Biochemistry multiple choice Flashcards
Which of the following is essential characteristic of a polar molecule?
Asymmetrical , distribution of charge
Isomers are different than isotopes in that
Isomers have the same chemical formula but different structures
Isotopes are atoms of the same element but different neurons
- When atoms from a _ and a _ element are brought together , which chemical bond will form?
Ionic bonds- metal + non-metal
Nonpolar covalent- two non-metals with the same electronegativity
Polar covalent- two non-metals with different electronegativity like carbon and hydrogen
London – two of the same element with low electronegativity
Hydrogen- H atoms and 3 atoms with high electronegativity n,o,f
- An amino acid always has an amino group , what other group is also present in all amino acids?
R group and carboxyl group
The following structural formula is representative of which functional group?
Hydroxyl- OH phosphate- po4
Carboxyl – COOH carbonyl- COH -co-
Amino – nh2
Sulfhydryl – SH
6,7,8 macromolecule structural formula
Carbohydrates – simple sugars –OH carbonyl
Lipids – 3 carbon with –oh on each or fatty acids carboxyl group
Proteins – amino group r group and carboxyl group
Nucleic acids – phosphate group , 5 carbon sugar, nitrogenous base
hydrocarbons (C4H10¬); carbohydrates (C6H12O6); lipids (C57H114O2); proteins (chains of amino acids) ; nucleic acids (central carbon with an amino group and a carboxyl group attached on opposite sides)
- in terms of the shape of a protein which of the following statements is false
Primary structure: formed by covalent bonds between amino acid subunits
Secondary: formed by hydrogen bonds between hydrogen and oxygen near the peptide bonds ( a helix) ( bpleated)
Tertiary structures: super-coiling of the polypeptide by side-chain interactions, including ionic, covalent bonds (disulfide bridges), and van der Waals forces. it contains more than covalent bonds
Quaternary structure: two or more polypeptides forming functional protein.
when a molecule of glycerol reacts with one or more fatty acids an ester linkage results. The formation of this linkage is a result of a reaction between
Condensation reaction takes place between a hydroxyl group of glycerol and carboxyl group of a fatty acid an alcohol and a carboxylic acid
11.Photosynthesis is:
process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. Photosynthesis in plants generally involved the chlorophyll and generates oxygen as a by-product. anabolic process and endogonic
in living organisms , buffers do which of the following?
- donate H+ ions when required and containing a substance that can remove H+ ions when there are too many in solution
- help to maintain the pH level inside a living organism
of the following characteristics , which is not true about enzymes?
They will bind their substrate and any isomer of their substrate. ( not true)
They undergo major chemical change after reacting with their specific substrate.
- in order for all condensation or hydrolysis reactions to occur, the specific enzyme that matches the substrate is required
- catabolic : work by binding to the substrate which weakens the bond between the two substances, forming 2 separate products
- anabolic : work by binding to the two substances, which allow the bond between the substances to form, creating a new larger molecule
at which temperature would you expect any enzyme extracted from a human tissue to have its optimal performance?
37
enzymes work as catalysts by doing which of the following?
decreasing the activation energy
competitive inhibition : substances compete with the susbtrate for an enzyme’s activite site
- non-competitive inhibition : substances bind to a binding site on an enzyme (other than the binding site) causing the enzyme to change its shape and lose affinity for the substrate
- allosteric inhibition: receptor sites some distance from the active site of certain enzymes that bind substances that may inhibit or stimulate an enzyme’s activity
