Biology Answers

You have a 750 mL bottle of vodka containing 43 % (w/v) ethanol (MM = 46.07 g/mol = 0.789 g/ml). How many molecules of ethanol are in the bottle

Demonstrate why sickle cell anemia could not have been a Mendelian dominant disease.

 Hint: See data below for the prevalence of the sickle cell anemia allele in various malaria zones.

Group

Unaffected

Carriers

Affected

Nigerians

0.739

0.240

0.019

S. Arabians

0.774

0.211

0.014

Greeks

0.774

0.211

0.014

Hint: Consider the general model for selection: Dq = ((pqw₁₂ + q² w₂₂)/w_avg) – q ; where average fitness (w_avg ) = p²w₁₁ + 2pqw₁₂ + q22w₂₂ and remember that w₁₁ is the fitness of genotype p2; w₁₂ is the fitness of genotype 2pq, and w₂₂ is the fitness of genotype q².

Hint: Use Python or Scrip to stimulate the generational model where the disease allele is dominant (and has lowest fitness) and compare that to when the allele is recessive and has lowest fitness. Finally, consider when the allele is recessive, but the heterozygote has higher fitness than either homozygote. Which simulation best fits the observed data?

The B.1.1.7 SARS-Cov-2 variant has been measured as having an R₀ of 1.1. If the generation time for COVID is 3 days in unvaccinated persons, how many people will be infected starting with an initial cohort of 1 infected individual in one month? *Hint this calculation assumes that unvaccinated people are following the 3Ws.

1.     Define demography. (1 mark)

Demography is a statistical study of population that keeps on changing over time through, birth rates, death, and migration rates.   

is my definition correct?

Speciation is the formation of a new species. Answer the following questions.

a.     You are having a conversation with Cindy, the magic turtle. Cindy is very curious about the formation of species. She tells you excitedly how one species of turtle inhabited the same geographical area, but ended up forming two different species over time. She admits she is a bit surprised by this; she thought that populations needed to be geographically separated from each other in order to form two different species. Explain to Cindy how speciation can occur without geographical separation. Name the type of pathway to speciation that occurred in this case. (3 marks)

Speciation can occur without geographical separation through sympatric speciation. Sympatric speciation is best defined as, when two populations share the same geographic area. Ecological isolation can reduce gene flow, and mutations can lead to genetic isolation. 

 is my answer correct?

a)     Assume the population of Bacteria B completely dies off. Bacteria A are now transferred to an open environment where they have lots of room for growth and a continual supply of food. Over the course of three days, the population of bacteria steadily increases as follows:

Day 1: 1500 bacteria

Day 2: 3000 bacteria

Day 3: 7000 bacteria

Day 4: 13,000 bacteria

Is this population of bacteria r-selected or k-selected? Explain how you arrived at your answer. Hint: Review your definitions of “r” and “k.” (2 marks)

This bacteria is k selected, because k-selected species mature slowly, they have a longer life span and they provide more parental care so that when their offspring matures it can survive in any environment.  is my answer right?

1.     Bacteria A and Bacteria B are considered hardy bacteria and can survive in extreme environments when grown individually. However, when they are grown together in a closed environment (on an agar plate), Bacteria A thrives, while Bacteria B eventually dies off. 

a)     Calculate the density per cubic centimetre of Bacteria A on the agar plate if there are 1500 bacteria on a 100cm³ plate. (1 mark)

Dp=N/A

1500/1000^3

=1.5 x10^-6 

this right?

1.     Bacteria A and Bacteria B are considered hardy bacteria and can survive in extreme environments when grown individually. However, when they are grown together in a closed environment (on an agar plate), Bacteria A thrives, while Bacteria B eventually dies off.

a)     Using your knowledge of competitive exclusion, explain what has happened. (2 marks)

Bacteria A and B are competition for the same limited resource on the agar plate, therefore both can’t live in the same place. So, one bacteria attacks the other until it dies.

 is this answer correct?

the fruit fly, has four pairs of chromosomes in each cell. As it grows, it reproduces more cells via mitosis. How many chromosomes would you expect to find in each new cell?

Can you help me solve this problem and show me the steps to find the answer? 50 dogs, 10 are white fur recessive, 40 are blue fur dominant. The homozgous is .70. What is the ratio dogs that are heterozgous?