The fundamental Unit of life Flashcards
(69 cards)
Who first discovered cells and in what year?
Robert Hooke in 1665
Hooke observed cells in a cork slice using a self-designed microscope.
What does the term ‘cell’ mean in Latin?
A little room
The term ‘cell’ was used by Hooke to describe the compartments he observed.
What is the cell theory?
All plants and animals are composed of cells, and the cell is the basic unit of life
Proposed by Schleiden and Schwann in 1838-1839 and expanded by Virchow in 1855.
What are unicellular organisms?
Organisms made up of a single cell
Examples include Chlamydomonas, Paramecium, and bacteria.
What is the basic unit of life?
Cell
Cells perform all basic functions necessary for living organisms.
What is the plasma membrane?
The outermost covering of the cell that separates its contents from the external environment
It is selectively permeable, allowing certain materials to enter or exit.
What is diffusion?
The spontaneous movement of a substance from a region of high concentration to a region of low concentration
Important for gas exchange in cells.
What is osmosis?
The net diffusion of water across a selectively permeable membrane toward a higher solute concentration
Affects the movement of water in and out of cells.
What happens to a cell in a hypotonic solution?
The cell gains water and may swell
Occurs because the outside solution has a higher water concentration than the cell.
What happens to a cell in an isotonic solution?
There is no net movement of water across the cell membrane
The cell remains the same size.
What happens to a cell in a hypertonic solution?
The cell loses water and may shrink
The outside solution has a lower concentration of water than the cell.
What is plasmolysis?
The shrinkage or contraction of the cell contents away from the cell wall due to water loss
Observed in living plant cells when they lose water.
What is the role of cell organelles?
Perform specific functions within the cell
Examples include making new materials and clearing waste.
What is the cell wall made of?
Cellulose
Provides structural strength to plant cells.
What is the function of the nucleus in a cell?
Control center of the cell, containing genetic material
Discovered by Robert Brown in 1831.
Fill in the blank: The process by which Amoeba acquires food is called _______.
Endocytosis
A process that allows cells to engulf food and substances.
What is the significance of magnifying lenses in biology?
Led to the discovery of the microscopic world
Enabled scientists to observe cells and their structures.
True or False: All cells have the same organelles regardless of their function.
True
All cells are found to have similar organelles.
What is the main difference between unicellular and multicellular organisms?
Unicellular organisms consist of a single cell, while multicellular organisms are made up of many cells
Multicellular organisms have specialized cells for different functions.
What are the three main features found in almost every cell?
- Plasma membrane
- Nucleus
- Cytoplasm
These features are essential for cell function and interaction with the environment.
What occurs when a living plant cell is placed in a hypotonic solution?
It swells due to water intake
The cell wall prevents it from bursting.
What is the function of chloroplasts?
Contain chlorophyll for photosynthesis
Found in plant cells, responsible for converting light energy into chemical energy.
What happens to a cell when it is placed in a concentrated salt solution?
The cell shrinks due to loss of water
Water moves out of the cell by osmosis.
What is the process of observing cells from our own body using a slide and methylene blue solution?
Taking a glass slide with a drop of water, scraping the inside surface of the cheek, and coloring the material with methylene blue for microscopic observation.
