exam 2 BSC 2010 spielbauer Flashcards
inheritance
traits passed from parents to offspring
blending inheritance
theory that genes of a child are a mix of the the parents
particulate inheritance
there are specific genes (parts) that are passed down from each parent, not just a mix of them
gregor mendel
father of genetics, did pea plant experiements, discovered particulate inheritance
cross-fertilization
fertilizing one plant with another plant
self-fertilization
fertalizing a plant with itself
character
observable physical features
trait
forms of characters (wrinkled vs smooth seeds)
true-breeding variety
always same color flower when crossed, same traits as parents
reciprocal cross
each plant recieves and donates pollen between each other
monohybrid cross
true breeding purple x true breeding white -> f1 -> selfed -> f2
P Generation
The parent generation, the originals
F1 generation
the first filial (child) generation
F2 Generation
the children of the F1, second filial generation
Gene
discrete particulate factors
Locus
place where DNA is
Allele
diff versions of the same gene
Genotype
what their genes are, ex AA or aa
Phenotype
How that gene is expressed, ex wrinkled or smooth
Dominant vs Recessive Allelle
Dominant is expressed over recessive
Law of Segreation
Allelles are segregated equally in gametes
Genotypic ratio
how their alleles were in relation (1:2:1)
Phenotypic ratio
how their appearance was in relation (3:1)
Test Cross
plant dominant phenotype (A-) is crossed with homo recessive (aa)
- Explain the differences between blending inheritance and particulate inheritance. What evidence did Mendel’s monohybrid cross uncover that supported particulate inheritance and didn’t make sense with blending inheritance?
blending inheritance suggests that the genes mix together - in the monohybrid cross, it wouldn’t make sense that there are 3 purple flowers and one white, they would all be light purple. In the next generation, it wouldn’t make sense that that 2 purple flowers would result in a white flower.
- Describe the two ways that Mendel controlled the mating of pea plants (involved pollen transfer) so he could know which parents produced specific offspring.
cross fertilization, chose the specific plants that he would transfer pollen to, and then also did a self hybrid in which he put the pollen on the same plant.
- What was the goal of Mendel’s experiments? What was he trying to understand?
How genes were passed on, and explain phenonmenon that did not makes sense with the idea of blending inheritance
- Explain the process that Mendel went through to do his monohybrid cross. Explain how he created the Parental generation, and F1 generation, and the F2 generation. What were the phenotypic ratios of each generation?
parental gen was created by true breeding crosses, f1 resulted in monohybrids(all Aa), and then f2 resultd in the 3:1 phenotypic ration and 1:2:1 genotypic ratio
- What patterns did Mendel observe in all 7 of his monohybrid crosses? How did the phenotypes present change from generation to generation? What about the phenotypic ratio in the F2 generation?
3:1 phenotypic ratio in the f2 generation
- Explain what is meant by the underlying 1:2:1 “potential offspring” ratio that Mendel saw in the F2 generation of his pea plant crosses. How did he find this underlying ratio? Why could some of the purple flowers produce white offspring, while the other purple flowers could not?
Some could produce white offspring because they both had the recessive allelle, and they could create a flower that had both recessive allelles so they became white, found the potential ration in the f3 generation
- Be able to define and explain the relationship between the terms: genes, alleles, genotype, phenotype, dominant, recessive, homozygous, and heterozygous.
genes are made up of allelles. the genotype is the allelles that an organism has and the phenotype is how they are expressed. Dominant genes express over recessive genes, and a homozygous organism has 2 of the same allelle and a heterozygous organism has 2 different allelles.
- Explain the Law of Segregation. What does it mean? And how does it relate to Mendel’s experiments?
each gamete recieves only one copy of an allelle
- Following the Law of Segregation, what alleles will an individual with Aa genotype put into each gamete? What about AA genotype? Or aa?
Aa (A, a, A, a) AA (A,A,A,A) aa(a,a,a,a)
- What is a Punnett square? What does it allow us to visualize? What do you write on the sides of the square, and what do you write in the intersections in the middle?
helps to vizualize the genetic probability of offspring
- Describe how a test cross works. What do these allow you to do?
allows you to find the genotype of a unknown dominant plant - if thye have white offspring they are hetero
- Imagine you did a test cross between an individual with a dominant phenotype but unknown genotype (A_) and a homozygous recessive individual (aa). If you got a phenotypic ratio of 50% dominant and 50% recessive, what genotype must the dominant parent (A_) have? Making a Punnett square may help.
