Exam 1 Flashcards
Force exerted by the hydrogen-bonded network of water molecules that brings two nonpolar surfaces together by excluding water between them is?
Hydrophobic force
Noncovalent bond in which an electropositive hydrogen atom is partially shared by two electronegative atoms is?
Hydrogen bond
Substance that releases protons when dissolved in water, forming a hydronium ion (H3O) is?
Acid
Type of noncovalent bond that is formed at close range between non-polar atoms is?
Van der Waals attraction
A 10-8 M solution of HCL has a pH of 8. True or false?
False. It would be neutral at pH of 7. Strong acids cannot become basic
Most of the interactions between macromolecules could be mediated just as well by covalent bonds as by noncovalent bonds. True or false?
False.
Three dimensional relationship of the different polypeptide chains in a multisubunit protein or protein complex is?
Quaternary structure
Common folding pattern in proteins in which a linear sequence of amino acids folds into a right handed coil stabilized by internal hydrogen bonding between backbone atoms is?
a Helix
The amino acid sequence of a protein is?
Primary structure
A region on the surface of a protein that can interact with another molecule through noncovalent bonding is?
Binding site
Self-propagating, stable aggregate made up of identical polypeptide chains layered into a continuous stack of B sheets is?
Amyloid fibril
The chain of repeating carbon and nitrogen atoms, linked by peptide bonds, in a protein is?
Polypeptide backbone
Common structural motif in proteins in which different sections of the polypeptide chain run alongside each other and are joined together by hydrogen-bonding between atoms of the polypeptide backbone is?
B sheet
Portion of a protein that has a tertiary structure of its own is?
Protein domain
Regular local folding patterns in a protein, including a helix and B sheet is?
Secondary structure
Each strand in a B sheet is a helix with two amino acids per turn. True or false?
True
Intrinsically disordered regions of proteins can be identified using bio-informatic methods to search genes for encoded amino acid sequences that possess high hydrophobicity and low net charge. True or false?
False
Loops of polypeptide that protrude from the surface of a protein often form the binding sites for other molecules. True or false?
True
Prion diseases can spread from one organism to another, providing that the second organism eats tissue that contains the gene encoding the protein involved in formation of amyloid fibrils. True or false?
False
A protein that serves both to link together a set of interacting proteins and to position them at a specific location in a cell is?
Scaffold protein
Type of metabolic regulation in which the activity of an enzyme acting near the beginning of a reaction pathway is reduced by a product of the pathway is?
Feedback inhibition
Protein produced by the immune system in response to a foreign molecule or invading microorganism is?
Antibody
Region of an enzyme surface to which a substrate molecule binds in order to undergo a catalyzed reaction is?
Active site
A protein catalyst that speeds up a reaction, often by a factor of a million or more, without itself being changed is?
Enzyme
The first example of a special family of small proteins whose members are covalently attached to other proteins to influence their activity or fate is?
Ubiquitin
Mutual effect of the binding of one ligand on the binding of another that is a central feature of the behavior of all allosteric proteins is?
Linkage
Enzyme that transfers the terminal phosphate group of ATP to a specific amino acid in a target protein is?
Protein kinase
Rate-limiting structure that forms transiently in the course of a chemical reaction and has the highest free energy of any reaction intermediate is?
Transition state
Protein that changes its conformation when it binds a regulatory molecule or when its covalently modified is?
Allosteric protein
A term often used to describe research focused on the simultaneous analysis of large numbers of proteins is?
Proteomics
Small molecule that is tightly associated with a protein catalyst and participates in the chemical reaction, often by forming a covalent bond to the substrate is?
Coenzyme
For a family of related genes that do not match genes of known function in the sequence database, it should be possible to deduce their function by using “evolutionary tracing” to see where conserved amino acids cluster on their surfaces. True or false?
False
Higher concentrations of enzyme give rise to a higher turnover number. True or false?
False
Enzymes that undergo cooperative allosteric transitions invariably consist of symmetric assemblies of multiple subunits. True or false?
True
Continual addition and removal of phosphates by protein kinases and protein phosphatases is wasteful of energy– since their combined action consumes ATP– but it is a necessary consequence of effective regulation by phosphorylation. True or false?
True
Conformational changes in proteins never exceed a few tenths of a nanometer. True or false?
False
If human DNA contains 20% C on a molar basis, what portion is T?
30%
What portion of each histone protein projects outward from nucleosomes?
N-terminal tail
Which of the following removes acetyl groups from histone trails?
HDACs
Which of the following is not a component of histone octamers?
H1
Each human chromosome contains
1 centromere, 2 telomeres, many origins of replication
The totality of the genetic information carried in the DNA of a cell or an organism is?
Genome
The three dimensional structure of DNA, in which two DNA chains held together by hydrogen bonds between the bases are coiled around one another is?
Double helix
Information containing element that controls a discrete hereditary characteristic is?
Gene
Describes the relative orientation of the two strands in a DNA helix; the polarity of one strand is oriented in the opposite direction to that of the other is?
Antiparallel
Two nucleotides in an RNA or DNA molecule that are held together by hydrogen bonds is?
Base pair
Human cells do not contain any circular DNA molecules. True or false?
False
Full set of chromosomes of a cell arranged with respect to size, shape, and number is?
Karyotype
Constricted region of a mitotic chromosome that holds sister chromatids together is?
Centromere
Any one of a group of small abundant proteins, rich in arginine and lysine, that form the primary level of chromatin organization is?
Histone