Protein Synthesis and Mutations

Purine

Purine

Adenine, Guanine → 2 rings

Pyrimidine

Cytosine, Thymine, Uracil → 1 ring

Transcription

Process of copying DNA into mRNA from template (antisense) strand, a lot like DNA replication - uses helicase, RNA polymerase,

RNA

ribonucleic acid, single stranded, ribose sugar, can leave the nucleus, uracil instead of thymine

mRNA

messenger RNA, genetic instructions in RNA based on DNA. Journeys out of the nucleus to the ribosomes in the cytoplasm

tRNA

transfer RNA, collects amino acids and then deposits them in right place using anticodons, binds and carries specific amino acids to the ribosome

rRNA

makes up the structure of the ribosome (along w/ proteins), along with proteins, makes up the ribosome

• They also help catalyze the formation of peptide bonds!

Uracil

replaces thymine in the RNA strand

Promoter region

the area where protein synthesis begins

Termination signal

a sequence that signals the end of transcription or translation

RNA polymerase

enzyme responsible for transcribing the genetic information stored in DNA to RNA

Translation

process through which ribosome creates protein from mRNA

Ribosome

where proteins are synthesized, link amino acids together in the order specified by the codons of the mRNA, have the small and large ribosome subunits

Codon

group of 3 nucleotides, codes for 1 amino acid

Anticodon

codon on tRNA that matches w/ codon on mRNA, allowing correct tRNA and amino acid to be attached

Amino acid

molecules that combine to make proteins, has amino group, R-chain, carboxyl group

Polypeptide

polymer for peptide, large number of amino acids bonded together, forms part of (or whole) protein

Mutation

cause a permanent change in DNA, can occur before birth or due to environmental factors (like radiation), could be beneficial, harmful, or have to effect on the body, mutations can impact the way proteins are synthesized from DNA (but not always), small-scale (gene), large-scale (chromosomal)

Frameshift mutation

insertion or deletion; because diff # of nucleotides everything gets shifted and messed up

Insertion

a nitrogenous base is inserted into the DNA strand, shifting all the nitrogenous bases down, altering the codons that follow it

Deletion

a nitrogenous base is removed from the DNA strand, shifting all the following nitrogenous bases up a spot, altering the following codons

Substitution

one nucleotide is swapped out for another

Missense

if the amino acid is changed, codon codes for something else

Nonsense

Codon changed to stop codon

Silent

nitrogenous base is changed out, but the codon still codes for the same amino acid

Chromosomal mutation

affect an entire chromosome or portion of a chromosome, entire genes altered, usually occurs during meiosis, overexpressing or incompletion of genes, can lead to un-viable cells

Translocation

part of diff chromosomes swapped

Insertion - part of 1 chromosome inserted into other

Nondisjunction

can happen in meiosis 1 or 2, chromosomes not evenly divided between cells

Single Chromosome Mutations

deletion, duplication, and inversion

Gene mutation

change individual base pairs, occur during DNA replication, meiosis, or mitosis, impacts proteins made during protein synthesis

TATA box

the flag for where protein synthesis should begin

Intron

non-coding remnants of DNA sequences that were once used to code for proteins

Exon

as we evolved, we learned how to make more complex proteins by combining different parts of DNA

Spliceosome

an enzyme responsible for gene “splicing”/taking out introns, made from snRNPs (RNA + RNA-binding proteins)

poly-A tail

makes the RNA molecule more stable and prevents its degradation, a long chain of adenine nucleotides that is added to a messenger RNA (mRNA) molecule during RNA processing, allows the mature mRNA molecule to be exported from the nucleus and translated into a protein by ribosomes in the cytoplasm, also involved in binding proteins to initiate translation

E, P, and A site

the sites in the ribosome where tRNA can attach to the codons and deposit its amino acid

Chromosomal Mutation Genetic Disorders

Down syndrome - caused by trisomy 21 (nondisjunction causes cell to have 3 chromosomes 21), mental impairments, heart defects

Turner syndrome - XO (only one X chromosome, males usually have XY chromosomes, females usually have XX), abnormal ovaries + sexual traits

Trisomy X - caused by XXX (scandalous), minimal abnormalities

Point Mutation Genetic Disorders

Cystic Fibrosis - caused by deletion mutation resulting in a misfolded protein, thick mucus, breath struggle, no fertile, less lifespan

Sickle-Cell Anemia - caused by substitution mutation resulting in an incorrect amino acid, change shape of blood cells, can't carry oxygen to blood (low hemoglobin)