BIO161 QUESTIONS AND ANSWERS A+ GRADED
Membrane
thin layer of tissue that covers a surface, lines a cavity, or divides a space or organ
amphipathic
having both a hydrophilic region and a hydrophobic region
the major types of lipids found in cell membranes are:
phospholipids
most phosph...
Membrane
thin layer of tissue that covers a surface, lines a cavity, or divides a space or organ
amphipathic
having both a hydrophilic region and a hydrophobic region
the major types of lipids found in cell membranes are:
phospholipids
most phospholipids are made up of
glycerol backbone attached to a phosphate group and two fatty acids
the phosphate head group is
hydrophillic
The two fatty acid tails are
hydrophobic
phospholipids behave in an interesting way in aqueous solutions
they spontaneously arrange themselves into various structures in which the polar head
groups on the outside interact with water and the nonpolar tail groups come together on
the inside away from water. This arrangement results from the tendency of polar
molecules like water to exclude nonpolar molecules or nonpolar groups of molecules.
Lipids with bulky heads and a single hydrophobic fatty acid tail are
wedge-shaped and packed into spherical structures called micelles
micelles
A spherical structure in which lipids with bulky heads and a single hydrophobic tail are
packed.
Lipids with less bulky head groups and two hydrophobic tails are roughly
rectangular and form a
bilayer
Bilayer
a lipid bilayer is a structured form of two layers of lipids in which the hydro phillic heads
are the outside surfaces of the bilayer and the hydrophobic tails are sandwiched in
between, isolated from contact with the aqueous environment
Are membranes self healing?
Yes, small tears in a membrane are rapidly sealed by the spontaneous rearrangement
of the lipids surrounding the damaged region because of the tendency of water to
exclude nonpolar molecules
Which of the choices is an example of kinetic energy?
1. electricity
2. a cell membrane
3. a C-H bond in a sugar molecule
4. gasoline in an autogas tank
5. a ball at the top of the stairs
,1. electricity
Which of the choices is an example of potential energy?
1. an electrochemical gradient across the cell membrane
2. flow of calcium ions through a membrane channel
3. contraction of a muscle cell
4. chemical transport, as in the sodium-potassium pump
1. an electrochemical gradient across the cell membrane
Which of the factors accounts for the higher potential energy of C-C and C-H
bonds compared to C-O and H-O bonds?
1. The C-C and C-H bonds are strong, thus requiring a lot of energy to hold
together.
2. The C-C and C-H bonds are weak, thus requiring a lot of energy to hold
together.
3. The C-O and H-O bonds are strong, thus requiring a lot of energy to hold
together.
4. The C-O and H-O bonds are weak, thus requiring less energy to hold together.
2. The C-C and C-H bonds are weak, thus requiring a lot of energy to hold together.
Many cellular processes represent work that requires the expenditure of energy.
Which of the actions is not a cellular process that requires the cell to expend
energy?
1. Synthesis of large biomolecules like proteins and nucleic acids.
2. Contraction of muscle cells.
3. Diffusion of water into cells.
4. Keeping sodium ion concentration lower inside a cell than outside the cell.
3. Diffusion of water into cells.
When chemical reactions occur the _____ but the _____.
1. atoms retain their identities; arrangement of bonds changes
2. identity of atoms changes; arrangement of bonds is retained
3. number of bonds per atom changes; total number of bonds is retained
1. atoms retain their identities; arrangement of bonds changes
When H2CO3 reacts to form CO2 and H2O, what is the net change in the number
of shared electron pairs?
1. 0
2. -3
3. -2
4.+2
1. 0
The transition state is that portion of the progress of a chemical reaction with a
large amount of energy found in _______ reactions.
1. both endergonic and exergonic
2. exergonic
3. endergonic
4. non-spontaneous
1. both endergonic and exergonic
Reactions in which there is a negative change in free energy (-ΔG) are:
1. non-spontaneous and endergonic.
, 2. spontaneous and endergonic.
3. spontaneous and exergonic
4. .non-spontaneous and exergonic.
3. spontaneous and exergonic
_____ are organisms that derive energy from sunlight.
1. Autotrophs
2. Chemotrophs
3. Phototrophs
4. Heterotrophs
3. Phototrophs
To which of the substances is ATP most closely chemically related?
1. glucose
2. guanine
3. phospholipid
4. testosterone
5. tryptophan
2. guanine
Synthesis of a protein is an example of a chemical reaction that is:
1. endergonic and catabolic.
2. exergonic and catabolic.
3. explosive.exergonic and anabolic.
4. endergonic and anabolic.
4. endergonic and anabolic.
Which of the statements is true of allosteric inhibitors of an enzyme?
1. Allosteric inhibitors increase the rate of enzyme activity.
2. Allosteric inhibitors are structurally similar to the normal substrate of an
enzyme.
3. Allosteric inhibitors decrease enzyme activity
4. Allosteric inhibitors bind to the active site of the enzyme.
3. Allosteric inhibitors decrease enzyme activity
One unifying feature of prokaryotic and eukaryotic cells is the presence of:
1. cell wall
2. mitochondria
3. DNA
4. a nucleus
5. cholesterol
3. DNA
Human blood types A, B, AB, and O differ by the sugars attached to the proteins
and lipids found in the red blood cell plasma membrane. The attachment of these
sugars, called glycosylation, occurs in which organelle?
1. Golgi
2. Chloroplast
3. Lysosome
4. Nucleus
5. Mitochondria
1. Golgi
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller SUPERGRADES01. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $10.99. You're not tied to anything after your purchase.
