Cell Biology Practice MCQs Flashcards
Which of the following is not true of integrin?
- Intracellular signals can activate integrins causing them to reach out and grab hold of extracellular structures.
- Integrin molecules serve as stable, permanent anchors that anchor a cell to the extracellular matrix.
- When integrin binds to the extracellular matrix, it stretches into an extended, activated state to attach to molecules on the inside of the cell.
- Integrins undergo extensive conformational changes on binding to molecules on either side of the plasma membrane.
2) Integrin molecules serve as stable, permanent anchors that anchor a cell to the extracellular matrix.
Which of the following determines the direction that cellulose microfibrils are laid down in the extracellular space of a plant cell?
- Amount of turgor pressure within a cell
- Orientation of microtubules on the cytoplasmic side of the plasma membrane
- Orientation of microtubules in the cell wall
- Availability of sugar monomers for cellulose microfibril elongation
- Orientation of cellulite on the cytoplasmic side of the plasma membrane
2) Orientation of microtubules on the cytoplasmic side of the plasma membrane
Microtubules don’t exist in the cell wall, only cytoplasmically.
Not 1 because it would be equal throughout the cell.
Not 4 because sugars would probably only effect the rate, not direction.
Which of the following techniques could be used to determine relative specific transcript levels between RNA samples?
1. Southern blotting
2. Western blotting
3. Eastern blotting
4. Northern blotting
4) Northern blotting
Analyses RNA in similar way to southern.
Which of the following would be expected to be essentially the same?
- cDNA libraries made from mouse liver and kidney cells.
- cDNA and genomic libraries made from mouse liver cells.
- genomic libraries made from mouse liver and kidney cells.
- cDNA and genomic libraries made from mouse kidney cells.
3) Genomic libraries made from mouse liver and kidney cells.
The genome will be the same
Not 1 cDNA is made from mRNA using reverse transcription – so different for different cell types.
Which of the following define the barrier between apical and basolateral surfaces of mammalian epithelial cells?
- Tight Junctions
- Gap Junctions
- Desmosomes
- Hemidesmosomes
- Adherens junctions
1) Tight Junctions
Which of the following is inconsistent with the function of gap junctions?
- They allow ATP-driven pumps to move substances between attached cells.
- They allow an electrical and a metabolic coupling between attached cells.
- They allow the cytoplasm of two adjacent cells to be continuous with each other.
- They allow inorganic ions to move directly between attached cells.
- They can open or close as needed.
1) They allow ATP-driven pumps to move substances between attached cells.
They are just holes, no pumps here.
Abnormally stretchy skin is part of a genetic syndrome that could result from which of the following?
- Increased production of collagen
- Loss of proteinase that cleaves procollagen.
- Hypersecretion of procollagen
- Synthesis of excess cellulose
- Overactivity of proteinase that cleaves procollagen.
2) Loss of proteinase that cleaves procollagen.
Would reduce the amount of collagen.
RTKs can activate the enzyme phosphoinositide 3-kinase, which phosphorylates inositol phospholipids. These phospholipids then do what?
- Activate Ras.
- Serve as phosphate donors in phosphorylation reactions.
- Serve as docking sites that recruit specific intracellular signalling proteins to the plasma membrane.
- Activate Ca2+ channels in the plasma membrane, promoting an influx of Ca2+ into the cytosol.
- Activate G proteins.
3) Serve as docking sites that recruit specific intracellular signalling proteins to the plasma membrane.
Targeted chemotherapies can alter intracellular signaling pathway at steps downstream of the EGFR. Which potential treatments could be effective for treating tumors like glioblastoma caused by overactivation of EGFR?
- Addition of a drug that inhibits serine and threonine kinase activity.
- Addition of a drug that blocks the phosphorylation sites on AKT.
- Addition of a drug that inhibits Ras GEF function.
- Addition of a drug that inhibits Ras GAP function.
- Addition of a drug that inhibits serine and threonine kinase activity.
- Addition of a drug that blocks the phosphorylation sites on AKT.
- Addition of a drug that inhibits Ras GEF function.
Inhibiting Ras GAP function could lead to the proliferation of cells.
The anaphase-promoting complex or cyclosome (APC/C) triggers the onset of anaphase by doing which of the following?
- Triggering the destruction of the condensins that hold the duplicated chromosomes in a condensed state.
- Phosphorylating the motor proteins that pull the spindle poles apart
- Triggering the destruction of the cohesins that hold the sister chromatids together.
- Cleaving spindle microtubules
3) Triggering the destruction of the cohesins that hold the sister chromatids together.
Anaphase is where the sister chromatids move.
Different cyclin-dependent protein kinases (Cdks) trigger different stages of the cell cycle in part because of which reason(s)?
- Their concentrations increase at different stages of the cycle.
- They are degraded at different stages of the cycle.
- Their activities increase at different stages of the cycle.
- All of the above are correct about the cyclin-dependent kinases.
3) Their activities increase at different stages of the cycle.
Because of the cyclin.
In-situ hybridisation…
- Uses antibodies to analyse protein expression patterns
- Uses nucleic acid probes to analyse RNA expression patterns
- Uses PCR to amplify genomic DNA in-situ
- Uses hybridisation to isolate specific regions of DNA together with associated proteins.
2) Uses nucleic acid probes to analyse RNA expression patterns
Which structural feature is common to all GPCRs?
A) 5 hydrophobic transmembrane domains
B) 7 hydrophilic transmembrane domains
C) 7 hydrophobic transmembrane domains
D) 10 hydrophilic transmembrne domains
C) 7 hydrophobic transmembrane domains
Which physiological processes are GPCRs involved in?
A) Sight
B) Taste
C) Smell
D) All of the above
D) All of the above
