WorksheetsBio Lecture notes exam 2 material (cells)
Total questions: 118
Worksheet time: 2hrs 31mins
What are cells?
the smallest unit of life that exhibit all the characteristics of life
protons, neutrons, and electrons
structures that are the site of protein synthesis
rigid outer coverings that can provide protection and resist osmotic pressure
Cells can work together to maintain an organism, or can be independent life forms
False
True
Cells do not come in a variety of structures and functions
True
False
The term "cell" was first coined by Robert Hooke. When examining cork with a lens, what did the cell outlines remind him of?
cell walls
flagella
cubicles (cellae)
nucleus
As info about cells accumulated with subsequent investigation, scientists began to propose ideas about the nature of cells. Increased understanding of cells was facilitated with advances in _________ _______ and ________.
(a)
The Cell Theory states how many principles about cells?
1
2
3
4
What are the 3 principles of cells in the Cell Theory?
Why are cells so small?
Small structures have a greater surface area/volume ratio than similar-shaped larger ones
Small structures have a small surface area/volume ratio than similar-shaped larger one
An increase in cell size would require an increase in material acquisition.
True
False
What is the basic structure of a cell? (3 main features)
The aqueous environment inside a cell. Contains organelles. Most are membrane-bound but not all. Jelly-like fluid alone is referred to as cytosol.
(a)
What are organelles?
Rigid outer coverings that can provide protection and resist osmotic pressure
Another name for cells
Structures that can perform specific cellular tasks
Small rotors that move the cell around
Jelly-like fluid contained in the cytoplasm is referred to as (a)
What are the major types of cells?
Nucleus
Prokaryotes and Eukaryotes
Eukaryotes
Prokaryotes
What is the architecture of the cell like?
Cytoplasm and phospholipid bilayer
Plasma membrane and cytoskeleton
Nucleus and Mitochondria
Ribosomes and cytosol
What are the 3 functions of the plasma membrane?
Membrane structure is important for accomplishing tasks
True
False
What is the structure of the membrane like?
A double layer of phospholipids
A double layer of phospholipids embedded with proteins with an inner and outer leaflet of bilayer
Nucleus and membrane organelles
Phospholipid tails
What is the structure of the membrane referred to?
Plant Cell
Animal Cell
Plasma Membrane
Fluid-Mosaic model
Why are membranes composed of a phospholipid bilayer?
To protect the cell and the nucleus
Both the internal and external environments of a cell are aqueous so since they are amphipathic they make a perfect bilayer
To help the cell grow and build
To help the cell reproduce since cells can't do it on their own
Molecules with both hydrophilic and hydrophobic properties are called (a)
Why is the membrane fluid?
B/c phospholipids do not link together.
B/c of the presence of cytosol
B/c nuclei and other cells do better when the membrane is fluid
B/c cells are fluid as a whole
Why is fluidity so important?
Fluidity helps the nucelus
Fluidity helps cells grow and build
Fluidity aids cells in changing shape, and with the internal transport of substances in the cell
Fluidity makes cells both hydrophobic and hydrophilic
Individual phospholipids can easily move laterally within their layer but not from inner to outer leaflet
True
False
The presence of (a) makes the membrane less fluid, but more resistant to water soluble molecules
Factors such as temperature, phospholipid type, hydrocarbon chain, length, and degree of saturation all impact fluidity
False
True
Since the internal portion of the membrane is polar, it acts as an excellent barrier to most water-soluble molecules, keeping the contents isolated
False
True
Permeability is also influenced by fluidity. What does it mean to have a high permeability?
Materials with a high permeability allow no flow
Materials with a high permeability allow easy flow
Materials with a high permeability allow slow flow
Materials with a high permeability allow mixture of molecules
What are the two major types of membrane proteins?
(a)
What are integral proteins?
What are peripheral proteins
Proteins that do not interact with internal proteins
Amphipathic proteins
Associate along the surface of the bilayer (internal or external surface of cell)
Transmembrane proteins
The functions of membrane proteins are: transport, enzymatic activity, cell-cell recognition, adhesion
True
False
What are the 3 major types of proteins found in membranes?
