Lecture 22-30 Flashcards
Metabolic pathways that lead to the synthesis of more complex compounds from simpler starting materials are known as ________.
a. anabolism b. catabolism c. manabolism d. a and b e. allosterism
a
Glycolysis occurs in the ________; the Krebs (TCA) cycle occurs in the ______ of eukaryotes and the ______ of prokaryotes.
a. cytoplasm, cytoplasm, cytoplasm b. mitochondria, cytoplasm, mitochondria c. cytoplasm, mitochondria, cytoplasm d. cytoplasm, photosynthesis, cytoplasm e. cytoplasm, mitochondria, mitochondria
c
How are new mitochondria produced?
a. They arise by fission from preexisting mitochondria. b. They bud off of the Golgi apparatus. c. They bud off of the rough endoplasmic reticulum. d. They self-assemble spontaneously. e. They arise through fusion.
a
How do mitochondria generate and store the energy used to produce most of the ATP made during aerobic respiration?
a. by producing heat b. by generating a heat gradient c. by generating an ionic (electrochemical) gradient d. by generating a Cl- ion gradient e. c and d
c
Peroxisomal enzymes __________.
a. produce hydrogen peroxide b. break down hydrogen peroxide c. include catalase d. a and b e. a, b and c
e
Organisms that can survive on carbon dioxide as their principal carbon source are called ________.
a. autotrophs b. heterotrophs c. chemotrophs d. phototrophs e. externotrophs
a
Organisms that use the energy stored in inorganic molecules, like ammonia, hydrogen sulfide and nitrites, to convert carbon dioxide to organic molecules like carbohydrates and proteins are called _____.
a. chemoautotrophs b. chemoheterotrophs c. photoautotrophs d. photoheterotrophs e. didliotrophs
a
What is the plant cell’s primary source of chemical energy?
a. CO2 b. ADP c. ATP d. NAD e. NADPH
c
What is the plant cell’s primary source of reducing power?
a. CO2 b. ADP c. ATP d. NAD e. NADPH
e
What color of light does chlorophyll absorb?
a. red b. blue c. green d. a and b e. a, b and c
d
Which of the following is a function of carotenoids?
a. They act as primary light collectors during photosynthesis. b. They act as secondary light collectors during photosynthesis. c. They draw excess energy away from excited chlorophylls and dissipate it as heat. d. b and c e. a and c
d
The PSII reaction center, also known as P680, _____________.
a. absorbs light most strongly at 680 nm b. reflects light most strongly at 680 nm c. absorbs light most weakly at 680 nm d. b and c e. absorbs light most strongly at 700 nm
a
For what purpose(s) does photosystem II (PSII) use absorbed light energy?
a. removing electrons from alcohol b. removing electrons from sugars c. generating a proton gradient d. removing electrons from water e. c and d
e
Which of the following activities contribute to the establishment of a H+ ion (proton) gradient across the thylakoid membrane?
a. splitting of water in the thylakoid lumen b. translocation of protons from the stroma to the thylakoid lumen by cytochromes c. reduction of NADP+ in the stroma d. reduction of NADP+ in the thylakoid lumen e. a, b and c
e
You inject an antibody against the protein actin into a living animal cell. After the injection, the cell begins mitosis and the process proceeds normally until cytokinesis would normally occur. Instead, the contractile ring does not form and cytokinesis does not occur. What do these results mean?
a. Cytokinesis is dependent upon microtubules. b. Cytokinesis is dependent upon microfilaments. c. The separation of chromosomes by the spindle is dependent upon microtubules. d. A major component of the contractile ring is microfilaments. e. b and d
e
You inject an antibody against the protein tubulin into a living animal cell. After the injection, the cell begins mitosis but the chromosomes do not become attached to the spindle; in fact, there is no spindle. The contractile ring does form however. What do these results mean?
a. The contractile ring is composed of microtubules. b. Cytokinesis is dependent upon microtubules. c. The separation of chromosomes by the spindle is dependent upon microtubules. d. The spindle is composed, at least in part, by microtubules. e. c and d
e
Which end of a microtubule is the fast growing end?
a. the plus end b. the end with beta-tubulin at the tip c. the end with alpha-tubulin at the tip d. the minus end e. a and b
e
The core of a cilium is called the ________.
a. troponeme b. dynomeme c. cilioneme d. axoneme e. flagelloneme
d
Which of the following is a family of molecular motors?
