1.1. Introduction to Cells Flashcards
What are the 3 main principles of cell theory?
- All living things are composed of cells
- The cell is the smallest unit of life
- Cells only arise from pre-existing cells
What are 3 examples of cells/tissues that do not conform the cell theory?
Striated muscle fibres, Aseptate fundal Hyphae, Giant Algae
Striated muscle fibers challenges the idea that…
Cells always function as autonomous units because they have multiple nuclei despite being a single membrane
How does Aseptate fungal Hyphae challenge cell theory?
It has a continuous cytoplasm, so challenges the idea that living structures are composed of discrete cells
How does Giant Algar challenge cell theory?
It may be too large, so challenges the idea that larger organisms are always made of many microscopic cells
What 7 characteristics are all living organisms capable of carrying out?
- Metabolism
- Reproduction
- Response
- Homeostasis
- Excretion
- Nutrition
- Growth
Define metabolism
Living things undertake essential chemical reactions that take place within an organism
Define reproduction
Living things produce offspring, either sexually or asexually
Define response
Living things are responsive to internal and external stimuli
Define homeostasis
Living things maintain a stable internal environment
Define excretion
Living things exhibit the removal of waste products
define nutrition
living things exchange materials and gases with the environment
define growth
living things can move and change shape/size
explain how paramecium show response
it’s surrounded by small hairs called cilia which allow it to move
expain how paramecium show nutrition
it engulf food via membranous feeding
explain how paramecium show metabolism
food particles are enclosed within small vacuoles that contains enzymes for digestion
explain how paramecium show excretion
solid wastes are removed via pores, pumping out wastes
explain how paramecium shows homeostasis
essential gases enter and exit via diffusion
explain how paramecium reproduce
divides by fission
what is important in the limitation of cell size
SA/Vol ratio
what do cell nedd to do to survive?
produce chemical energy, exchanging materials with the environment
what is the rate of metabolism affected by?
larger cells need more energy to sustain essential functions
how does SA/Vol ratio change with increasing cell size
as a cell grows, volume increase faster than surface are, leading to a decreased SA/Vol ratio
what will happen if the metabolic rate exceeds the rate of exchange of vital materials and wastes?
if metabolic rate exceeds the rate of exchange of vital materials and water (low SA:Vol ratio), the cell will eventually die