(a)
What are transport proteins?
Serve as "ID tags" for the cell
Trigger responses in the cell if a specific molecule binds to it
Movement of substances in and out of cell
What are the 3 components of transport proteins?
What do channels do in transport proteins?
Interact with integral proteins
Act as pores creating passage ways through the bilayer
Embed into the membrane
Interact with the phospholipid bilayer
Water channels are called (a)
What are gated channels in transport proteins?
Can open and close in response to stimuli
Binds to molecules to move them in and out
Serves as "ID Tags"
move substances in and out of cell
(a) in transport proteins acutally bind to molecules to move them in and out
What are receptor proteins?
Proteins that transport in and out of cells
Proteins that serve as "ID tags" for the cell
Trigger responses in the cell if a specific molecule binds to it. If molecule binds, an intracellular response occurs
Proteins that bind to molecules
What are recognition proteins?
Proteins that transport materials in and out of the cell
Proteins that open and close in response to stimuli
Trigger responses in the cell if a specific molecule binds to it
Serve as "ID Tags" for the cells. Proteins with C, H, O attached
With the help of the (a) proteins immune systems recognize domestic cells and is important for coordinating interaction between different cell types.
The selective (a) membrane is critical for creating distinct internal and external environments of a cell. It also acts as a barrier, but still, needs to transport materials in and out of the cell. Some materials cross, others don't.
How are materials transported across membrane barriers?
by proteins
Solutes have thermal energy present, which causes them to be in constant random motion
permeability
aquaporins
Molecules in fluids move in response to gradients
True
False
What are gradients?
Physical differences in two regions of space
Energy stored in bonds between atoms
Materials that serve as "ID Tags" for the cell
When a transport protein bonds to a receptor protein
The most common gradients are the result of concentration differences, therefore called (a) (chemical) gradients. (Food dye into water)
(a) Gradients also cause movement of molecules
(a) gradients are important in biological processes
What is it called when molecules move naturally/passively with gradients from areas of high to low concentration. Requires no energy input.
Natural Transport
Passive Transport
Protein Transport
Cell Transport
How do some molecules move passively into cells? Do they move with concentration gradients?
receptor proteins, yes
Transport proteins, yes
Simple diffusion, yes
recognition proteins, no
In simple diffusion the molecules are ______ to pass in between the lipid bilayer of molecules, such as gases like O2. ____, uncharged molecules readily diffuse.
small enough
large enough
medium size
The (a) the gradient, the faster diffusion takes place
Without regulation, diffusion will occur until the concentration gradient is eliminated and molecules are equally dispersed. One example could be food coloring in a glass of water.
False
True
When molecules are equally dispersed across a membrane due to diffusion, the system is said to have reached ______ _____. There is no net movement across the membrane.
(a)
A specific type of diffusion that involves water is called (a)
Water also moves with concentration gradients across a membrane. The higher the concentration of dissolved substances, the lower the concentration of water.
False
True
The movement of water in and out of the cell depends on the comparison of _____ concentration inside vs. outside the cell.
solvent
solute
dynamic
simple
The ability of a surrounding solution to cause a cell to gain or lose water
Isotonic
Osmosis
Tonicity
Hypotonic
What is isotonic?
equal movement of water in and out of cells. Solute concentration= inside and outside cell
net water movement INTO cells
net water movement OUT of cells
when cells swell
What is hypotonic?
Net water movement OUT of cells
More solutes in extracellular environment than inside cell.
Net water movement INTO cells. Outer environment has a lower solute concentration. Cells swell. Cells possessing a cell wall can resist this expansion.
equal movement of water in and out of cells. Solute concentration= inside and outside cell
What is hypertonic?
When a cell swells
Net water movement INTO cells
Equal movement of water in and out of cells.
Net water movement OUT of cells. Outer environment has a higher solute concentration. A plant cell undergoes plasmolysis. Cell shrivels.
