Download BCH 367 Exam 1 Review Questions with Detailed Answers and more Exams Nursing in PDF only on Docsity!
BCH 367 EXAM 1 REVIEW QUESTIONS
WITH CORRECGT DETAILED ANSWERS.
All biomolecules can be divided into just ________ main categories - ANSWER- four Over _______ of the human body is made up of H, O, C, and N - ANSWER- 99% Proteins Structure - ANSWER- linear polymer that folds into 3D structure Monomers of proteins - ANSWER- Amino Acids Polymer bonds in protein - ANSWER- Peptide bond Major functions of proteins - ANSWER- Signals, receptors, strucutre, mobility, defense, catalysis, etc. Nucleic acids structure - ANSWER- Linear polymer that forms predictable base pairs Monomers of nucleic acids - ANSWER- nucleotides Name of polymer bond in nucleic acids - ANSWER- Phosphodiester bond Major functions of nucleic acids - ANSWER- Information storage and transfer Lipids Structure - ANSWER- Dual chemical character with hydrophobic and hydrophilic regions
of Monomers in Proteins - ANSWER- 20
of Monomers in Nucleic Acids - ANSWER- 4
Major Functions of Lipids - ANSWER- Fuel storage, signaling, and barriers Carbohydrates Structure - ANSWER- Diverse structures, can form branched polymers Monomers in carbohydrates - ANSWER- Monosaccharides
of monomers in carbohydrates - ANSWER- MANY
Major functions of carbohydrates - ANSWER- Fuel, cell identification, cell-to-cell interaction sites
Central dogma - ANSWER- describes the basic principles of biological information transfer & specifies the process through which we go from genetic information of DNA to the proteins that perform so many cellular functions Information Flow in Central Dogma - ANSWER- Dna - > (transcription) RNA - > (translation) Protein In replication.... - ANSWER- Input Biomolecule = DNA ; Output Biomolecule = DNA ; Enzyme = DNA Polymerase In transcription... - ANSWER- Input Biomolecule = DNA ; Output Biomolecule = RNA ; Enzyme = RNA Polymerase In translation... - ANSWER- Input Biomolecule = RNA ; Output Biomolecule = Protein ; Enzyme = Ribosome
of membranes in nucleus - ANSWER- two
Fucntion of nucleus - ANSWER- The information center that holds the DNA of the organism ; Nuclear pores enable transport in and out
of membrances in Mitochondria - ANSWER- two
Function of Mitochondria - ANSWER- Energy production centers that produce ATP through respiration
of membranes in chloroplasts - ANSWER- two
Function of Chloroplasts - ANSWER- Photosynthesis centers that convert light to chemical energy ; Only in plants and algae
of membranes in SER (smooth endoplasmic reticulum) - ANSWER- one
Function of Smooth Endoplasmic Reticulum - ANSWER- Membraous sack used for processing exogenous chemicals ; Smooth, no ribosomes
of membranes in RER (Rough Endoplasmic Reticulum) - ANSWER- one
Function of Rough Endoplasmic Reticulum - ANSWER- ER where proteins destined for cellular membrances or for secretion are synthesized ; Rough due to ribosomes
of membranes in Golgi Complex - ANSWER- one
Function of Golgi Complex - ANSWER- Stacked membranes involved in protein sorting and preparation of secretory granules
What are Van der Waals interactions? - ANSWER- Very weak interactions that result from transient asymmetries in charge distribution ; Assymetries include partial positive and negative charges Mechanism of covalent bonds - ANSWER- Shared electrons Charge magnitude of covalent bonds (S/M/L) - ANSWER- Large, about 0.5 electrons Bond distance of covalent bonds (in Angstroms) - ANSWER- Small Bond energy in covalent bonds (in kiloJoules per mole) - ANSWER- Strong Mechanism of Ionic Bonds - ANSWER- attraction of oppositely charges ions Charge magnitude of ionic bonds - ANSWER- Large, at least 1 electron Bond distance of Ionic Bonds - ANSWER- Larger Bond Energy of Ionic Bonds (in kiloJoules per mole) - ANSWER- Weak Mechanism of Hydrogen Bonds - ANSWER- attraction caused by unequal charge distributions Charge magnitude of Hydrogen Bonds - ANSWER- Medium, partial electron Bond distance in Hydrogen Bonds - ANSWER- Larger Bond energy of Hydrogen Bonds - ANSWER- weak-weaker Mechanism of Van der Waals - ANSWER- attraction caused by transient charge asymmetries Charge Magnitude (S/M/L) - ANSWER- Small, fleeting asymmetries Bond distance of Van der Waals - ANSWER- Larger Bond energy of Van der Waals - ANSWER- weakest 2nd Law of Thermodynamics - ANSWER- The total entropy of a system and its surrounding always increases in a spontaneous process (T/F) Water molecules form an ordered structure around nonpolar molecules - ANSWER- True
