Cell & Molecular Biology Final Exam Review

Given the following membrane (reverse-nonpolar heads on inside), what type of solvent would you expect to drive the formation of this structure.

Nonpolar solvents such as CH2-CH2-CH3

Carrier Proteins…

Change conformation during transport of small molecules or ions.

The complete oxidation of glucose…

produces carbon dioxide

Which of the following ending statements is not correct? One difference between electron microscopy and light microscopy is that…

no staining of the sample is required

Which of the molecules shown below is most polar?

b.

Most of the membrane enclosed eukaryotic organelles are in the _______ range.

1,000-10,000 nm

Gel electrophoresis is used to…

separate proteins or DNA fragments

snRNAs are synthesized in the…

nucleus and move to the cytoplasm to pick up proteins to become functional, then return to the nucleus

Prokaryotes contain which of the following?

Ribosomes, a single circular chromosome, and DNA

Considering the dry mass of a cell, which of the following is found in the greatest amount?

Organic molecules

Which of the following is true of GTP binding proteins?

Activity of these proteins is mediated by the exchange of GTP for GDP

The building blocks of RNA are…

nucleotides

The primary function of the ribosome is…

protein synthesis

Studies of cell function in the context of the whole animal that is applicable to human genetics would best be carried out in…

Transgenic mice

Intrinsically disordered proteins always have ___ while structured proteins always have _____.

a=primary structure

b=secondary structure

c=tertiary structure

d=quaternary structure

1. a

2. ab or abc

Many pathways in metabolism converge to conserve on the number of reactions and intermediates required to carry out metabolism. The degradation of fats and carbohydrates converge at which of the following intermediates?

acetyl-CoA

What initiates the depolymerization of the nuclear lamina so that the nuclear membrane can break down during mitosis?

The globular heads of the lamins are phosphorylated by a kinase

The two strands of DNA in a double stranded helix lie…

antiparallel

The breakdown of ATP to ADP + Pi is an exergonic reaction, yet ATP is a good energy storage form. ATP does not rapidly break down because…

activation energy keeps it from occurring rapidly

Which of the following is the strongest bond or interactions in an aqueous environment?

Hydrogen bonds

Which of the following structures or organelles are not enclosed by a membrane?

Nucleolus, ribosomes, and cytoskeleton

Chromatin that contains sequences that are not transcribed in the cell being examined but are transcribed in other cells types is called…

Facultative heterochromatin

E. coli is not a good cell model for…

RNA processing

Evidence that Earths early atmosphere contained little oxygen includes…

less oxidized state of iron in the geologic record

Some of the following are examples of how the nucleus is organized, structurally and functionally. Select the items that do not fit this description.

Cytoskeleton and N terminus and C terminus

DNA replication…

is accomplished by way of complementary base pairing, is accomplished by enzymes called DNA polymerases, is template-directed.

The following reaction of glycolysis illustrates the principle of energy coupling in the cell. The ______ conversation of 1,3-Bisphospoglycerate to 3-Phosphoglycerate ________ to ________ conversion of ADP to ATP.

Exergonic, drives, endergonic

Which of the following is true about enzymes? Enzymes…

can couple endergonic and exergonic reactions

The directionality of nuclear transport is determined by the concentration of ran(GTP) and ran(GDP) found in the nucleus versus the cytosol. In turn, the concentration of these molecules is determined by _____ being located in the nucleus, and ______ being located in the cytosol.

Ran GEP; Ran GAP

The type of probe used for hybridization to a southern blot is a(n)…

nucleic acid

A nucleotide is an example of a…

building block

Newly replicated DNA is located in a few hundred spots in the nucleus because there are..

a few thousand origins of replication active at any one time, but they are located in a few hundred discrete clusters

RNA WORLD (EXTRA CREDIT)

???

Which of the following proteins binds to N-terminal signal sequences on the lumenal side of the ER membrane?

Signal peptidase

Which of the following organelles are composed of proteins that were synthesized on free ribosomes?

ribosomes, mitochondria, peroxisomes, nucleus, and chloroplasts

Which of the following are involved in noncyclic flow of electrons in photosynthesis?

Photosystems I and II, cyt bf complex, and NADP reductase

Which actin binding protein is involved in the formation of closely spaced actin bundles?

fimbrin

A new drug has been developed that increases the rate at which microtubule monomers dissociate from filaments. Which of the following do you expect to be affected by this drug?

mitotic spindle formation

Which of the following are locations of protein synthesis?

Chloroplasts, endoplasmic reticulum, and in the cytosol

Membrane lipids are synthesized on _____ using _______.

the cytosolic side of the ER; water-soluble precursors

Extracellular matrix (ECM) is composed of polyscaccarides and proteins that must also adhere to cells. The components of the matric are linked together by _________. An example of such a protein is ________.

adhesion proteins; fibronectin

Which two proteins provide a link between the actin-spectrin network of the cell cortex and the transmembrane proteins embedded in the plasma membrane?

ankyrin and protein 4.1

One type of cell surface molecule that can be involved can be stable interactions between cells is ______.

cadherins

Which of the following proteins can hydrolize a nucleotide?

tubulin and actin

Proteins that are coded by nuclear genes and are destined for the mitochondria, peroxisomes, and chloroplasts are synthesized _______.

on ribosomes free in the cytosol

During cotranslational targeting to the ER, the protein is transported into the lumen of the ER…

through the translocation complex

Desmosomes interact with which part of the cytoskeleton?

