Cell Biology Unit 1

FRAP

Photobleaches a sample then captures an image after equilibrium is restored.

Phase contrast microscopy

Displays regions of the sample where light has been refracted more than in other parts of the sample

Immunoflourescence microscopy

Attaches a fluorochrome to an antibody that can interact with proteins in the sample

cryoelectron microscopy

freezes a sample in liquid nitrogen before blasting it with electrons to create an image

scanning electron microscope

coats the surface of a sample with a heavy metal and detects the electrons that bounce off of the surface

deconvolution of fluorescent microscopy

you want to confirm if your cells are producing the protein BAP when exposed to an environmental toxin. You genetically modify your cells to produce BAP with GFP attached. Which method would be most useful for confirming that your cells are expressing BAP when exposed to the environmental toxin.

which of the following are advantages of most light microscopy techniques over electron microscopy techniques

Most light microscopy techniques can be performed in living cells, light microscopy generally have multiple functionalities ( i.e. can use different visualizing techniques) whereas electron microscopy are generally set up for only one function

which of the following best describes a cell line

a lineage of cells descended from a stem cell or oncogenic cell

which of the following limitations of cultured cell systems?

Animal cell cultures are less complex than the actual cells and tissues from which they are derived. Cell cultures made from primary cells cannot reproduce indefinetly. Most animal cell cultures require a surface to attach to.

cluster analysis

interpretation of several microarrays over time or across a concentration

RNA -seq

reverse transcription of mRNA are amplified with cDNAs before quantitative analysis

organoid

3d structures of multiple cell types that interact

dna microarray

glass plate with several nucleotide sequences attached fluoresces where nucleotide fragments attach

centrifugation

separates cell or cellular components by density/weight

Which of the following lipids contribute to membrane fluidity. Select all that apply

phospholipids, cholesterol, sphingolipid

Which organelle is primarily responsible for synthesis of plasma membrane lipids?

ER

The cytosolic (interior) and exoplasmic (exterior) leaflet of a biological membrane is composed the same. In other words the two leaflets are compositionally identical.

false

lipids can move around the surface of a membrane and even flip between faces

true

phosphoglycerides are …

amphipathic

which of the following is not likely to be found as part of a biological membrane

nucleic acids

which type of amino acids are likely to be found embedded in the interior of a biological membrane

nonpolar

passive anda ctive transport of ions generates the resting membrane potential

true

above is a disgram represting the movement of several substances across the epithelium of a kidney tubule. Which of the following terms best describes the membrane proteins colored in blue that are responsible for transporting Cl-, HCO3, Na +, and H+

transporter

Which of the following does not affect the rate at which substances with be transported via facilitated diffusion

the solubility of the substance

ATP powered pumps are the only transport proteins that use active transport

false

which of the following molecules will require being transported by a membrane protein across the membrane. Select all that apply

Albumin (hydrophilic protein), Sodium Ion (Na+)

Muscle cells (myocytes) typically have very high concentrations of sodium outide of the cell and negative resting membrane potentials generated from the excess positive charges outside of the cell. When signated to contract, sodium channel proteins open, allowing sodium ions (Na+) to move into the cell until the concentration of sodium ions inside the cell is slightly higher that the concentration of sodium ions outside the cell. Which of the following explains why?

Both the electrical and concentration gradients push sodium ions into the cell

Which of the following statements about osmosis are true

None of these are true

Cancer cells frequently fool immune cells by doing which of the following to evade detection. Select all that apply.

Reducing opsonin binding sites, producing the surface antigens of undamaged cells

Moczek and Rose (2009) studied the distal-less gene (Dll) in horned beetles to learn if it was involved in horn development. They exposed larvae to siRNA then recorded the phenotype of the adults. Which of the following best explains why RNAi of Dll affected leg, antenna, and horn development?

The DII gene regulates more than horn growth

All transport proteins use active transport

false

Figure 1 from Abalymov et al (2018) shows the location of CaCO3 particles at first deposit (A), 3 hours after deposit (B) and 24 hours after deposit (C). The scale bar is 5 um. Which of the following techniques does the image above use?