(T/F) The segregation of nonpolar molecules minimizes surface area of ordered water molecules - ANSWER- True (T/F) Amino Acids are Zwitterions - ANSWER- True What type of amino acids are only used in proteins? - ANSWER- L Amino acids (T/F) Amino acids are chiral - ANSWER- True The four groups of amino acids are: 1. _______, 2. ________, 3. _________, and 4. ________ - ANSWER- 1. Hydrophobic amino acids with nonpolar R
- Polar amino acids where charge in R is unevenly distributed
- Positively charged amino acids at physiological pH
- Negatively charged amino acids at physiological pH Glycine - ANSWER- Hydrophobic Amino Acid Alanine - ANSWER- Hydrophobic Amino Acid Valine - ANSWER- Hydrophobic Amino Acid Leucine - ANSWER- Hydrophobic Amino Acid Isoleucine - ANSWER- Hydrophobic Amino Acid Methionine - ANSWER- Hydrophobic Amino Acid Proline - ANSWER- Hydrophobic Amino Acid Phenylalanine - ANSWER- Hydrophobic Amino Acid Tryptophan - ANSWER- Hydrophobic Amino Acid Serine - ANSWER- Polar Amino Acid Threonine - ANSWER- Polar Amino Acid Tyrosine - ANSWER- Polar Amino Acid Cysteine - ANSWER- Polar Amino Acid Asparagine - ANSWER- Polar Amino Acid Glutamine - ANSWER- Polar Amino Acid Lysine - ANSWER- Positively charged AA
(T/F) The peptide bonds in the peptide backbone are planaor (the peptide bonds have double-bond character, which lead to a planar geometry - but rotations can occur at the alpha carbon) - ANSWER- T (T/F) Each protein has a well-defined amino acid sequence specified by a gene - ANSWER- T Knowing this sequence is valuable because: - ANSWER- 1. Sequence determine the protein's structure and function
- Alterations in sequence can lead to disease
- Sequence provides evidence of evolutionary history Protein secondary structures are: - ANSWER- Regular structures in proteins formed by hydrogen bonding in the backbone (Examples: Alpha helices, Beta Sheets, Coiled coil, Collagen helix) Are Alpha helices right/left handed? (Protein Secondary Structure) - ANSWER- Right- handed Are B form helices right/left handed? (Protein Secondary Structure) - ANSWER- right handed In an alpha helix, hydrogen bonds are formed between _____ and ______ groups ____ residues away (Protein Secondary Structure) - ANSWER- CO ; NH ; 4 (T/F) Essentially all alpha helices are right handed (Protein Secondary Structure) - ANSWER- T All CO and NH bonds between residues participate in ___________ bonding (Alpha helices) (Protein Secondary Structure) - ANSWER- hydrogen Beta sheets are formed from ___________ bonding between ___________ strands (Alpha Helices) (Protein Secondary Structure) - ANSWER- hydrogen ; polypeptide (T/F) In a beta sheet, strands can be parallel, anti-parallel, or a combination of both (Protein Secondary Structure_ - ANSWER- T In a beta sheet, side chains are _______ and _______ the sheet (Protein Secondary Structure - ANSWER- below ; above In a beta sheet, _____ and _____ enable chains to turn back on themselves, and often have hydrophilic R groups (Protein Secondary Structure) - ANSWER- loops ; turns Coiled coil (fibrous structures) (Protein Secondary Structure) - ANSWER- Two right- handed alpha helices coil into a left-handed superstructure via Van der Waals interactions or disulfide bonds (Example: the alpha-keratin in hair, horns, and nails)
Collagen Helix (fibrous structures) (Protein Secondary Structure) - ANSWER- three stranded superhelical cable formed by hydrogen bonds between strands (Example: Collagen in tendons, ligaments, and skin) Protein Tertiary Structures are: - ANSWER- Structures formed as a result of side chain interactions between residues that are far apart in sequence Examples of Protein Tertiary Structures: - ANSWER- 1. Disulfide bonds between cysteine residues
- Globular proteins like myoglobin
- Motifs or supersecondary structures (Helix-turn-helix motif: commonly used for DNA- binding proteins
