evolution test Flashcards
point mutation
when only one nucleotide is affected
missense mutation
when only one nucleotide is changed and this impacts the amino acid added to the polypeptide chain
silent mutation
when a nucleotide changes but the resulting amino acid does not
nonsense mutation
when a codon is changed to a STOP codon
frameshift mutation
when a nucleotide is inserted or deleted and it shifts every base that follows
frameshift insertion
when a base pair is added, shifting the reading frame and changing the amino acid
frameshift deletion
when a base pair is deleted, shifting the reading frame and changing the amino acid
substitution mutation
when a base pair is replaced
a, t, c, g, u
adenine, thymine, cytosine, guanine, uracil
promoter
the nucleotide sequence that acts as a binding site for RNA polymerase
terminator
DNA sequence that ends transcription
intiation
first stage of transcription: RNA polymerase attaches to the promoter, it opens the double-helix, and starts to synthesize RNA
elongation
second stage of transcription: newly formed RNA strand grows and the molecule peels away from the DNA template as it forms, DNA returns to its original double-helix and RNA polymerase adds free nucleotides to the DNA template using H bonding
termination
last stage of transcription: RNA polymerase reaches the terminator, it detaches from the DNA/RNA, and the newly synthesized RNA is released for traveling into the cytoplasm
founder effect
a small group of individuals form a new population from a larger population
bottleneck effect
sudden reduction in population size due to environmental change
helicase
enzyme that separates/unzips the anti-parallel DNA strands in DNA replication
primase
enzyme that adds RNA primers to the DNA strands
DNA polymerase 3
adds free nucleotides to form new DNA strands, creates identical molecules of DNA by following base-pairing rules
DNA polymerase 1
removes RNA primers and replaces them with DNA nucleotides
ligase
attaches Okazaki fragments to DNA strand
adaptation
trait developed over time that helps a species become better suited for an environment
homology
underlying structural or molecular similarity but has different function, which can show reveal evolutionary relationships
vestigial structures
remnants of features that served important functions in the organism’s ancestors
natural selection
process where organisms better adapted to survive their environment live longer to reproduce
5’ end
phosphate group
3’ end
free hydroxyl group
semi-conservative
conserves the original DNA- half new and half original in newly formed DNA mQ
codon
3 nucleotides read together; DNA and RNA sequences
chargaffs rule
theres an equal amount of A to T and C to G
anti-parallel
running parallel but in opposite directions: phosphate to hydroxyl (5 to 3) and hydroxxyl to phosphate (3 to 5)
genetic drift
change in a population’s gene pool due to chance (natural disaster/event)
gene flow
change in a population’s gene pool due to movement into/out of the population
RNA polymerase
enzyme in transcription that binds to the promoter and makes a strand of mRNA by adding free nucleotides as it moves along the DNA strand; free bases are added to the mRNA strand in the order that the DNA strand codes for
mRNA
messenger RNA: carries the DNA’s instructions and directs protein synthesis
tRNA
transfer RNA: carries the corresponding amino acid to the ribosome as each codon on the mRNA is read
polypeptide
chain of amino acids
anti-codon
complementary triplet codon on the tRNA that base-pairs with the mRNA codon during translation
start codon
codon that begins the chain of amino acids
stop codon
codon that codes to stop the chain of amino acids
okazaki fragments
short segments of nucleotides that are added discontinuously to the lagging strand in DNA replication
replication bubble
structure formed when helicase separates the two DNA strands during replication
replication fork
Y-shaped region where the double-helix is being unzipped into two strands
leading strand
where nucleotides are added continuously towards the fork
lagging strand
where nucleotides are added in short segments
non-coding/template strand
strand whose codons code for mRNA
coding strand
strand of anticodons whose sequence will be the same as the mRNA
pedigree
a diagram that shows how a trait is inherited over several generations –> Huntington’s Disease
trinucleotide repeat
repetition of the same three nucleotides; connect to Huntington’s Disease: more repeats = earlier onset
electrode
device conducting electricity that showed frequencies trinucleotide repeats; because DNA is slightly negative, will move to the positive end
gene pool
total collection of alleles in a population
What were Darwin’s contributions to our understanding of evolution?
wrote The Origin of Species → launched the era of evolutionary biology called his theory ‘descent with modification’, which explains that… all life is connected by common ancestry
& descendants have accumulated adaptations to changing environments over time
fossils
imprints or remains of organisms that lived in the past- show similarities/differences between past and present organisms & reveal extinction of many species
homologies
– underlying similarity but different function
structural and molecular homologies reveal evolutionary relationships & vestigial structures – remnants of features that served important functions in the organism’s ancestors
genetics
mutations and sexual reproduction produce the genetic variation that makes evolution possible, researchers compare genome sequences from many species, counting the nucleotide differences provides information on how long ago different species diverged from a common ancestor → more nucleotide differences means two species have evolved separately for a longer time
species evolve and not individuals?
individual people cannot adapt to changing environments because adaptations occur over generations therefore species evolve over a vast amount of time not individuals
6 conditions for natural selection to occur
variation, overproduction of offspring, competition for survival, differential survival, reproduction, inheritance
