Genetics & Evolution

Question 1

If we insert the human gene for insulin into bacteria, the bacteria will produce human insulin. How is this possible?

Answer 1

Because bacteria can reproduce asexually, cells can code and decode to proteins as normal humans

Question 2

Since all the cells in a person’s body contain the same DNA, why do only our pancreatic cells produce insulin?

Answer 2

Because some of our cells can be turned on or off to fulfill certain functions

Question 3

After sequencing a molecule of DNA, you discover that 20% of the bases are cytosine (C).
What percentage of the bases would you expect to be guanine (G)? What percentage of the bases would you expect to be thymine (T)?

Answer 3

There will be 20% Guanine because Guanine and Cytosine are complimentary, this leaves 60% to be Thymine

Question 4

Since DNA is contained in the nucleus of eukaryotic cells but protein synthesis occurs at ribosomes outside of the nucleus, how is the information in DNA conveyed to the ribosomes?

Answer 4

Through mRNA and transcription

Question 5

How many nucleotides are necessary to code for a protein that is 100 amino acids long?

Answer 5

300 (1 amino acid = 3 nucleotides)

Question 6

The DNA coding strand for a gene is AGT ATG GCC CGT ACA and reads from left to right. What messenger RNA would be sent to the cytoplasm? What about the amino acid (AA) sequence?

Answer 6

UCA UAC CGG GCA UGU

Question 7

How many different types of gametes could a person with the genotype AABbCc produce?

Answer 7

4 types of gametes
ABC Abc ABc AbC

Question 8

DNA paternity testing has become the most widely accepted method for establishing who the father of a child is when there are doubts. In one case the mother refused to supply a sample of her DNA, but the man claiming to be the father had his DNA and that of the baby’s taken and analyzed. Is it possible to establish who the father is in this method even if the mother’s DNA is not available to compare?

Answer 8

Yes, because the child receives equal DNA from the mother and father, because you are testing for DNA from the father the mother’s DNA is not needed

Question 8

For some time, Russian prisons have been running on drastically reduced budgets. As a result, when inmates contracted tuberculosis (TB; caused by an infection of the lungs by a particular bacteria species), treatment with antibiotics was often halted before all TB bacteria had been killed by the antibiotics in an infected prisoner. It is now observed that strains of antibiotic resistant TB have appeared in the Russian prison population. Such strains have now reached the United States when freed prisoners have emigrated. Based on what we’ve learned so far this semester, what might provide a scientifically valid explanation of the appearance of antibiotic-resistant TB?

Answer 8

They became resistant to tuberculosis because they were not given enough/strong enough treatment to eliminate TB

Question 9

What are the possible genotypes for a man and woman with color blindness and for a man and woman with “normal” color vision?

Answer 9

• Male colorblindness Xby
• Male normal XBY
• Female colorblindness XbXb
• Female normal XX

Question 10

A color-blind woman married a man with “normal” color vision, and they have children.
What percent of their male children will be affected by color blindness?
What percent of their female children will be affected by color blindness?

Answer 10

100%, 0%

Question 10

A “normal” man is going to marry a “normal” woman who already has had a color-blind son by
another man. What are the probabilities of this new marriage producing a color-blind child?

Answer 10

25% chance of being colorblind

Question 11

Genetic inheritance is being studied in a certain species of plant in which orange flower color (O) is dominant to white (o) and round leaf shape (S) is dominant to oval (s). A true-breeding orange-flowered, round-leaved male plant (Plant A) is mated with a true-breeding white-flowered, oval-leaved female plant (Plant B) to produce a dihybrid offspring plant (Plant C). Assuming normal Mendelian genetics and independent inheritance of these two traits, which gametes might be produced by PlantC?

Answer 11

Oo,So,Os,Ss

Question 12

Suppose male fruit flies with the HHNN genotype mate with female flies with the hhnn genotype. H=hairy legs, h= hairless legs; N= normal wings, n=shriveled wings. About what percentage of offspring flies will have hairy legs and normal wings?

Answer 12

100%

Question 13

What are the mechanisms of evolution? How do they differ?

Answer 13

Mutation refers to the change in the genetic makeup of an organism affecting the gene pool of a population.

gene flow is the transferring of alleles from population to population

Genetic drift is the effect of chance on a population’s genes pool

Natural selection is the greater chance of survival based on favorable traits

Question 14

Natural selection, Darwin argued, was an inevitable outcome of three principles that operated in nature. Explain each of these principles.

Answer 14

The first principle Darwin argued was that the characteristics of an organism were to be passed down from parents to their offspring.

The second principle was that organisms are in competition for resources because the population of organisms outweighs that of resources necessary for survival

The last principle is that offspring who inherit characteristics better suited for their environment are more likely to survive than others with less favorable characteristics

Question 15

Variation is important for evolution, because it provides the fitness differences upon which natural selection operates. Sexual reproduction is an important source of variation in plants and animals, but what about asexually reproducing organisms like bacteria? Where does their variation come from?

