Lecture 2: Biological Information Flow

what are the building blocks of DNA and RNA

nucleotides made of a nitrogenous base, sugar, and phosphate

what base are found in DNA

adenine (A), thymine (T), cytosine (C), and guanine (G)

what bases are found in RNA

adenine (A), uracil (U), cytosine (C), and guanine (G)

What does antiparallel mean for DNA strand

the two strands run in opposite directions: 5’ → 3’ and 3’ → 5’

two processes of cell division (mentioned in class)

mitosis produces somatic cells; meiosis produces gametes

why is recombination important

it generates gentic noevlty

what is transcription

process of using DNA information to produce RNA

what gets transcribed

discrete segments of DNA known as genes

what are the major parts of gene structure

promoters, enhancers, introns, exons, and UTRs

what is a promoter

untranscribed sequence before a gene that helps control the timing and extent of transcription

what do transcription factors do

bind promoters and help position RNA polymerase at the transcription start site

what is translation

process of using genetic information to produce a protein

what is the relationship between amino acid sequence and protein structure

the primary amino acid sequence forms the basis for complex protein structures

what do proteins do

perform essentially all cellular functions

how many bases make a codon

three

why is the genetic code called redundant

multiple codons can correspond to the same amino acid, so not all mutations change the amino acid

mutation

a change to a single base-pair

why are mutations important

they are the ultimate source of all genetic variation, both benefical and harmful

what can cause mutation

DNA replication errors, chemicals, radiation, and oxidative damage

do all mutations change the protein structure

no. the genetic code is redundant, some mutations do not change the amino acid

what can insertions and deletions do to translation

they can disrupt the reading rfame and alter the resulting protein

chromosomes in humans

46 chromosomes, 23 pairs

is chromosome number related to organismal complexity

no; species vary widely in chromosome number

polyploidy

having more than two sets of chromosomes

where is polyploidy more common

it is more common in plants but also occurs in animals

what is genome size

the amount of DNA contained in an organisms genome

is genome size related to organismal complexity

no; genome size and gene number are unrelated

what is “junk DNA” (according to lecture)

DNA including introns, pseudogenes and repetitive sequences such as transpsons

basic flow of biological info

DNA → RNA → Protein