- Domains - compact globular units Disulfide bonds are (Protein Tertiary Structures): - ANSWER- Covalent disulfide bonds that occur between two cysteine residues in a protein Myolglobin: Hydrophobic Interior (Protein Tertiary Structure) are: - ANSWER- Hydrophobic residues that dominare the interior of the protein to provide a binding pocket for heme A pair of histidines enable binding of the ____ and ______ atoms of the heme (Protein Tertiary Structure) - ANSWER- iron ; oxygen Protein Quaternary Structures are: - ANSWER- Structure formed by interaction between different polypeptide chains A subunit in a Protein Quaternary Structure is: - ANSWER- a polypeptide chain that is part of ht eprotein quaternary structure (T/F) The native structure of a protein is the most thermodynamically stable structure - ANSWER- T (T/F) Not all proteins have a stable or structured final configuration - ANSWER- T Intrinsically unstructured proteins (IUPs) are (Thermodynamics and Protein Structure): - ANSWER- Proteins which do not have a well-defined 3D structure, can switch slates upon interaction with other proteins, and are important for signaling and regulation Metamorphic Proteins are (Thermodynamics and Protein Structure): - ANSWER- proteins that exist in an ensemble of structures of approximately equal energies Prion - ANSWER- a proteinaceous infectious particle (PRotein + infectION) PrP^SC - ANSWER- (SC=scrapie) is slightly less stable that PrP
Cytosine, Uracil, and Thymine are examples of: - ANSWER- pyrimidines The Watson-Crick base pairing mechanism states that: - ANSWER- Base pairs are stabilized using hydrogen-bonds
- Guanine (G) and Cytosine (C) connect with three bonds
- Adenine (A) and Thymine (T) connect with two bonds If the sequence of one strand is known, the sequence of the other strand can be defined by using the base pairing method In base stacking: - ANSWER- Hydrophobic interactions drive bases to the interior of the helix and stabilize its structure Base stacking is: - ANSWER- stacking of the bases one atop the other leads to Van der Waals interactions
- cumulative effect of these interactions is strong The DNA double helix can be separated enzymatically by: - ANSWER- enzymes called helicases Heat can be applied to ______ the H-bonds and Van der Waals interactions in a process called _______ - ANSWER- heat ; denaturation The temperature at which the helices separate is called the _______ - ANSWER- melting temperature (Tm) Separated complementary strands can spontaneously __________ when the temperature falls below T_m ; and can be called _______ or ___________ - ANSWER- rehybridize ; annealing ; renaturation The bases in DNA are: - ANSWER- Adenine (A) Cytosine (C) Guanine (G) Thymine (T) The bases in RNA are: - ANSWER- Adenine (A) Cytosine (C) Guanine (G) Uracil (U) The base pairings in DNA are: - ANSWER- G to C A to T The base pairings in RNA are: - ANSWER- G to C A to U
Is DNA double stranded/single stranded in cells? - ANSWER- double Is RNA double stranded/single stranded in cells? - ANSWER- single The sugar component in DNA is: - ANSWER- Deoxyribose The sugar component in RNA is: - ANSWER- Ribose The stability of DNA in a cell is: - ANSWER- Very stable The stability of RNA in the cell is: - ANSWER- Messenger RNA (mRNA) is frequently broken down (not stable) Major functions of DNA: - ANSWER- Long term information storage; contains the "parts list" of the organism Major functions of RNA: - ANSWER- Short-term information carrier; mRNA provides the template for making proteins Nucleotide Nomenclature - ANSWER- 1. Nucleoside: sugar + base
- Nucleotide: sugar + base + phosphate Purines: - osine postfix Pyrimidine: - idine postfix Number of phosphates: (1) Monophosphate, (2) Diphosphate, (3) Triphosphate Adenine can be named by: - ANSWER- DNA: deoxyadenosine RNA: adenosine Cytosine can be named by: - ANSWER- DNA: deoxycytidine RNA: cytidine Guanine can be named: - ANSWER- DNA: deoxyguanosine RNA: guanosine Thymine/Uracil can be named: - ANSWER- DNA: Thymidine RNA: Uridine The "A form Helix" shape is: - ANSWER- stocky (short and wide) The "B form helix" shape is: - ANSWER- Intermediate (Not stocky but not lanky) The "Z form helix" shape is: - ANSWER- lanky (tall and thin) The screw sense for the A Form Helix is: - ANSWER- right-handed The screw sense for the B Form Helix is: - ANSWER- right-handed
