Exam 2 Flashcards
A phospholipid is a
nonpolar lipid molecule that is made amphipathic by the addition of a phosphate
Cooking oil and gasoline are NOT amphipathic molecules because they
Do not have a polar or charged ions
Phospholipids and triglycerides both
have a glycerol backbone
Which of the following is a large organic molecule that is NOT assembled by polymerization of a few kinds of simple subunits ?
a steroid
Lipids that form membranes have what kind of structure ?
polar heads and nonpolar tails; the nonpolar tails interact with water
Which aspect oh phospholipids is most important to the formation of bilayers ?
They are amphipathic
Which of the following crosses lipid bilayers ?
a small , nonpolar molecule like oxygen
Which of the following does not cross the lipid bilayers ?
a sodium ion
Which of the following is TRUE of osmosis ?
in osmosis , water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration
Celery stalks that are immersed in freshwater for several hours become stiff. Similar stalks left in a 0.15 M salt solution becomes limp. From this we can deduce that the freshwater ..
is hypotonic and the salt solution is hypertonic to the cells of the celery stalks
A patient was involved in a serious accident and lost a large quantity of blood. In an attempt to replenish body fluids , distilled — equal to the volume of blood lost– is added to the blood directly via one of his veins. What will be the most probable result of this transfusion ?
The patient’s red blood cells will swell and possibly burst because the blood has become hypotonic compared to the cells
Under what circumstances does membrane transport require energy ?
whenever a solute is moved against its gradient
Where would you most likely find an integral membrane protein ?
spanning the cell membrane , with parts of the protein visible from both the inside and the outside of the cell
Which of the following types of molecules are the major structural components of the cell membrane ?
phospholipids and proteins
For a protein to be an integral membrane protein , it would have to be ?
amphiphathic , with at least one hdrophobic region
All of the following are part of a prokaryotic cell EXCEPT ?
the nucleoid
Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules ?
proteins
Acell with a predominance of free ribosomes is most likely ?
primarily producing proteins in the cytosol
Which type of organelle or structure is primarily involved in the synthesis of oils , phospholipids and steroids ?
smooth endoplasmic reticulum
Which organelle often takes up much of the volume of a plant cell ?
vacuole
Which organelle is the primary site of ATP synthesis in eukaryotic cells ?
mitochondrion
Which plant cell organelle contains its own DNA and ribosomes ?
mitochondrion
Thylakoids , DNA and ribosomes are all components found in ?
chloroplasts
Which structure is common to plant and animal cells ?
mitochondrion
Why is the smooth endoplasmic reticulum unable to synthesize proteins ?
No ribosomes are attached to its surface
Suppose a young boy is always tired and fatigued , suffering from a metabolic disease. Which of the following organelles is most likely involved in this disease ?
mitochondria
Which structure - function pair is mismatched ?
Roguh ER - protein sorting
Which of the following would you NOT find in a plant cell ?
collagen
What is a major difference between the extracellular matrix (ECM) of a plant cell and the ECM of an animal cell ?
plant ecm is primarily carbohydrate in nature , whereas animal ecm is mainly proteins
Plasmodesmata in plant cells are most similar in function to which of the following structures in animal cells ?
gap junction
In plant cells , the middle lamella ?
allows adjacent cells to adhere to one another
A cell with membrane bound proteins that selectively bind a specific hormone is called that hormone’s
target cell
Lipid soluble signaling molecule , such as testosterone , cross the membranes of all cells but affect only target cells because …?
receptors are present only in target cells
List the three components that make up the hydrophilic head of a phospholipid
- charged group
- phosphate
- glycerol
This type of transport requires energy to move substances across the membrane
active transport
A cell with 1% solute is in a hypertonic environment.What can be the percentage of solute for the solution outside of the cell ?
10%,anything above 1%
Name a function of cytoskeleton in prokaryotic cell
cell shape
This type of DNA , small , supercoiled , and circular DNAis found in bacteria cell
plasmid
Name an unicellular eukaryotic cell
yeast
Name given to the interior of the Rough ER
lumen
This organelle is a reservoir for Ca2+ ions
smooth ER
This membranous structure is used to transport protein
vesicle
The name given to the solution outside the thlakoid membrane
stroma
The name given to the space of the cristae of mitochondria
matrix
This structure is made up of protein to link cytoskeleton of adjacent cells
Desmosome