Aa, because there is no way for the recessive phenotype to appear with a AA for the parent.
multiplication rule
multiply independt events to find the prob that they will both happen
independent events
one does not influence the other, the probabilities are seperate
addition rule
add probs of mutally exclusive events to find the probability of either happening (or)
mutually exclusive events
dont have anything to do with the other
law of independent assortment
genes are seperate from each other and go into gametes seperately
dihybrid cross
pairs of traits to show tht they assort independently
pedigree
diagram that shows the inheritance pattern in a family
rare dominant allele
dominant, but rarely expressed (every affected individual has affected parent)
rare recessive allelle
heterosygotes can carry but many not be affected (2 heterosygotes can result in the affected offspring with a ratio of 3:1 affected)
- Explain why it is possible for a Rr x rr cross to produce offspring that are all rr.
because everything is just probability, each child has a 50% chance of being rr
- Why can we relate pennies to genotypes and flip outcomes to alleles? Think about the Law of Segregation.
This is because each allelle has an equal chance of being in the gamete, so it is all chance just like a coin flip
- Explain the basic rules of probability. What is the probability of a guaranteed event, an impossible event, or an event with multiple outcomes?
100%, 0%, < 100%
- What is the probability of you and another person independently flipping pennies and both landing on heads? What rule of probability are you applying here?
1/4, multiplication
- Explain the Law of Independent Assortment. What does it imply about the possible combinations of alleles when you are looking at the inheritance patterns of two genes? (If alleles of different genes can assort independently, will you always see the same combination of alleles? Or can there be any combination?
since they assort independently, and two genes can be in any combinations. They aren’t linked to each other. for example, green peas dont necearrisly have to be round or yellow peas don’t neceassrily have to be wrinkly, its all about the probabilyt of them happening together.
- Assume you found that the probability of producing yellow seeds in a monohybrid cross is 3/4, and the probability of producing wrinkled seeds from a different monohybrid cross is 1/4. If the alleles follow the Law of Independent Assortment, how would you calculate the probability of yellow and wrinkled seeds being produced in a dihybrid cross? (Remember the rules of probability)
3/4 x 1/4 = 3/16
- Describe how Mendel did his dihybrid cross. How did the process compare to his monohybrid cross?
he tracked two different traits instead of just one
- Assuming alleles follow the Law of Segregation and the Law of Independent Assortment, what possible alleles can be given by the genotype RRYY? What about rryy? Or RrYy?
RRYY(RY, RY, RY, RY) rryy (ry, ry, ry, ry) RrYy(RY, Ry, rY, ry)
- What is a pedigree? What do they show us, and how are they useful? How do they relate to Mendel’s laws of Segregation and Independent Assortment?
shows patterns of familial inhertiance, can show how traits are given and then expressed in each generation and how it is random
- Describe the patterns seen in the pedigree of a rare dominant allele.
every affect person has an affected parent
- Describe the patterns seen in the pedigree of a rare recessive allele.
often hidden until two heterosygous parents have a kid, and the kid displays the trait.
Chromosomal Theory of Inheritance
chromosomes follow mendels laws, and thats how/why they work
Sex-linkage
breaks law of segregation, genes may only be carreid on specific sex chromosomes
sex chromosomes
xx (female) xy(male)
gene-linkage
genes taht are close to each other on the same chromosomes are usually assorted into gametes together (breaks law of independent assortment)
sex-linked inheritance
traits associated with a particular sex
x-linked recessive
males are much more likely to have them, have affected maternal grandfathers and can only pass it to their daughters
thomas hunt morgan
demonstrated that traits could be carreid on sex chromosomes - mostly on eye color in fruit fliies
hemizygous
only one copy of some genes, males
wild type
the more common one in the wild
alfred sturtevant
morgan’s student, discovered crossing over
gene mapping
map the genes on the allelle using percentages, can predict whehter the genes are more likely to cross over or not
centrimorgans(cM)
measurement of gene mapping on an allelle
- How is the law of segregation seen in the segregation of alleles and homologous chromosomes into gametes?
each gamete gets one copu of each homologous chromosome
- How is the law of independent assortment seen in the segregation of alleles and homologous chromosomes into gametes?
chromosomes are assorted into gamete independently of one another
- How does sex-linkage break the law of segregation?
