LS15 FINAL STUDY GUIDE 2026
COMPLETE QUESTIONS AND ANSWERS.
⫸ on average, indiv differ in their dna sequence at. Ans: 0.1% of their
bases: 3M differences out of 3B base pairs
⫸ blood. Ans: can isolate cells that came from perpetrators, get to
repeating parts, indication - random population to compare to
⫸ short tandem repeats (STRs). Ans: repeating units, usually 4-5
nucleotides long
diff alleles may repeat different amount of times
call it a locus: location on chromosome
noncoding - doesn't code for any product, protein, built, etc. "junk dna"
⫸ nucleotides. Ans: A, T, C, G
⫸ supposed there are 10 alleles for str 1, each with the same frequency
in the population. what is the likelihood that a random person has the
same genotype as the perpetrator's DNA found at a crime scene? Ans:
1/100 (why???)
,⫸ homozygous. Ans: has to inherit same allele, same for STRs
10, 10 x 12, 14 not homozygous if 10 12 or 10 14
⫸ more questions about possible STR allele combos. Ans: cross them
like a punnett suqare still
⫸ for an str locus -> many (2 or 3 dozen or even more!). Ans: alleles
exist within the population, but each individual can only have two of
them
⫸ many individuals have different. Ans: STR loci: at different pace and
how many of them
⫸ creating a DNA fingerprint. Ans: 1. dna fragment containing each
STR region is amplified. results in huge numbers of those fragments
2. fragments separated by size, using electrophoresis
3. str region is stained on gel
⫸ US combined DNA index system (CODIS) database includes. Ans:
20 STR, scattered across human genome.
⫸ human paternity testing. Ans: analyzing 1 locus
what do the bands represent?
,- represent fragment that's been cut on each side, amount of distance
related to how many repeats there are.
which pair of people are the parents of each?
⫸ dna fingerprinting challenges and controversies. Ans: 1. overlap of
strs
2. how many strs should we compare?
3. how likely is a match? multiply 4 probabilities of matching 1 band by
each other. -> can juries understand this?
4. are there subpopulation differences? does it matter if every person
within a subpopulation has the same alleles for an str? why?
5. do humans make mistakes?
6. how sure do we wanna be?
⫸ what are some things that living systems need? Ans: fuel
1. raw materials for growth
2. energy to do things that won't happen spontaneously (ex: walking,
growing new tissue, adding muscle mass, reproduction)
⫸ fuel comes from. Ans: energy stored in chemical bonds
⫸ who creates energy initially? Ans: photosynthetic organisms
, ⫸ how to release energy. Ans: breaking bonds that are lower
⫸ photosynthesis. Ans: put energy in from the sun, building up bonds in
carbs that are later converted
⫸ photosynthesis is like. Ans: eating in reverse
⫸ what is doing "work". Ans: breaking bonds and reforming new bonds
releases energy that can be harnessed to do "work"
⫸ how do we power machines? Ans: gasoline and many other fuels
but for our purposes: break the bond, form a bond at lower energy,
harness extra energy to do stuff
⫸ hydrocarbons. Ans: molecules with chains of carbon and hydrogen
atoms (5-12 carbons)
⫸ car engines. Ans: combust hydrocarbons, forming new bonds,
releasing energy that can be harnessed
⫸ examples. Ans: heptane (gasoline) has 16 Hs, methane has 4 Hs,
propane has 8 Hs
COMPLETE QUESTIONS AND ANSWERS.
⫸ on average, indiv differ in their dna sequence at. Ans: 0.1% of their
bases: 3M differences out of 3B base pairs
⫸ blood. Ans: can isolate cells that came from perpetrators, get to
repeating parts, indication - random population to compare to
⫸ short tandem repeats (STRs). Ans: repeating units, usually 4-5
nucleotides long
diff alleles may repeat different amount of times
call it a locus: location on chromosome
noncoding - doesn't code for any product, protein, built, etc. "junk dna"
⫸ nucleotides. Ans: A, T, C, G
⫸ supposed there are 10 alleles for str 1, each with the same frequency
in the population. what is the likelihood that a random person has the
same genotype as the perpetrator's DNA found at a crime scene? Ans:
1/100 (why???)
,⫸ homozygous. Ans: has to inherit same allele, same for STRs
10, 10 x 12, 14 not homozygous if 10 12 or 10 14
⫸ more questions about possible STR allele combos. Ans: cross them
like a punnett suqare still
⫸ for an str locus -> many (2 or 3 dozen or even more!). Ans: alleles
exist within the population, but each individual can only have two of
them
⫸ many individuals have different. Ans: STR loci: at different pace and
how many of them
⫸ creating a DNA fingerprint. Ans: 1. dna fragment containing each
STR region is amplified. results in huge numbers of those fragments
2. fragments separated by size, using electrophoresis
3. str region is stained on gel
⫸ US combined DNA index system (CODIS) database includes. Ans:
20 STR, scattered across human genome.
⫸ human paternity testing. Ans: analyzing 1 locus
what do the bands represent?
,- represent fragment that's been cut on each side, amount of distance
related to how many repeats there are.
which pair of people are the parents of each?
⫸ dna fingerprinting challenges and controversies. Ans: 1. overlap of
strs
2. how many strs should we compare?
3. how likely is a match? multiply 4 probabilities of matching 1 band by
each other. -> can juries understand this?
4. are there subpopulation differences? does it matter if every person
within a subpopulation has the same alleles for an str? why?
5. do humans make mistakes?
6. how sure do we wanna be?
⫸ what are some things that living systems need? Ans: fuel
1. raw materials for growth
2. energy to do things that won't happen spontaneously (ex: walking,
growing new tissue, adding muscle mass, reproduction)
⫸ fuel comes from. Ans: energy stored in chemical bonds
⫸ who creates energy initially? Ans: photosynthetic organisms
, ⫸ how to release energy. Ans: breaking bonds that are lower
⫸ photosynthesis. Ans: put energy in from the sun, building up bonds in
carbs that are later converted
⫸ photosynthesis is like. Ans: eating in reverse
⫸ what is doing "work". Ans: breaking bonds and reforming new bonds
releases energy that can be harnessed to do "work"
⫸ how do we power machines? Ans: gasoline and many other fuels
but for our purposes: break the bond, form a bond at lower energy,
harness extra energy to do stuff
⫸ hydrocarbons. Ans: molecules with chains of carbon and hydrogen
atoms (5-12 carbons)
⫸ car engines. Ans: combust hydrocarbons, forming new bonds,
releasing energy that can be harnessed
⫸ examples. Ans: heptane (gasoline) has 16 Hs, methane has 4 Hs,
propane has 8 Hs
