Lecture 1 Flashcards
What characteristics are shared by living organisms?
- Organised from the atom to the biosphere
- Use materials and energy from the environment
- Reproduce offspring
- Growth and development
- Maintain a relatively constant internal environment (homeostasis)
- Respond to internal and external stimuli
- Evolutionary history through which organisms change over time
How are living things organised? (Atom to Biosphere)
Atom Molecule Cell Tissue Organ Organ system Organism Population Community Ecosystem Biosphere
How do we classify humans?
Domain - Eukarya Kingdom - Animalia Phylum - Chordata Class - Mammalia Order - Primates Family - Hominidae Genus - Homo Species - Sapiens
What distinguishes humans?
- Cultural heritage or patterns of our behaviour passed from one generation to the next
- Highly developed brains
- Completely upright stance
- Creative language skills
- Varied tool use
- Modification of our environment for our own purpose which may threaten the biosphere
Concept of Cells
All organisms are composed of cells, and new cells only come from pre-existing cells.
Concept of Homeostasis
The internal environment of an organism stays relatively constant
Concept of Genes
Organisms contain coded information that dictates their form, function and behaviour
Concept of Ecosystem
Populations of organisms interact with each other and the physical environment
Concept of Evolution
All organisms have a common ancestor, but each is adapted to a particular way of life
Why are most cells small?
- Small cells have a larger amount of surface area compared to volume
- An increase in surface area allows for more nutrients to pass into the cell and wastes to exit the cell more efficiently
- There is a limit to how large a cell can be and be an efficient and metabolically active cell
What are common microscopes used to view cells?
- Compound light microscope
- Lower magnification
- Uses light beams to view images
- Can view live specimens - Transmission electron microscope
- 2-D image
- Uses electrons to view internal structure
- High magnification, no live specimens - Scanning electron microscope
- 3-D image
- Uses electrons to view surface specimens
- High magnification, no live specimens
What are the 2 major types of cells in all living organisms?
Prokaryotic cells
- Thought to be the first cells to evolve
- Does not have a nucleus
- Represented by bacteria and archaea
Eukaryotic cells
- Have a nucleus that houses DNA
- Many membrane-bound organelles
What do prokaryotic and eukaryotic cells have in common?
- A plasma membrane that surrounds and delineates the cell
- A cytoplasm that is the semi-fluid portion inside the cell that contains organelles
- DNA
Where did eukaryotic cells come from?
- Cells gains a nucleus by the plasma membrane invaginating and surrounding the DNA with a double membrane.
- Cells gain an endomembrane system by proliferation of membrane.
- Cells gain protomitochondria.
- Cell gains protochloroplasts.
What are the characteristics of the plasma membrane?
- It is a phospholipid bilayer
- It is embedded with proteins that move in space
- It contains cholesterol for support
- It contains carbohydrates on proteins and lipids
- Selectively permeable