W4 Practice
In muscle contraction, ______ and myosin filaments slide across each other
actin
As described in this chapter's Investigating Life essay, some bacteria contain magnetosomes, which allow bacteria to
align with Earth's magnetic field
How do vesicles carrying proteins destined for secretion move to the plasma membrane?
along microtubules
_____ junctions link cytoskeletal filaments of adjacent animal cells in one place, like a rivet.
anchoring
In bacterial cells, what is the function of flagella?
cell movement
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
gap junctions
channels for the exchange of substances between adjacent animal cells
An organelle found in plant cells and some members of the kingdom Protista but not in animal cells is a
chloroplast
What plant organelle is shown in the image and contains photosynthetic pigments?
chloroplast
Short, numerous, hairlike structures that surround some cells like a fringe, are powered by microtubules, and have coordinated movements are called
cillia
anchoring junctions
connect animal cells to the extracellular matrix or to adjacent animal cells in one place
central vacuole in plants
contains enzymes, salts, pigments, sugars, and acids
The ______ includes all of the cell contents between the nucleus and the cell membrane.
cytoplasm
food vacuole in amoebas
digest nutrients engulfed by cell
a prokayotic cell
does not have a nucleus
Nuclear pores have proteins that open and close, controlling flow of cell solutions and molecules in and out of the nuclear envelope (a double-thick membrane). In this, nuclear pores are similar in structure and function to
gap junctions
A eukaryotic cell
has membrane-bounded organelles.
In eukaryotic cells, the nucleus is an organelle that functions in
housing the cell's DNA
The head of a phospholipid is ______, meaning its polar covalent bonds attract water, but the tails of a phospholipid are _____ and this water-insoluble.
hydrophillic; hydrophobic
What is the function of recognition proteins in the plasma membrane?
identify the cell as belonging to the body and certain tissue type
The ____ microscope is ideal for viewing living cells that are between 200 nanometers and 1 millimeter in size.
light
What type of microscope passes light through a transparent or thinly sliced specimen to generate true-color views of cells?
light microscope
Organelles carry out specialized functions in the cell and are enclosed by
membranes
A wild duck needs a steady supply of energy to be able to fly for hours. Domesticated chickens rarely fly. As a result, you would expect to find _____ in the breast muscles of wild ducks than in domesticated chickens.
more mitochondria
In prokaryotic cells, DNA congregates in an area called the
nucleoid
The area within the cytoplasm of a prokaryotic cell where the circular DNA molecule is found is called the ______ and is not bounded by a membrane.
nucleoid
the most prominent organelle visible in most eukaryotic cells is the
nucleus
The main organelles and structures involved by distinct function with milk production and secretion in their correct sequence are
nucleus, nuclear pore, rough ER, smooth ER, transport vesicle, Golgi apparatus, and vesicle for secretion
Within the cytoplasm of eukaryotic cells, there are multiple specialized compartments called
organelles
primary cell wall
outer, more flexible layer of the cell wall
All cells are surrounded by cell membranes, also called plasma membranes, that separate the cytoplasm from the
outside environment
Biological membranes are selectively ____, meaning they allow only specific types of molecules to pass into or out of the cell.
permeable
In cell membranes, what part of a phospholipid molecule is oriented toward the outside of the bilayer?
phosphate head
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
What molecules are key components of cell membranes and are arranged in bilayers to form membranes?
phospholipids
Tunnels called ______ occur in the cell walls of two adjacent plant cells and allow the cells to communicate and exchange materials with each other.
plasmodesmata
Water, nutrients, hormones, and some organelles flow between adjacent plant cells through special channels in the cell wall called
plasmodesmata
a central vacuole of a mature plant cell
produces turgor pressure
In all cells, RNA and ribosomes play a role in the production of ______, which are molecules that carry out all of the cell's work.
proteins
What component of cell membranes functions in a diversity of roles, including recognition, transport, adhesion, and facilitating reactions?
proteins
contractile vacuole (paramecium)
pumps excess water out of the cell
middle lamella
region where adjacent cell walls meet
A structure found in cells of all three domains, prokaryotes and eukaryotes, is the
ribosome
secondary cell wall
rigid, innermost portion of the cell wall
Lipids called ______, which include cholesterol, are membrane components that aid in membrane fluidity.
steriods
Why are ions and polar molecules unable to pass directly through a cell membrane?
the interior of the phospholipid bilayer is hyrdophobic.
