1. Intro + Cell Theory Flashcards
What did Robert Hooke (1665) do?
First observation of cells:
- He looked at the champers of a cork and noticed they look like prison cells
- Chambers of a cork: dead cell walls
What did Anton van Leeuvenhoek (1673) do?
Improved magnifying power of microscope lenses
What is light microscopy?
When you have a microscope with a light at the bottom
- Typical microscopes you see in class
What is electron microscopy?
Microscopes where you send a beam of electrons to the subject of interest
- Interaction of electrons with the subject gives information about its structure (more 3D looking)
What is fluorescence microscopy?
When you attach a fluorescent mark to a subject of interest + excite it with certain wavelengths that causes the markings to show
What did Schleiden, Schwann, and Virchow establish?
The Cell Theory:
- Schleiden: botanist, found that plant embryos arise from a single cell
- Schwann: zoologist, animal embryos arise from a single cell
Virchow: zoologist, added that cells can arise only from preexisting cells (tenant 3)
What are the 3 tenants of cell theory?
- All living organisms are composed of one or more cells
- Each cell is the structural and functional unit of life
- Cells can arise only from pre-existing cells
What are some exceptions (3) to cell theory? What do they have in common?
Viruses, viroids, prions
- They require a host
Describe a virus
- Small amounts of nucleic acids with a protein coat
- Requires a cell for reproduction
How do you classify viruses outside a living cell?
inert
Describe a viroid
Small circular RNA lacking a protein coat
- Needs host to replicate
Describe a prion
Proteinaceous infectious particles
- has NO nucleic acids
What part of the cell encloses all of its other parts?
Cell membrane/plasma membrane
What is cytoplasm vs cytosol?
Cytoplasm
- All contents found inside the cell
Cytosol
- Jelly-like internal fluid environment of a cell minus the organelles
What is prokaryote vs eukaryote?
Prokaryote: before nucleus
- Most abundant organisms on Earth
Eukaryote: true nucleus
How would you draw:
- Bacteria
- Archaea
- Eukarya
on the tree of life?
Eukarya
/
Bacteria Archaea
\_____/
||
- All plants and animals lie when the eukarya
- Eukaryotes are hypothesized to descended from the archaea
What is the central dogma?
The process of turning DNA -> RNA -> Protein
Theory: genetic information only flows one way
Describe prokaryotes:
- What is the form of their chromosome?
- What are the two domains?
- They have a single circular chromosome
- Bacteria: have many plasmids, have cell wall surrounding cell membrane
- Archaea: often inhabit extreme environments
What do prokaryotes rely on for support
cell wall + rigid protein framework
What are the domains of eukaryotes?
- Protists
- Fungi
- Plants
- Animals
What is the unique feature of cells in fungi
- contains chitin, a modified polysaccharide
What are autotrophs vs heterotrophs
- autotrophs: produce their own food
- heterotrophs: gain energy from chemical sources
What is the difference between animal cells + plant cells
- plant cells have cell walls, contributing to turgor pressure
What is turgor pressure
- Something that gives plant cells structure, arising from large water-filled vacuoles
What is the cytoskeleton? What kind of cells have it?
- Features of eukaryotes
- provides internal support for cells
- An internal protein scaffolding that can be remodeled quickly
What is the difference between rough and smooth endoplasmic reticulum (ER)?
- Rough ER: have ribosomes for protein synthesis
- Smooth ER: lacks ribosomes
What are model organisms
- non-human species that are used to understand specific biology concepts
- etc. bacteria for DNA replication
