L7 Nitrogen Structures Flashcards
Proteins and nucleic acids are distinguished by the ______ content in their building block molecules
Nitrogen
Small, specific amines, or subunit/ monomers that build proteins are called:
amino acids
Nitrogen-containing ring structures that chelate a metal ion in the center of the ring, specialized to hold the ion in place without bonding it
amino acids
Amino acids contain: (3)
- NH2 amino group
- Carboxyl group
- R- group (aliphatic or aromatic group)
A polypeptide becomes a protein when:
When it develops into its secondary and tertiary structure by folding
What joins two amino acids?
Amide or peptide bond
Amide/ peptide bond is formed by:
Dehydration synthesis
What is the most abundant molecule in the cytoplasm besides water?
Glutathione, an essential tripeptide and antioxidant molecule
What is glutathione composed of?
3 amino acids: glutamic acid, cysteine, glycine
What is the main function of glutathione in the cytoplasm?
Relieve oxidative stress from cellular processes and toxins
What is the active part in glutathione?
thiol (sulfhydryl) group - SH - is the active oxidant scavenger
How many amino acids are used in making proteins in humans
20
How many essential amino acids are there?
8
In animals, only the _-form enantiomer amino acids and only _- chiral amino acids are incorporated into proteins
L- form enantiomer
a-chiral amino acids
What are the 2 classifications of the 20 amino acids?
- Essential and non-essential
2. Hydrophobic and hydrophilic
What are the properties that give multiple, diverse possibilities for protein conformation? (4)
- Disulfide bridges
- Charged or uncharged molecules
- Hydrogen bonds
- Hydrophobic/ hydrophilic
Cysteine and methionine are _____-containing aminos that are important in protein folding and integrity by forming _____ ______
sulfur; disulfide bridges
Roles protein play in biological systems (7)
- Enzymes
- Structure (connective tissue, skin, collagen)
- Messengers/ hormones/ regulatory molecules (metabolism regulation- insulin and glucagon)
- Transport (hemoglobin, plasmalemma transport and channel proteins
- Movement- tendon, muscle (actin, myosin)
- Defense- immunoglobins, or B-cell mediated (humoral) immunity
- Nutrient storage- milk protein, albumin
A polypeptide produced by a ribosome that is a linear, unfolded chain of a.a. linked with peptide bonds
Primary structure
Polypeptide structure formed by hydrogen bonding between specific a.a.
Secondary structure
This structure folds the polypeptide even further, as disulfide bonds, charge attraction/ repulsions and hydrophobic/hydrophilic attractions are lined up. Most proteins are complete at this stage
Tertiary structure
Polypeptide structures created when 2 or more tertiary proteins form similar weak bonds between each other, creating massive, multi-protein molecules
Quaternary structure
Molecules that will be acted upon by the enzyme
Substrate
Splitting or joining molecules and flipping conformations occur in:
active sites
______ and ______ like ATP, vitamins, ions, and porphyrins are part of or introduced into the active site to facilitate reactivity
coenzymes and cofactors
What catabolizes proteins from food in the stomach and intestines?
Proteases
Enzymes that hydrolyze proteins and release a.a. into the bloodstream via small intestine absorption:
Proteases
Complex heterocyclic amine molecules important in enzymatic processes:
Porphyrins
Porphyrins ______ metal ions into their structure and therefore utilize the ______ _______ properties of the captured metal ion
chelate; electron cloud
Where are porphyrins usually found?
Active site of enzymes
One variation of Vitamin B-12 is ________ and its chelate is _________
cyanocobalamin; colbalt
A metal ion with numerous valence states, and is polychromatic
Cobalt
Cyanocobalamin is a strong, shocking deep ____ color due to the _______ ion
pink; cobalt
Nucleotides are composed of:
Nitrogenous base
Monosaccharide (simple sugar)
Phosphate group
Nitrogenous bases are ________ amines and are: (2)
heterocyclic
- Purines
- Pyrimidines
Purines have _ rings
Pyrimidines have _ rings
2; 1
Cytosine, Thymine and Uracil are:
pyrimidines
Guanine and adenine are:
purines
Thymine is found in ___ only
DNA
Uracil is found in ___ only
RNA
What are the sugars in nucleosides and nucleotides?
ribose (RNA)
deoxyribose (DNA)
Xanthines are a group of ______ and are very common in nature (plant pigment, caffeine)
purines
Nucleosides are:
A nitrogenous base plus a ribose/ deoxyribose
The phosphorylation of a nucleoside forms:
nucleotide
_____ _____ medicines are incorporated into HIV’s RNA, causing ______ errors as the virus tries to reproduce
nucleoside analogs; translation
What is used as a base for some of the most important molecules in the cell? (ATP, NADH, cAMP)
Adenosine
cAMP stands for
cyclic adenosine monophosphate
cAMP is a __________ molecule used in the cytoplasm that regulates a cell’s _________ by stimulating energy use
messenger; metabolism
cAMP is a modified ______ molecule that in higher concentration causes the cell’s metabolism to _______
adenosine; increase
Caffeine inhibits the enzyme _______, which breaks down cAMP, thus prevents cAMP from being degraded and keeps cellular activity higher
phosphodiesterase
Linear, unbranched chains of bonded nucleotides (DNA or RNA) are called:
nucleic acid
Nucleotides are bonded via:
Sugar-phosphate backbone
Nucleotide bases in DNA and RNA:
DNA and RNA: Adenine, Guanine, Cytosine
DNA only: Thymine
RNA only: Uracil
DNA/RNA pairing:
DNA: AT and GC
RNA: AU and GC
DNA molecules are attracted to their complementary pair by ________ ______
hydrogen bonding
(T/F) RNA is a single-strand nucleic acid
TRUE
DNA has one function:
Storage molecule for genetic data
RNA is found in 3 distinct types
rRNA- ribosomal RNA
tRNA- transfer RNA
mRNA- messenger RNA
___ and ____ are usually folded and hydrogen bonded; ____ exists as an open, un-bonded strand
rRNA and tRNA
mRNA
Where are rRNA made?
cell nucleus
Ribosome organelles are made in the nucleus, and are made out of:
half rRNA and half enzymatic protein
active site of ribosome is composed of rRNA
mRNA is _________ from DNA in the nucleus, and is a sense copy (________) of one strand of DNA
transcribed; anti-sense
mRNA carries the _______ code from the nucleus to the cell’s manufactories as information packets called ________
protein; codons
A single-strand nucleic acid, hundreds of nucleotides long:
mRNA
A short nucleic acid, oddly folded, single strand of RNA bases
tRNA
tRNA carries _____ ______ into the protein synthesis process in the _______
amino acids; ribosomes
How many types of tRNA
20 (for the 20 a.a. used in human protein)
The _________ is the 3-base portion of the chain of tRNA which matches up to the _____ on messenger rNA
anticodon; codon
tRNA has two sites:
a.a. attachment site
anticodon site
