Biology- Biological Diversity Flashcards
(118 cards)
systematics
study of evolutionary relationships among organisms
Eukaryotic cells
- chromosomes consist of a very long, linear DNA molecule package w/ histone proteins and enclosed in a nucleus -have organelles -flagella and cilia, when present are made of the protein tubulin arranged in “9+2” microtubule arrays
Prokaryotic cells
-a single chromosome w/ short, circular DNA. Histone proteins may/may not be present. Some cells contain plasmids -no nucleus -no organelles -flagella, when present, consist of the globular protein flagellin note: flagella use proton motive force to spin
autotrophs
make their own organic molecules; uses light or chemicals such as H2S, NH3, NO2-, NO3-
photoautotrophs
use light energy
chemoautotrophs
use energy obtained from inorganic substances (as in chemosynthesis). Examples of inorganic substances that are used: hydrogen sulfide (H2S), ammonia (NH3), and other nitrogen compounds
heterotrophs
obtain energy by consuming organic substances made by autotrophs; some heterotrophic organisms are parasites, saprobes (obtain their energy from dead matter)
obligate aerobes
need oxygen to live
obligate anaerobes
can survive only in the absence of oxygen
facultative anaerobe
grows in the presence of oxygen but, when oxygen is absent, can switch to an anerobic metabolism
what are the 3 domains?
archaea, bacteria, eukarya
Archaea groups (2. Extremophiles)
live in extreme environment; Halophiles (salt lover) high [salt] environment; most are aerobic and heterotrophic; others anaerobic and photosynthetic with pigment bacteriorhodospin. Thermophiles (heat lover) are sulfur-based chemoautotroph.
Archaea groups (1. methanogens)
obligate anaerobes that produce CH4as by-product of obtaining energy from H2 to fix CO2 (mud, guts)
Archaea (similarities with eukaryotes)
- DNA of both archaea and eukaryotes are associated with histone; not bacterial DNA.
- Ribosome activity is not inhibited by antibiotics streptomycin and chloramphenicol unlike bacteria
Archaea
prokaryotes; archaeal cell walls contain various polysaccharides, not peptidoglygan (as in bacteria), cellulose (as in plant), or chitin (as fungi).
Phospholipid components such as glycerol is different (isomer of either bacteria or eukaryotes). Hydrocarbon chain is branched (straight chain for others) and ether-linkages instead of ester-linkages.
halophiles
are extremophiles; they live in environments w/ high [salt].
- Most are aerobic and heterotrophic
- others are anaerobic and photosynthetic w/ the pigment bacteriorhodopsin
thermophiles
are extremophiles that live in hot (60 to 80 C) environments such as hot springs or geysers. Most are sulfur-based chemoautotrophs.
How are bacteria distinct from archaea and eukaryotes?
- Bacterial cell walls (peptidoglycan, a polymer of a monosaccharide w/ amino acids)
- Bacterial DNA is not associated w/ histone proteins.
- Ribosome activity is inhibited by the antibiotics streptomycin and chloramphenicol.
What features have been used to categorize bacteria?
- mode of nutrition
- ability to produce endospores (resistant bodies that contain DNA and a small amount of cytoplasm surrounded by a durable cell)
- means of motility (flagella, corkscrew motion, or gliding through slimy material)
- shapes: cocci (spherical), bacilli (rod shaped) and spirilla (spirals)
- thick peptidoglycan cell wall (gram-positive), thin peptidoglycan wall (gram-negative) covered w/ a layer of lipopolysaccharides.
What are the four kingdoms in Eukarya?
Kingdom Protista
Kingdom Fungi
Kingdom Plantae
Kingdom Animalia
Kingdom Protista
consist of algaelike, animalike, funguslike, unicellular, or multicellular
Kingdom Protista (algaelike members)
all obtain energy by photosynthesis. All have chlorophyll
convergent evolution
features that arise among groups independently
charophytes
lineage of the chlorophytes are believed to be the ancestors of plants