Unit 4 - The Plasma Membrane and Cellular Transportation
What are the three characteristics of a molecule that can pass through the plasma membrane?
(1) It is small. (2) It is polar/neutral. (3) It can diffuse oxygen and carbon dioxide.
What are the two classifications for cell transports?
(1) Passive transport - requires no energy. (2) Active transport - requires energy. The energy used for active transport and the energy used by a cell is ATP.
Which of the following is not a type of passive transport? (1) Diffusion (2) Osmosis (3) Exocytosis (4) Facilitated diffusion
(3) Exocytosis
Which of the following is not a type of active transport? (1) Endocytosis (2) Exocytosis (3) Facilitated diffusion (4) Transport against the concentration gradient
(3) Facilitated diffusion
Which situation would increase the fluidity of the plasma membrane? (1) Decreasing the temperature. (2) Increasing the number of proteins. (3) Increasing the number of cholesterol molecules. (4) Increasing the number of carbohydrates.
(3) Increasing the number of cholesterol molecules.
From our raisin lab, which of the following had the lowest average: (1) No water (2) 1% solute water (3) 5% solute water (4) 10% solute water (5) Tap water
(4) 10% solute water - the salt extracted water (hypertonic).
Which of the following is not a component of the cell membrane? (1) Cholesterol (2) Proteins (3) Phospholipids (4) Cytosol (5) Carbohydrates
(4) Cytosol
Which of the following plasma membrane components is NOT paired with the proper description of its function? (1) Phospholipid bilayer - stop free movement of materials into or out of the cell. (2) Carbohydrates - identify chemical signals of surrounding substances. (3) Cholesterol - provide fluidity for membrane. (4) Protein - provide a hydrophobic barrier to stop molecules from entering the cell.
(4) Protein - provide a hydrophobic barrier to stop molecules from entering the cell.
Which of the following is not a component of the plasma membrane? (1) Phospholipids (2) Proteins (3) Cholesterol (4) Carbohydrates (5) Nucleic acids
(5) Nucleic acids
The energy molecule of the cell, needed to move substances from an area of low concentration to an area of high concentration is ___.
ATP
Why does active transport require energy?
Active transport goes against the concentration gradient (it goes low to high).
What type of a substance will enter the cell through endocytosis?
Bacteria.
In the diagram, structures A and B (yellow) is the:
Carbohydrates.
The component of cell membranes that help identify chemical signals:
Carbohydrates.
What is B? What is it's function?
Carbohydrates; to identify chemical signals and other cells. They are only found on the outer surface.
In the image of the plasma membrane, structure G (orange) is a:
Carrier Protein.
What is G? What is it's function?
Carrier protein; they are responsible for the facilitated diffusion of sugars, amino acids, and nucleosides across the plasma membranes of most cells.
What proteins do active transport processes use?
Carrier proteins - they carry molecules through the membrane by changing shape.
What type of proteins do active transports use?
Carrier proteins.
In the image of the plasma membrane, structure i (orange) is the:
Channel Protein.
What is F? What is it's function?
Channel protein; to transport the ions and water molecules quickly through the membrane.
What proteins do passive transport processes use?
Channel proteins.
What type of proteins do passive transports use?
Channel proteins.
In the image of the plasma membrane, structure H (purple) is:
Cholesterol.
The component of cell membranes that maintains fluidity by preventing phospholipids from sticking together:
Cholesterol.
What is E? What is it's function?
Cholesterol; to prevent the phospholipids from sticking together. It also makes the membrane more flexible.
In the image of the plasma membrane, structure j (purple) is the:
Cytoskeleton.
What is diffusion?
Diffusion is a type of passive transport where the particles move from a high concentration to a low concentration area. The particles move through the phospholipid bilayer and are always randomly moving.
What is endocytosis?
Endocytosis is a type of active transport where a cell surrounds and takes in a large particle (phagocytosis) or solution (pinocytosis) from the environment.
Refer to the diagram. What process is shown?
Endocytosis.
What is equilibrium?
Equilibrium is a type passive transport where particles randomly move, but there is not a change in concentration.
What is exocytosis?
Exocytosis is a type of active transport where a cell expels a large particle to the environment. The particle is too large to fit through a protein.
Refer to the diagram. What process is shown?
Exocytosis.
What is facilitated diffusion?
Facilitated diffusion a type of passive transport where dissolved materials move into a cell through a channel protein. It is called facilitated diffusion because it is diffusion made easier through channel proteins.
What is homeostasis?
Homeostasis is the maintenance of a constant internal environment. The plasma membrane is selectively permeable, meaning it allows some material in, while keeping others out. A cell can only stay alive if it maintains homeostasis.
The process of maintaining the cells environment is:
Homeostasis.
What is C? What is it's function?
Hydrophilic heads; to allow water to dissolve.
What is D? What is it's function?
Hydrophobic tails; to not allow water to dissolve.
Look at the picture of elodea cells. Note how the cells are bulging out on the sides. They have most likely been placed into a ___ solution.
Hypotonic.
Which of the four groups of biological macromolecules makes up two of the four parts of the plasma membrane?
Lipids.
In the image of the plasma membrane, structure C (single building block of structures A and B) is:
Monosaccharide.
Which of the four groups of biological macromolecules is absent in the plasma membrane?
Nucleic Acids.
What is osmosis?
Osmosis is a type of passive transport where water is diffused through special channel proteins.
In the image of the plasma membrane, structure E is the:
Phospholipid Bilayer.
