Exam 1: The Central Dogma (Transcription & Translation)

the central dogma

how we go from DNA to a protein

transcription

gene of DNA to mRNA strand

occurs in nucleus

translation

mRNA to a protein

occurs in the cytoplasm

gene

a segment of DNA that encodes for a protein

structure of DNA nucleotides

deoxyribose (DNA) or ribose (RNA) sugar

phosphate (has negative oxygens which help it bind to other things)

a nitrogenous base (ATCG)

nitrogenous base pairing

A & T (adenine and thymine)

C & G (guanine and cytosine)

what does DNA separate into during transcription

a coding strand and a template strand

what strand is used to transcribe into mRNA

template strand

differences between DNA and RNA

nitrogenous bases (U instead of T in RNA)

two-stranded vs. one-stranded

sugar: deoxyribose vs. ribose

why is it mRNA

the code of a single gene

messenger RNA because it is created in the nucleus and transported into the cytoplasm

how does the mRNA become a protein

ribosomes put together amino acids based on the mRNA sequence (codes of three bases correspond to types of amino acids)

codon

group of 3 nitrogenous bases that code for 1 amino acid

groups of amino acids

grouped by functionality/chemical properties

charged, polar, nonpolar, special cases

charged amino acids

attracted to other charged molecules

polar amino acids

hydrophilic

nonpolar amino acids

hydrophobic

special case amino acids

ex: cysteine has a sulfur which allows for disulfide bonds

codon chart

shows how to convert 3 RNA nucleotides into an amino acid

start codon

AUG/Met

beginning of every protein - tells the ribosome to start making the protein

stop codons

UAA, UAG, UGA

tells the ribosome that the prior amino acid is the last in the chain

stop codons are not amino acids, just stop signs

another name for a protein

polypeptide

tRNA

transfer RNA - like a shuttle that helps ribosomes assemble the protein by carrying the corresponding amino acid of the anticodon

once it drops off the amino acid, it leaves to go find another one

purpose of extra bases on the sides of an mRNA

insulation to help protect the strand from damage during movement from the nucleus to the cytoplasm

what connects the amino acids

peptide bonds

genetic mutations

changes in the nucleotide sequence that cause the ribosome to bring a different amino acid which leads to a different protein with a different (wrong) function

example of a genetic mutation

sickle cell disease

the mutated amino acid is now hydrophobic instead of charged, which changes the shape of an RBC to a sickle