Biol 1703 exam 1

A major research study is published in a peer-reviewed journal that demonstrates an increased incidence of cancer in people who live in cities close to overhead electrical wires, compared to people who live farther away from these power lines. The results are statistically significant and are widely disseminated in articles by respected media outlets. The news spreads fear around the world that very low-level electromagnetic fields, to which we are all commonly exposed, are dangerous to human health. Which of the following statements would be a valid conclusion based on the science

the findings of increased cancer rates will not be sufficient to prompt cities to move electric power lines until independent scientists can conduct studeies that eliminate other possible reasons for the increased cancer incidence found in one study.

To differentiate between misinformation and legitimate science you should ask three questions: Is the provider of information credible? Does the provider of the information have the expertise to vouch for the claim? And

Is there a consensus among relevant scientific experts?

After 12 years of painstaking work, researchers managed to grow an Asgard archaeon species in a laboratory bioreactor. Which of the following characteristics of this organism is most relevant to our understanding of the evolution of eukaryotes?

a. cellular protrusions extending from the cell body, intertwined with two other prokaryotic species

Which of the following elements is NOT a component of the cytoskeleton?

nucleosomes

Antibiotics tend to target features that are unique to bacterial cells and absent from eukaryotic cells, such as out ow. Which of the following would present a safe target for a new antibiotic?

Peptidoglycan

Which of the following is considered key evidence in support of the endosymbiosis theory of organgenesis?

D. all of the above ( mitrochondrial have both inner and outer membranes, Ribosomal RNA of mitochondria is similair to bacterial RNA, Ribosomal RNA of chloroplasts is similair to bacterial RNA)

A scientist wants to examine a structure inside of a eukaryotic cell that is hypothesized to influence the organization of DNA, but is unable to fluorescently labeled. Which microscope will be most useful?

Transmission electron microsope

Which organelle is the mystery organelle in the diagram below? WHat kind of cell is it?

Nucleus; eukaryote

Which bactera are photosynthetic?

Cyanobacteria/ blue-green algae

As you look at a series of cells under a light microscope, you notics that they are connected with cell walls and contain chloroplasts and large vacuoles. Becasue you have studied diligently in you celllulat and molecular biology class you are able to determine you are looking at

Plant cells

An ionic bond between two atoms is formed as a result of the

Transfer from one atom to the other

The complex macromolecules of the cell are built from simpler molecular monomer subunits that are linked together through what type of chemical reaction?

condensation

Which of the following monomer building blocks is necessary to assemble phospholipids around and inside cells

fatty acids

What type of bond is indicated by the arrow in the diagram below?

Phosphodiester

Which bond .interaction is weakest on its own but strong through an additive of many interactions?

Van der Waals

Which is necessary for hydrolysis to occur?

H2O

WHich monomer is used to construct protein?

Amino acids

A nucleoside is different from a nucleotide in that a nucleoside has

no phosphate group

Glucose and ribose are both

sugars

NADH is used for while NADPH is used for _

Catabolic processes; anabolic processes

When there is an excess of nutrients available in the human body, insulin is released to stimulate the synthesis of glycogen from glucose. This is a specific example of a/an ___ process, a general process in which larger molecules are made from smaller molecules

Anabolic

The 2nd Law of thermodynamics dictates that disorder in a system is always

increasing

ΔG° indicates the change in the standard free energy as a reactants is converted to product. Given what you know about these values, which reaction below is teh most favorable?

Glucose » CO2 +H2O ΔG°=-686 kcal/mol

Enzymes facilitate chemical reactions by:

lowering the activation energy of the reaction

What is the role of ATP in the cell

All of the above ( activated carrier molecule, Store energy in phosphoanydride bonds, Drives unfavorable reactions by creating phosphorylated high energy intermediates)

Oxidation is ____ while reduction is ____.

Loss of electrons; gain of electrons

---

______store and transfer energy in a form that cells can use

Activated carriers

_____ and _____ are complementary processes that result in organisms obtaining useful chemical-bond energy they need to survive

Photosynthesis; cellular respirations

Catabolic pathways result in lost _____, consistent with the 2nd law of thermodynamics

Heat

Two or Three helices can sometimes wrap around each other to form_____. The stable wrapping of one helix around another is typically driven by___.

coiled-coils; hydrophilic interactions

____ generally carry extracellular signals from cell to cell.

Signal Proteins

Which of the following statements about allosteric regulators is FALSE?

Allosteric regulators block the active sites of enzymes.

Molecular chaperones can work by creating an isolation chamber What is the purpose of this chamber?

This chamber serves to protect unfolded proteins from interacting with other protein in the cytosol, until protein folding is completed.

Motor proteins use the energy in ATP to transport organelles, rearrange elements of the cytoskeleton during cell migration, and move chromosomes during cell division. Which of the following mechanisms is sufficient to ensure the unidirectional movement of a motor protein along its substrate?

A conformational change is coupled to ATP hydrolysis

Prions propogate by:

Inducing conversion in normal proteins to an abnormal form through binding

The binding site where the reaction occurs on an enzyme is called the:

Active site

Which lab techniques is used to visualize the structure of a protein using diffraction patterns?

X-ray crystallography

What should be the label for the item indicated by the question mark?

Ligand

What additional stabilizing bond is used by proteins, particularly in extracellular environment?

Disulfide bonds

Fredrick Griffith’s experiment provided important insights into bichemical basis of heredity when he observed that a harmless strain of Streptococcus pneumoniae could be transformed into a virulent strain when it was combined with:

Heat killed virulent Streptococcus pneumoniae

How did Nettie Maria Stevens contribute to the field of genetics?

Discovered saex chromosomes in mealworms, which would later be termed X and Y

Hershey and Chase used radiolabeled macromolecules in phage viruses to identify the material that contained heritable information that was transferred to their bacterial hosts. What radioactive atom was used to track proteins during this experiment?

35 S

Which scientist too the infamouse photograph 51 of DNA

Rosalind Franklin

The ___ uses ___ to condense and decondense chromatin as it positions

Chromatin remodling complex; ATP

Which of the following may be modified to mark regions of the genome for transcriptional activation or silencing

Tail of H3 histone

Which animal displays the phenotype (physical characteristic) consistent with mosaic X- inactivation?

Tortoisehell cats

Because hydrogen bonds hold the two strands of a DNA molecule together, the strands can be seperated without breaking any covalent bonds. Every unique DNA molecule “melts” at a different temperature. In theis context Tm ( melting temperature) is the point at which two strands speterate, or become denatured. Assuming the sequencing represent double stranded DNA molecules, which molecule will melt at the lowest temperature?

TATTGTCT

Certain genes that were active in early development become subsequently repressed when development is complete. Where would these genes be found in an interphase chromosome?

Heterochromatin

Eukaryotic cells use ___ to recognize specific chromatin modifications and spread them to the nucleosomes nearby as part of an effective means of epigenetic inheritance.

Reader-writer complexes

Specific regions of eukaryotic chromosomes contain sequence elements that are absoluteltly required for the following proper transmission of genetic information from a mather cells to each daughter cell. Which of the following is NOT known to be ome of these required elements in eukaryotes?

protein coding regions