Because changes in cell shape can alter its ability to function, cells have certain mechanisms in place to attempt to maintain a proper water balance, also known as ______. In other words, ability of some cells to regulate water movement of cell. Organisms that live in water do this. Found in protists.
osmoregulation
turgor pressure
contractile vacuoles
symporter
______ in some microorganisms pump water out to prevent lysis by osmotic water diffusion into the cell.
Osmoregulation
Contractile Vacuoles
Facilitated Diffusion
Flaccid
(a) pressure is the force within the cell that pushes the plasma membrane against the cell wall. Water content in the large central vacuole of plants helps provide this pressure on the cell walls. Plants need it to help stay upright.
Loss of turgor pressure (water) can cause wilting where the cells become ______. This is what happens when plasmolysis occurs.
symporter
flaccid
selectively permeable
diffused
All molecules can move through the lipid bilayer barrier always. Size and/or polarity do not matter.
False
True
The membrane is...
facilitated and net diffused
active or passive
differentially or selectively permeable
both liquid and solid
Membrane proteins allow passage through the bilayer
False
True
Molecules with the right size, shape, and other characteristics can fit into channels or carriers and be transported across with gradients
False
True
When molecules with the right size, shape, and other characteristics fit into channels or carriers to be transported across with gradients this process is called what (aided by proteins). In other words, a channel or transport protein that allows material to diffuse across membrane.
passive transport
active transport
sodium-potassium pumped
facilitated diffusion
How can substances be moved across concentration gradients?
by the fluidity of the membrane
energy (ATP) must be expended to "accumulate" substances
molecules must be transported
by the phospholipid bilayer
The movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy and moving against gradient.
facilitated diffusion
passive transport
active transport
cotransport
What is the second reason substances can be moved against concentration gradients?
By the usage of net diffusion
By the usage of membrane proteins. Proteins act as pumps to transport materials
By the usage of the phospholipid bilayer
By the usage of energy
A well studied example of proteins working as pumps is called the _____
facilitated diffusion pump
sodium-potassium pump
contractile vacuole pump
cotransport pump
Most of the time, active transport of one substance can be used to establish a concentration gradient in order to transport a second substance
False
True
Consider pumping water uphill, that can then provide energy for turning a wheel when flowing back downhill. This process is called....
Simple Diffusion
Turgor Pressur
Dynamic Equilibrium
Cotransport
One carrier builds a high concentration of a substance on one side of the membrane, the substance then moves back via facilitated diffusion through a (a) , bringing along another substance. In other words, both molecules move in the same direction.
If a substance is moved in the opposite direction of its partner, the carrier is called an (a)
How are some materials taken in that are too large to be transported through the plasma membrane?
These materials can be engulfed in a process called receptor-mediated endocytosis
These materials can be engulfed in a process called endocytosis
These materials can be engulfed in a process called pinocytosis
These materials can be engulfed in a process called phagocytosis
How many types are there of endocytosis?
4
1
3
2
What process is explained? "A region of the plasma membrane surrounds the material and pinches it off into a vesicle inside the cell"
exocytosis
pinocytosis
phagocytosis
endocytosis
What type of endocytosis is this: The extracellular fluid is surrounded and internalized. The fluid contains dissolved substances. In other words, small dissolved molecules and fluid are engulfed.
(a)
_____ is an active transport of one substance the creates a gradient used to move a 2nd substance across the membrane.
Simple Diffusion
Turgor Pressur
Dynamic Equilibrium
Cotransport
What type of endocytosis happens when large particles are surrounded and engulfed....
phagocytosis
pinocytosis
exocytosis
receptor-mediated endocytosis
What type of endocytosis happens when material binds a receptor cell before being engulfed.
exocytosis
phagocytosis
pinocytosis
Receptor-mediated endocytosis
The particular biomolecule a receptor protein binds to is called it _____. This is formed from receptor-mediated endocytosis.
microtubule
coated pit
ligand
antiporter
In phagocytosis, membrane regions with these receptors (coated pits) are then pinched off.
