bio 3
Which statement is NOT part of the modern cell theory?
Cells are able to synthesize their entire complement of biomolecules.
How are lysosomes distributed between different types of eukaryotic cells?
Cells that process a lot of larger nutrients, such as liver cells, have larger amounts of lysosomes then other cells.
Suppose the Golgi apparatus was destroyed in a plant cell but all other functions remained. Which of the following would be immediately TRUE of this cell?
It could no longer modify and package proteins for delivery.
What makes the rough endoplasmic reticulum rough?
It is covered with ribosomes.
What is the main function of the nucleolus?
It is the site of ribosome-subunit synthesis.
The plasma membrane of liver cells is embedded with:
LDL receptor proteins.
The movement of molecules from areas of low concentration to those of high concentration against chemical gradients is best described as:
active transport.
Endocytosis
allows a cell to capture large molecules and bring them into the cell.
Endocytosis:
allows a cell to capture large molecules and bring them into the cell.
Cell walls
are not completely solid, having many small pores
If the solution surrounding a cell contains the same amount of solute as the cytoplasm the osmotic condition is said to be:
isotonic
The role of cholesterol in the plasma membrane of animal cells is to:
keep the plasma membrane flexible, especially at low temperatures.
Nucleus is to nucleolus as _________ is to __________.
library, a room in the library where instruction manuals are used to build knitting machines
The principal components of cell membranes are:
lipids
Most cholesterol that circulates in the bloodstream is in the form of:
low-density lipoproteins.
Facilitated diffusion of magnesium ions (Mg++) would occur OUT of a cell if the Mg++ concentration was ________ outside the cell than inside, and ________.
lower, Mg++ could move through a transport protein across the membrane
Which of the following organelles is responsible for degrading waste within the cell?
lysosome
Which of the following organelles are enclosed by a double membrane?
mitochondria and chloroplasts
Diffusion?
net movement of particles from areas of high concentration to areas of low concentration
Cellular "fingerprints":
can help the immune system distinguish "self" from "non-self."
Glycoproteins are membrane proteins with bound:
carbohydrates
Interacting systems of molecules enclosed in compartments called __________ evolved 3.8 billion years ago in living organisms.
cells
All cells in the body receive chemical signals that circulate in the blood. Only which cells are able to respond to these signals?
cells with the necessary receptors
Odors and taste are all:
chemical signals.
The largest structure in a eukaryotic cell is the ____________ and is surrounded by ______ membranes.
nucleus; two
Diffusion across the cell's outer membrane:
occurs without the input of energy.
Prokaryotic organisms lack:
organelles
Active transport, the moving of molecules from areas of low concentration to that of high concentration across the membrane, are usually coupled to processes that:
cost energy.
Mitochondria have a "bag within a bag" structure. This is necessary to:
create two distinct regions with a concentration differential, a form of potential energy.
The passive transport of water across a membrane from a solution of lower solute concentration to a solution of higher solute concentration is best described as:
osmosis
The transport of water across a membrane from a solution of lower solute concentration to a solution of higher solute concentration is best described as:
osmosis
The inner scaffolding of the cell, made from proteins, is:
cytoskeleton
Which of the following is known as the "cuddle hormone"?
oxytocin
Hydrophobic molecules can pass freely through the plasma membrane, but ions and polar molecules are impeded by the hydrophobic core. For this reason, plasma membranes can be considered:
partially permeable.
The movement of molecules across a membrane from an area of high concentration to one of low concentration is best described as:
passive transport.
What are the three types of endocytosis?
phagocytosis, pinocytosis, and receptor-mediated endocytosis
What cellular structure makes it possible for a cell to differ structurally and biochemically from its surroundings?
plasma membrane
Plants have cell walls to give them more structural strength. In order to facilitate movement of molecules from one plant cell to another, there are channels called ___________________ that run through the cell walls.
plasmodesmata
Nuclear ______ are specialized holes in the ________- layered nuclear envelope that separates the nucleus from the ___________.
pores; two; cytoplasm
The function of cell vacuoles are to store nutrients, physically support the surrounding cell, and to deter predators from eating the cell. What two other services can vacuoles provide?
producing flashy pigments and managing waste
Within eukaryotic cells, the ribosomes are the primary site for which of the following?
protein assembly
Mammalian cells take in many molecules including hormones, antibodies, and blood proteins. This process is coordinated by proteins that recognize their specific target molecule. This process is best described as:
receptor-mediated endocytosis.
