Item 3 Flashcards
(71 cards)
1
Q
There are approximately 10 _ cells in the human body, or 10^14
A
10 trillion
2
Q
Cells are physically linked by _ _
A
gap junctions
3
Q
In most instances, cells communicate through _ _
A
chemical messengers
4
Q
Gap junctions link adjacent cells and are formed by _, plasma membrane proteins
A
connexins, which form structures called connexons
5
Q
T OR F: connexons form connexins
A
false - connexins form connexons
6
Q
Most often, cells communicate via chemical messengers in the form of _, molecules that bind to proteins reversibly
A
ligands
7
Q
Free-floating _ exist in the cell
A
ribosomes
8
Q
Primary _somes are in the cell
A
primary lysosomes
9
Q
Cytosol is found in _CF
A
ICF
10
Q
Hydro_ phosphate heads interact with fluid on both the ICF and ECF sides of a cell, whereas hydro_ tails exist between them
A
hydrophilic phosphate heads (like water) vs hydrophobic fatty acid tails within (keep a water barrier)
11
Q
The _ apparatus is in a cell
A
Golgi apparatus
12
Q
The _ is the powerhouse of a cell
A
mitochondrion
13
Q
The _ surrounds the nucleolus
A
nucleus
14
Q
The cell contains _ _ reticulums
A
smooth endoplasmic reticulums
15
Q
Are carbohydrates generally polar or nonpolar?
A
polar
16
Q
Are triglycerides polar or nonpolar?
A
nonpolar
17
Q
What two speciaized structures can phospholipids form in an aqueous environment?
Micelles
_
A
phospholipid bilayer
18
Q
Phospholipid bilayers and micelles each contain lipid layers of phospholipids aligned such taht polar heads face the _ _ and the nonpolar tails face _ _
A
aqueous environment; each other
19
Q
Phospholipid bilayers have both a polar region and a nonpolar region, and are said to be _ molecules
A
amphipathic molecules
20
Q
Glycogen is composed of subunits of _
A
glucose
21
Q
Proteins are composed of subunits of _
A
amino acids
22
Q
Nucleic acids are composed of subunits of _
A
nucleotides
23
Q
_ _ function in the storage and expression of genetic information
A
nucleic acids
24
Q
_ helps build and repair cells and body tissues, including the skin, hair, muscle, and bone. _ [same] is also important for blood clotting, immune system responses, hormones, and enzymes
A
protein
25
_ is used to store energy without exerting an osmotic force that would draw water into the cells, making the cells swell and possibly burst. A single large storage molecule will not draw in nearly as much water
glycogen
26
The four types of chemical interactions responsible for tertiary protein structure in the order of their strength of bonding:
hydrogen bonds - form between polar R groups
ionic bonds - form between ionized or charged R groups
van der Waals forces - electrical attractions between the electrons of one atom and the protons of another atom
_ _ - form between the R groups of two cysteins
covalent bonds
27
Weak chemical interactions between R groups are easily disrupted by changes in pH or temperature with a process called _
denaturation
28
Disulfide bridges, covalent bonds that provide a strong chemical interaction between protein R groups, are critical to the structure of antibodies and to the structure of the hormone _
insulin
29
What type of chemical force does not cause the insulin molecule to fold into its three-dimensional structure?
