Biology 2107                                                                                                                           Fall,  2023

Test #2

 

 

Name: __________________________ Student ID:  __________________

 

 

Please circle the letters that precede the most appropriate answer to the question asked.  Be aware, there is only one answer to each question.  

 

Section 1 (20 pts.)

 

1.         Given that, in barley plants, the allele for tall stalks is dominant over short stalks and the allele for wide

leaves is dominant over thin leaves. Assuming "independent assortment", what would be the best way to determine the genotypes of a given barley plant that exhibits tall stalks and wide leaves?

 

A   Undertake a "Test cross" between a Tall stalk and thin leafed barley plant against itself

B   Undertake a "Test cross" between a Tall stalk and Wide leafed barley plant with a short stalk and wide leafed barley plant

C   Self cross a Tall stalk and Wide leafed barley plant

D    Undertake a "Test cross" between a Tall stalk and Wide leafed barley plant against  a short stalk and thin leafed barley plant

E    Review BIOL2107 notes, just one more time… not a viable option, at this time.

 

2.   How many “valence” electrons does carbon have in its outer shell?

 

A.            2

B.             3

C.             5

D.            4

E.             7

 

3.        In  Labrador retrievers, the allele for a black coloured coat (B) is dominant to the allele for brown fur coat colour (b). However, if a lab has two copies of the "recessive allele" for a "pigment-depositing gene" (e), it can only have yellow coloured fur. In a cross of two doubly heterozygous black labs (BbEe x BbEe), what fraction of the next generation would one expect to have yellow fur?

 

A.            3/8

B.             1/8

C.             1/16

D.            1/4

E.             5/8

 

4.   Given its ability to scrutinize allelic frequencies, the Hardy Weinberg equilibrium can determine..

 

A.             Precisely when a population will become extinct

B.             Precisely when a population became extinct

C.            The geographic movement of a population over time

D.            When a population went through a disaster, such as a “bottleneck”

E.             How long life has been around on earth

 

5.   At which phase in cell division do homologous chromosomes segregate

 

A.             Anaphase II of Meiosis

B.             Prophase I of Meiosis

C.            Metaphase II of Meiosis

D.            G phase 2 of Mitosis

E.             Anaphase I of Meiosis

F.             Metaphase of Mitosis

 

 

6.   If the atomic weight of sodium is 23, and the atomic weight of chlorine 35.5.  When 58.5 grams of sodium chloride are dissolved in a final volume of 2 liters of water, the solution is said to be:

 

A.             0.5 molar

B.             58.5 molar

C.            1 molar

D.            Cannot tell, because you cannot tell whether sodium chloride is formed between ionic or covalent bonds

E.             23 micromolar

F.             12.5 molar

 

7.   Which one of the following statements is a good “generalization” -according to the lectures and lecture notes.

 

A.       Bases accept H+; Acids donate H+

B.       If a compound increases the OH+ ion concentration when added to water, then the compound is said to be acidic

C.      All acids dissolve fully in water

D.     Acids accept H+; bases donate H+

E.     The pH value is defined as the positive logarithm of hydrogen concentration in moles    per liter (molar concentration).

 

8.   Hypertrichosis, hairiness of the pinna of the ear, is inherited as a Y-linked trait in humans. If a man with hypertrichosis and a woman (who doesn’t) plan to have children, as both of them had taken BIOL2107, what is the most likely outcome that they can foresee?

 

A.             All offspring will have hypertrichosis

B.             Half the offspring will have hypertrichosis

C.            All the male offspring would be sterile

D.            Only half the female offspring would express hypertrichosis

E.             All offspring will have phenotypically normal ears

 

9.  RNA molecules are transported from the nucleus to the cytoplasm in eukaryotes through:

 

       A       The rough endoplasmic reticulum.

      B       The smooth endoplasmic reticulum.

      C       The Golgi apparatus.

      D       Nuclear pores

      E       Liposomes

 

10.   If two genes demonstrate "independent assortment", which assumption is most likely true?

 

 G.   Crossing over between the genes does not occur
 H.   The two genes are located on different chromosomes or are far enough away from each other on 
        the same chromosome as to always allow for crossovers to occur.

 I.    The two genes are located in very close proximity to each other on the same chromosome   
 J.   The two genes are located on the X chromosome
 K.    Mendel had something to do with it, and neither is dominant over the other.
 L.   The expression of one gene has NO effect on the expression of the other

 

 

Section 1  (12 pts).
In the next several questions each question is worth 3 pts. 
Please circle your evaluation of the statement given.  If you believe the statement to be “False” then explain why you think so in the space provided.
 