since genes are sometimes only carried on one chromosome, females can only give an x an and males can only give an y to a son
- How does gene-linkage break that law of independent assortment?
its not exactly completely random as genes taht are closer together on chromosome are usually assorted into gametes together
- What is sex-linkage, and what piece of evidence did it provide that helped support the chromosomal theory of inheritance?
when genes are on a sex chromosome, and it supported the idea that genes are on chromosmes
- What is gene-linkage, and what piece of evidence did it provide that helped support the chromosomal theory of inheritance?
when chromosomes cross over, they are likely to stay together if they are closer, meanign that the recombinant frequence is lower - doesnt always happen
- What is sex-linked inheritance? What are the common features of a rare recessive x-linked disorder? How does sex-linkage help explain these patterns?
affects son, affects his maternal grandfather, daughters are carriers
- Describe Thomas Hunt Morgan’s experiment that led to the discovery of sex-linkage.
flies, red eye father, white eye mother, white eye son, which shows how the mother can give x chromosome to the son, also how the father’s dominant red eyes did not give the son red eyes /
- Explain why males cannot give an X chromosome to their sons but can give one to their daughters.
because for the son they have to give a y chromosome
- Explain how gene mapping works. What can we infer about genes by comparing the percent of recombinant offspring in crosses like Morgan’s (AaBb x aabb)?
if the recombinant percentages are high, they are likley far way from each other on the chromosome, and if they are low, they are likely close together
- What does a smaller percentage of recombinant offspring imply about the relative location of two genes on a chromosome? (in an AaBb x aabb test cross)
they are probably close together
- What does a larger percentage of recombinant offspring imply about the relative location of two genes on a chromosome? (in an AaBb x aabb test cross)
farther away from each other
- What does having 50% recombinant offspring imply about the relative location of two genes? (in an AaBb x aabb test cross)
farthest apart from each other
- If you got a recombinant frequency of 15% between genes A and B, a recombinant frequency of 10% between A and C, and a recombinant frequency of 5% between genes B and C, which gene would be between the other two on the chromosome?
A C B
incomplete dominance
intermediate phenotype
codominance
2 allelles of a gene display both at the same time ( blood)
discrete traits
clear categories depending on the allelles (purple v white flowers)
quantitiative traits
vary within a range (height, weight, etc)
polygenic trait
character affected by multiple genes (wheat kernels have 3 diff geners taht contribute to color)
pleiotropy
one gene affects multiple characters (gene for a diseases affects other parts of the body
epistasis
one gene can influence anothers gene’s impact on a character
phenotypic plasticity
enviornment can influence a gene’s impact on a character
lethal allele
causes the death of an empbryo when homozygous
lateral gene transfer
transfer of genetic material between individuals
conjunction
transfer of DNA between prokaryotes
transformation
DNA from the enviornment into the prokaryote
transduction
tranfer from one p to another through a virus
plasmids
circular DNA molecule distinct from the chromosome in prokaryotic cells
sex pilus
initiates contact btw cels
conjugation tube
tube that allows info to pass from donor to recipient (not recprical)
antibiotics
kills bacteria
antibiotic resistance
bacteria that survives passes on its resistant genes so the bacteria contineus to survive
alexander fleming
discovered penicillin the first antibiotic
- Diploids can only carry two copies of a gene in their cells. How is it possible for a gene to have more than two alleles?
it has other alleles, each diploid jsut carries two
- Explain the difference between incomplete dominance and codominance. (This can be tricky. Remember that incomplete dominance is the dominant allele not being fully dominant over the recessive, compared to codominance is two dominant alleles not being able to block the phenotype of the other, so they are both present.) Refer to the examples from class to make sure you know the difference.
incomplete results in the blending of the two phenotypes (light purple eggplants), whereas codominance displays both phenotypes fully (blood)
- Compare/contrast discrete and quantitative traits.
discrete -> either or , purple or white quantitiative -> scale, height weight
- Compare/contrast a polygenic trait and pleiotropy.
polygenic -> multiple genes influence one character
pleiotropyy -> one gene affect multiple characters
- How can pleiotropy allow one gene to impact multiple characteristics?
cycstic fibrosis, causes a problem that shows up in multiple places in the body
- What is epistasis? Describe an example.
