CH 3: Cells
Protists, plants, fungi, and animals are organisms in the domain ______.
Eukarya
The ______ is a protein network that occurs within the cytosol, provides support, and helps form ______.
cytoskeleton ; cell to cell connections
Biological membranes are selectively ______, meaning they allow only specific types of molecules to pass into or out of the cell.
permeable
What is the most ancient type of life on Earth?
prokaryotes
All living things consist of one or more
Blank 1: cells, living cells, or cell
The ______ is a series of flattened sacs that sorts and packages materials into vesicles to be sent to the cell membrane.
Golgi apparatus
What type of microscope passes light through a transparent specimen to generate true-color views of cells?
light microscope
The organelle that is the site of photosynthesis in plant cells is the ____, which is a type of plastid.
Blank 1: chloroplast or chloroplasts
The cell membrane can be described as a(n) ____ mosaic because many of the diverse components can move freely within the cell membrane.
Blank 1: fluid
The cell wall openings in plant cells called plasmodesmata are most similar to ____ junctions in animal cells.
Blank 1: gap
Cellular respiration extracts energy from food and takes place in the organelle called a ____
Blank 1: mitochondrion or mitochondria
Lipids, detoxifying enzymes, and membrane components are produced and stored in the ____ endoplasmic reticulum.
Blank 1: smooth, smooth ER, ser, or smooth endoplasmic reticulum
What plant organelle is shown in the image and contains photosynthetic pigments?
Chloroplast
Key genetic sequences suggest that archaea are more closely related to members of domain ______ than they are to members of Domain Bacteria.
Eukarya
What prominent structure in the eukaryotic cell is highlighted by blue color in the picture?
Nucleus
Match each type of intercellular junction with its correct description.
Plasmodesmata - tunnels for the exchange of substances between adjacent plant cells. Tight junctions - fuse cell membranes of adjacent animals cells, forming a barrier. Anchoring junctions - connect animal cells to the extracellular matrix or to adjacent animal cells in one place. Gap junctions - channels for the exchange of substances between adjacent animal cells.
______ cells are the simplest forms of life and lack a nucleus.
Prokaryotic
Select a component of the cell membrane that is able to move laterally within the membrane, giving it the description of a fluid mosaic.
Proteins (NOT: Water does not move laterally within the membrane. Water is very polar, and the interior of the cell membrane is hydrophobic.)
______ microscopes bounce electrons off the outside of a metal-coated three-dimensional object to observe the exterior texture.
Scanning electron
What is the function of a ribosome?
To manufacture proteins
______ proteins are embedded in the cell membrane and act as passageways for water-soluble materials into or out of the cell.
Transport
What type of cell membrane protein allows molecules and ions to enter or exit the cell?
Transport proteins
True or false: Bacteria are the most abundant and diverse organisms.
True
Domain Eukarya includes ______.
all organisms with eukaryotic cells
The rigid ______ of most bacterial cells surrounds the cell membrane, protecting the cell and giving the cell shape.
cell wall
What surrounds the cell membrane of most bacteria and provides structure and protection?
cell wall
Whether bacterium or blue whale, every organism is made of
cells
What is the network of protein fibers and tubules inside the cell that provides support and aids in cell division and movement?
cytoskeleton
The phosphate "head" end of a phospholipid is ______, meaning its polar covalent bonds attract water, but the tails of a phospholipid are ______ and thus face away from water.
hydrophilic; hydrophobic
The portion of the phospholipid bilayer indicated by the circle in the picture is ______. (The sectioned view shows the phospholipid bilayer made of ions and polar molecules, and lipids and small nonpolar molecules. A circle is drawn in the center.)
hydrophobic
All cells have a cell ______ that surrounds the cytoplasm and forms a boundary between the cell and its environment.
membrane
What eukaryotic organelle is shown in the picture and functions in the production of cellular energy by cellular respiration?
mitochondrion
All cells are surrounded by cell membranes, also called plasma membranes, that separate the cytoplasm from the
outside environment.
The cell membrane is composed of a type of lipid molecule called a(n) ______, which has two fatty acids and a phosphate group extending from a glycerol molecule.
phospholipid
The endoplasmic ______ is a network of membranes originating at the nuclear envelope and winding through the cell.
reticulum
The nucleolus is a dense spot in the nucleus where components of ______ are assembled.
ribosomes
Proteins to be secreted outside the cell are formed at ribosomes on the surface of the ______ endoplasmic reticulum.
rough
What structure is colored red in this image of the endomembrane system and has ribosomes covering its exterior?
rough endoplasmic reticulum (NOT: The Golgi apparatus does not have ribosomes attached to its exterior and does not originate at the nuclear envelope.)
What are the structures indicated by the arrows in the picture that have pinched off the Golgi apparatus and will deliver their contents to another part of the cell?
vesicles (NOT: Peroxisomes originate from the endoplasmic reticulum; they do not pinch off of the Golgi.)
