Lecture 3 and 4 Cell Theory Flashcards
Who was Robert Hooke?
invented the microscope, first to publish a picture of a cell, geological studies, first people to prove that seabed could become a mountain top
Who was Anton Moonhawks?
Anton Moonhawks: identified first microorganisms, stem cells, animal cells
What are the three generalizations of Cell theory?
1. All organisms are composed of one or more cells. 2. The cell is the basic structural and functional unit of all living organisms. 3. Cells arise only from the division of preexisting cells.
Which of the following are eukarya?
Bacterium Archaean Protist Algae Fungal Cells Animal Cells Plant Cells
Protist Algae Fungal Cells Animal Cells Plant Cells
What is the Universal Phylogenetic Tree
The Tree of Life
• Three domain system, based on a comparison of ribosomal RNA genes, divides microorganisms into: • Bacteria (true bacteria). • Archaea. • Eukarya (eukaryotes).
In the tree of life diagram, why are mitochondria and chloroplasts divergent from Bacteria?
Chloroplast and mitochondria were bacteria, we have bacterial dna, different organisms can merge together, share metabolism, theory that they originated from an endosymbiotic relationship with bacteria
What are the three basic Basic Features of Cell Structure and Function?
• As the basic structural and functional units of all living organisms, cells carry out the essential processes of life • Cells contain DNA and RNA, which carry hereditary information and direct the manufacture of cellular molecules • Cells use energy, respond to changes in their environment, reproduce, and pass on hereditary information
What is the largest cell?
Egg yolk
Light microscopes?
Light microscopes - use dyes that stain particular structures in the cell based on their chemical structure. Resolution down to 0.2 m
Magnification?
Magnification – the ratio of
the object viewed (e.g.
400:1)
Resolution?
Resolution – Minimum
distance two points can be
separated
Different Types of light microscopes are used to reveal different structures/functions within cells. Name some types of light microscopes
• Bright Field/Dark Field • Phase-constrast • Differential interference contrast • Confocal laser scanning…
Electron Microscopes
Electron Microscopes - use
electrons rather than light
Transmission E.M.
Transmission E.M. - specimen thin sectioned. Electrons passed through structure. practical resolution down to 2 nm
Scanning E.M.
Scanning E.M. - specimen
coated in gold. Electrons
scanned over specimen,
emitted electrons captured.
Scanning Tunnelling
Microscope
Scanning Tunnelling
Microscope - highest clarity.
resolution to atomic level (0.1-
0.2 nm)
Why are cells so small?
Cell size is limited by surface area-tovolume ratio Surface area determines the amount of substances that can be exchanged between a cell and the outside environment Doubling the diameter of a cell increases its surface area by four times but increases its volume by eight times The bigger the cell the harder it is to take in nutrients and remove waste products
What is the plasma membrane?
What is the lipid bilayer?
- plasma membrane, a bilayer made of lipids
with embedded protein molecules - surrounds cell
- hydrophobic barrier to water-soluble substances
–Selected substances can penetrate cell
membranes through transport protein
channels
–Selective transport of ions and watersoluble molecules maintains the specialized
internal environments required for cellular
life
What’s the difference between eukaryotic and prokaryotic cells?
Prokaryotes (domains Bacteria
and Archaea) –The nucleoid region has no boundary
membrane. –Many species of bacteria have few
internal membranes.
- lack nuclear enveloppe
Eukaryotes (domain Eukarya) –The true nucleus is separated from the surrounding cytoplasm by membranes. –Cytoplasm typically contains extensive membrane systems that form organelles. - eukaryotic cells have a membrane-bound nucleus and prokaryotic cells do not.
why are prokaryotes no longer a group?
Both bacteria and archaea were, until recently, grouped together as prokaryotes
The term “prokaryotic cell” is still used and refers to a
particular cell architecture, i.e., one lacking a nucleus
More advanced biochemical and genetic techniques
revealed that they are evolutionarily distinct and the term
“prokaryote” has fallen out of use by microbiologists
Name the parts of Bacteria and Archeae
pili, plasma membrane, cell wall, capsule, nucleoid, cytoplasm ribosomes