_____ 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
An understanding of cellular biology is helping us find new treatments for many diseases.
true
Endosymbiosis theory is proposed in large part because of the resemblance of mitochondria and chloroplast structures to prokaryotes.
true
Plasmodestmata
tunnels for the exchange of substances between adjacent plant cells
How do sperm move to fertilize eggs?
with flagella made of microtubules
Select all of the following that are components of phospholipid molecules, which are the main constituents of cell membranes.
- two fatty acids - phosphate group - glycerol molecule
In bacterial cells, the nucleoid is where the cell's ____ congregates.
DNA
Most cells have a small size that is less than 0.1 mm in diameter to maximize surface area relative to volume.
True
Single-celled organisms are the most abundant organisms on the planet.
True
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
tight juntions
fuse cell membranes of adjacent animal cells, forming a barrier
select all of the following that are found in chloroplasts.
- DNA - stroma - ribosomes - photosynthetic pigments - thylakoids
Select all of the following that are able to pass freely through the phospholipid bilayer.
- O2 and CO2 - lipids - small nonpolar molecules
Select all of the following that are examples in which the ratio of surface area to volume of cells is increased.
- amoebas have extensions that are examples in which the ratio of surface area to volume of cells is increased. - paramecia are horizontally flattened in shape. - nerve cells are long and thin.
Select all of the following that are true about lysosomes.
- can fuse with vesicle carrying debris from outside the cell or damaged organelles. - contain enzymes tagged with sugars - enzymes inside the lyosome perform hydrolysis reactions
Select all of the following that differ between domains Bacteria and Archaea.
- chemical composition of flagella - evolutionary relationships to eukaryotes - molecules that compose the cell membranes
Select all of the following that describe tight junctions.
- create the "blood-brain barrier" - membrane proteins connect to actin in the cytoskeletons of adjacent cells - join adjacent cells into sheets
Select all of the following that are true about organisms in Domain Bacteria.
- earth's oldest organisms - some are used to make pharmaceuticals - some live in human intestines and help with digestion - important decomposers and producers
Select all of the cell parts that are involved in the endomembrane system.
- endoplasmic reticulum - Golgi apparatus - lysosomes - vacuoles - nuclear envelops
Select all of the following that are present in bacterial cells.
- enzymes, cytoplasm, ribosomes, DNA
Select all of the functions of the bacterial cell wall.
- give the cell its shape - prevent the cell from bursting - protect the cell
Cells need increased surface area for diffusion of nutrients and wastes. Cells increase their surface area by
- having microscopic extensions of the cell membrane - having a flattened shape - being long and thin - having specialized organelles to move components throughout the cell
Select all of the characteristics of eukaryotic cells.
- larger than prokaryotic cells - system of internal membranes - nucleus
Select ways that cells avoid surface area limitations.
- long or thin shape - efficient transportation system within cell
Select all of the following types of cells that usually possess cell walls.
- plant - archaea - bacteria - fungi - algae
Select all of the following that are able to move laterally within the cell membrane, giving it the description of a fluid mosaic.
- proteins - phospholipids
Select all of the following that are components of cell membranes.
- proteins - phospolipids - steroids
Select all of the following that are true about prokaryotes?
- simplest types of life - lack a nucleus - most ancient forms of life on Earth
Some members of the Archaea domain are often referred to as extremophiles because many live in conditions of extreme
- temperature - salinity - heat - acidity
Key genetic sequences suggest that archaea are more closely related to members of domain ______ than they are to members of Domain Bacteria.
Eukarya
_____ cells are the simplest forms of life and lack a nucleus.
Prokaryotic
Flagella move by way of dynein proteins that connect microtubules and force them to shift back and forth to bend or rotate the flagella.
True
What type of microscope allows resolution of objects that are about 5 nanometers in size?
electron
plasma membrane
encloses the cytoplasm and lies just under the secondary cell wall
Peroxisomes are organelles that originate at the ______ and contain enzymes that dispose of toxic substances.
endoplasmic reticulum
Proteins that increase the speed of chemical reactions on the cell membrane and in other parts of the cell are called ______.
enzymes
What is the function of membrane proteins that are enzymes?
facilitate chemical reactions
All living cells have a cell wall
false
Because mitochondria, chloroplasts, and other plastids have their own DNA and ribosomes within double membranes, they are also considered cells.
false
Most living cells are small in size because they need a small ratio of surface area to volume.
false
In some types of bacteria, appendages called ______ rotate like a propeller and allow movement forward or backward.
flagella