True
False
The reverse process of endocytosis is called (a)
In _______ secreted materials are released from the cell in this way.
phagocytosis
pinocytosis
exocytosis
receptor-mediated endocytosis
(a) is a combination of endo and exocytosis. Substances enter, move through, then exit cell.
The fluid nature of the cell membrane has no effect on endocytosis and exocytosis. Additionally, it is not necessary for formation and fusion of vesicles.
False
True
The function of the (a) helps to provide cells structure, shape, and movement capabilities.
What are the 3 different components of the cytoskeleton?
Hollow tube with largest in diameter made of alpha and beta tubulin protein. Are built and disassembled as needed, originate from MTOC, make up cilia and flagella are ____________. Additionally, plant cells have many but animals only have one.
Microfilaments
Microtubules
Intermediate filaments
Actin
Animals have one microtubule known as a (a) which contains centrioles.
Microtubules provide cell and organelle stability, in particular resisting compression.
True
False
(a) are hair-like structure that move in a coordinated fashion. They can either propel a cell through its environment, or move the outer environment in a particular direction.
(a) are constructed exactly the same as cilia, except they are longer and less numerous. They propel some protists and animal sperm cells.
Thinnest cytoskeletal component that are long, thin rods composed of the protein called actin. They are also built and disassembled as needed. Their strength allows a cell to cope with stretching and tension. They from a cortex.
Microtubules
Intermediate filaments
Microfilaments
Centrosome
Underneath the cell membrane microfilaments form a (a) to help maintain shape. They from a 3-D network just below the plasma membrane that helps maintain the cell's shape by generating a region of gel-like consistency.
____________ are sized in between the other two. They vary in protein composition and size depending on the cell type. They are not present in all cells. Arrangement is similar to a coiled rod. Also involved with maintaining the cell's shape and resisting mechanical stress.
Endocytosis
Microfilaments
Microtubules
Intermediate filaments
Keratin is an example of intermediate filaments
True
False
How do cell surfaces differ in plant cells vs. animal cells?
___ _____ are found in plants. They are primarily composed of polysaccharides. The cellulose runs through the wall like on cables. The parallel cables are H bonded to each other increasing strength. Cellulose can make up 30% of the plant's dry weight.
(a)
An extracellular matrix is found in ____
Plants
Animals
Both plants and animals
Extracellular matrix are composed mainly of the fibrous proteins called _____
gradients
antin
cholesterol
collagen
Collagen fibers are bound to proteins in the ECM called _______. It is connected to the cell surface by membrane by membrane proteins called ________
proteins, antin
integrins, fibronectins
fibronectins, integrins
filaments, keratin
The integrins are bound to actin filaments in the cytoplasm, uniting the ECM with the internal cytoskeleton.
True
False
What is the purpose of cell surface specialization?
To from compounds
To reproduce
To communicate
To form bonds
How many types of cell-cell connections are there?
1
2
3
4
_____ protein strands that extend into and out of the cell anchoring them like velcro. The internal portion anchors to intermediate filaments.
Desmosomes
Tight junctions
Gap junctions
Plasmodesmata
_______ proteins that fuse together between cell membranes to prevent leakage such as attachments found in lining of urinary bladder.
Desmosomes
Tight Junctions
Gap Junctions
Plasmodesmata
Pairs of channels that connect insides of adjacent cells. Used for cell to cell communication similar to air ducts. Heart cells are connected by these called intercalated discs that allow for very rapid transmission of electrical impulses throughout the entire tissue. Ions and electrical charges.
Desmosomes
Tight Junctions
Gap Junctions
Plasmodesmata
Continuation of plasma membrane is shared between cells. These from tunnels through the adjacent cell walls of plants. These structures connect virtually all plant tissues.
Desmosomes
Tight Junctions
Gap Junctions
Plasmodesmata
How can the cell membrane transmit info from outside the cell to the inside?
Process called active transport
Process called signal transduction
Process called plasmodesmata
Process called passive transport
Proteins embedded in the membrane called signal transduction are crucial to this process.
True
False
Membrane protein that binds a signaling molecules
Signal Protein
Signal Transduction
Signal Receptors
Signal Membrane