In the image of the plasma membrane above, structure F (blue) is a:
Phospholipid Head.
In the image of the plasma membrane, structure D (green) is a:
Phospholipid Tail.
What are the four components the cell/plasma membrane is made up of?
Phospholipid bilayer, proteins, carbohydrates, and cholesterol.
What is A? What is it's function?
Phospholipid bilayer; to be a water-based barrier that consists of hydrophilic heads and hydrophobic tails.
What is the process where cells lose water?
Plasmolysis.
What are the two parts of a phospholipid?
Polar globular heads that are able to dissolve in water and non-polar straight that cannot dissolve in water.
The component of cell membranes that transport molecules which enter and leave the cell:
Proteins.
The ability of the cell membrane to allow some materials in while keeping other materials out:
Selective Permeability.
What is the role of carbohydrates in the plasma membrane?
The carbohydrates are located on the outer surface of the cell. They help identify chemical signals and cells.
The reason that cells must be able to transport materials into and out of the cell is because ___.
The cell must remain in homeostasis, bring in nutrients, and be able to get rid of waste.
What is the role of cholesterol in the plasma membrane?
The cholesterol is spread through the phospholipid tails and prevents the phospholipids from sticking to each other. It makes the membrane more flexible.
What are the two layers of the phospholipid bilayer?
The hydrophobic inner layer and hydrophilic outer layer.
Why is the plasma membrane called a fluid mosaic model?
The plasma membrane is flexible and can change shape (fluid) and it is made up of individual pieces (mosaic).
What are three ways the plasma membrane helps maintain homeostasis?
The plasma membrane: (1) Maintains proper conditions (i.e., temperature, water, etc.) (2) Obtains nutrients. (3) Gets rid of waste.
What is the role of proteins in the plasma membrane?
The proteins are mixed in with the phospholipid bilayer. It regulates enters and exits the cell.
When it requires energy to move dissolved materials into or out of the cell it is known as ___.
active transport
The cell membrane maintains homeostasis by ___.
allowing some substances in and keeping some substances out
The ___ on a cell membrane are only on the ___ surface of the cell.
carbohydrates, outer
Sometimes proteins found in the membrane have to change their three dimensional shape to move a substance across the membrane. The type of protein that would do this would be a ___.
carrier protein
When a plant cell is placed in a hypertonic solution, ___ occurs.
cell shrinking
If the cell were a city, the plasma membrane would be the ___.
city limits
When there is a higher concentration of dissolved substances on one side of the membrane than the other, it creates a/an ___.
concentration gradient
The net movement of particles from an area of higher concentration to an area of lower concentration is ___.
diffusion
When a cell surrounds and takes in a large particle from the environment it is known as ___.
endocytosis
When particles in a solution continue to move at random, but no further change in concentration occurs, the particles have reached ___.
equilibrium
When a cell expels a large particle to the outer environment it is known as ___.
exocytosis
When dissolved materials move into or out of a cell using a channel protein and when they are going from an area of high concentration to an area of low concentration it is called ___.
facilitated diffusion
The idea which explains that the cell membrane is flexible and the parts are able to move around is the ___.
fluid mosaic model
If RBCs (red blood cells) are placed in pure water (hypotonic), water will move from the pure water to our cells. The cells will ___.
grow
The phospholipid ___ is ___ which allows it to dissolve in water.
head, polar
Cells need to be able to move needed items into the cell and remove unwanted items out of the cell. Cells do this through cellular transport. Cells need to be able to transport materials so that they can maintain ___.
homeostasis
Water molecules will not easily pass through the plasma membrane without the help of a channel protein. This is because water molecules are polar and the interior of the membrane is ___.
hydrophobic
Phospholipids tails are ___ while phospholipids heads are ___.
hydrophobic, hydrophilic
When the solution surrounding a cell has a lower concentration of water than the solution inside the cell, the cell is in a/an ___ solution.
hypertonic
When the solution surrounding a cell has a higher concentration ofwater than the solution inside the cell, the cell is in a/an ___ solution.
hypotonic
If RBCs (red blood cells) are placed in solution with the same salt as the RBC (isotonic), water will move ___ . The cells will ___
in and out, stay the same
When the fluid surrounding a cell is the same concentration as the fluid inside the cell, the cell is in a/an ___ solution.
isotonic
The diffusion of water across a membrane is ___.
osmosis
When it does not require energy to move dissolved materials into or out of the cell it is known as ___.
passive transport
Two layers of phospholipids that form the main structural component of cell membranes is known as the ___.
phospholipid bilayer
The outer boundary of a cell responsible for maintaining homeostasis is the ___.
plasma membrane
If RBCs (red blood cells) are placed in extra salty water (hypertonic), water will move from our cells to the salty water. The cells will ___.
shrink
The phospholipid ___ is ___ which prevents it from dissolving in water.
tail, non-polar
When plant cells are placed in a hypotonic solution they do not burst. This is because ___.
the cell wall prevents this from occurring
The above process requires energy in the form of ATP because ___.
the particles are moving against the concentration gradient
A cell membrane must be a bilayer so that ___.
the phospholipids can keep their hydrophobic tails away from water
If a cell is placed into a solution that has the same concentration as the inside of the cell ___.
water will enter and leave the cell at the same rate
If a cell is placed into a pure water solution ___.
water will rush into the cell faster than water will leave the cell
If a cell is placed into a very strong salt solution ___.
water will rush out of the cell faster than it will enter the cell