Answer 15

Asexual reproduction means that the offspring are exact copies of their parent organism, variation does not occur unless a mutation was to pass onto the organism

Question 16

The Phoenix Zoo kept the only remaining population of Arabian Oryx for ten years in captivity. Finally,when the captive population was high enough and the habitat was better protected in Arabia, some of these Oryx were shipped back to Arabia and released into the wild. In the wild most of the newly released Oryx died of starvation, overheating or were killed by predators. Why is this result not unexpected?

Answer 16

Because these animals had adapted to their lifestyle in that of the zoo, they were not accustomed to the lifestyle needed to survive in the wild like hunting for food, finding shelter, and fighting diseases and predators. Because of this they could not survive once they were released.

Question 17

On a yachting trip in the South Pacific you discover a previously unknown island. You notice that there is a population of especially fluffy and particularly cute long-eared rabbits living there. These rabbits seem to have no predators at all on the island, and their mating habits seem to be perfectly random. When they are first surveyed, they have an average ear length of about 18 cm. When they are sampled again in five years, what will likely be true of their ear length? What about the offspring number?

Answer 17

Their ear length will likely remain the same because they have no environmental pressures forcing them to adapt in any way, this also includes how many offspring they produce. The offspring number and ear length will remain constant.

Question 18

Consider a population of spiders. Because the particular birds that are the main predators of these spiders have trouble locating lighter spiders, the darker spiders are eaten more often than the lighter ones. However, the darker spiders have an advantage over the lighter ones in finding and catching insect prey. What is likely to happen over many generations to the coloration of the spiders?

Answer 18

The coloration of the spiders over generations depends on which trait/color is fitted for the environment the best.

Question 19

Compare and contrast various forms of learning including habituation, imprinting, associative learning and cognitive learning and recognize examples of each.

Answer 19

Habituation: an animal stops responding to a stimulus, for example a dog fears a vacuum and runs away each time it comes close to it but over time the dog becomes familiar with it and no longer runs away

Imprinting: early in an animal’s life it begins forming attachments for example, a baby bird will recognize its mother and will continue to follow her around

Associative learning: learning through interactions both consciously and unconsciously, for example touching a hot pan makes you jerk your hand away and you learn to not touch a pan while it is hot.

Cognitive learning: learning through problem solving and critical thinking, for example asking students to reflect on what they have learned

Question 20

Why are certain birds more likely than mammals to form monogamous pairs?

Answer 20

Birds are more likely to form monogamous pairs because it is more work to care for their offspring, one parent is not sufficient enough to care for their offspring, one is in charge of taking care of the eggs and the other hunting for food.

Question 21

Among sexually reproducing species, females tend to have more choice in selecting a mate than males. Why?

Answer 21

Because they have more to lose if they choose poorly

Question 22

What is DNA made of? What is its charge?

Answer 22

Nucleotides and it is negatively charged

Question 23

What is the synthesizing enzyme for DNA called?

Answer 23

DNA Polymerase

Question 24

How are genes turned on and off?

Answer 24

Genes are turned on and off through a process called “gene regulation,” where proteins called transcription factors bind to specific regions of DNA to either allow or block the process of transcription

Question 25

What are two ways of tracking traits through generations? What are some advantages and disadvantages of each method?

Answer 25

Punnett square is one of the methods to track traits, but a disadvantage is it can only work for small samples. Another method is the pedigree tree which can track families over generations unlike punnett squares.

Question 25

Provide an example of how an organism carries a recessive trait but it is not expressed in its phenotype.

Answer 25

Recessive alleles are not visible unless they are homozygous recessive (ex: xx). When they are heterozygous dominant (Xx) the dominant trait masks the recessive trait so visibly it is impossible to tell if an organism carries a recessive trait or is homozygous dominant.

Question 26

What is speciation?

Answer 26

Forming of a new species

Question 27

What is natural selection?

Answer 27

Higher chance of survival for individuals of a population who have more favorable heritable traits that evolve over time

Question 28

What is convergent evolution?

Answer 28

Convergent evolution is when different species develop similar structures

Question 29

Heritability values can range between 0 and 1. What does a value of 0.5 mean?

Answer 29

A 0.5 value means that half of the trait is influenced by genetics while the other 50% is due to environmental factors.

Question 29

How would you design an experiment to test the effect of a certain fertilizer on growth of a plant?

Answer 29

To design a controlled experiment to test the effect of fertilizer on plant growth, you would need two groups of plants. One group would be the experimental group and would receive the fertilizer, while the other group would be the control group and would not receive the fertilizer

Question 30

What are homologous traits? Provide an example.

Answer 30

Homologous traits are shared traits from two species, for example, wings of a bird and an insect are homologous

Question 31

What do the heritability values 0 and 1 mean?

Answer 31

0 means genetic factors do NOT influence trait varience while 1 means trait varience is completely under genetic control.