Which of the following types of human cells does NOT contain DNA?
red blood cells
Which of the following is NOT an important structural feature on the surface membrane of an animal cell?
ribosomal proteins
Which of the following is found in both prokaryotic and eukaryotic cells?
ribosome
The rough ER is to __________ as smooth ER is to _________ .
sandpaper, writing paper
The lysosomes in a human cell contains approximately ________ types of digestive enzymes.
50
Which of the following describes pinocytosis?
A cell performs endocytosis, bringing in dissolved particles and liquids.
How are phospholipid molecules that make up the surface membrane of a cell organized?
A two-layered structure is formed, with the hydrophobic tails facing in to each other, sandwiched between the hydrophilic heads that face the interior of the cell and the exterior environment.
The rough ER is the site of protein synthesis and the smooth ER is the site of lipid synthesis. What is the third compartment of the endomembrane system and what is that compartment's function?
Golgi apparatus: finishes the processing of the proteins and sorts them for export out of the cell
A unique characteristic of mitochondria is that they are inherited from the female parent only. Select the correct explanation for this phenomenon from the choices below.
Male sperm cells have mitochondria, but because the sperm contrinbutes DNA but no cytoplasm, no mitochondria are passed to the egg at fertilization.
Mitochondria are thought to have evolved from free-living bacteria that were incorporated into eukaryotic cells by endosymbiosis. Which of the following pieces of evidence for this hypothesis is INCORRECT?
Mitochondria can survive and reproduce independently when removed from the host cell.
Which of the following facts supports the claim that mitochondria developed from bacteria that, long ago, were incorporated into eukaryotic cells by the process of phagocytosis?
Mitochondria have their own DNA.
Which of the following is NOT a correct statement about passive transport across the cell membrane?
Passive transport may involve chemical energy in the form of ATP.
People who consume food laden with too much cholesterol or saturated fat often come to have:
People who consume food laden with too much cholesterol or saturated fat often come to have:
The pH of the liquid inside a lysosome is acidic, about 4.5. The molecules normally found inside the lysosome are designed to work best at this pH. Which of the follow statements is the BEST explanation for why the pH of the lysosome interior is so low?
Protective: if the corrosive broth of a lysosome ever leaked out, the digestive enzymes in it would become non-functional in the higher pH of the cytoplasm.
How is osmosis across the cellular membrane controlled?
The membrane is impermeable to the solute, so water moves in and out of the cell to maintain a concentration equilibrium between the interior and exterior of the cell.
Which of the following statements is TRUE about a plasma membrane?
The molecules that make up the membrane are lipids.
Which of the following is the most important factor governing a cell's particular type of interaction with other cells?
The pattern of glycoproteins and glycolipids on the cell's surface.
What major advantage does the presence of organelles offer eukaryotic cells?
They separate chemicals into different compartments, concentrating them for certain reactions.
In chemistry class we learn the rule "like dissolves like" when studying why polar substances dissolve in each other (like sucrose in water) and why non-polar substances dissolve in each other (like fats in oil). Which of the following statements illustrates this rule?
Transmembrane proteins remain in the plasma membrane even though they are not attached to anything.
______________ are found in all metabolically active cells and are involved primarily in transporting materials within, into, and out of cells.
Vesicles
Which of the following is the most important factor governing a cell's particular type of interaction with other cells?
Whether or not the cell is eukaryotic or prokaryotic.
Each molecule of LDL is:
a cholesterol globule coated by phospholipids.
The hydrophilic head of the cell membrane is composed of:
a glycerol linked to a phosphorus-containing molecule.
