What is life? Flashcards
1
Q
What are the criteria of life?
A
- Stable internal environment (homeostasis)
- Organized structure
- Metabolism
- Growth/ development
- Ability to produce
- Ability to adapt to the environment
- Responsiveness to environmental stimuli
2
Q
Panspermy theory
A
Life has been formed outside of the earth and arrived at us. (Meteorites may carry organic compounds, amino acids, and fatty acids) This theory does not explain the origin of extraterrestrial life
3
Q
Oparin theory
A
Live organisms may have arisen from non-live chemical substances on the ancient earth
4
Q
Primordial organic soup
A
Pre-biotic oceans of earth could promote the generation of the “primordial organic soup”
5
Q
Oparin coacervate droplets
A
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6
Q
“Deep sea vent” theory
A
- Release of hidrogen-rich molecules leading to high concentrations of them in the rocks
- Mineral catalyzers could be available in appropriate concentration
7
Q
Other theoris
A
- Prebiotic pizza
- Prebiotic pancake
- Bubble theory
- Uray - Miller experiment
- RNA world - theory
8
Q
Major steps of the chemical evolution
A
- formations of ribozymes that are capable of limited self-replication (RNA world)
- Ribozymes that catalyzed the synthesis of small proteins (ribozyme synthesis)
- Proteins proved to be better catalyzers than ribozymes
- Nucleic acids used for genome purposes
- Lipid bilayers were formed spontaneously by long phospholipids
9
Q
Three domains of cellular life
A
- Bacteria
- Archea
- Eucaryotes
10
Q
What is virus?
A
- They are dominant biological entities on earth
- Ocheans contain more viral particles than cells
- They also have the largest number of genetic variants
- Most unique genes are found in viral genomes
- The giant mimivirus (that infects amoebas) have larger genome than many bacteria and archaea
- Major conveyors of HTG (Horizontal gene transfer)
11
Q
What is a cell?
A
- A membrane-enclosed system capable of maintenance of its structure and capable of reproduction
- The basic and smallest unit of life
12
Q
Size of a cell
A
- Prokaryote cells: 1-10 micron
Eukarotic cells: 10-100 micron
13
Q
The main difference between prokaryote and eukaryote cells
A
Prokaryote:
- NO NUCLEUS
- circular chromosome
- Division by fission
- Nucleotid
- Inner (plasma membrane)
- Cell wall
- Periplasmic space
- Outer membrane
Eukaryotic cell
- a nucleus with paired chromosomes
- Asexual and sexual reproduction
- Nuclear membrane
- Plasma
- Golgi
- Mitochondrion
- Peroxisome
- Lysosome
- Secretory vesicle
- Rough endoplasmatic reticulum
