Unit 2 Exam Review Bio 181
The process through which cells can detect and respond to signals in their extracellular environment is called
Cell communication
What do contact-dependent signaling and paracrine signaling have in common?
Cells release a signal that affects neighboring cells.
What structure easily distinguishes a plant cell from an animal or bacterial cell?
Chloroplast, nucleus, Golgi apparatus
A key is placed into a keyhole, then turned, and the door opens. When considering the components of cell signaling, the action of turning the key would best correspond to
Conformational change in the receptor once bound to the hormone
Which of the following correctly describes bases that pair with each other in the DNA double helix?
Cytosine bonds with guanine
You are given two nucleic acids; one RNA and the other DNA. What are the main features to determine which is the DNA?
DNA will have a double stranded structure. DNA will have uracil instead of thymine in its nitrogenous bases Adenine will be present in the DNA
Sodium ions move from one cardiac muscle cell to an adjacent cell causing them to contract in unison. This is an example of
Direct Intercellular signaling
When performing hypothesis testing, the steps that most accurately describe the process you must go through include __________. (Check all that apply.)
-analyze data to support or reject hypothesis. -observe a natural phenomena. -develop hypotheses to explain phenomena. -design experiments to determine if predictions are correct or not.
Which order best fits the way in which you would conduct the five stages of scientific method?
1) Observe 2) Develop 3)Design 4) Analyze 5) Confirm or reject
Determine the order of the processes occurring as a protein travels through the endomembrane system.
1) Translation of protein into the Rough ER 2) Attachment of protein to cargo receptors 3) Pinching of vesicle into the cytoplasm 4) Transportation to the Golgi 5) Movement through the cis, medial and rans regions 6) Release of the protein out of the cell.
If a specimen contains 30% adenine (A) in its DNA, how much cytosine (C) will it contain?
20%
A phospholipid has ______ fatty acids attached to glycerol, whereas a fat has _______.
2;3
How might a plant cell compensate for the excessive membrane fluidity that occurs during prolonged exposures to elevated temperature?
Alter the lipid composition to have longer phospholipid tails and fewer double bonds
What process best characterizes Ca2+ movement from the cytosol (low Ca2+ concentration) into the endoplasmic reticulum (high Ca2+concentration)?
Calcium Movement involves active transport
Lipids in the form of triglycerides, phospholipids, steroids, and waxes are all important for life to occur. Select all those processes that relate to lipid functions.
Hormone production Energy storage Cell formation Prevention of water loss. Blood Plasma Formation
When placed in an aqueous solution, amphipathic molecules will orient themselves with
Hydrophobic hydrocarbons chains in the middle, and hydrophilic head groups facing the water
In order to study a cell at lower temperatures, a researcher must artificially increase its membrane fluidity. What would be a reasonable strategy for increasing plasma membrane fluidity at low temperatures?
decrease the length of the phospholipid fatty acyl tails
Na+ ion concentrations are higher outside the cell than inside the cell. What type of transport system is required to move Na+ ions in and out of the cell?
Na moves into the cell by facilitates diffusion and out of the cell by active transport
Why would a diet containing unsaturated fats that form triglycerides be better for an athlete when considering energy levels and health?
Saturated fats are packed closer together, making their breakdown for energy release less efficient and forming unnecessary fat deposits
When designing a butter with a higher ratio of unsaturated to saturated fats you would need to take care not to remove all saturated fats. What is the main reason for this
Saturated fatty acids are linear in structure and form closely packed structures that are more solid at room temperature
Sodium concentrations are higher outside and glucose concentrations are higher inside the cell. Using the same membrane protein for Na+ and glucose transport, what is it called when a Na+ electrochemical gradient is used to drive glucose transport into the cell against its concentration gradient?
Secondary active transport
Diabetics can be given insulin that binds to receptors on cells throughout the body increasing glucose uptake. Insulin is an example of a
Signal
After a night of drinking too much alcohol, a person will rely on which organelles to help detoxify and recover?
Smooth Endoplasmic reticulum
The gonads produce steroids. The specific steroid-producing organelles in gonad cells are
Smooth endoplasmic reticulum
The movement of sucrose and H+ into the cell by the same membrane protein reflects the actions of what type of transporter?
Symporter
The protective layer outside of the plasma membrane of the plant cell is called
The cell wall
What makes phospholipids good at forming cellular membranes?
The polar and non polar regions create an amphipathic bilayer of phospholipids
Which membrane component is most important for allowing large, charged molecules to pass through the membrane?
Transmembrane Proteins
Because carbon and hydrogen share similar electronegativities, they will form nonpolar covalent bonds with each other.
True
When body temperature drops below normal, a person starts shivering uncontrollably. This is an example of negative feedback.
True
Whether a signaling molecule operates locally or over long distances, it must bind to a specific receptor to elicit a cellular response.
True
The function of a cell is related to the amount of surface area it has. Is this statement true or false and why?