covalent bonds
hydrogen bonds
ionic bonds
van der Waals forces
covalent bonds
30
The _ contains everything inside the cell except the nucleus
cytoplasm
31
The gel-like ICF is the _
cytosol
32
The _, structures made up of a variety of biomolecules, carry out specific functions in the cell, much as the organs carry out specific functions in the body
organelles
33
_ organelles are separated from the cytosol by one or more membranes, and non_ organelles have no such boundary with the cytosol
membranous organelles vs nonmembranous organelles
34
The _ _ separates the nucleus from the cytoplasm and those of the membranes around organelles
nuclear envelope
35
The _ _, the structure of the plasma membrane, consists of phospholipids, cholesterol, proteins and carbohydates
fluid mosaic
36
The phospholipid bilayer is considered a _ since the phospholipids and the other molecules in the membrane are not linked together by chemical bonds and can move about laterally and even occasionally move from one side of the bilayer to the other
fluid
37
Water crosses the lipid bilayer through aquaporins because water molecules are _
polar
38
Electrons sharing in covalent bond that are equal sharing are considered _ classes of covalent bonds
nonpolar
39
Nonpolar covalent bonds are said to be hydro_
phobic (i.e., they easily diffuse across a lipid bilayer)
40
Polar covalent bonds are said to be hydro_
philic (i.e., they do not diffuse across a lipid bilayer)
41
DNA exists as thin threads called _
chromatins
42
Nuclear _ allow selective movement of molecules between the nucleus and the cytoplasm
Nuclear pores
43
The _ is the site of synthesis of ribosomal RNA (rRNA)
nucleolus
44
Glycolysis involves the use of _ enzymes that break one glucose molecule into two molecules of pyruvate
ten
45
Molecules that are to be released from the cell are stores in membrane-bound secretory _
vesicles
46
The _ _ consists of an elaborate network of membranes enclosing an interior compartment called the lumen
endoplasmic reticulum
47
_ endoplasmic reticulum is attributable to the presence of ribosomes, complexes of rRNA and proteins that function in protein synthesis. It is closest to the nucleus and consists of flattened sacs with ribosomes attached to its external surface
rough
48
_ endoplasmic reticulum consists of tubules and does not have ribosomes attached to it. It is the site of the synthesis of lipids, including triglycerides and steroids, and is a site for storage of calcium ions
smooth
49
The _ uses smooth endoplasmic reticulum with detoxification enzymes that break down toxic substances in the blood
liver
50
The _ _ consists of membrane-bound flattened sacs called cisternae, which processes molecules synthesized in the endoplasmic reticulum and prepares them for transport to their final location, such as packaging them into vesicles
Golgi apparatus
51
_ are small spherical organelles surrounded by a single membrane which contain enzymes that degrade intracellular debris and extracellular debris that has been taken into the cell
lysosomes
52
_ are spherical organelles slightly smaller than lysosomes and are surrounded by a single membrane. They function in the oxidation and thereby degradation of molecules such as amino acids, fatty acids and toxic foreign matter. They use the enzyme catalase to breakdown hydrogen peroxide into water and oxygen, preventing toxic building of hydrogen peroxide
peroxisomes
53
_ are most abundant in the liver and kidney cells that remove oxidative waste products from the body
peroxisomes
54
_-_ disease is a genetic disorder in which mutated genes produce lysosomal enzymes that are less effective, creating a buildup of gangliosides inside cells which damages them, causing adverse effects
Tay-Sachs Disease
55
_ function in directing the development of a structure called the mitotic spindle during cell division
centrioles
56
White blood cells destroy bacteria by bringing it inside the cell in a vesicle using which process?
a) exocytosis
b) phagocytosis
c) pinocytosis
d) transcytosis
e) receptor-mediated endocytosis
b) phagocytosis
57
A cell is placed into a solution that has the same osmolarity. However, one of the ions in the solution is able to move across the membrane (the cell does not contain this ion). After a period of time, the solution into which the cell was placed would become ________.
hypotonic
58
A cell is placed into a solution that has the same osmolarity. However, one of the ions inside the cell is able to move across the membrane (the solution the cell was placed into does not contain this ion). After a period of time, the solution into which the cell was placed would become ________
hypertonic
59
Which of the following statements about the Na+/K+ pump is FALSE?
64)
______
A)
Two potassium ions are moved into the cell per ATP.
B)
It is a form of primary active transport.
C)
Three sodium ions are moved out of the cell per ATP.
D)
The pump is also an enzyme.
E)
The pumps activity is regulated through allosteric modulation
e) The pumps activity is regulated through allosteric modulation
60
Which of the following statements about primary active transport is FALSE?
62)
______
A)
The Ca2+ pump always moves calcium into the extracellular fluid.
B)
Energy is used to change the affinity of the transporter for the solute being transported.
C)
The Na+/K+-pump transports two potassium ions into the cell and three sodium ions out of the cell.
D)
ATP directly provides the energy for transport.
E)
Phosphorylation of the carrier protein covalently regulates the carrier
The Ca2+ pump always moves calcium into the extracellular fluid.
61
In secondary active transport with sodium, which of the following is FALSE?
59)
______
A)
Sodium binds to a carrier molecule, changing its binding properties for another molecule to be transported across the cell membrane.
