Cells Flashcards
(29 cards)
What is the name for the study of all aspects of a cell?
Cytology
What does cell theory state?
- All organisms are made up of one or more cells
- Cells are the smallest units of life
- All cells come from pre-existing cells
Who were the first people to “observe” cells?
- Robin Hooke 1665, homemade microscope, looking at cork
- Antonie Van Leeuwenhoek few years later, living cells, animalcules (little animals)
- Matthias Schleiden 1838, “plants made of independent, separate beings called cells”
- Theodor Schwann 1839, similar statement as ^, but animals
What did Louis Pasteur do?
In the 1880s, he performed experiments with chicken broth. He sterilized it by boiling it and showed that living things did not spontaneously appear.
Which statement of the cell theory did Pasteur’s experiment’s results support?
The statement about how all cells come from pre-existing cells.
What are the functions of life?
- Metabolism (chemical reactions, respiration)
- Excretion
- Reproduction
- Growth
- Response to surroundings
- Homeostasis
- Nutrition
What is Paramecium?
A unicellular organism belonging to the kingdom known as Protista. Eats by engulfing
What are some traits of the light microscope?
- Relatively cheap
- Can observe living things
- Can see color
- Magnifies up to 2000x
What are some traits of the electron microscope?
- Expensive
- Magnifies up to 500 000x
- Specimens are dead (vacuum?)
What are the relative sizes of cells and their sub units?
Cells are relatively big, then organelles, then bacteria, then viruses, membranes, and molecules
How do you calculate magnification?
Total magnification=size of image/size of specimen
Why are cells not infinitely big?
Surface area to volume ratio
How does an organism develop?
Usually begins as a single cell after sexual reproduction. Then the cell divides and differentiates for different cell types. The type is based on which genes become active
What happens after differentiation?
Cells are specialized with only a segment of DNA being active (although they do contain all of the DNA), some might also lose ability to reproduce like muscle or nerve cells. If they do keep reproducing, the offspring will differentiate into same cell types as parents
What are emergent properties?
The whole is more than the sum of its parts. Each cell does their job in addition to interacting with other cells to perform other functions
What are stem cells?
Cells that can differentiate and become any other cell
What is the difference between pluripotent stem cells and tissue-specific stem cells?
Pluripotent stem cells (embryonic stem cells) can differentiate into any other type of cell while tissue-specific stem cells reside in one type of tissue and can only become cells of the same type of tissue.
What is Stargardt’s disease?
A recessive, inherited disease caused by a gene that codes for a defect in production of Vitamin A. Vitamin A is needed for light-sensitive cells in the retina to function. A person with Stargardt’s disease will start losing their central vision within the first 20 years of their life, then they begin losing peripheral vision and they eventually become blind
What are some examples of stem cell treatment?
- Tissue-specific blood stem cells are used to treat leukemia by replacing the damaged bone marrow
- Pluripotent stem cells are starting to be used as treatment for Stargardt’s disease to protect and regenerate photoreceptors in the retina
What is the size of most prokaryotic cells?
Between 1 and 10 micro meters in diameter
What is the prokaryotic cell wall made of?
In most prokaryotes the cell wall is composed of a carbohydrate-protein complex called peptidoglycan. Some bacteria also have a polysaccharide outside the cell wall to adhere to stuff
Where is the cell membrane in relation to the cell wall?
The membrane is inside the cell wall
What are the organelles of prokaryotic cells?
- Capsule (to adhere to stuff)
- Cell wall (protection and structure)
- Cell membrane (regulates import and export)
- Cytoplasm (many reactions happen here)
- Ribosomes (protein synthesis)
- Nucleoid (hereditary information (one chromosome), controls cell activity, reproduction)
- Plasmid (small ring of DNA with specific genes)
- Pili (attachement (mostly to other bacteria))
- Flagellum (movement)
What is binary fission?
The way in which bacteria reproduce. Very similar to mitosis except there is no nuclear membrane or centrioles and there is only one chromosome that replicates itself
