Cell Bio Exam 2 Clicker Questions

Question 1

In electron microscopy

Answer 1

Heavy metals are used to “stain” biomolecules

Question 2

Specific membrane compartments such as lysosomes and peroxisomes can be isolated from cell lysates by differential centrifugation?

True or False

Answer 2

True

Question 3

Gel filtration chromatography

Answer 3

Can separate proteins based on size/shape

Question 4

True/False: Two ways that antibodies can be used for immunodetection of cellular proteins are:

By decorating them with gold particles to enable their visualization in EM when bound to cell proteins

By labeling them for use in detecting proteins extracted from cells and separated on gels then blotted to membranes (so called immunoblot)

Answer 4

True

Question 5

Proteins can be studied by mass spectrometry – in this method

Answer 5

Proteins are fragmented and sized to identify them

Question 6

Activator or repressor proteins which bind DNA to regulate the transcription of genes do so mainly by

Answer 6

Non-covalent interactions between the protein and specific bases in the major groove of DNA

Question 7

The type of enzyme which phosphorylates the RNA polymerase in the previous slide is a

Answer 7

Kinase

Question 8

In eucaryotes the processing steps of mRNA capping and splicing occur in the cytoplasm.

True or False

Answer 8

False

Question 9

True or False: Prokaryotes use a single RNA polymerase, whereas eukaryotes have three.

True or False

Answer 9

True

Question 10

Non-coding regions are removed from pre-mRNA transcripts by _________.

Answer 10

spliceosomes

Question 11

miRNAs function to

Answer 11

regulate the translation of cognate mRNAs

regulate the degradation of cognate mRNAs

Question 12

snRNPs are important components of

Answer 12

spliceosomes

Question 13

Non-coding regions are removed from pre-mRNA transcripts by complexes containing _________.

Answer 13

snRNAs

Question 14

Amino acyl tRNA synthetases attach amino acids to their correct tRNAs via a covalent bond.

True or False

Answer 14

True

Question 15

The ribosome has three sites - EPA and tRNAs with attached amino acids enter via the E site and leave via the A site once the peptide bond forms to the growing protein

True or False

Answer 15

False

Question 16

A protein isusually tagged for degradation by proteasome activity bywhich ofthe followingproteins?

Answer 16

Ubiquitin

Question 17

The primary role of the proteasome in cells is?

Answer 17

the regulated degradation of proteins

Question 18

The enzyme required for transcription is

Answer 18

RNA polymerase

Question 19

Transcription is the transfer of genetic information from

Answer 19

DNA to mRNA

Question 20

A promoter site on DNA

Answer 20

initiates transcription

Question 21

Which site of the tRNA molecule hydrogen bonds to a mRNA molecule

Answer 21

anticodon

Question 22

What types of amino acids are expected to be found in the membrane spanning protein domains serving to localize an “integral membrane” protein to membrane bilayers.

Answer 22

non polar

Question 23

Covalent bonds in macromolecules are primarily important for

Answer 23

Linking together monomers

Question 24

MicroRNAs regulate the activity of protein-coding genes by doing which of the following?

Answer 24

inhibiting the translation of mRNAs

promoting the degradation of mRNAs

Question 25

Which amino acid is involved in the formation of disulfide bonds?

Answer 25

Cysteine

Question 26

When a transcription regulator (for example an activator or repressor) binds to DNA, its most important interactions occur with which of the following?

Answer 26

nucleotide pairs in the major groove of the double helix

Question 27

When proteins are composed of more than one polypeptide chain such as the structure of hemoglobin containing two alpha subunits and two beta subunits, or the heterotrimeric G protein associated with GPCR signaling, this level of protein structure refers to the

Answer 27

quaternary structure

Question 28

FRAP is _____, while FRET is_____.

Answer 28

a method for determining protein mobility: a method for determining proximity of two proteins

Question 29

Which of the following methods provides information concerning the secondary and tertiary structures of the proteins under study?

Answer 29

X-ray crystallography

NMR

Question 30

Cholesterol is an amphipathic molecule

True or False

Answer 30

True

Question 31

Which of the following movement(s) occurs least frequently for phospholipids in membrane bilayers:

Answer 31

Movement into the other leaflet of the bilayer

Question 32

Proteins that aid the movement of phospholipids from one leaflet of a membrane bilayer to another are known as:

Answer 32

Flippases

Question 33

An increase in cholesterol content will tend to make membranes:

Answer 33

Less permeable and less flexible

Question 34

Membranes are more fluid in nature when hydrocarbon tails are ___ and ___.

Answer 34

unsaturated; short

Question 35

Of the following choices regarding hydrocarbon tails, which would be the least fluid?

Answer 35

no double bonds and 20 carbons long

Question 36

Where are membrane phospholipids first synthesized and inserted into membranes?

Answer 36

The cytosolic surface of the ER

Question 37

The best way to determine if a protein is able to move in a membrane would be?

Answer 37

Fluorescence Recovery After Photobleaching Experiment (FRAP)

Question 38

All transmembrane proteins float and diffuse freely in the bilayer of the plasma membrane in the same manner as phospholipids

True or False

Answer 38

False

Question 39

Membrane spanning proteins are typically extracted from membranes by using:

Answer 39

Addition of detergents such as SDS

Question 40

Which of the following types of membrane associated proteins will be extractable from the membrane by salt and without detergents:

Answer 40

Proteins non-covalently associated with other membrane proteins

Question 41

Eukaryotic cells have membrane compartments whose lipid bilayers are typically asymmetric with regard to the distribution of their contents between the two leaflets of the bilayer

True or False

Answer 41

True