Read each question carefully !

 

11.   With respect to proteins the term Tertiary structure” refers to the 3D organization of various protein subunits in

            a complex protein, resulting in the assembled structure of a series of subunits in to a protein, like haemoglobin. 

 

True                                                               False

 

___this description is for quaternary structure_______________________

 

12.   During Mitosis microtubular spindle fibres attach to the chromosomes through “kinetochores”.

 

True                                                               False

 

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13.       Excluding lipids, macromolecules can be considered to be molecules, whose molecular weight is greater than 999 Daltons.

 

True                                                               False

 

 

14.     The “Golgi apparatus” is an organelle in eukaryotes that modifies newly synthesized proteins for “export”  and/or passage around the cell

 

True                                                               False

 

 

 

 

Section 2 (53 pts)

 

Please answer the following questions in the space provided, using short, concise answers.

 

 

2.1 (6 pts.)

 

(a)  Give an example of a disaccharide and state from what monosaccharide(s) is it formed and how?

 

   ____Sucrose from glucose & fructose,  removal of water (condensation)________________________________

 

or

   ____Lactose from glucose & galactose, removal of water (condensation)_______________________________

  

or

   ____Maltose from glucose, removal of water (condensation)_________________________________________

 

2.1 (6 pts.)

 

            (b)  Define 2 major differences between each the following types of molecules:

 

Carbohydrates and Proteins 

 

            alpha carbon, amino “acid”s  peptide bonds, vs. CHO, fatty acyl side chains, forming or not form

lipid bilayers, or micelles,  true vs false macromolecules, hormones? Waxy or oily

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   Similarities: Fundamentally Carbon, hydrogen and Oxygen , energy storage/source, CH2O___

 

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2.2.  (5 pts.) Briefly discuss the concept of phenotypic changes due to “gene interactions”,

giving at least one specific example of such an occurrence.

 

   _____Epistasis, complementary genes, ABO blood groups etc._____________________________________

 

   _____Labradors. Albino’s Purple Petal colour in pea plants.________________________________________

 

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2.3 (8 pts.)

 

Differentiate between an ionic bond and a hydrogen bond: giving an example

of each.

 

   Diagram

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As opposed to sharing of electrons_____________________________________________________

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2.4.a (4 pts.) Complete the structures of the two molecules below. 

 

           H                                                  H

NH2 – C – COO -                       NH2 – C – COO-

            I                                                    I

 

 

 

 

 

2.4.b (2 pts.) Explain what makes each of your drawn structures important.

 

 

  

A group of images of different types of molecules

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2.5. (6 pts.) Differentiate between “X”-linkage and “autosomal” linkage.

 

 

             X-linked inheritance is a pattern of inheritance in which the transmission of traits depends on the genes in the sex chromosomes. Only one ZX in males, therefore NO recombination and whatever is on the X chromosome will be expressed. 

Autosomal linkage is when proximal gene pairs on the same chromosome don’t undergo recombination (through chiasmata) with each other to the same extent as they normally would do, and the parental associations are “more frequent”.

 

 

2.6 (6 pts.) What is the difference between “Exergonic” and “Endergonic” reactions

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Exergonic : means "releasing energy in the form of work". In thermodynamics, work is defined as the energy

moving from the system (the internal region) to the surroundings (the external region) during a given process.

Negative Gibbs free energy.

 

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Endergonic:  chemical reaction in which the standard change in free energy is positive, and an additional driving

force is needed to perform this reaction. In layman's terms, the total amount of useful energy is negative

(it takes more energy to start the reaction than what is received out of it) so the total energy is a negative net result. 

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2.7. (5 pts.)

 

What’s the difference between “wild-type trait” and a “dominant trait”?  Please give an

example of a dominant trait that is NOT the “wild-type” trait.

 

____Wild  type allele is the allele that is present most in a population, and can be either dominant or recessive (or neither).

 

Dominant allele is the allele that will normally show through, even in the presence of its “recessive” allele 

 

_eg.  Huntington’s disease._____________ ____________________________________________________

  

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2.8. (5 pts.) 

 

The frequency of two alleles in a gene pool is 0.20 (A) and 0.80(a).

 

If you assume that the population is in Hardy-Weinberg equilibrium

Calculate the percentage of individuals with homozygous recessives for this particular gene in this population.

______p2 +2pq+ p2 =1 _____________________________________________________________________

 

______0.8 x 0.8 =   0.64  = 64%___________Do not need to calculate the value all the way______________

  

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BONUS

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