(bio) Unit 0 - The beginning of the end Flashcards
Who invented the light microscope
Hans Lippershey , Hans and Zacharias Janssen around 1590
Cell Theory ; who discovered it and what did they see
Robert Hooke ; viewed slices of tree bark “cellula”
What did Antoine Van Leeuwenhoek do/observe? (2)
- Worked with glass
- became a huge improvement in quality of lenses
(300x magnification became possible) of compound microscope - First to observe single celled protists from pond water , bacteria, blood cells, banded pattern in muscle cells, giarda and sperm
Robert Brown the botanist and the cell theory
noticed that every plant cell contained a round structure (nucleus)
Matthias Schleiden (another botanist)
- all plant tissues are composed of cells
- embyronic plant always arose from a single cell
Theodor Schwann (zoologist)
- similar observations in animal cells
- recognition of structural similarities between plants and animals
Who formulated the cell theory
Schwann
Describe the cell theory (3 facts)
- All organisms consist of one or more cells
- The cell is the basic unit of structure for all organisms
- all cells arise only from pre-existing cells
Describe the Scientific Method (5)
- make observations
- use inductive reasoning to develop a hypothesis
- Make predictions based on hypothesis
- Make further observations or design and carry out controlled experiments to test hypothesis
- interpret results to see if they support your hypothesis
Describe a theory
- a hypothesis that has been tested critically (under many different conditions/ investigators/approaches)
- widely accepted by most scientists in the field
- “solid ground” of science
What is more solid than a theory
a LAW
Basic Properties of all Cells (5)
- Highly complex and organized
- Use the same “genetic program” - Central Dogma
- Acquire and use energy to carry out chemical rxns
- Engage in mechanical activities (transport/ assembly/ movement )
- Respond to signals (environmental, molecular)
What are the two domains of prokaryotes?
- eubacteria (all have cell walls)
- archaebacteria (all have cell walls, best known are extremophiles; halophiles, acidophiles, thermophiles )
What are the 4 groups of eukaryotes?
- protists (single cell)
- fungi
- plants
- animals
Describe the ‘generic’ prokaryotic cell
- no membrane bound nucleus
- ‘naked’ DNA (fewer proteins), single, circular strand
- cell wall in addition to plasma membrane
- very small, no need for cytoskeletal transport systems
Describe protists and give examples
a type of eukaryote - very diverse group
- mostly single cells, but some colonies
ex. algae, water molds, slime moulds, protozoa
Describe fungi
a type of eukaryote
- single cells (yeasts) and multicellular (mushrooms)
- cell walls, heterotrophs
- dependent on external source of organic compounds
Describe plants
a type of eukaryote
- multicellular
- have cell walls
- autotrophs
Describe animals
a type of eukaryote
- multicellular
- no cell walls
- heterotrophs
Describe the endomembrane system
- internal membranes that are either in direct contact or connected via transfer of vesicles (sacsof membrane)
this includes; nuclear envelope, membrane. ER, golgi apparatus, lysosomes, vacuoles
What two organelles have their own genomes
- Mitochondria - generate energy to power cell
- Chloroplasts - using energy from sunlight convert CO2 derived carbon to carbohydrate
they both contain dna that encodes SOME of their own proteins
Describe the role of the Rough ER and the Golgi apparatus in the Secretory Pathway
Rough ER: synthesis of proteins for … export, insertion into membranes, lysosomes
Golgi Apparatus: collection, packaging, and distribution
Describe the endocytic pathway
- cell ‘stomachs’ have enzymes that can digest biological macromolecules such as
- worn-out organelles
- material brought into cell by phagocytosis
How did eukaryotic ells acquire mitochondria and chloroplasts?
Endosymbiont Theory
- organelles evolved to gradually become more complex
- eukaryotes originally originated as predators (certain organelles evolved from smaller prokaryotes engulfed by larger cell
Evidence for supporting the endosymbiont theory (5)
Mitochondria and chloroplasts…
1. Similar size, reproduce by fission
2. Have double membranes , engulfing mechanism
3. have their own ribosomes
4. Have their own genomes
5. genetically similar to ‘parent’ bacteria , not eukaryotic cell it was engulfed by
Importance of Cytoskeleton
- cell shape, motility, movement
- movement of materials within cells (eg chromosomes during mitosis)
fun little thing: contribution of model organism e. coli
DNA replication, gene transcription, translation
fun little thing: contribution of model organism saccharomyces cerevisae
cell cycle
fun little thing: contribution of model organism Arabidopsis thaliana
all flowering plants closely related
fun little thing: contribution of model organism drosophila melanogaster
genetics, development
fun little thing: contribution of model organism C. elegans (“the worm”)
First animal genome to be sequenced
Fun little thing: contribution of model organism mouse
‘model mammal’
Genetics well understood
