biochemistry Flashcards
how is a covalent bond formed
when unpaired electrons are shared
what is a redox reaction
electrons transferred from one molecule to another
what is oxidation
loss of electrons
what is reduction
gain of electrons
what is an exergonic reaction
delta g negative
occur spontaneously
what is an endergonic reaction
delta g positive
cant occur spontaneously
what is coupled to allow many reactions in the body to occur
an unfavourable reaction (positive delta G) and a favourable one (negative delta G) such as breakdown of ATP and H2O
what is metabolism
all the reactions taking place in the body
what can metabolism be divided into
catabolism and anabolism
what is catabolism
breadking down complex molecules into smaller ones
releases energy
what is anabolism
synthesising complex molecules from smaller ones
consumes energy
what is an acid
proton donaters
what is a base
proton acceptors
what does the strength of an acid depend on
how readily it donates a proton
how is acid strength measured
the acid dissociation constant, Ka
what is the equation for pH
pH = -log10[H+]
what is the Henderson-Hasselbalch equation
ph = pka + log [base]/[acid]
what is a buffer
a solution used to control the ph of a reaction mixture
when does ph = pka
when the [acid] is equal to the [conjugate base]
what is the primary structure
one dimensional, the sequence of amino acid residues
what is the secondary structure
the localised conformation of the polypeptide backbone
what is the tertiary structure
the 3D structure of an entire polypeptide
what is the quaternary structure
the spatial arrangement of polypeptide chains in a protein with multiple subunits
what bond holds secondary structures together
hydrogen
what are the 3 types of secondary structures
alpha helix
beta strands and sheets
triple helix
where is the collagen triple helix found
bone and connective tissue
how is a collagen triple helix formed
three helical chains twisted around each other to form a right handed superhelix
what is the superhelix in the collagen triple helix called
tropocollagen
what are the two types of tertiary structure
fibrous and globular proteins
name two fibrous proteins
collagen and keratin
name two globular proteins
myoglobin and haemoglobin
what type of protein is water soluble
globular
what can denature a protein
heat
ph
a variety of chemicals
what is a sugar and a base called
nucleoside
what makes up a nucleotide
phosphate
sugar
base
what end can new bases be added to in a growing DNA strand
3 prime
what enzyme adds new bases to a growing dna strand
DNA polymerase
what bond forms between bases in dna strands
hydrogen
what type of process is dna replication
semi conservative
what is rrna
ribosomal rna - combines with protein to make ribosomes
what is trna
transfer rna - carries the amino acids to be incorporated into the protein
what is mrna
messenger rna- carries the genetic information for protein synthesis
what determines what amino acid will bind to a specific trna
anticodon sequence
how is transcription initiated
rna polymerase binds to promotors on DNA
what enzyme separates dna strands
helicase
what enzyme binds AA to their tRNA
aminoacyl-tRNA synthetases
what enzyme catalyses formation of peptide bonds between amino acids
peptidyl transferase
what moves the ribosome along mRNA
EF-2 (elongation factor)
what is a point mutation
change in a single base in dna
what is a missense mutation
change of amino acid sequence
what is a nonsense mutation
creates a new termination codon, changes protein due to premature stop
what is a silent mutation
degeneracy of genetic code, no effect on amino acid sequence or protein function
what is a frameshift mutation
addition or deletion of 1 or 2 bases, changes triplets, amino acids and protein
what is vmax
the maximum rate of a reaction
what is the michaelis constant
Km - the substrate conc where the initial reaction rate is half vmax
where is vmax on a graph
intersection of y axis
where is km on a graph
intersection with x axis
where does orthosteric inhibition occur
at the same site (competitive)
what varies in competitive inhibition
Km
what varies in non competitive inhibition
Vmax
how is glucose transported
Na+/glucose symporters
GLUT 1-5 = passive facilitated diffusion transporters
what is pyruvate and how many molecules are made during glycolysis
3 carbon molecules x2
how many ATP produced in glycolysis
4