Intermediate filaments

A proton gradient is established in mitochondria by pumping protons into the…

intermembrane space

Actin filaments are the cytoskeleton components that bind to…

tight junctions

When ATP binds to myosin, it causes myosin to…

dissociate from the actin filament

In cellular respiration, the advantage of transferring electrons through an electron transport chain rather than directly from NADH to oxygen is that…

the amount of usable energy released is more so more ATP can be synthesized

Which of the following organelles does not follow the universal genetic code?

Mitochondria

The glyoxylate cycle occurs in the…

peroxisomes

If the pH difference across the thylakoid membrane during photosynthesis was 3 units, the concentration of protons would be _____ times as much on one side as compared to the other.

1000

Which of the following is not a transmembrane protein?

cofilin

Membrane proteins located on the inner face of the plasma membrane are synthesized on..

free ribosomes

In cellular respiration, electrons are ultimately donated to…

None of the options apply (donated to oxygen)

The phospholipid bilayer of the plasma membrane is asymmetrical with respect to phospholipid composition in the two layers. One result of this asymmetry is…

a net charge exists on the inner face of the membrane

Cilia are projections of the plasma membrane supported by…

microtubules

Which of the following is not a step in the secretory pathway?

lysosomes and peroxisomes

Signals that target proteins for synthesis on the ER membrane and specify transmembrane domains can be classified based on where they are located in the protein or how they function. The signals can function to target synthesis to the ER or stop translocation. Using this classification, which hydrophobic signals are required to specify the following muli-pass transmembrane protein that is synthesized with an N terminal signal sequence?

3 target sequences, 3 stop sequences

Which is the following is a molecular motor protein?

kinesin

Which of the following is an example of an intermediate filament protein?

keratin

Glycosylation of proteins occurs…

both in the endoplasmic reticulum and Golgi depending on the type of glycosylation

Which of the following occur with N-linked glycosylation?

a performed carbohydrate is attached to the protein

The sequences that are removed from a pre-rRNA and therefore are not part of the mature rRNA are called…

non-transcribed spacer sequences

Histones are ______ proteins.

positively charged proteins because they contain basic amino acids

DNA associated with the nucleosome core particle…

is wrapped around the outside of core histones

Telomeres…

contain DNA repeats

Transcriptionally active chromotin differes in structure from inactive chromatin. Typical characteristics are active chromotin include…

modification of the histones by acetylation

Chromatin that is highly condensed even during interphase and is typically not transcribed in any cell of the organism is called…

constructive heterochromatin

Which of the following do you expect to contain actively transcribed genes?

Euchromatin

Annotating a genome refers to…

describing the functional significance, such as locating the genes

During DNA synthesis, the newly synthesized strand grows…

in the 5' to 3' direction.

DNA polymerase required all of the following:`

A template, a primer to extend, deoxynucleotides, the help of an enzyme to separate the double stranded DNA

DNA synthesis carried out by DNA polymerases require all of the follwoing:

Deoxyribonucleoside triphosphates, DNA template, RNA primer

The clamp loading protein…

None of the options apply///

Telomerase…

extends the ends of linear DNA

The enzyme that plays a critical role in removing and filing end spaces left by RNA primers during replication in E. Coli is…

I

Which of the following diagrams is not a correct replication forks?

C

Which of the following enzymes can be used to synthesis RNA using DNA as the template?

RNA polymerase

Photolyases…

break the covalent bond between two thymines

In the first step of base excision repair, DNA glycosylase…

removes a nitrogen base

An example of a cis acting element is a…

Promotor

A simple method of transcription termination in E. coli involves

A symmetrical inverted repeat, a stable stem and loop structure, a string of As in the template, release of the RNA transcript from the template

The cap found at the 5 end of the mature mRNA contains…

a nucleotide with 3 phosphates between itself and the next nucleotide

Processing of pre-tRNAs can include all of the following

cleavage of the 5 end, cleavage of the 3 end , addition of CCA at the 3 end, modification of selected bases

Transferrin receptor RNA is regulated by the level of iron inside the cell. When iron is plentiful in the cell,….

the mRNA is degraded

The final product of gene expression is…

either protein or RNA

To get the functional product of a gene, which of the following are steps that can be involved in expressing the phenotype?

transcription initiation, protein modification, protein degradation, mRNA capping, protein folding

Translation is…

protein synthesis

Initiation of translation in eukaryotes begins by recognition of the ______.

cap by initiator factors complexed with the small ribosomal subunit followed by scanning for the start codon

The ______ activity of the ribosome catalyzes peptide bond formation during protein synthesis.

peptidyl transferase

The P site of the ribosome is the site where…

a tRNA holding the peptide is bound

Monocistronic messages contain…

one translation start site

Based in the illustration below the codon for glutamine is…

CAG

If an exon, intron junction is upstream of the translation start codon, this means that the intron is in the…

5' untranslated region (UTR)