unit 3 study guide- biology
Which best explains why the nucleus is important to cells?
The nucleus contains coded instructions for making proteins.
Why have scientists most likely classified archaebacteria and eubacteria together?
They are both prokaryotes.
Which is true of phospholipids located in the plasma membrane?
They have hydrophobic tails and hydrophilic heads.
Cells use transport vesicles to transport large substances from the cell. Which is true about the structure of the transport vesicles and the cell membrane?
They have the same type of phospholipid bilayer.
What do all organisms have in common?
They use DNA and RNA to pass on information.
A freshwater plant is placed in a container of saltwater. What will most likely happen to the cells of the plant
They will shrink because water will move out of them.
Which factor affects osmosis through a membrane?
concentration of water on both sides of the membrane and the permeability of the membrane
In eukaryotic organisms, interaction between which organelles is most important for cell shape, tensile strength, and communication between cells?
cytoskeleton and cell membrane
Which contains a nucleus?
eukaryote
ups/post office
golgi apparatus
In general terms, how does cholesterol mainly effect the cellular plasma membrane?
It determines fluidity of the cellular plasma membrane.
What will most likely be the result if all of the mitochondria are removed from a plant cell?
It will be unable to carry out respiration.
A red blood cell is placed in a beaker containing distilled water. What will most likely happen to the cell?
It will swell.
Which best describes a selectively permeable plasma membrane?
Only certain substances can pass through the membrane.
Why do living things require energy for active transport?
Organisms move substances against the gradient.
which best describes the function of a ribosome?
Ribosomes use RNA to synthesize proteins.
When placed into a solution that is 30% water and 70% salt, what would happen to a cell that has a 70% water concentration?
The cell will lose water and shrink to reach equilibrium with the environment.
A cell is placed in a highly concentrated salt solution. What will most likely happen to the cell if left in the solution?
The cell will shrink in size, losing water due to osmosis.
Why is it important that the inner membrane of the mitochondria be folded in both plant and animal cells?
The folded membrane increases the surface area for energy production.
If a cell is placed in a high-salinity solution, how does it attempt to maintain a balance of water inside itself?
The plasma membrane pumps water back into the cell to counteract osmosis out of the cell.
How does a prokaryotic autotrophic organism compare to a plant cell?
The prokaryotic organism lacks a membrane-bound nucleus, but both make their own food.
A red blood cell is soaked in a solution of lower than normal salt concentration. Which might happen to the red blood cell when homeostasis is not maintained?
The red blood cell may burst.
How does a substance cross the plasma membrane against a concentration gradient?
The substance is recognized by a protein embedded in the membrane and, using energy, is carried to the cytoplasmic surface of the membrane.
What causes your fingers and toes to become wrinkled when you are in the water for a long time?
The surrounding water flows into your skin.
How are phospholipids arranged in the plasma membrane?
a double layer, hydrophobic tails facing each other
Which could be used to represent the plasma membrane's job?
a gatekeeper allowing cars in and out of a parking lot
There was no oxygen in early Earth's atmosphere. Through which group of organisms was oxygen most likely first introduced into the environment?
autotrophic prokaryotes
Which statement provides evidence that mitochondria most likely evolved when a primitive eukaryotic cell engulfed a prokaryotic bacteria?
both mitochondria and bacteria have a circular DNA molecule.
If a molecule of water passed through the cell wall, which cell structure would it encounter next in order to enter the cell?
cell membrane
Which is a rigid structure that protects plant cells and helps them keep their shape?
cell wall
Which plant structure is mainly composed of cellulose?
cell wall
Which organelle in a plant cell captures sunlight and converts the energy into food?
chloroplast
Which pair of organelles is responsible for the energy supply to eukaryotic cells?
chloroplasts and mitochondria
highway system
endoplasmic reticulum
What is the end result of diffusion across a cell's membrane?
equal concentrations of the solute on both the inside and outside of the cell
Which process requires ATP in order to release particles from a cell to maintain homeostasis?
exocytosis
Which structure do both Euglena, a unicellular eukaryote, and some prokaryotic bacteria have in common?
flagellum for movement
A cell completes the synthesization of a protein by adding a carbohydrate to the protein's structure. At which site in the cell is the carbohydrate added?
golgi apparatus
Proteins that are synthesized in ribosomal subunits undergo extensive post-translational modification and are packaged and directed to the appropriate destination. Which structural component of a cell is involved in such modification?
golgi apparatus
protein factories
ribosomes
A fossilized cell is discovered that has a singular circular chromosome and a plasma membrane. It does not have membrane-bound organelles. To which group of organisms does this cell most likely belong?
prokaryote
Which has no membrane bound organelles and is considered a simple cell?
prokaryote cell
Which difference best describes the DNA containing structures in prokaryotic and eukaryotic cells?
Eukaryotes have a true nuclear membrane that surrounds its DNA, where prokaryotes do not.
Which molecules form the bilayer of the cell membrane?
phospholipid
What structure does the cell rely on to help regulate proteins exiting the cell?
plasma membrane
Which structure maintains homeostasis, contains active transport pumps, and is composed of two layers of phospholipids?
plasma membrane
Which can be found only in prokaryotes that is used to transfer genetic information from one cell to another?
plasmids
Which best determines whether a molecule crosses a cell membrane?
polarity and concentration
A student is observing a microscopic organism. They have observed the organism to have ribosomes, a cell wall, a plasma membrane, and circular DNA. Which type of organisms would this organism most likely be grouped with?
prokaryote
An enzyme in the Golgi apparatus catalyzes the addition of phosphates to which class of molecule?
protein
Which would least likely be able to cross the phospholipid bilayer of the cell membrane?
protein
What structures within the plasma membrane allow the passage of ions or large molecules?
protein channels
A chemical is added to cells, stopping all the activity of ribosomes. What is the result?
protein synthesis starts
recycling center
lysosomes
Nucleoli are organelles within the nucleus that serve what function?
synthesize the components of ribosomes
Which organelles work together to provide a plant cell with structure and support?
the cell wall and large central vacuole
In a cell, a newly synthesized protein requires modification by the addition of a carbohydrate. Which structure will transport the protein from the site of synthesis to the site of modification?
the endoplasmic reticulum
Which organelle works with the cell wall to keep a plant cell rigid?
the large central vacuole
Which is a difference between active and passive transport?
Active transport requires ATP, while passive transport does not.
Which is true about cell membranes?
Cell membranes form barriers around the cell.
The human body processes and eliminates food waste using the organs of the excretory system. Which organelle performs a similar function in humans at the cellular level?
lysosome
Which organelle performs the digestion of bacteria within white blood cells?
lysosome
Which organelle provides energy to a cell?
mitochondria
power plant
mitochondria
A student examines an electron photomicrograph of an unidentified cell and determines that it is a eukaryote. Which structure did the student identify in order to come to this conclusion?
mitochondrion
Which cellular organelle is thought to have evolved from a prokaryote that was able to use oxygen?
mitochondrion
Which organelle is responsible for generating energy for the plasma membrane to perform active transport?
mitochondrion
Which uses energy to maintain cellular homeostasis?
movement of a solute from low to high concentration
Which kind of cell has the greatest number of mitochondria?
muscle cell
Which organelle is responsible for the direction of all cellular functions?
nucleus
Which structures contain all the others?
nucleus
city hall
nucleus
Which two organelles are most important in the production of proteins in a cell?
nucleus and ribosomes
Which form of transport permits water to cross a semi-permeable membrane from areas of high concentration to low concentration?
osmosis
What is the main function of the chloroplasts in plant cells?
to produce glucose