Ion sensitive fluorescent dye

Above (from Yu et al 2007) shows the amount of telomerase activity (y-axis) in several different cell cultures (x-axis). H1 ESC is an embryonic stem cell line, iPS are induced pluripotent stem cells from two different primary cells (IMR90 and foreskin). Which of the following interpretations of the data shown above are correct? Select ALL that apply.

The telomerase activity of primary cells is usually very, very low.
The iPS cells are behaving like embryonic stem cells.

The sodium-glucose transporter (SGLT) normally transports sodium and glucose into the cells of the kidney tubules. Which of the following statements are a likely consequence if a person develops kidney disease and this transporter's normal function is reduced or stopped? Select ALL that apply.

The cell would starve from low glucose levels.
The sodium-potassium pump activity would be reduced to compensate.

Saponins are a group of amphipathic compounds produced by the fruits of soapnut trees. Although soapnuts have been used frequently as clothing detergent and shampoo alternatives, ingesting them is toxic. Which is the likely explanation for this toxicity?

Saponins disrupt membrane lipid integrity.

How are cells separated in flow cytometry?

Surface antigens

ABC proteins are covalently bound by an inorganic phosphate to activate.

False

Phagocytosis is a regulated (e.g. not constitutive) process.

true

imaged pancreatic cells using an H&E stain (A1, B1, and C1) on the left and the same cells visualized with a different technique on the right (A2, B2, C2). Which of the following techniques was used to visualize the images on the right?

Polychromatic Polarization Microscopy (PPM)

The figure below (from Pillans et al, 2004) shows the maximum activity of the Na-K pump in various tissues of bull sharks acclimated to salt water (SW) or freshwater (FW). The rectal gland is responsible for changing the osmolarity of blood whereas kidneys change the osmolarity of urine. Using the figure below, which of the following statements is/are supported by the data? Select ALL that apply.

Bull sharks are secreting more concentrated urine in SW than in FW.
The Na-K pump is always expressed more highly in the rectal gland than in the gills.

Which organelle would be most visible (stained) using methylene blue?

Mitochondrion - stains acidic molecules with negative charge, stains DNA, mitochondria has most DNA

An advantage of fluorescence microscopy is that it can be performed in living cells.

False

Which method would be most appropriate for identifying the chromosome location of a gene?

FISH - identifies where the sequence is and how much it is being expressed

Mitochondria can generate ATP by allowing protons to cross the membrane via ATP Synthase. Alternatively, protons can cross the membrane through proton leaking, which can generate heat without generating ATP. Mammals, which have evolved the ability to maintain elevated body temperatures, use proton leaking to raise their body temperatures. Which of the following changes likely facilitated the evolution of this trait? Select ALL that apply.

Fewer ATP synthase proteins in the mitochondrial membrane

Pan et al (2013) studied the function of the gene MCU in mice muscle cells. They compared mice with two functional copies of the gene (MCU+/+) to mice with no functional copies (MCU-/-). They added an ion fluorescent dye (Rhod-2) dissolved in isoproterenol that reacts to calcium ions to the muscle slurry. Based on the graph presented? Select ALL that apply.

MCU transports calcium.

V-class pumps are covalently bound by an inorganic phosphate to activate.

false

Which of the following is required for light microscopy but NOT required for electron microscopy preparation?

All of these steps are required for both

Which of the following is a requirement of most animal cell cultures but NOT most bacterial or yeast cultures?  Select ALL that apply.

Serum , Solid surface with cell surface proteins

Which of the following types of molecular interactions drive most of the lipid-protein interactions in membranes?

noncovalent bonds

Which of the following is not likely to be found as part of a biological membrane?

nucleic acids

Which feature of membrane lipids would contribute to the natural curvature of some plasma membranes, such as the inner membrane of mitochondria?

the size of the phosphate head (ex phosphocholine versus phosphatidylethanolamine)

Which type of amino acids are likely to be found embedded in the interior of a biological membrane?

nonpolar

Which of the following categories of membrane lipid are amphipathic?  Select ALL that apply.

sphingolipids, phosphoglycerates, glycolipids, sterols