Unit 5 - Gene Expression, the Central Dogma, and Mendelian Inheritance

central dogma

dna > rna > protein

gene expression

the process by which the information in genes is expressed as proteins through transcription and translation

intron

a non-coding segment of DNA within a gene that is transcribed into pre-mRNA, but is later removed before the final, functional mRNA is produced

exon

a segment of DNA that is present in the final, mature mRNA transcript and often codes for a protein

promoter (TATA box)

a region of DNA that contains the signals needed to initiate the transcript of a specific gene

transcription factors (TFs)

proteins that control the rate of gene transcription by binding to specific DNA sequences, thereby controlling how and when genes are turned off or on in a cell

RNA splicing

what removes introns and joins exons to help make mature mRNA?

5’ capping, RNA splicing, and 3’ polyadenylation

what 3 processes make final, mature mRNA?

translation

the process of synthesizing a protein by decoding the genetic information in mRNA

transfer RNA (tRNA)

a type of RNA molecule that acts as an adapter during protein synthesis by transferring a specific amino acid to a growing polypeptide chain at the ribosome

codon

a sequence of three nucleotides which together form a unit of genetic code in a DNA or RNA molecule

AUG

what is the start codon that codes for methionine (Met) ?

UAG, UAA, UGA

what are the 3 stop codons?

P site, A site, and E site

what are the 3 binding sites for tRNA in translation?

anticodon

a three nucleotide sequence located at one end of tRNA which is complementary to a corresponding codon in mRNA

true-breeding

describes a trait whose physical appearance in each successive generation is identical to that in the previous one

allele

a different form of a gene that affects the same trait

homozygous

an individual who has two identical versions (alleles) of the same gene, one inherited from each parent

heterozygous

an individual who has two different versions (alleles) of the same gene, one inherited from each parent

phenotype

an organism’s observable physical, biochemical, and behavioral traits

genotype

an organism’s complete genetic makeup. can also refer to the specific alleles an individual carries. the combination of alleles an organism possesses. 

testcross

a genetic cross used to determine if an individual is homozygous dominant or heterozygous

monohybrid cross

a cross between two homozygous parents that differ in a single trait, resulting in F1 monohybrid offspring

law of independent assortment

one set of alleles of a gene pair segregates independently of another set of alleles for a different gene pair

dihybrid cross

a cross between F1 dihybrids. can determine whether two genes are transmitted to offspring as a package or independently

monohybrid

an organism that involves the inheritance of a single trait

dihybrid

an organism that involves the inheritance of two traits

pedigree

a family tree that describes the interrelationships of parents and children across generations

incomplete dominance

a form of intermediate inheritance in which one allele for a specific trait is not completely expressed over its paired allele. the phenotype of F1 hybrids is somewhere between the phenotypes of the two parental varieties.

codominance

when a gene has more than two alleles. two or more dominant alleles affect the phenotype in separate, distinguishable ways

epistasis

when one gene can mask the effect of another. expression of a gene at one locus alters the phenotypic expression of a gene at a second locus

complete dominance

when phenotypes of heterozygotes and dominant homozygotes are identical