BIO 315: Exam 1 Flashcards
(22 cards)
What is the definition of life?
A self-organizing, self-replicating, non-equilibrium system.
What are the macromolecules needed for life, and in what percentage?
Polypeptides = 50 - 55%, Deoxyribonucleotides = 2 - 5%, Ribonucleotides = 15 - 20%, Lipids = 10%, Polysaccharides = 6 - 7%
What are microbes? Name some examples.
These are forms of LIFE that are too small to be seen with the naked eye. Examples: Fungi, Algae, Protists.
Before the three-domain classification was invented, how were groups of life separated?
Into Prokaryotes & Eukaryotes
What do prokaryotes lack that eukaryotes have?
Membrane-bound organelles, including a true nucleus.
What are the three domains of life?
Bacteria, Archaea and Eukarya
How were the three domains of life discovered?
By sequencing and then comparing the small subunit ribosomal RNA genes of different organisms.
We aligned and concatenated a set of __ ribosomal protein sequences from each organism to give the three domain tree.
Fill in the blank
16
Archaea are more similar to which of the other two domains
Eukarya
To which domain do viruses belong?
None! Viruses are not microbes, and technically, they are not living things. They require a host cell to replicate, and they have minimal biochemical activity outside of their host cell.
Are viruses smaller or larger than bacteria, in general?
Viruses are MUCH SMALLER than bacteria.
What are viruses composed of?
Viruses are composed of DNA OR RNA particles, surrounded by a capsid. This capsid may have proteins on it, called capsomeres, and the capsid may be covered by an envelope.
What are viral envelopes made out of?
They’re made out of lipids and proteins.
What is an example of an envelope virus?
The flu virus is an example of an envelope virus.
Most bacterial cells have how many chromosomes?
1
How many ybp have microbial organisms existed?
3.5 billion ybp.
Who were the two scientists that discovered the microbial soup that was similar to life on primitive earth.
Stanley Miller & Harold Urey
What did iron-containing surfaces do to provide the right environment in primordial life?
They helped “stick” molecules to their surfaces.
What molecule served as both a genetic information storer AND as an enzyme?
Ribozymes! They contain both RNA and an enzyme.
What was the original primordial form of plasma membrane?
A single lipid layer known as the micelle, where the hydrophobic tails are on the inside, and the hydrophilic head groups are all on the outside.
Why did cells switch from single stranded RNA to double stranded DNA for storing genetic information?
Because the double strand provides a back up and DNA is more stable than RNA.
What is Endosymbiotic Theory
Endosymbiotic theory described the possible way eukaryotic cells were formed: Prokaryotic microbes ingested other prokaryotic microbes. If the ingested microbes could use oxygen for energy they became mitochondria.
If the ingested microbes could use carbon-dioxide to make organic molecules using light energy, they became chloroplasts.