a. myosins b. kinesins c. dyneins d. motorins e. a, b and c
e
Which of the following molecular motors is associated with microfilaments?
a. kinesins b. dyneins c. myosins d. a and b e. a, b and c
c
What part of the molecular motor kinesin is responsible for binding to the cargo to be hauled?
a. the motor domain b. the neck c. the rodlike stalk d. the fan-shaped tail e. all of the above
d
A _____ moves the cell in a direction ________ to itself.
a. cilium, perpendicular b. cilium, parallel c. flagellum, perpendicular d. cilium, diagonal e. a and d
a
Each step that kinesin makes along a microtubule is about 8 nm. How many tubulin subunits correspond to this distance?
a. 1 b. 3 c. 4 d. 2 e. 5
d
When microtubules grow out of a centrosome, which end is associated with the centrosome?
a. the plus end b. the minus end c. the N-terminal end d. the C-terminal end e. the 5'- end
b
Which of the following cell processes involve microfilaments?
a. movement of chromosomes during mitosis b. phagocytosis c. cytokinesis d. b and c e. a, b and c
d
Which of the following words best describes the structure of an actin filament?
a. single actin strand b. triple helix c. hyperpolar filament d. double helix e. supercoil
d
What motor is associated with microfilaments?
a. myoglobin b. kinesin c. myosin d. dynein e. myometrium
c
Where does the energy to run myosin motors come from?
a. GTP b. ATP c. proton gradient d. CTP e. creatine phosphate
b
What causes rigor mortis?
a. In the absence of ATP, cross-bridges do not detach from the actin thin filament. b. In the absence of ATP, cross-bridges will not attach to the actin thin filament. c. In the absence of ADP, cross-bridges do not detach from the actin thin filament. d. In the absence of ADP, cross-bridges will not attach to the actin thin filament. e. When organism dies the cross-bridges denature rapidly.
a
What is a major influence in determining the organization and behavior of actin filaments inside cells?
a. actinin-binding proteins b. tubulin c. actin-binding proteins d. dynein e. a and c
c
As a fibroblast moves, its leading edge extends from the cell as a broad, flattened, veil-like protrusion called a ________.
a. pseudopodium b. lamella c. lamellipodium d. podium e. extensor
c
During embryonic development, the generation of new tissues is often triggered by ________.
a. the disappearance of cadherins from the cell surface
b. the appearance of cadherins on the cell surface
c. the breakage of cadherins at the cell surface
d. the disintegration of cadherins inside the cell
e. a and b
e
What type of cell adhesion molecule is associated with cells being held together by adherens junctions at the site of the junction? a. adherins b. selectins c. IgSFs d. integrins e. cadherins
e
Each connexon is constructed of ___ protein subunits.
a. 2
b. 4
c. 6
d. 8
e. 10
c
What kind of molecule does not pass through a gap junction?
a. ions
b. cAMP
c. inositol phosphate
d. peptide hormones
e. cGMP
d
What lines the plasmodesmata?
a. integral membrane proteins
b. peripheral proteins
c. carbohydrates
d. the plasma membrane
e. DNA
d
What is the arrangement of collagen fibers in tendons that allows them to resist large pulling
forces during muscle contraction?
a. perpendicular to the long axis of the tendon
b. parallel to the long axis of the tendon
c. parallel to the direction of the pulling force
d. perpendicular to the direction of pulling force
e. b and c
e
Which of the following is a characteristic of glycosaminoglycans (GAGs)?
a. repeating trisaccharides
b. repeating disaccharides
c. very acidic
d. very basic
e. b and c
e
Why are proteoglycans able to occupy so much space?
a. They are highly sulfated and thus negatively charged.
b. They attract and bind large numbers of cations.
c. They attract and bind large numbers of anions.
d. They attract lots of water.
e. a, b and d
e
What forms the barrier of the tight junctions that seals off the space between adjacent cells?
a. paired rows of aligned integral membrane proteins
b. paired rows of aligned phospholipids
c. paired rows of carbohydrates
d. paired rows of polynucleotides
e. a and d
a
What kind of cell adhesion molecule mediates transient interactions between circulating
leukocytes and vessel walls at inflammation and clotting sites?
a. IgSFs
b. integrins
c. selectins
d. cadherins
e. calmodulins
c
Which of the following exposures can transform cells into cancer cells?
