Chapter 1- Themes In The Study Of Life Flashcards
Reductionism
The approach of reducing complex systems to simpler components that are more manageable to study
What is an emergent property?
The arrangement and interaction of parts as complexity increases
What is a system?
A combination of components that function together
What are the characteristics of life?
- highly organized structure
- energy processing
- homeostasis
- responds to environment
- reproduction
- change over time
Eukaryotic cell
Subdivided by internal membranes into various membrane enclosed organelle
The biggest organelle that contains the cells DNA
Nucleus
Cytoplasm
The entire region between the nucleus and the outer membrane of the cell
Chloroplasts
An organelle found in eukaryotic cells that carries out photosynthesis
Prokaryotic Cells
DNA is not separated from the cells by a nucleus
DNA
Deoxyribonucleic Acid
Genes
The units of inheritance that transmit information from parent to offspring
Selective permeability
Membranes allow some substances to cross more easily than others
Amphipathic
A molecule that has both a hydrophilic and hydrophobic region. A phospholipid is amphipathic
Fluid mosaic model
Draw the fluid mosaic model and check in the book
The membrane is a fluid structure with a “mosaic” of Various proteins embedded in or attached to a double layer (bilayer) of phospholipids.
Freeze-fracture
Splits a membrane along the middle of the bilayer using liquid nitrogen.
Fluidity of membranes
A membrane is held together by hydrophobic interactions which are much weaker than covalent bonds. Most of the lipids and some of the proteins can shift about laterally. They do so several times per second. It is much more difficult to shift vertically and is only one once a month because the hydrophilic part of the molecule must cross the hydrophobic region.
Integral proteins
Penetrate the hydrophobic interior of the lipid bilayer of a cell.
Peripheral proteins
Appendages loosely bound to the surface of the membrane of a cell
Membrane carbohydrates
Short, branched chains of fewer than 15 sugar units
Glycolipids
A membrane carbohydrate covalently bonded to lipids
Glycoproteins
A membrane carbohydrate covalently bonded to a protein
Synthesis and sidedness of membranes
The asymmetrical arrangement of proteins, lipids and their associated carbohydrates in the plasma membrane is being build by the endoplasmic reticulum and the Golgi apparatus. See fig 7.12
Supramolecular structure
Many molecules ordered into a higher level of organization
Permeability of the lipid bilayer
No polar molecules are hydrophobic and can dissolve in the lipid bilayer as cross it easily.
Polar molecules do not cross vey rapidly.
Transport proteins
Function by having a hydrophilic channel that certain molecules or atomic ions use as a tunnel through the membrane figure 7.10a
