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46 Cards in this Set

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What is the borderline between living and nonliving?
viruses
How do viruses reproduce?
when put in a cell viruses can reproduce itself and kill the cell
Can viruses feed?
no
Viruses have a center core that is made up of ______.
nucleic acids (RNA or DNA)
What surrounds the core?
a capside made of protein which serves as a protective covering
What surrounds the capsid?
an envelope which is a protective covering against host
Which is bigger, a virus or bacterium?
bacterium
What is a bacteriophage?
a virus that affects a bacterium
Describe the lysogenic cycle.
1. phage genetic material incorporated into bacterial DNA
2. phage genome may replicate with bacterium for many generations
3. bacterium divides and phage genome is passed onto offspring
Describe the lytic cycle.
1. many copies of phage protein and genetic material is produced
2. conditions cause phage to enter lytic phase
3. mature phages assemble; released when phage enzymes lyses bacterial cell wall
What is a hypothesis for where viruses came from?
DNA/RNA escaped cell and coded for a protective coat, forming a virus
What is a viroid?
short strand of DNA with no protein coat that interferes with host gene regulation and cause several diseases
What is a prion?
a strand of protein that is normally harmless, but if it changes shape it can cause fatal brain disease (ex. mad cow disease)
Describe a bacterium.
-prokaryotic
- ribosomes for protein production
- circular chromosomes
- have plasmids
Describe how bacteria reproduce.
no true sexual reproduction, but they just split in half
What is the oldest fossil?
that of a photosynthetic bacteria in oxygen-poor environment
What are the 2 kingdoms of bacteria?
Kingdom Archaea - ancient bacteria
Kingdom Eubacteria - "true" bacteria
What are the 2 phyla of K. Eubacteria?
P. Schizophyta and P. Cyanophyta
P. Cyanophyta used to called ______ and it contains ________.
blue-green algae - photosynthetic bacteria
Which is smaller, archaea or eubacteria?
archaea
How does archaea bacteria differ from eubacteria?
Its cell membrane is structurally different and simpler than eubacteria, it has simpler ribosomes, and found in extreme environments that are mainly anaerobic.
What are the 5 different types of Archaea bacteria?
- pressure tolerant
- thermophiles
- extreme halophiles
- pH tolerant
- methanogens
Where are pressure tolerant bacteria found?
deep in the ocean floor in deep sea vents
How can bacteria survive in deep sea vents?
Volcanic gases up through vents, heat water, disperse nutrients (sulfur and phosphorous), archaea use these nutrients
Where are thermophiles found?
in hot springs; they can survive in extremely hot environments by living off of sulfur
Where are extreme halophiles found?
very salty water like the Great Salt Lake and the Dead Sea
Where are pH tolerant bacteria found?
very low pH (<1) like a bog
Where are methanogens found?
in bogs and bottom of swamps where they can live on methane
What 3 shapes do Eubacteria come in?
cocci (circular)
bacilli (rod-shaped)
spirilli (squiggly)
What does "strepto" mean?
string
What does "staphylo" mean?
ring
Describe a bacterium.
-has cytoplasm, ribosomes, 1 chromosome, plasma membrane, and no organelles
What is the cell wall of a bacterium made of?
a polysaccharide and a protein OR a lipid
In a bacterium, what is outside of the cell wall?
a capsule
What are the pili on bacterium for?
- to help attach bacterium to substrate
- involved in sexual reproduction (conjugation)
How can one figure out if peptidoglycan is gram positive or gram negative?
gram positive stains purple and gram negative does not
How does bacteria reproduce?
- binary fission
- recombinant bacteria
What are the 3 types of recombinant bacteria?
1. transformation
2. transduction
3. conjugation
Describe transformation.
living bacteria picks up DNA of dead bacterium and incorporates it into DNA
Describe transduction
same as transformation except that transfer is done by a virus
Describe conjugation.
2 bacteria form a bridge made of pili and homologous pieces of DNA travel across bridge, sometimes exchange plasmids; (+) and (-) bacteria needed for "reproduction"
Describe cyanobacteria.
- Has chlorophyll a
- no chloroplastas
- secondary photosynthetic pigments (usually blue)
- most have gas vacuoles
What do cyanobacteria use the gas vacuoles for?
to make themselves heavier or lighter
What are the 5 metabolic/ecological roles of Eubacteria?
1. decomposers (Schizophyta)
2. autotrophs (cyanophyta)
3. symbiants (+, -, 0)
4. pathogen (neg. symbiant)
5. chemosynthesis (break down other organic materials)
What is nitrogen-fixing bacteria?
Bacteria that nitrogen from atmosphere and converts it to ammonia and another group converts it to nitrogen that we can use.
Where are nitrogen-fixing bacteria found?
in soil and root nodules of legumes