a. radiation
b. carcinogenic chemicals
c. certain viruses
d. a and b
e. a, b and c
e
Estrogen ___________.
a. may promote breast cancer development
b. is a steroid hormone
c. is not mutagenic
d. may raise the risk of tumorigenesis by causing target cell growth and division
e. all of the above
e
What is the most important property of a cancer cell, whether it is in the body or the culture dish?
a. its chromosome complement
b. its loss of growth control
c. its size
d. its secretions
e. its inability to divide
b
How do cancer cells differ from normal cells in their capacity for cell division?
a. Normal cells have a limited capacity for cell division; cancer cells are seemingly immortal.
b. Normal cells age so that they eventually become unfit to grow and divide; cancer cells
continue to divide indefinitely.
c. Cancer cells tend to have greater affinity for their host tissue than do normal cells.
d. a and b
e. b and c
d
What enzyme possessed by cancer cells but lacking in normal cells is thought to contribute to the seeming immortality of cancer cells? a. telomerase b. RNA polymerase c. DNA-directed DNA polymerase d. reverse transcriptase e. RNA-directed DNA polymerase
a
The long life of stem cells and indefinite number of cell divisions that they undergo allows them
to ________.
a. accumulate more mutations than less mitotically active somatic cells
b. have a better chance at developing a malignant transformation
c. be protected against malignant transformation
d. be protected from viral infection
e. a and b
e
The \_\_\_\_\_\_\_\_\_ pathway of apoptosis is one in which external stimuli activate apoptosis via a signaling pathway. a. extrinsic b. external c. intrinsic d. peripheral e. integral
a
What is the name of an extracellular messenger protein that is named for its ability to kill
tumor cells and also serves as an apoptotic stimulus.
a. tumor angiogenesis factor
b. tumor death factor
c. tumor necrosis factor
d. necromancer factor
e. tumorigenic factor
c
After activation by stressful stimuli, certain pro-apoptotic proteins like Bax translocate from
the _____ to the _____.
a. cytosol, outer mitochondrial membrane
b. cytosol, inner mitochondrial membrane
c. outer mitochondrial membrane, cytosol
d. inner mitochondrial membrane, cytosol
e. cytosol, inner chloroplast membrane
a
What molecule, when incorporated into the outer surface of apoptotic bodies, serves to identify them as such? a. phosphatidylserine b. phosphatidylinositol c. phosphatidic acid d. phospholipase C e. proteoglycan
a
Why is it important that apoptotic cell death occurs without spilling cellular content into the
extracellular environment?
a. The release of cellular debris would trigger inflammation, which could cause
significant tissue damage.
b. Release of cellular debris would cause enhanced cell growth.
c. Cellular debris would invariably be toxic.
d. Cellular debris would raise the pH of the extracellular fluids immediately.
e. Cellular debris would lower the pH of the extracellular fluids immediately.
a
What are the processes, sequentially, that decode DNA into an RNA sequence and then decode the RNA into a polypeptide?
a. translation followed by transcription
b. transcription followed by translation
c. transduction followed by protein synthesis
d. transcription followed by transduction
e. transliteration followed by transformation
b
What advantage do the cristae confer on the mitochondria?
a. They allow the mitochondria to shrink.
b. They greatly increase the surface area for aerobic respiration machinery.
c. They confer resiliency on the cells.
d. They allow swelling of mitochondria.
e. They activate the matrix.
b
What is the immediate (proximal) source of energy that powers molecular motors?
a. hydrolysis of GTP
b. hydrolysis of ATP
c. proton gradient
d. H+ gradient
e. condensation of ATP
b
Why do tumor cells die after exposure to drugs that either disrupt or stabilize the structure of microtubules?
a. Mitosis is stopped in the presence of the drugs.
b. Tumor cells attempt cell division, even in the absence of a functional spindle, killing the cells.
c. There is a checkpoint that prevents the entry into mitosis.
d. The drugs cause the disintegration of the tumor cell membranes.
