Unit 1: Protein & Nucleotides Flashcards
(29 cards)
DNA
Deoxyribonucleic Acid (G, C, A, T)
- Double-stranded
RNA
Ribonucleic Acid (G, C, A, U)
- ribose (sugar) has a hydroxyl group (OH) on the 2’ carbon atom
- additional O makes RNA more unstable
- mRNA (messanger), tRNA (transfer), rRNA (ribosomal)
- single-stranded; flexible
Pyrimidines
Smaller nitrogenous base (cytosine, uracil, and thymine)
Purines
Larger nitrogenous base (adenine and guanine)
Name the 5 bases and their location
thymine (DNA), uracil (RNA) and cytosine, guanine, adenine (both)
Which nitrogenous bases bond together?
In DNA: guanine -> cytosine, adenine -> thymine
In RNA: guanine -> cytosine; adenine -> uracil
Which directions do nucleotides bond?
to the 5’ and the 3’
name protein functions
transportation, storage, gene expression, enzymes that catalyze chemical reactions in cells, structure, regulation, movement, signaling, and protection/defense
name RNA functions
enzymes to catalyze reactions, stores and transfers information, replicates DNA molecules, synthesizes proteins for cells, and regulates gene expression
name DNA functions
stores information
protein
molecules formed from subunits called amino acids; one or more polypeptides that have a biological function
amino acids
carbon bonded to an amino group (NH^2), a carboxyl group (COOH), a hydrogen atom, and a R-group
-each type has a different R-group and they can control the functions
- 20 standard amino acids
- short chain is peptide; longer chain is polypeptide
- has primary, secondary, tertiary, and quaternary structure
- monomer of protein
primary structure
a unique sequence of amino acids in a polypeptide
- determines the overall shape and function in a protein
secondary structure
describes how sections of a polypeptide sometimes fold along its length, and the most common of these structures are α-helixes and β-pleated sheets
tertiary structure
a single polypeptide chain “backbone” with one or more protein secondary structures
quaternary structure
proteins which are themselves composed of two or more polypeptides and are folded in a multi-subunit complex.
Genome
all genetic information of an organsim
3 conversions in cells
- DNA -> RNA (transcription)
- RNA -> Proteins (translation)
- RNA -> DNA (reverse transcription)
eukaryotes
cells with nuclei
- protein flow of info: DNA -> pre-mRNA -> mature mRNA -> proteins
- processes mRNA
gene
a section of DNA that codes for one or more related proteins or functional RNA
promoter
a sequence of DNA nucleotides that is an attachment point for the enzyme RNA polymerase, which synthesizes RNA
- before trancription starts
transcription
DNA strands briefly separate, and only the template strand is used. RNA is synthesized in the 5’ -> 3’ direction, so the template strand is read 3’ -> 5’. Terminator is a sequence of DNA nucleotides near the end of a gene that is transcribed and also contains the signal to stop transcription. pre-mRNA, an eukrayote, is the result.
mRNA processing
Regions of eukaryotic genes that code for a product (exons) are interrupted by regions that will not code for the product (introns). This elimination of introns while fusing the exons is called splicing. Enzymes add a 5’ cap (guanine nucleotide with three phosphates) to the 5’ end while they add a poly(A)tail of adenine nucleotides to 3’ end.
genetic code
specifies how nucleotide sets encode the amino acids found in proteins
- amino acids are determined by three sets of three DNA or RNA nucleotides called codons
- AUG : start codon, methionine
- UAA, UAG, UGA : stop codons
- unambiguous, nonoverlapping, redundant, and nearly universal in organisms
