1.1 Living Things Consist of Cells Flashcards
The cell membrane defines a cell and
Seperates the cell from surroundings
What are the three points of the Cell Theory?
- All organisms consist of cells or the products of cells.
- All cells come from pre-existing cells by the process of cell division.
- Cells are the smallest independent units of life and the building blocks for all life.
8 Functions of Life
Metabolism - chemical reactions in the cell
Reproduction - producing offspring
Movement - internal or external movement
Sensitivity or response to stimuli - responding to environment
Homeostasis - maintaining eternal balance
Excretion - eliminate waste or other toxic substances
Nutrition - can obtain food for energy
Growth - ability to grow
How did the invention of the microscope contribute to the development of the Cell Theory and when and who invented it?
1655, Robert Hooke, Allowed scientists to observe cells. Proved all living organisms are made of cells.
Define the term organism and how they are classified based on their cellular structure.
An organism is any living thing that carries life. They are classified as unicellular or multicellular.
Why is the cell considered the smallest independent unit of life?
They carry out all essential life functions including metabolism, growth and reproduction independently.
What is DNA? Why is it important for cellular function and heredity?
DNA is a molecule found in chromosomes. It is responsible for cell division. It is important for cellular function as it produces molecules like proteins. And for heredity due to the passing of genetic characteristics from parents to offspring.
Fluid Mosaic Model
Fluid: The ability of the phospholipids to move sideways.
Mosaic: The pattern of protein molecules that are embedded or attached to the phospholipid bilayer.
Unicellular vs Multicellular
Unicellular - Consists of one cell that peforms all functions. E.g. bacteria
Multicellular - Consists of two or more specialised cells that work together. E.g. humans
How does DNA fit into the nucleus of a cell despite its long length?
Due to the DNA wrapping tightly around proteins called histones and condensing into chromosomes.
How do cells arise from pre-existing cells refering to heredity?
By the process of cell division (mitosis or meiosis). This makes sure that genetic information is passed on to new cells for growth and repair and reproduction in organisms.
The Cell Membrane
- found in all cells
- seperates cell from surroundings
- controls entrys and exits of all substances to the cell
- thin
- bilayered and made of phospholipid molecules
