoplasm
22
Q
Discuss the different modes of nutrition bacteria use and know the primary one that most bacteria use
A
- majority are heterotrophs - require an organic nutrient as a carbon source to make organic structures
- phototrophs - obtain energy from light
- chemotrophs - obtain energy from chemicals
- autotrophs - require CO2 (in some form) as a carbon source
23
Q
Discuss how prokaryotes metabolism varies with oxygen
A
- obligate aerobes - require oxygen for cellular respiration
- obligate anaerobes - are poisoned by oxygen and use fermentation or anaerobic repiration
- facultative anaerobes - can survive with or without oxygen
24
Q
Distinguish between the three groups of archaea: thermophiles, methanogens, and halophiles.
A
- thermophile - thrive in very hot
- halophiles - thrive in very salty
- methanogens - live in swamps, marches, km under ice and produce methane as a waste product (greenhouse gas
25
Distinguish between commensalism, mutualism, and papasitism
* commensalism - one organism benefits while neither harming nor helping the other in any significant way
* mutualism - both symbiotic organisms benefit
* parasitism - an organism called a parasite harms but doesn't kill the host initially
26
Explain why bacteria and archaea are in their own domains.
* they are slightly different
* archaea have some similarities to eukaryotic cells (ie rRNA sequences, RNA polymerase); not sensitiy to antibiotics
* bacteria has unique rRNA sequences; RNA polymerase is small and simple; sensitive to antibiotice and has a peptidoglycan cell wall
27
Discuss the importance of bacteria. Understand their role with fixing nitrogen. E.g. Anabaena
* decomposers
* symbiotic relationships like in the gut
* important in fixing nitrogen into organisms for use.
28
Discuss how humans try to prevent, remove, control and treat bacterial diseases and substances contaminated by bacteria
* physical removal - washing hands and surface
* kill bacteria - disinfectants; antibiotics; sterilization by heat
* food processing - boiling, steaming, frying, cold temperatures
* prevention - vaccine
* treatment - antibiotics
29
Characterize the features common to the members of kingdom protista
* small, usually unicellular
* micro and macroscopic
* all like moist habitats
* nucleus is distinct with single or multiple nucleated cells; have organelles but no tissues or organs
* locomotion via flagella, cilia, pseudopodia
* resistant stages (cyst/test/shells, spores)
* mode of life (free living, mutualistic, commensatlistic, parasitic)
* nutrition (chemoheterotroph, photoautotrophs)
* reproduction (asexual or sexual reproduction by meiosis and the union of gametes)
* osmoregulation via contractile vacuoles
30
Discuss in general terms the diversity inherent in the protist kingdom, including modes of nutrition, body forms, motility, and reproduction
* nutrition (chemoheterotroph, photoautotrophs)
* reproduction (asexual or sexual reproduction by meiosis and the union of gametes)
* locomotion via flagella, cilia, pseudopodia
* resistant stages (cyst/test/shells, spores)
31
Know the five supergroups and briefly describe and compare the representative species for the five supergroups
* Excavata
* Chromalveolata
* Archaeaplastida
* Rhizaria
* Unikonta
32
Briefly describe and compare the phyla within each supergroup. Understand characteristics that are unique to each phyla
* Excavata - Euglenophyta (unicellular, two flagellas located on their front, excavated feeding groove on one)
* Chromalveolata - Pyrrophyta/Dinophyta (unicellular, motile, and marine with two flagella(spiral flagella), cellulose plates, mixotrophs, asexual); Ciliophora (cilia, free living, motile with some sessile, mulitinucleated, asexual and sexual via conjugation); Bacillariophyta (glassy crystalline appearance cell walls contain silica, important phytoplankton, asexual); Brown Algae (almost all marine, multicellular and photosynthetic, flagellated sexual gamets and asexual zoospores)
* Rhizaria - Foraminifera (calcium carbonate test with pores, heterotrophic, reproduction is by binary fission, when die collect at bottom to form chalk); Radiolaria (single celled with glassy sicla skeletons, pores allow cytoplasm to protrude through forming axopods, marine plankton which are heterotrophic)
* Archaeaplastida - Rhodophyta (all marine, very simple filaments or complex morphology, cell wall contains cellulose, chlorophyll and accessory pigments called phycobilins, reproduction asexual and sexual);
* Unikonta -
33
Indentify the protist that cause backpackers' diarrhea, African sleeping sickness, used as an indicator for organic pollution, is responsible for blight of potatoes, red tides, viginal STD, ect.
* backpackers' diarrhea - Excavata - Euglenaphyta - Giardia intestinalis
* African sleeping sickness - Excavata - Euglenaphyata - Trypanosoma
* indicator for organic pollution - Excavata - Euglenaphyat - Euglenids
* blight of potatoes - Chromalveolata - Brown Algae - water mold (Phytofora infestons)
* red tides - Chromalveolata - Pyrrophyta/Dinophyta - Dinoflagellates
* viginal STD - Excavata - Euglenaphyta - Trichomonas vaginalis
34
Discuss the protists and bacteria that collectively compose phytoplankton and their importance
* communities of mostly microscopic organisms (bacteria, some algae, diatoms, & dinoflagellates) that drift in currents near the waters surface
* decomposes and creates oxygen
35
Discuss the protist that causes malaria and the vector it uses to infect its host
* Plasmodium - parasite that causes malaria
* Parasites spread through tiny infectious cells called sporozoites
* Mosquito harboring sporozoites bites human transmitting the parasite
36
Describe what is unique about the reproduction of red algae
•Sexual reproduction involves alternation of generation but there are NO flagellated cells.
37
Be able to explain the life cycle of the brown algae Laminaria. See lecture notes and PowerPoint.
•Reproduction is varied with flagellated sexual gametes and asexual zoospores. Alternation of generationis exhibited. Part of life as a haploid, part as diploid and both stages are multicellular.
