Flashcards in 1.1 Introduction To Cells Deck (15)
Give an example of a cell that is considered abnormal
Striated muscle: skeletal muscle fibres are larger than normal cells (30mm) and have many nuclei.
Aseptate fungal hyphae: not divided into individual cells, one abn. Large
Giant algae: cells several cm long
What are the seven functions of life?
Nutrition (obtaining food for energy and growth), Metabolism (chemical reactions to release energy), Growth (irreversible increase in size), Response (perceiving changes in environment), Excretion (expelling waste matter), Homeostasis (keep conditions inside organism within tolerable limits), Reproduction (producing offspring sexually or asexually)
What does the cell theory state?
1. All living organisms are composed of cells
2. Cells are the smallest unit of life. Sub cellular structures cannot survive independently
3. Cells come from pre-existing cells
What are some common features of cells?
Surrounded by membrane which separates cell contents from outside.
Contain genetic material which contains instructions needed for cells activities.
Energy release system to power activities.
How do you calculate magnification?
Mag = size of image (ruler) / size of specimen (scale bar)
How does the Paramecium perform the functions of life?
Nutrition: eats bacteria (oral groove), Metab. : metabolize food to create energy, Growth: it grows, Response: trichocysts are defense like tiny bullets, Excretion: waste goes out through anal pore, Homeostasis: Contractile vacuole controls water balance, Reproduction: asexually through mitosis
Why is the surface area to volume ratio important to cell size?
As a cell grows it's volume increases faster than surface area. Surface becomes too small to allow enough food to enter the cell to feed it. Also, if there is too much waste and not enough space to get it out, the cell will die.
What are the advantages to being multicellular?
Organism can grow in size and cells will differentiate so the organisms can grow in complexity.
What is differentiation?
Cells develop in different ways to take on specific functions. Differentiation allows for emergent properties - different cell types interact with each other to allow more complex functions to take place
How does differentiation occur?
All cells have same genes. When cells differentiate some genes are expressed but not others. Only genes useful to the task that needs to be done are "turned on"
What are stem cells?
Cells that have the capacity to self-renew by cell division and to differentiate.
They are unspecialized, can divide repeatedly, differentiate into many types of cells, have late nucleus relative to cytoplasm volume.
What are some types of cells in relation to differentiation?
Totipotent - can differentiate into any type of cell. Pluripotent - can differentiate into anything except placenta. Unipotent - can only become one thing
What are some of the conflicting views on stem cell research?
Embryonic stem cell research (are we killing a person, are embryos people, etc)
Animal cruelty (experimentation)
Can save millions of lives (leukaemia, Stargardt's disease)
What is Stargardt's disease and how can people benefit from stem cells?
Genetic disease that affects retina cells and causes vision to become worse and worse. Develops in children 6-12. Embryonic stem cells can develop into retina cells which can be injected into eyes to restore vision.