Chapter 4 Flashcards
(40 cards)
Who invented the first compound microscope?
Hans and Zacharias Janssen
What did Antonie van Leeuwenhoek observe with his microscope?
Several types of living cells, including sperm.
Who discovered and named “cells” by looking at cork?
Robert Hooke
What did Robert Brown discover in plant cells?
The nucleus.
What are the three components of the cell theory?
1) All organisms are composed of one or more cells. 2) The cell is the smallest unit of life. 3) All cells arise from pre-existing cells.
What is the smallest unit of life?
The cell.
What are the three common features of all cells?
Plasma membrane, nucleus/nucleoid region, cytoplasm.
What limits the size of a cell?
The surface-to-volume ratio.
Why is the surface-to-volume ratio important?
Cells must be small for efficient exchange of materials with their environment.
What does the plasma membrane do?
It separates the cell from its environment and regulates the flow of substances in and out.
What is the difference between a nucleus and a nucleoid?
A nucleus is membrane-bound, while a nucleoid is a region where DNA is localized in prokaryotic cells.
What are the main components of the cytoplasm?
Cytoskeleton, ribosomes, membrane systems, and a semifluid substance.
What is the role of the lipid bilayer in the plasma membrane?
It forms the boundary between the inside and outside of the cell and regulates the entry and exit of substances.
What is a biofilm?
A community of microorganisms living within a shared layer of polysaccharides and glycoproteins.
What are the two domains of prokaryotic cells?
Bacteria and Archaea.
What are bacterial flagella and what do they do?
Flagella are whip-like structures that enable bacteria to move.
What are plasmids?
Small, circular DNA molecules found in some bacteria.
What is the function of ribosomes in prokaryotic cells?
They are the sites where proteins are assembled.
What is the main difference between prokaryotic and eukaryotic cells?
Eukaryotic cells have a nucleus and membrane-bound organelles, while prokaryotic cells do not.
What is the function of the nucleus in eukaryotic cells?
It contains the cell’s hereditary material and controls cell activities.
What organelles are involved in protein synthesis in eukaryotic cells?
Ribosomes, rough endoplasmic reticulum, and Golgi bodies.
What is the function of the rough endoplasmic reticulum?
It modifies and transports proteins made by the ribosomes attached to it.
What does the smooth endoplasmic reticulum do?
It synthesizes lipids and detoxifies harmful substances.
What is the role of the Golgi body?
It processes, sorts, and packages proteins and lipids for transport.