True. A cell with the same mass can increase surface area with structures like microvilli that enhance absorption functions
Fats and fatty acids
are insoluble in water
If the tight junctions in the intestine were disrupted
bacteria could move from the intestines to the bloodstream causing an infection
What process best characterizes Ca2+ movement from the cytosol (low Ca2+ concentration) into the endoplasmic reticulum (high Ca2+ concentration)?
calciums movement involves active transport
The first, innermost energy shell of an atom
can have a maximum of 2 electrons
When one atom loses an electron to another atom, it results in the formation of
cation and anions that can form ionic bonds
Which level of organization is common to all life forms?
cell
Table salt forms from sodium and chloride via hydrogen bonding. Group starts
false
Unlike animals, plants lack a cell junction where small molecules can move from one cell to another cell.
false
Scientists working on an Arctic glacier discover a population of microbes living in frigid temperatures. Which component of the cell membrane might contribute to maintaining the fluidity of plasma membranes under freezing conditions?
high levels of unsaturated phospholipid tails within the lipid bilayer
A plant will begin flowering in response to changes in length of daylight, temperature, and light quality. This is an example of which unifying principle of life?
living organisms interact with their environment
The nucleus is to eukaryotes as the ________ is to prokaryotes.
nucleoid
A substrate binding to an enzyme is most similar to a signal molecule binding to a
receptor
The process that most involves the selective uptake of a specific cargo molecule into the cell through receptor binding and aggregation is
receptor meditated endocytosis
n some cases, just a few hormone molecules binding to the surface of a cell can trigger a very large response because
the signal is amplified by activation of enzymes that each catalyze multiple reactions
An explanation for a biological process that is substantiated by a large body of evidence is called a
theory
What is the appropriate order of the stages of investigating whether maple trees drop their leaves in the autumn because of colder days?(1) Maple trees are grown in two greenhouses where the only variable is temperature (15°C vs. 10°C).(2) The hypothesis is rejected.(3) There is no statistical difference in the number of leaves dropped at 10°C as compared to 15°C.(4) The observation is that maple trees drop their leaves in autumn.(5) The hypothesis is that maple trees drop their leaves because of colder temperatures.
4,5,1,3,2
A patient has a variety of cellular problems, including proteins in the endomembrane system going to the wrong locations, and no synthesis of estrogen or testosterone. Identify the organelle-symptom pair that is defective.
A problem in the rough ER is responsible for the protein location problem, and a problem in the smooth ER is responsible for the estrogen and testosterone problem.
______ bind two or more ions or molecules and transport them in opposite directions across a membrane.
Antiporters
A cell responds to a signal it sent. This is an example of
Autocrine signaling
A cell secretes a growth factor that binds to receptors on its own membrane preventing it from proliferating. This is an example of
Autocrine signaling
The release of the protein insulin from pancreatic cells occurs by _____
Exocytosis
A researcher hypothesizes that crocodile gender is determined by the incubation temperature of the egg. The hypothesis states that an average nest temperature of 32-33°C results in the birth of male crocodiles, while nest temperatures above or below that incubation temperature range result in female crocodiles. What is a valid, testable prediction based on this hypothesis?
Incubation of any crocodile egg at 32 C, will result in a male crocodile
A cell secretes a growth factor that binds to receptors on neighboring cells causing them to proliferate. This is an example of
Paracrine signaling
A community of organisms interacting with their physical environment is a/an
ecosystem
Hormones are released from one cell and act on other cells in distant organs. This is an example of
endocrine signaling
When insulin is secreted from the pancreas and acts on muscle cells to increase glucose uptake, this is an example of
endocrine signaling
For heart muscles to beat in a coordinated rhythm ions must move from one cell to the next through ________.
gap junctions
You inject a dye into a cell and observe that it moves into adjacent cells. This would occur through ________.
gap junctions
Eukaryotes differ from prokaryotes, in part because eukaryote cells
have a membrane bound nucleus
Whether the external temperature is hot or cold, birds maintain an internal body temperature of approximately 40°C. This is an example of
homeostasis
In water, MgCl2 dissociates into Mg2+ and Cl-. Based on this information what type of bond is involved in the formation of MgCl2?
ionic
passive diffusion
is a spontaneous process
A dehydration reaction
is used to form polymers
When grouping organisms, which classification is most general for a particular type of organism?
kingdom
A researcher created a synthetic, semifluid, monolayer material, formed from lipids embedded with proteins that allow the passage of other molecules. This is similar to a cell's plasma membrane, except for which difference?
plasma membranes have bilayers, not monolayers
Gap junctions in animal cells are most similar to ________ in plant cells?
plasmodesmata
Boa constrictors on an island are an example of a/an __________.
population
Water diffuses through certain organs such as the kidneys and bladder much faster than would occur by passive diffusion through a lipid bilayer alone. What accounts for this more rapid rate of water transport in these organs?
presence of aquaporin channels for facilitated diffusion of water
A cell wall is present in
prokaryotic and plant cells
The macromolecules that can accomplish the widest range of biological functions are
proteins
The best way to describe cellular membranes is
semifluid with lipid rafts
The gonads produce steroids. The specific steroid-producing organelles in gonad cells are
smooth ER
If contents of the intestines can leak into the blood then ________ must have been damaged.
tight junctions
If lithium has an atomic number of 3 then it will have 1 valence electron.
true
Lipids and carbohydrates can both be used by animals to store energy.
true
The cell is the basic structural/functional unit common to all living organisms.
true
When table salt dissolves in water, the salt is called the solute.
true
