Midterm 1: Lec 2 Slides Flashcards
What did the Miller & Urey experiment prove?
Organic molecules can be made from inorganic molecules (especially under conditions similar to those of primitive Earth)
What is the “RNA World” hypothesis?
RNA existed before DNA- and protein-based life; DNA probably evolved from RNA and became the primary molecule for info storage
Hierarchical organization of life(?)
Atoms, molecules, organelles, cells, tissues, organs, organ system, organism (in ascending order)
Tissue
Group of similar cells that carry out a particular function in an organism
4 tissue types
Epithelial (forms boundaries), connective, nervous (brain, nerves), muscle
Organ
Structure composed of more than one tissue type (e.g., skin is epithelial cells over connective tissue)
Types of muscle tissue
Skeletal, cardiac, smooth
What are the characteristics of living things (5)?
- Cellular organization
- Sensitivity (response to stimuli)
- Growth (energy released by interconverting molecules is used to grow)
- Reproduction
- Homeostasis (maintain relatively constant internal conditions)
What is the difference between anabolism and catabolism?
Anabolism is complex molecule from simpler one (building); catabolism is complex molecule broken down into simpler one
Virus structure
Nucleic acid core surrounded by protein sheath (sometimes a lipid envelope)
Why are viruses not considered organisms (and therefore alive)?
- No cell membranes, nucleus, or organelles
- Cannot reproduce alone (need host cell)
- Don’t carry out metabolism
Cell theory principles (3)
- All organisms made of cells
- Cell is basic building block of life (chemical reactions of life take place in cells)
- All cells arise by division of pre-existing cell
Why are cells small?
Need to have large surface area-to-volume ratio to function (if cell too large, not enough material will be able to enter to accommodate large volume)
What do cells need to do to survive?
- Obtain and process energy
- Convert genetic info of DNA into protein
- Allow biochemical reactions to occur
Where is DNA in prokaryotic cells?
Coiled in a nucleoid region, which is in direct contact with cytoplasm (prokaryotes can have more than one)
Which types of organisms are prokaryotes and which are eukaryotes?
Eukaryotes: plants, animals, fungi, protists
Prokaryotes: Eubacteria and Archaebacteria
Which bacteria carry out photosynthesis?
Cyanobacteria
How do flagella move and what are they made of?
Complex protein ring structures anchored in plasma membrane form a motor unit that rotates the flagellum and propels cell - made of flagellin (protein)
