lecture 7: intro to cells Flashcards
What is the basic Cell Theory?
- All organisms are made of one or more cells
- Cell = basic unit of life
- All cells come from preexisting cells
What is a cell and how is its structure?
- Simplest collection of matter that can live
- Fundamental unit of structure, function, and reproduction of organisms
- All organisms are composed of one or more cells
- Cells make up tissues & organs
- Cell structure is diverse (different shapes and sizes) and correlates to its function
What are the 4 main types of tissues in vertebrate animals?
- Nervous
- Muscle
- Epithelial
- Connective
How big are eukaryotic and prokaryotic cells?
Cells = 1-100 micrometers (um) Prokaryotic = 1-10 um Eukaryotic = 10-100 um
What is microscopy?
Essential tool to study cell structure and other aspects of its biology
What is magnification?
Ratio of an object’s image to its real size (4X, 10X, 40X…)
What is resolution?
Ability to observe two nearby objects as being distinct form one another (in nm)
What is constrast and how do you increase it?
- How well an object stands out from its surroundings.
- Can be increased in stains and florescent tags
What are the 4 important parameters in microscopy?
- Magnification
- Resolution
- Contrast
- 2D vs 3D image
What is the main difference between a light and an electron microscope?
Electron microscope has higher magnification and resolution.
What are the 5 shared features in all cells?
- Plasma membrane
- Chromosomes
- Cytoplasm
- Ribosomes
- Cytoskeleton
What are the 2 majors types of cells and its categories?
- Prokaryotic (unicellular): Bacteria and Archaea
2. Eukaryotic (uni/multicellular): Animals, Plants, Fungi, Protists
What is the 2 main differences between a prokaryotic cell and an eukaryotic cell?
Eukaryotic is 1.larger and 2.more complex
Do larger organisms have larger cells than smaller organisms?
No, they just have more cells.
What is one reason why cell size is limited?
Volume of cell increases faster than the surface area —> acquiring nutrients & elimination of waster become harder —> needs more and more nutrients, but can not keep up with transport of nutrients and wastes as they are transported in and out of the cell via the cell membrane/surface area
What are the 2 ways eukaryotic cell adapts to the SA:V problem?
- Using microvilli (long, thin projections) to increase cell surface wthout significantly increasing the volume
- Decreasing active cell volume: in plant cells, large central vacuole = metabolically dead, so no need for nutrients and do not produce waste
2 main components of plasma membrane structure?
- Phospholipid that forms bilayer
2. Membrane-bound proteins with various functions
What are the 2 functions of plasma membrane and how are they accomplished?
- Selectively permeable barrier: regulates materials in and out cell (homeostasis)
- Accomplished by phospholipid bilayer and transport proteins - Cell joining & cell communication
- Accomplished by proteins in membrane
Which 2 characteristics influence a chemical’s permeability? (from plasma membrane)
- Size: smaller is better
- Polarity (hydrophobic vs hydrophillic): nonpolar/hydrophobic is better
* it is a mix of both*
How do phospholipids contribute to the selectively permeable barrier?
Prevent mid/large polar molecules and ions from crossing the membrane
How do transport proteins contribute to the selectively permeable barrier?
Facilitate transport of certain polar molecules and ions
What are viruses?
Very small (20-300 nanometers nm) and abundant infectious particles consisting of nucleic acid genome + outer covering
How can a virus be considered “alive”?
Must enter host cell & use host’s biosynthetic machinery to reproduce and synthesize its proteins —> viruses = obligate intracellular parasites
How do viruses work?
Each type of virus infects specific unicellular species/cell type in a multicellular species —> viruses are specific for each target
- “Disguise” and trick cells to make think that they need them
1. Virus enter host cell
2. Replicate itself
3. Transcription and manufacture of capsid proteins
4. New virus particles exit cell - new virus particles are self-assembled*