B)
Sodium always moves into the cell.
C)
The molecule being transported into the cell may move in or out, depending on the carrier molecule.
D)
The molecule being transported moves down its electrochemical gradient.
E)
ATP is necessary to produce an electrochemical gradient for sodium ions across the cell membrane.
D)
The molecule being transported moves down its electrochemical gradient.
62
Which of the following statements about the Ca2+ pump is FALSE?
58)
______
A)
Calcium is actively transported from an organelle into the cytosol.
B)
Calcium is actively transported from the cytosol into the extracellular fluid.
C)
It maintains low cytosolic calcium levels.
D)
The pump is also an ATPase.
E)
It is a form of primary active transport.
A)
Calcium is actively transported from an organelle into the cytosol.
63
Vesicles formed during phagocytosis or endocytosis often fuse with the membrane of which of the following organelles?
77)
______
A)
rough endoplasmic reticulum
B)
mitochondria
C)
peroxisome
D)
lysosome
E)
smooth endoplasmic reticulum
E)
smooth endoplasmic reticulum
64
Epithelial cells are polarized with different structures on either side of the cell. The portion of the cell that faces the lumen is called the ________ membrane.
80)
______
A)
basolateral
B)
ablumenal
C)
basement
D)
transport
E)
apical
e) apical
65
he extent of ion movement through the ________ space between epithelial cells is determined by the extent of ________ coupling between neighboring epithelial cells.
81)
______
A)
transcellular : tight junctional
B)
paracellular : tight junctional
C)
transcellular : gap junctional
D)
transcellular : desmosomal
E)
paracellular : gap junctional
B)
paracellular : tight junctional
66
The movement of a number of molecules across the apical surface of the epithelial cell by secondary transporters is coupled to the ________ gradient that is maintained by the ________ on the basolateral surface of the epithelial cell.
82)
______
A)
Na+ : Na+ channel
B)
K+ : K+pump
C)
Ca2+ : Na+/K+ pump
D)
K+ : K+ channel
E)
Na+ : Na+/K+ pump
E)
Na+ : Na+/K+ pump
67
What is the name for the fluid that is found inside a red blood cell?
A) extracellular fluid
B) intracellular fluid
C) interstitial fluid
D) Plasma
B) intracellular fluid
68
You have cells with an osmolarity of 300 mOsm due to impermeant solutes. What would happen to the cells if you placed them in a beaker containing 300 mOsm of impermeant solutes and 200 mOsm of urea?
a) urea would move into the cells via diffusion and water would move out of the cells to compensate so the cells would shrink
b) urea would remain outside the cells and therefore water would move into the cells and the cells would swell
c) urea would remain outside the cells and therefore water would move out of the cells and the cells would shrink
d) urea would move into the cells via diffusion and water would follow so the cells would swell
d) urea would move into the cells via diffusion and water would follow so the cells would swell
69
You discover a new cellular transport protein that transports sodium. You create an artificial membrane that is similar to the lipid portion of the plasma membrane but only contains your newly discovered protein and no other proteins. You place the membrane between two chambers. Chamber A has a solution of 1 M sodium and Chamber B has a solution of 0.5 M sodium. You discover that sodium can move from chamber B to A but only in the presence of ATP. What class/type of transporter have you discovered?
a) a channel protein that is gated and requires the binding of ATP to open
b) a sodium pump that works via primary active transport
c) a transporter that works via facilitated diffusion
d) a transporter that works via secondary active transport
b) a sodium pump that works via primary active transport
70
What would happen to glucose transport if you increased the number of glucose transporters in the plasma membrane of the cell, but kept the glucose concentrations of glucose outside and inside the cell the same?
a) at equilibrium, the overall amount of glucose that had been transported would be less
b) the rate of glucose transport would decrease
c) at equilibrium, the overall amount of glucose that had been transported would be more
d) the rate of glucose transport would increase
d) the rate of glucose transport would increase
71
Insulin is a hormone that lowers plasma glucose levels. The release of insulin is regulated by negative feedback. What does that mean?
a) low levels of plasma glucose will stimulate insulin release
b) plasma glucose has no effect on insulin release
c) low levels of plasma glucose will inhibit insulin release
d) high levels of plasma glucose will inhibit insulin release
c) low levels of plasma glucose will inhibit insulin release