one gene influences the expresssion of the other -> labs, they have one gene that says whether they are black or brown and another that says whether the color is deposited or not (if not they are yellow)
- What is phenotypic plasticity? Describe an example.
organisms phenotypes are variable depending on the enviornemnt
- What are lethal alleles? Describe an example. How are lethal alleles able to be maintained in a population?
allelles that kill the animal as an embryo, maintained through heterosygous carries who dont express it but can pass it on
- Describe lateral gene transfer, and compare it to vertical gene transfer (from parents to offspring).
one prokaryote to the next, not through parents and offspring
- Name and describe the three ways that prokaryotes use lateral gene transfer.
conjunction - create a lol conjunction tube and send over DNA, transformation - incorporation of genetic materal from the enviornment, transduction, prokaryote to virus to another prokaryote
- Describe the steps involved in bacterial conjugation involving the transfer of plasmids.
plasmid transfered through conjugation tube as a single strand, and then the other strand is recreated in the donor and recipient
- Explain antibiotic resistance and how it can spread in a population of prokaryotes. Why is this a problem?
the living bacteria have the genes to resist the antibiotic and then they lateral gene transfer to the other ones the stay alive genes and then they grow back stronger
DNA binding dyes
developed in the early 1900s
flow cytometry
tracked the amoutn of DNA, - S, G2, and M had twice as much DNA compareds to G1
transformation experiment
found that bacteria could incorporate env DNA into their own
r strain
non-deadly strain, when present with heat killed s strain, can be deadly
s strain
deadly strain, when heat killed is non deadly
dna-degrading protein
when added, the mice did not die
hershey-chase experiment
bacteriophages (virus) inject either a protein or DNA into bacteria to replicate themselves- found they injected DNA
bacteriophages
virus taht injects DNA into bacteria to repliate the virus
32 p isotope
tags the DNA
35 S isotope
tags the protein
centrifuge
whirly thingy that seperates the viruses and the bacteria, bacterial cells on the bottom
pellet
the lower part - had viral DNA
supernatant
upper part, proteins and the virus
nitrogenous bases
purines ( adenine and guanine) pyramindes (thymine and cytosine (smaller)
adenine
purine, big, binds with T
guanine
purine big, bind with C
thymine
pyraminde (small), binds with A
cytosine
pyramidine (small), bind with G
purines
A+G
pyrimidines
T + C
erwin chargaff
discovered that there was an equal amount of purines to pyrimidines
rosalind franklin
created an image of the atoms in DNA
x-ray crystallography
xray source to a lead screan to aDNA sample that imprinted on a photographic plate
watson and crick
combined the knlowdge of DNA to determine the strucutre
antiparallel strands
found taht the strands must be the opposite of the other
complementary base pairing
A must go with T and C must go with G
semiconservatie replication hypothesis
each parental strand is a template for a new strand
conservative replication hypothesis
both strands act as a single tamplate and produce one fully daughter molecule
dispersiec replication hypothesis
parent is dispersed among 2 daughter molecules
meselson stahl experiment
found that DNA replication was semi conservative
15 n
dense DNA indicator
14 n
the medium, the default
DNA replication intiation
unwindig the double helix and synthesizing RNA primers
dna replication elongation
synthesizing new strands of DNA using each of the strands a a template
dna repliation termination
ends the synthesis of DNA
replication bubble
forms at the origin, creates a big bubble and lil forks pop up to start teh replication
replication fork
lil pieces that are ready to start the dna repliation, look more like combs tbh
DNA helicase
unzips ur genes
topoisomerase
untwists the DNA so it doesnt look like a twizzler
primase
creates short RNA strands that start the DNA
primers
lil RNA strands that start the DNA
dna polymerase
attaches to the primers and adds nucleotides to the 3’ end
5’ end
beginning
3’ end
end
leading strand
built continuously
lagging strand
built discontinuously
okazaki fragments
lil discontinous fragment
DNA ligase
joins the okazaki fragments together
end- replication problem
when the replication fork reaches the end of the chromosome, the leading strand is complete but the lagging strand has a lil piece cut off so the chromosome keeps getting shorter
telomeres
reptitice non-coding sequences at the ends of eukaryotic chromosomes to protect coding regions
telomerase
adds telomeres back on
- What was the circumstantial evidence that DNA is the molecule of inheritance? List and describe how each piece of evidence was discovered.
