Unit 3 Bio Quiz Diversity
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why are viruses non-living?
-Not made up of cells (no cytoplasm, organelles or cell membrane) -lack enzymes and ribosomes -must infect a host in order to reproduce
what are viruses made up of
-Viral genome (DNA, RNA) -viral capsids (a protective protein coat) -membranous envelope (sometimes, but a lipid bilayer formed by the host) -Spikes/ glycoproteins
how was viruses classified
• Genetic material (DNA or RNA) • structure • host range • mode of replication
what is “lock and key” i viruses?
virus spikes match specific host cell receptors
once a virus has entered the host how does it begin to manufacture viral proteins
uses the hosts -ribosomes -enzymes -amin acids -ATP
what are bacteriophages and what is the short form
viruses that infect bacteria -phage
what are the two viral cycles i viruses
-lytic cycle -lysogenic cycle
what are the 5 steps of the lytic cycle
• attachment • entry (penetration) • synthesis • assembly • release
what is attachment in the lytic cycle
when a virus binds to specific receptors on the cell surface
what is entry of the lytic cycle
virus enters cell either through direct fusion or endocytosis
what is synthesis of the lytic cycle
the viral genome is replicated and viral proteins are built
what is assembly of the lytic cycle
viral genome and protein coats are assembled into new viral particles
what is release of the lytic cycle
naked virus leaves cell by rupturing the cell membrane
what is the lysogenic cycle
a long term viral cycle where virus stays in a host without killing it
what happens to viral DNA in the lyosogenic cycle
it integrates into the hosts chromosomes/ DNA -creating a provirus
what happens in the lysogenic cycle once the provirus is formed
the provirus reproduces with the host cell and the virus becomes inactive
what happens when the host cell divides in lysogenic cycle
viral DNA is copied and passed to daughter cells
what can trigger a virus to leave lysogenic cycle to go to lytic
environmental stress (UV light, Chemicals)
what are the tree types of biodiversity? How are they interrelated?
Ecosystem diversity: different habitats, niches and biological communities species diversity: variety of species Genetic diversity: sum of all different forms of genes and combinations of genes within particular species
what is a keystone species
an organism that holds an ecosystem together -Their survival is critical to the ecosystem.
why is biodiversity important to humans
-cleans water -provides oxygen -recycle nutrients
what are some threats to biodiversity
-habitat loss -hunting -pollution -climate change -natural disasters
what is modelling
when scientists use data + predictions to make their own predictions about the impact climate change has on an ecosystem
how does climate change effect food sources and what is the impact on the organisms
-earlier spring –> earlier plant growth and lose nutrients by the time animals arrive -Flooding in other areas – floods fields -more rain, snow, ice makes it harder to reach food Impact on organisms -less access to food= less energy -populations decrease