Test 1 Flashcards
4 raw materials needed for life
hydrogen, oxygen, nitrogen, and carbon
can be defined as the study of essential macromolecules present in cells, including DNA,
RNA, and proteins, and the biological pathways between them
molecular biology
Chemical reactions are at the base of most of biological functions – they are based on energy
transfer
catalysis
When gametes are formed, there is an equal segregation of the alleles
law of segregation
for two genes located on the same chromosome, the further away they are, the (higher or lower) the chance they will not be linked during gametes formation (meiosis)
higher
cell cycle composed of G1, S, and G2
Interphase
chromosomes are decondensed and not visible
interphase
each chromosome is duplicated in this phase and the chromosome becomes a tetraploid
S phase
pairs of identical
chromosomes linked by a structure called
centromere.
sister chromatids
Formation of the centrosome, the
nucleus disappears (mitosis)
prophase
Alignment of chromosomes (mitosis)
Metaphase
Separation of chromosomes at the
centromere (mitosis)
anaphase
Division of the whole cell,
formation of new nuclei (mitosis)
telophase
abnormal
segregation of
chromosomes
nondisjunction
according to which each
gene codes for a specific polypeptide with
catalytic properties.
one gene, one enzyme
Nucleic acids are
polymers
For ribonucleic acid and deoxyribonucleic acid, monomers are
nucleotides
backbone of the molecule is provided by the
phosphate groups and sugars
a key modification in DNA. It occurs at the
nitrogenous bases and regulates DNA folding –
what is known as “chromatin state”. This has deep effects on gene expression.
methylation (adding ch3)
modifications vary more, and can affect also the sugars or include
substitutions of nitrogenous bases.
RNA modifications
modifications occur mostly at the R-group of selected amino acids.
protein modifications
can stabilize the three-dimensional structure of proteins and nucleic acids
ionic bonds
The formation of a chemical bond is an blank process
exothermic
he attractive, non-covalent interaction between the electrons of the pi orbitals of closely located molecules or functional
groups.
pi stacking
an arrangement of atoms which cannot be moved
without breaking and re-forming covalent bonds
configuration
an arrangement that can change based on rotation
around an axis etc.
conformation
two molecules sharing the same molecular formula but that cannot be superposed.
stereoisomers
stereoisomers that are one the mirror image of the other.
enantiomers
a system capable of resisting changes in pH, consisting of a conjugate acid-base pair in
which the ratio of proton acceptor to proton donor is near unity.
buffer solution
Two major properties of buffer solutions
- its ph
- buffer capacity
the sequence of amino
acid residues in a polypeptide
primary strucuture
the organized
elements that favor folding
secondary strucuture
the three-dimensional
organization of a protein, in domains and
motifs
tertiary structure
the formation of
multi-protein complexes
quaternary structure
group includes
amino acids with side
chains made of
hydrocarbon chains plus
methionine (which has a
thioether group)
group 1- apolar proteins
Group of amino acids that can easily be involved in H-bonds/interact with water.
group 2- polar
Aspartate and glutamate can be
involved also in salt bridges.
Amide group
3rd group - negatively charged
Repeating structural elements with defined spatial properties,
held together by weak
interactions, particularly H-bonds
secondary structure
specific arrangements
of secondary elements that can be found in
multiple proteins. They can represent a
whole domain or part of one.
structural motifs
a whole, independent functional unit within a protein
domain
The process through which a protein
reaches its native three-dimensional
conformation
protein folding
The two major driving forces to achieve
folding are
van der waal’s interactions
hydrophobic interactions
shuffles S-S bonds until the final conformation has been reached;
protein disulfide isomerase
molecule bound to a protein (any kind of molecule, including another protein)
ligand
complementary to the ligand (physico-chemical properties!
a binding site
the “breathing” of a protein; small or large re-arrangements
conformational flexibility
changes in the conformation of any macromolecule in response to ligand binding such that
the binding site of the macromolecule better conforms to the shape of the ligand – tighter binding!
induced fit
in a protein complex, a change in the conformation of a protein subunit (like an enzyme)
in response to ligand (substrate) binding that renders that alters the binding affinity of the other subunits
to the ligand – e.g., increased affinity after the first ligand is bound to the first subunit
cooperativity
can either be a metal ion or a coenzyme (metallo-organic molecule)
cofactor
a coenzyme or inorganic cofactor covalently bound to an enzyme
prosthetic group
an enzyme that includes all the molecules that make it active (cofactors etc)
holoenzyme
the protein portion of an enzyme
apoenzyme
the molecule that undergoes the enzyme-catalyzed reaction
substrate
typically a pocket with a well-defined spatial orientation of chemical groups, amino
acids, or cofactors
active site
one enzyme usually catalyzes only one reaction
reaction specificity
1/2 Vmax =
Km
V0 = (Vmax[S])/Km + [S]
Michaelis-Menten equation
Vmax =
Kcat [Et]
Vo =
(Kcat[Et][S])/Km + [S]
undergo conformational changes as a consequence of the binding of a modulator (ligand)
allosteric proteins
they have distinctive binding/kinetic properties
They show sigmoidal saturation curves
allosteric proteins
occurring to the side chain (R group) of amino acid residues. Oftentimes these reactions directly involve ATP.
Covalent modifications