Which of the following structures is NOT present in the cell membrane?
a glycogen band between the phospholipids layers.
Which of the following is a cellular characteristic of ALL eukaryotes?
a nuclear membrane
In a green leaf, each cell has:
about 40-50 chloroplasts.
If the concentrations of a particular molecule are equal on both sides of the membrane, facilitated diffusion will:
be ineffective.
The cell connections represented above are:
desmosomes
The lysosome:
digests and recycles cellular waste products and consumed materials.
The nucleus:
directs cellular activity and stores hereditary information.
Water naturally moves _________ a concentration gradient
down
To absorb large particles, cells engulf them within their plasma membrane in a process called
endocytosis
Where are cell membrane components synthesized?
endoplasmic reticulum
According to the theory of endosymbiosis, the origin of chloroplasts probably involved:
engulfing of small photosynthetic prokaryotes by larger cell.
Membrane-bound vesicles containing a substance synthesized by a cell fuse to the outer cell membrane and release their contents to the outside world. What is this process called?
exocytosis
You measure the concentration of a polar molecule inside and outside of a cell. You find that the concentration is high outside but gradually increasing inside the cell. You also measure the ATP concentration inside the cell and find that it remains constant. Your best hypothesis for the process that is occurring would be:
facilitated diffusion
Polar molecules and many charged molecules like water, ions, amino acids, and sugars pass across the membrane via:
facilitated diffusion.
Which of the following types of cell would you expect to have the fewest mitochondria?
fat cells
Eukaryotic cells may contain all of the following EXCEPT:
flagella
Passive transport, the moving of molecules from areas of high concentration to that of low concentration across the membrane, are usually coupled to processes that:
gain energy for the cell.
Which of the following allows the passage of small molecules between animal cells?
gap junctions
The cytoskeleton:
helps to coordinate intracellular movement of organelles and molecules.
Phospholipids assemble spontaneously into bilayers driven by the attraction of their "tail" portions to each other and of their "head" portions to each other. The tail regions are:
hydrophobic
The lipids within the fluid mosaic of the plasma membranes are held in place by:
hydrophobic interactions.
If the solution surrounding a cell contains more solute than the cytoplasm, the osmotic condition of the solution is said to be:
hypertonic
If a cell is put into a solution with a higher concentration of solute than is present inside the cell, the solution is ____________. The cell will __________. If a cell is put into a solution with a lower concentration of solute than is present inside the cell, the solution is _____________. The cell will _________.
hypertonic; shrink; hypotonic; swell
If the solution surrounding a cell contains less solute than the cytoplasm the osmotic condition is said to be:
hypotonic
The smooth endoplasmic reticulum:
synthesizes lipids and detoxifies molecules.
What is the most important barrier protecting the inner contents of an animal cell with its exterior environment?
the cellular membrane
In Tay-Sachs disease, a genetic mutation causes an malfunction in a certain organelle that leads to a backup of molecules and proteins, ultimately interfering with the entire functioning of the cell. Which organelles are primarily affected by this disease?
the lysosomes
A scientist tries to build a eukaryotic cell in her laboratory. She remembers to include most of the organelles, but forgets one. Among other abnormalities, her newly created cell cannot synthesize the enzymes needed to detoxify drugs and poisons. Which organelle is missing?
the smooth endoplasmic reticulum
A cell's interior is considered isotonic to the surrounding fluid when:
the solute concentrations are the same within and outside the cell.
Sugar and CO2 are dissolved in water to make carbonated soft drinks. Which of the following is the solute?
the sugar and the CO2
In the brain of a prairie vole the regions associated with bonding and caring for young would be most likely:
to have the most receptors for vasopressin and oxytocin.
The function of cholesterol in membranes is:
to reduce membrane fluidity at higher temperatures.
Osmosis deals only with ___
water
The "fingerprint" found on the outsides of cells is the BEST underlying explanation for:
why you cannot catch HIV by casual contact.
In some plants, a secondary cell wall is laid down that contains a complex molecule called lignin. A mass of plant cells embedded with lignin is known to you as:
wood.