Select all of the following that are able to pass freely through the phospholipid bilayer without the assistance of transport proteins.
-small nonpolar molecules -lipids -O2 and CO2
Select all of the following that are functions of the cytoskeleton in the cell.
-aid for cell division -structural support -transportation
Microfilaments, intermediate filaments, and microtubules comprise the ______, which is a network of proteins that provide a structural framework within the cell.
cytoskeleton
Select all of the following that may be components of cell membranes.
-proteins -phospholipids -steroids (Reason: Steroids, including cholesterol in animal cell membranes, help maintain fluidity in a cell membrane; NOT Reason: Mitochondria are organelles that have their own membranes.)
Select all of the functions of cell walls.
-regulate cell volume -impart shape -prevent the cell from bursting
In this picture of the endomembrane system, the structure in the black circle indicated by the arrow is called the
Golgi apparatus. (is typically comprised of a series of five to eight cup-shaped, membrane-covered sacs called cisternae that look something like a stack of deflated balloons)
What is the network of sacs and tubules that extends off the nuclear envelope and is where proteins and lipids are produced?
endoplasmic reticulum (NOT: The Golgi apparatus does not extend off the nuclear envelope and is not the site of protein and lipid synthesis ; The cytoskeleton is a network of actin, microtubule, and intermediate filaments that functions in support and movement of the cell.)
Organelles called lysosomes contain ______ that break down food particles, old organelles, and other cellular debris.
enzymes
What organelle of the endomembrane system breaks down debris, food, and old cell parts with special dismantling enzymes?
lysosome
What structure is in the red circle in this image of the nucleus? (The sectioned view of the animal cell has a semi-spherical structure in blue. The magnified view of this blue structure shows circular dots on the surface and a solid sphere at the center, surrounded by cell membrane highlighted yellow. The sphere at the center of blue structure is circled red.)
nucleolus
In eukaryotic cells, the DNA that codes for the cell's proteins is stored in a membrane-bounded organelle called the
nucleus
The cell structure that manufactures proteins is called a
ribosome.
What structure is indicated by the arrow in this picture of the endomembrane system and lacks ribosomes covering the exterior?
smooth endoplasmic reticulum
Molecules called ______, which include cholesterol, are membrane components that aid in membrane fluidity.
steroids
Membranous spheres that transport materials inside the cell as part of the endomembrane system are called
vesicles. (Not: Ribosomes are cell structures that manufacture proteins.)
Select the three components of the cell theory devised in the mid-1800s.
-All cells originate from preexisting cells. -The cell is the fundamental unit of all life. -All organisms are made of one or more cells.
Select all of the following that are present in both prokaryotic cells and eukaryotic cells.
-RNA -DNA -cytoplasm -ribosomes (*Eukarotes have nuclei; prokaryotes do not; Not all cells contain pigment*)
Select all of the following types of organisms that usually have cell walls.
-algae -bacteria -archaea -plants -fungi (NOT: Animal cells lack cell walls).
Select all of the following that differ between domains Bacteria and Archaea.
-molecules that compose the membranes -evolutionary relationship to eukaryotes
Select all of the following that are true about organisms in Domain Bacteria.
-some live in human intestines and help with digestion -Earth's oldest organisms -some are used to make pharmaceuticals -important decomposers and producers
Select all the roles that membranes play in cells.
-transport substances into and out of the cell -receive and respond to external stimuli -enclose organelles in eukaryotic cells
The ____ theory states that all life is composed of one or more cells, which are the fundamental units of all life.
Blank 1: cell, cellular, early cell, or unified cell
The molecule shown in the picture is a (The head is made up of glycerol with a phosphate group. The glycerol shows that the nitrogen is bonded to four carbon atoms. Three carbons are bonded with three hydrogen atoms each. The fourth carbon is bonded with two hydrogen atoms and a carbon which is bonded to two hydrogen atoms and an oxygen of the phosphate group. In the phosphate group, p is single bonded to three carbons and double-bonded to an oxygen atom. Another oxygen in the phosphate group is bonded to a 3-membered carbon chain in which C1 is bonded to two hydrogen atoms, C2 is bonded to a hydrogen and an oxygen atom, and C3 is bonded to two hydrogen atoms and an oxygen atom. The tails are made up of fatty acids, which are bonded to an oxygen atom that is bonded to C2 and C3. The first fatty acid has an 18-membered carbon chain in which C1 is double bonded to oxygen, and C18 is bonded to three hydrogen atoms where all the other carbons are bonded to two hydrogen atoms. The second fatty acid has an 18 membered carbon chain in which C1 is double-bonded to an oxygen atom, C18 is bonded to three hydrogen atoms, C15 and C16 are double bonded, and each is bonded to a hydrogen atom where the other carbon atoms are bonded to two hydrogen atoms.)
phospholipid.