BMB280-Test 1

Which of the following monomer building blocks is necessary to assemble selectively permeable boundaries around and inside the cell? A. sugars B. fatty acids C. amino acids D. nucleotides

B. fatty acids

Replication origin is defined as:

Nucleotide sequences in the chromosome ( or plasmid) at which DNA replication is initiated

Which organelle is the "information storage site" of a cell?

Nucleus

What does the Km value indicate with respect to enzyme-substrate interactions?

The substrate concentration required to reach 1/2 Vmax

A um is

10 ^-6 meters

There are two properties of fatty acids that affect how tightly they pack together: the length of the hydrocarbon chain and the number of double bonds. The degree of packing in turn influences the relative mobility of these molecules in the membrane. Which of the following would yield the least mobile or highest melting temperature phospholipid.

16 carbons with no double bonds

The ____ energy is defined as the energy required to move a substrate molecule from ground state to the transition state

Activation

Which list of amino acids is considered nonpolar

Alanine, valine, phenylalanine

The four major biological macromolecules are:

carbohydrates, lipids, proteins, nucleic acids

Which of the following amino acid form disulfide bonds ?

cysteine

The two common secondary structure Alpha helix and beta sheets from and are stabilized by hydrogen bond between?

C=0 and N-H of the peptide backbone

Which interaction is most important in enhancing the solubility of macro molecules in water?

Hydrogen bonds ( H bonds)

True or False: Binding of allosteric molecules cause conformational change at an enzyme's active site resulting in either an increase or decrease in catalytic efficiency

True

True or False: Cells exist by acquiring an utilizing energy. They carry out a wide variety if chemical reactions. Engage in mechanical activities. Are able to respond to stimuli and are thus capable of self regulation. Cells can also evolve.

True

True or False: Enzymes alter the rate of reaction

True

True or False: The 1st and 2nd laws of theromodynamics state that 1. energy cannot be created or destroyed and 2. in the universe, the degree of disorder can only increase

True

True or False: The presence of double bonds in the hydrocarbon tail of fatty acid causes a kink in the hydrocarbon tail which prevent tight packing of lipids and greater membrane fluidity

True

True or false: Equilibrium is defined as the state in which the forward and reverse rates of chemical reaction are equal so that no net chemical change occurs, Delta G = 0

True

For the reaction YàX at standard conditions with [Y] = 1 M and [X] = 1 M, ΔG is initially a large negative number. As the reaction proceeds, [Y] decreases and [X] increases until the system reaches equilibrium. How do the values of ΔG and ΔG° change as the reaction equilibrates?

a. ΔG becomes less negative and ΔG° stays the same.

The energy used by the cell to generate specific biological molecules and highly ordered structures is stored in the form of___

chemical bonds

Which of the following expressions accurately describes the calculation of pH?

pH = -log 10[H+]

Protein structures have several different levels of organization. Consider the definitions below and select the one that best fits the term "protein domain"

A protein segment that folds independently and is often found in different kinds of protein

Centromere

A special DNA sequences that allows duplicated chromosomes to be separated during metaphase

Cells use two major source for energy to drive anabolic reactions. They are?

ATP hydrolysis and oxidation -reduction reactions

Proteins are important architectural and catalytic components within the cell helping to determine its chemistry, its shape and its ability to respond to changes in the environment. Remarkably all of the different proteins in a cell are made from the same 2 ____. By linking them in different sequences, the cell can make protein molecules with different conformations and surface chemistry and therefore different functions.

Amino acids

Chemical reactions carried out by living systems depend on the ability of some organism to capture and use atoms from nonliving sources in the environment. The specific subset of these reactions that build macromolecules from nutrients in food can be described as _____

Anabolic

Which of the following organelles has both an outer and an inner membrane A. endoplasmic reticulum B. Mitochondrion C. Lysosome D. peroxisome

B. Mitochondrion

Which of the following is a non covalent bond A. single bond B. double bond C. triple bond D. hydrophobic interaction

D. hydrophobic interaction

For the reaction Y-> at standard conditions with [Y] = 1M and [X] = 1 M and delta G is initially large negative number. As the reaction proceeds, [Y] decreases and [X] increases until the system reaches equilibrium. How do the values of delta G and and delta G change as the reaction equilibrates

Delta G becomes less negative and delta stays the sam e

Which item below is NOT a cell organelles? A. peroxisome B. Mucleus C. endoplasmic reticulum D. Golgi apparatus E. cytosol

E. cytosol

Polar molecules result from the unequal sharing of____ in covalent bonds

Electrons

The second law of thermodynamics states that the disorder in any system is always increasing. In simple terms you can think about dropping NaCl crystals into a glass of water. The solvation and diffusion of ions is favored because there is an increase in _______

Entropy

Catysts are molecules that lower the energy barrier for a given reaction. Cells produce their own catalysts called ____

Enzymes

DNA is synthesized by covalently linking a nucleoside triphosphate to the previous nucleotide, constantly adding a growing chain. For DNA, the new strand becomes part of a stable helix. The two strands are complementary in sequence and anti parallel in directionality. What is the principal force that holds these two strands together?

Hydrogen bonds

Which of the following non covalent bond relies on repulsion from water.

Hydrophobic effect

The complete transfer of electrons from one atom to another can result this type of bond?

Ionic bond

Which characteristic exits only in eukaryotic cells?

The genetic material is isolated from the cytoplasm by a double membrane

A large structure within the nucleus where ribosomal RNA is transcribe in to rRNA ribosome subunits are assemebled is the:

The nucleolus

Diffusion which is the random movement of molecules or small particles is solution is driven by?

Thermal energy

Proteins are polymers of this biomolecule

Amino acids

Which organelle is the site of photosynthesis in plants?

Chloroplast

Nucleosome

Beadlike structural unit of a eukaryotic chromosome composed of a short length of DNA wrapped around a core of histone proteins; includes a nucleosomal core particle (DNA plus histone protein) along with a segment of linker DNA that ties the core particles together.

The region on the surface of a protein that interacts with another molecules through the formation of multiple noncovalent is known as a ____

Binding site

True or False: For a protein to change its conformation, it must break a peptide bond

False

True or False: Hydrolysis is a chemical reaction that involves cleavage of a covalent bond with the accompanying the consumption of H20

False

The common histone tail covalent modifications are?

Phosphorylation, methylation, acetylation

The terms N-terminus and C- terminus refer to the ends of:

Proteins

Hemoglobin which is composed of more than one protein subunit is a good example of ____ structure.

Quaternary

Telomere

Repetitive nucleotide sequence that caps the ends of linear chromosomes and reduces the tendency for chromosome shortening during replication