DNA, genes and chromosomes + DNA and protein synthesis

what is an allele?

what is a gene?

what is a chromosome?

different version of a gene

section of DNA on a chromosome that codes for the production of one or more polypeptide chains and functional RNA

a structure consisting of a long, coiled molecule of DNA and its associated proteins, by which genetic info is passed from generation to generation

what are homologous chromosomes?

what is a locus?

what is a genome?

what is a proteome?

a chromosome pair, one paternal and one maternal, with the same gene loci

fixed position of a gene on a chromosome

the entire set of genes in a cell

the full range of proteins that a cell/organism is able to produce

what is the code in DNA?

what does DNA carry and why?

what are the three important features?

triplet code- three bases code for one amino acid

genetic code- allow cell to make proteins

features- non-overlapping, degenerate and universal

what does non-overlapping, degenerate and universal mean?

non-overlapping- each base is only part of one triplet

degenerate- more than one triplet can code for an amino acid

universal- same triplet always codes for same amino acid in all organisms

how does the gene code info?

specific sequence of bases on 1 strand of DNA controls the sequence of amino acids in proteins i.e primary structure, and therefore the tertiary structure and function of that protein

how do mutations lead to non-functional proteins?

different base sequence leads to..

different amino acid sequence (primary structure) leads to..

bonds forming in diff places , so there is a

different tertiary structure in the protein coded for by that gene

if protein is an enzyme, active site will change shape, substrate won’t fit and fewer/no ES complexes will form

what is a codon?

what is a triplet?

what are histones?

a sequence of three bases on mRNA that codes for a specific amino acid

a sequence of three DNA bases that codes for an amino acid

proteins that, together with DNA, form chromosomes in the nuclei of eukaryotic cells

what are ribosomes made of and what is their function?

rRNA and protein

site of translation and protein synthesis

how is mRNA formed and what are its features?

formed by transcription

single polypeptide chain

smaller than DNA, bigger than tRNA

single helix/linear strand

A,U,G,C

manufactured in nucleus, found throughout cell

least stable

has a codon

what are the features of tRNA?

single polynucleotide chain

smallest molecule

clover leaf shaped molecule

A,U,C,G

manufactured in nucleus, found throughout cell

more stable than mRNA, less stable than DNA

forms hydrogen bonds within complementary sections of the molecule

carries a specific amino acid

has an anticodon

what is non-coding DNA?

what are introns?

what are exons?

in eukaryotes, much of the DNA doesn’t code for synthesis of proteins

some non-coding DNA between genes- contains multiple repeats of base sequences

introns- non coding section within genes/ non coding sequence of DNA

exons- coding region within genes/ sequence of DNA that codes for an amino acid sequence

what are the differences between prokaryote and eukaryote DNA?

prokaryote- no introns, small and circular, not associated with histones

eukaryote- introns, long and linear, associated with histones

what is splicing?

what do mRNA molecules do after?

in pre-mRNA in eukayotic cells, introns are removed

leave nucleus thru nuclear pores

which bases are specific for a particular amino acid?

what do stop codes do?

which codon is used as a start code and what does it mean?

first two bases + any third base will do- reduces chance that a change in the bases will alter the function of the polypeptide

indicate the end of a section of mRNA, after which translation stops

AUG- removed in the processing stage that converts the polypeptide into a functional protein