Iowa State 2120 Bio Exam 1

How does one determine the number of covalent bonds an element will likely form?

The number of valence electrons

The figure shows a solute molecule surrounded by a hydration shell of water. Based on your knowledge of the polarity of water molecules, the solute molecule is most likely:

positively charged

An atom has four electrons in its valence shell. What types of covalent bonds is it capable of forming? (choose all that apply)

single bonds, double bonds, triple bonds

In a normal cellular protein, where would you expect to find a hydrophobic amino acid like valine?

either in the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains

The chemical reaction depicted above

results in a peptide bond.

The figure above represents a cell.

If the inside of the cell is hypertonic relative to the outside of the cell, the cell..

expand due to a gain of water on the inside of the cell.

Which of the following is not a feature of the fluid mosaic model?

Proteins that span the lipid bilayer are enriched for hydrophilic amino acids in the transmembrane regions.

If line B represents the curve for membrane permeability of a membrane enriched for phospholipids with unsaturated fatty acids, which curve would be the one for phospholipids with saturated fatty acids?

C

A cell with a predominance of free ribosomes is most likely

primarily producing proteins in the cytosol

Suppose a young boy is always tired and fatigued, suffering from a metabolic disease. Which of the following organelles is most likely involved in this disease?

mitochondria

Which of the following can be found in prokaryotic cells?

Ribosomes

Which of the following macromolecules leaves the nucleus of a eukaryotic cell through pores in the nuclear membrane?

mRNA

How are proteins transported to their correct location in the cell?

Proteins contain molecular "zip codes" that allow them to be shipped to the correct cellular compartment.

Which of the following chemical bonds have the lowest potential energy?

C-O bonds

In eukaryotic cells, which of the following organelles is important for the synthesis of proteins that are targeted for the cell membrane or other organelles?

Rough Endoplasmic Reticulum

Which of the following is one characteristic feature of a carrier/transporter protein present in the plasma membrane of a cell?

It facilitates diffusion of a specific type of molecule or ion.

The four most abundant elements in living things are...

carbon, hydrogen, nitrogen, oxygen

A covalent chemical bond is one in which

outer-shell electrons of two atoms are shared so as to fill the outer electron shells of both atoms.

The ionic bond of sodium chloride is formed when

the negative charge on a chloride ion is attracted to and balanced by a positive charge on a sodium ion

Monomers that can be polymerized to form proteins are

amino acids

A peptide bond results when the following functional groups are covalently linked by a dehydration reaction:

Amino and carboxyl groups

Alpha helices (α-helices) in proteins are stabilized by:

Intrastrand hydrogen bonds

If a reaction is endergonic, then which of these statements is true?

Energy must be added for the reaction to proceed.

What is a transition state?

the intermediate complex formed as covalent bonds in reactants are being broken and re-formed during a reaction

(Q006) Which of the following statements is TRUE?

Nonpolar amino acids tend to be found in the interior of proteins.

Cytoskeletal elements can be distinguished from each other based on their structure, protein composition and size (diameter). Which of the following options orders cytoskeletal elements by diameter from the largest to the smallest?

Microtubules, keratin filaments, actin filaments