e. none of the above
b
Name two structures within a cell that can destroy proteins and give one reason why some proteins need to be destroyed. [2 marks]
proteosome and lysosome
because they become worn out, mutated, oxidized, misfolded
Name two microtubule-based cell motility structures and provide one difference that distinguishes them from each other. [2 marks]
cilia and flagella
usually there are multiple short cilia, but only one or two long flagella
Name one signaling chemical, identify its type of receptor, and name one downstream effect that would follow from this signal-receptor interaction. [3 marks]
ON EXAM*
- **ON EXAM:
- signaling chemical: insulin
- receptor: RTK
- downstream effect: decrease blood glucose levels by producing glycogen and fat, as well as inhibiting gluconeogenesis
A patient’s liver cells are having difficulty responding to an extracellular signal that induces glucose uptake. Suggest one possible cause for this problem, and indicate how you could use gene therapy to correct the problem. [2 marks]
- cause: Type 2 diabetes where the receptors are no longer sensitive to insulin
- gene therapy: PTP gene knockout to make receptors insulin sensitive again by removing a phosphate from the insulin receptor
What do all cancer-causing agents have in common?
a. They can all alter the genome.
b. They are all soluble in water.
c. They can all alter lipid membranes.
d. They all resemble nucleotides.
e. They all can alter proteins present in the cell cytoplasm that are responsible for the onset of
cancer.
a
Which of the following statements does not reflect differences between cancer cells and
normal cells?
a. failure of cancer cells to carry out apoptosis, while normal cells can
b. aneuploidy in cancer cells, while normal cells have a normal chromosome complement
c. apparent immortality of cancer cells, while normal cells undergo a finite number of divisions
d. the absence of telomerase in cancer cells and its presence in normal cells
e. slowing of normal cell growth rates in response to environmental stimuli, while cancer cells
divide in an uncontrolled fashion
d
Which of the following statements does not help explain why cancer is relatively rare?
a. Cancer development requires more than one genetic alteration. b. Cancer development is a multi-step process characterized by a progression of permanent alterations in a single cell line. c. Cancer development is a multi-step process characterized by a progression of permanent alterations in multiple cell lines. d. Multiple changes are required to make the cell non-responsive to the body's regulatory machinery. e. Numerous mutation-detection and corrective mechanisms exist in cells.
c
The glycocalyx consists of:
a. integral membrane proteins
b. extracellular fibrous proteins such as the basement membrane
c. oligopolysaccharides on the exterior face of the membrane, attached to integral membrane proteins
d. cytosolic glycoprotein scaffold
e. the protein layer surrounding the nucleus.
d
Collagen fibrils show _________ cross-linking with age, which results in ___________ elasticity of the skin in the elderly.
a. increased; increased
b. increased; decreased
c. decreased; increased
d. decreased; decreased
e. decreased; no change in the
b
If antibodies specific to fibronectin are exposed to an embryo through which neural crest cells
are migrating, what happens?
a. Neural crest cell movements are inhibited.
b. Neural crest cell movements are excited.
c. Neural crest cells die.
d. Neural crest cells divide.
e. Neural crest cells are unaffected and migrate normally
a
From what structure do cilia and flagella emerge?
basal bodies
What is responsible for degrading misfolded proteins in the cytoplasm?
proteasomes
The core of a cilium is called the _______________
axoneme
Which of the following is normally associated with the cilia of organisms from protists to mammals?
a 9+2 pattern
The outer and inner chloroplast membranes contain distinct translocation complexes named __________, respectively that work together during protein import.
Toc and Tic complexes
Treatment of lysosomal storage disorders with substrate reduction therapy involves ____________.
administration of small molecular weight drugs to inhibit the synthesis of the substances that accumulate in the disease
The following ARE functions of cilium
- moving the cell from place to place
- a role in sensory function in monitoring the properties of extracellular fluids
- moving fluid and particulate materials past the cell
The following IS NOT a function of the cilium
moving vesicles down the nerve cell axon
All collagen family members consist of __________ chains arranged in a ____________. (hint: col-la-gen)
- 3
- triple helix
The loss of cadherin function may be instrumental in what disease state?
the spread of malignant tumors
Evidence strongly suggests that the bent conformation of an integrin is ____________ and unable to bind its ligand.
inactive
Which procedure below would lead to the visualization of the dynamic movements of specific proteins as they move through a single living cell? The proteins can be seen through the microscope eyepiece and the cells do not have to be killed for the protein to be detected.
fusion of the green fluorescent protein gene to the gene encoding the protein to be tracked through the cell
In cell biology and with respect to microtubules and microfilaments, the word “dynamic” means
ever-changing
