Chapter 3 Cells Flashcards
Vacuole
Membrane-Bounded storage sac in a cell, especially the large central vacuole in a plant cell
Smooth Endoplasmic Reticulum
Portion of the ER that lipids and detoxifies poisons
Within a single cell, which of the following is physically the smallest?
Phospholipid Molecule
How do plant cells form cell walls?
A plant cell secretes the components of its cell wall through its plasma membrane. The primary wall is the first to be secreted; it is thin and flexible compared to the secondary wall, which is thicker and tougher. The secondary wall is internal to the primary wall.
List the features that all cells share; then name three structures found in eukaryotic cells but not in bacteria or archaea.
All cells have DNA, RNA, protein, ribosomes, cytoplasm, and a cell membrane. Three examples of structures found only in eukaryotic cells include a nucleus, endoplasmic reticulum, and mitochondria. (Other answers are possible as well.)
Anchoring Junctions
Connection between two adjacent animal cells that anchors intermediate filaments in a single spot on the cell membrane
Contemporary cell biology focuses on what?
the role of genetic information, the cell’s chemical components, and the metabolic processes inside cells
Eukaryotic
Organism composed of one or more cells containing a nucleus and other membrane-bounded organelles
Describe how animal cells use junctions in different ways.
Tight junctions create an impermeable seal between adjacent cells. Anchoring junctions act as “rivets” that secure cells in place. Gap junctions allow adjacent cells to exchange ions and other materials.
Pioneered Cell Biology
Robert Hooke and Antony van Leeuwenhoek
Cytoskeleton
Framework of protein rods and tubules in eukaryotic cells
One property that distinguishes cells in domain Eukarya from those in domain Bacteria is the presence of
Membranous Organelles
What type of cellular junction prevents stomach acid from leaking into the abdomen and digesting internal organs?
Tight Junctions
Lysosomes
Organelle in a eukaryotic cell that buds from the Golgi apparatus and enzymatically dismantles molecules, bacteria, and worn-out cell parts
List the chemicals that make up cell membranes.
The main chemicals in cell membranes are phospholipids, steroids, and proteins.
Nucleolus
A structure within the nucleus where components of ribosomes are assembled
Gap Junction
Connection between two adjacent animal cells that allows cytoplasm to flow between them
Cilium (pl. cilia)
One of many short, movable protein projections extending form a cell
Rank the following in order from smallest to largest: ant, prokaryotic cell, actin molecule, microtubule, nitrogen atom. What type of microscope (if any) would you need if you wanted to see each?
From smallest to largest, the order would be nitrogen atom, actin molecule, microtubule, prokaryotic cell, ant. The nitrogen atom and individual actin molecule could only be seen with an electron microscope. Microtubules and prokaryotic cells are best seen with an electron microscope, although they are visible with a light microscope. An ant is visible with the unaided eye.
Microfilament
Component of the cytoskeleton; made of the protein actin
Scientists that formulated Cell Theory
Schneider, Schwann, and Virchow
How does the formation of the cell theory illustrate the process of science?
Schleiden and Schwann integrated their own observations with those of many other scientists as they developed their theory, which at first had two parts. Virchow added a third component in 1855, and the theory has expanded further since that time, illustrating that scientific theories are subject to change as new information becomes available. The cell theory includes many testable hypotheses and although it is potentially falsifiable, all observations to date have supported the theory.
Imagine that you found a cell that releases many proteins into the bloodstream. What organelles might be especially active in this cell? What would each of these organelles be doing?
The organelles of the endomembrane system work together to synthesize, package, and release proteins from a cell, so they would be especially active. DNA is transcribed into RNA in the nucleus. The RNA molecule leaves the nucleus and moves to the rough endoplasmic reticulum, where a ribosome translates the nucleic acid message into a protein. The ER then packages the protein in a vesicle, which transports it to the Golgi apparatus. The protein is modified in the Golgi apparatus, packaged in another vesicle, and released from the cell.
Imagine that you could engineer a cell that exchanges gases efficiently with the environment and quickly metabolizes sugars. Describe your cell’s size and shape. What organelles would be abundant?
Gas exchange occurs most efficiently in small cells with highly folded membranes. Mitochondria are the organelles that convert sugars into energy that the cell can use. So this cell would likely be small, with a folded membrane and abundant mitochondria