Cell Organization, Structure, and Function Flashcards
Chapter 3
What is the basic unit of structure and function in living things?
The cell.
What are unicellular organisms?
Organisms that exist as a single cell, e.g., bacteria.
What are colonial organisms?
Organisms that exist as a group of cells, e.g., some algae like Volvox.
What are filamentous organisms?
Organisms that exist as thread-like structures, e.g., Spirogyra.
What are multicellular organisms?
Organisms made up of numerous cells, e.g., animals and plants.
Who first observed cells in 1665?
Robert Hooke
What did Anton van Leeuwenhoek call the living cells he observed?
Animalcules.
Who proposed that all plants are made of cells?
Matthias Schleiden, in 1838.
Who proposed that all animal tissues are made of cells?
Theodor Schwann, in 1839.
State the Cell Theory
- All organisms are composed of one or more cells and life processes of metabolism and
heredity occur within these cells. - Cells are the smallest living things, the basic units of organization of all organisms.
- Cells arise only by division of previously existing cells.
What characterizes prokaryotic cells?
-Lack of a Nucleus
-Absence of Membrane-Bound Organelles
-Presence of a Cell Wall
-Ribosomal Structure:
Have 70S ribosomes, which consist of 50S and 30S subunits.
-Prokaryotic cells reproduce asexually by binary fission
What characterizes eukaryotic cells?
-Contain a Nucleus
-Linear DNA and Chromosomal Structure:
-Absence of Cell Wall
-Ribosomal Structure:
Have 80S ribosomes, which consist of 60S and 40S subunits.
Membrane-Bound Organelles:
What is the nucleoid in prokaryotes?
A region containing the circular genetic material, not enclosed by a membrane.
Where is genetic material stored in eukaryotes?
In the nucleus.
What is cytoplasm?
A semi-fluid matrix that fills the cell and contains sugars, amino acids, and proteins.
What is the cytosol?
The fluid portion of the cytoplasm.
What is the function of the plasma membrane?
Regulates the movement of substances in and out of the cell.
What is the bacterial cell wall made of?
Murein or peptidoglycan.
What is the function of the cell wall in prokaryotic cells?
Provides shape, rigidity, and protection against bursting.
What are mesosomes?
Infoldings of the bacterial cell membrane that aid in cell division.
What are bacterial ribosomes responsible for?
Protein synthesis.
What is the function of bacterial capsules?
They enable bacteria to stick to surfaces and provide additional protection.
What is the function of bacterial flagella?
Movement.
What are plasmids?
Small, self-replicating DNA molecules that confer survival advantages, such as antibiotic resistance.
