Chapter 3 Flashcards
What is the basic unit of life?
A cell
Why is the cell the smallest example of a living entity?
There is no smaller entity that can meet the criteria for life.
• Is able to reproduce and grow
• Responds to stimuli
• Remains homeostatic
• Takes in and uses materials from the environment
• Adapts to its environment
T or F: All living organisms are made up of cells.
True
In what units are cells measured?
Micrometers (µm)
What is the average diameter of the human cell?
100 micrometers (µm)
What is a zygote?
The first cell of a new multicellular organism. It is created when a sperm cell fertilizes an egg cell
What are the two broad classifications of cells?
■ Prokaryotes
■ Eukaryotes
What is included in the Prokaryotic group?
Two groups of bacteria:
■ Eubacteria
■ Archaebacteria
What is included in the Eukaryotic group?
■ Animals
■ Plants
■ Fungi
■ Some single-celled organisms called protists
What is a plasma membrane?
An outer membrane that regulates what enters and exits a cell. The membrane is a phospholipid bilayer.
Selectively permeable
A plasma membrane of a cell allows only certain molecules to enter the cell.
Cytoplasm
A semifluid medium that contains water and various types of molecules suspended or dissolved in the medium. The presence of proteins accounts for the semifluid nature of the cytoplasm. Cytoplasm contains organelles.
Organelles
Membranous structures and any well-defined subcellular structure.