dna is present in the cell nucleus and in chromosomes, doubles during hte s phase of the cell cycle and there is twice as much in diploid cells vs haploid cells
- Describe the Transformation experiment, and how it provided strong evidence that DNA is the molecule of inheritance.
r strain and s strain, r strain is non deadly and the s train is deadly. when heat killed, the s strain is non deadly, but when added to the r strain it becomes deadly again. this is because there is DNA being communicated between the 2. Then when adding a dna degrading protein, it is non deadly again, meaning DNA is what is transferring genetic information
- Describe the Hershey-Chase experiment, and how it provided strong evidence that DNA is the molecule of inheritance.
bacteriophages are virsuses that inject something into bacteria to create more of themselves. In order to see what they injected, they radioactively tagged phosporous (to identify DNA) and sulfur (to identify proteins) and put them in a centrifuge. They knew the virus would be on the top and the bacteria would be on the bottom, so they wanted to see which tagged thing would be on teh top or bottom. dound phosphorous on the bottom, concluded they were injecting DNA
- List the chemical components that compose DNA. Compare/contrast purines and pyrimidines.
phosophate and deoxyribose backbone, nucleic acid bases, adenine and guanine are purines and cytosine and thymine are pyrimidines. purines are bigger
- Describe the discovery made by Erwin Chargaff regarding the ratios of the bases found in DNA. Think about why these ratios help in our understanding DNA structure and function.
the amount of A and G = the amount of C and T
- Describe the discovery made by Rosalind Franklin regarding the shape of DNA.
discoveredi t was a helical molecule
- Describe the discovery regarding the structure of DNA that Francis Crick and James Watson found that Rosalind Franklin also discovered.
found that it was a helix with antiparallell strands
- Given everything discovered regarding the makeup and shape of DNA, describe its structure. What aspect of its structure allows both strands to contain the same genetic information?
anti parallell strands with complementary base paring so taht it can contain information in both strands
- Describe the three DNA replication hypotheses.
semi conservative - each strand gets a complemantary strand to create 2 new strands
conservative - original dna creates an entirely new copy
dispersive - the new and old dna is dispersive and share parts
- Describe how the Meselson-Stahl experiment was performed and how it provided evidence for the semiconservative DNA replication hypothesis.
n15 isntead of n14, but put in a n14 medium, and then the dna replicated - > first time, created intermediate weight DNA and then the second time it was have heavy and half light
- List and briefly describe the three steps of DNA replication.
intiation - elongation - termination
- Describe the initiation of DNA replication. Explain the function of DNA helicase, topoisomerase, primase, and primers.
repliaction bubble forms, replication forks form, and helicase unzips the genes while topoisomersase makes sure they dont turn into a twizzler, primerase makes primers which are little RNA segments that start the DNA
- Describe the elongation of DNA during replication. Compare/contrast the elongation of the leading and lagging strands. Which one is composed of Okazaki fragments? What does that mean, and how are they combined into a single, continuous DNA strand? Explain this process and the components involved.
lagging is made up of okazaki fragments because its made up of lil pieces taht ligasse stitches together. leading strand is chillin and continues onward and completely finishes
- Describe the termination of DNA replication. Compare/contrast termination when replication forks meet, when the leading strand reaches the end of the chromosome, and when the lagging strand reaches the end. What problem occurs when the lagging strand reaches the end of the chromosome? Why is this an issue?
leading strand ends normally, whole thing is replicated, where as the lagging strand has a little bit cut offf, but its ok bc telomeres
- Describe the end-replication problem. How are we able to overcome this problem?
at the end of replication a bit of DNA is cut off
- Describe what a telomere is and how they work.
little bit at the end of the chromosome that doesnt mean anything
- Describe telomerase and how it functions.
creates new code for the telomere so taht they can keep getting cut off
somatic mutation
occur in somatic/body cells - can impact individual but do not impact offspring
germline mutation
occur in gametes and are passed to offspring and future generations
incorporation error rate
the probability that an incorrect base wll be inserted is about 1 in 100,000
nucleotide mismatch
when an incorrect base is input and it doesn’t match - quickly repaired
proofreading
when it recognizes a mismatch, backs up and then fixes itself
mismatch repair
protein complexes scan the DNA for wacky hydrogen bodning and removes/replaces the nucleotide
mismatch repair protein
protein complexes scan the DNA for wacky hydrogen bodning and removes/replaces the nucleotide