Biology Answers

When comparing DNA and RNA ... WHICH ONE IS CORRECT?

RNA does not contain a phosphate group

RNA is a double helix where DNA is a single helix

RNA does not exist in the nucleus

Uracil replaces Thymine in RNA

Describe the general structure and function of a neuron and myelin sheath, explaining the formation and transmission of an action potential, including all-or-none response and intensity of response; the transmission of a signal across a synapse; and the main chemicals and transmitters involved; i.e., norepinephrine, acetylcholine and cholinesterase.

Preparation of the correct buffer is key to any good biological experiment and it is important that you understand how to calculate the mass of each chemical required to make that buffer and what the resulting concentration of those constituents will be in moles per litre.

Your text book explains that moles are just a way to express the amount of a substance, such that one mole is equal to 6.02 x 10²³ particles of that substance. These particles can be can be atoms, molecules, ions etc, so 1 mole of water is equal to 6.02 x 10²³ water molecules, or 1 mole of Na⁺ is equal to 6.02 x 10²³  Na⁺ ions. Since different chemicals have different molecular weights (based on the number of protons and neutrons each atom contains) 1 mole or 6.02 x 10²³ atoms of oxygen (O) will have a mass of 16g whereas 1 mole or 6.02 x 10²³ atoms of sodium (Na) will have a mass of 23g

If you need more information on moles, please read Encyclopedia Britannica's Moles website. 

Although you may sometimes see it written as g/litre, the concentration of solutions is more often described in term of molarity since it better defines the chemical properties of a solution because it is proportional to the number of molecules or ions in solution, irrespective of molecular mass of its constituents. However, it is not possible to measure moles on a laboratory balance, so in the first instance chemicals are measured by mass (milligrams, grams, kilograms etc) and the number of moles is calculated using the known molecular mass (often called molecular weight and abbreviated to M.W.) of the chemical. As indicated earlier, the molecular mass of a chemical is based on the number of protons and neutrons that is contained in each atom (eg NaCl is made up of one molecule of Na, M.W. = 22.99g and one molecule of Cl, M.W. = 35.45g, so the M.W. of NaCl is 58.44g). These values can be found in the periodic table however the molecular mass of chemicals is generally provided by any vendors of the products and so can also be found on various suppliers’ websites.

When the concentrations of solutions are as described as ‘molar’, this refers to number of moles per litre eg a 3-molar solution of NaCl will contain 3 moles of NaCl in 1 litre of water. As indicated above, the M.W. of NaCl is 58.44g, so in 58.44g there are 6.02 x 10²³ NaCl molecules ie 1 mole. So, for 3 moles of NaCl you would need to dissolve 175.32g in 1 litre of water (175.32/58.44 =3) whereas If you only dissolved 29.22g of NaCl in 1 litre of water this would result in a 0.5 molar solution (29.22/58.44= 0.5)

1.     As directed you need to check the periodic table and pick up the atomic masses for each of the component atoms in the compounds. For example, for NaCl you need to pick the atomic weight of both sodium and chlorine and then add them to two decimal places to obtain the molecular mass of NaCl. Be sure to multiply the atomic masses by the number of individual atoms of the same element present in each compound before finally adding to the masses of other component atoms of other elements to make up the total molecular masses. 

2.     From there you can calculate the number of 'moles' of each compound by multiplying the provided weight of compound used in the PBS solution by their respective molar mass conversion factors (i.e. 1L divided by the molecular mass you have calculated in the first step) 

3.     Now, the molarity in Mol per Litre (mol/l) is given by the 'number of moles' of each compound (calculated in step 2 above) divided by the given volume of the solution.

For more information on how to calculate morality, refer to wikiHow's 4 Ways to Calculate Molarity.

Using periodic table found in your textbook, calculate (to 2 decimal places) the molecular mass for each of the compounds used to make PBS.

Create the following table and fill it in with the mass of each component required to make 1 litre of 10 x PBS (the recipe for 10x PBS is below question 2) and their final molar concentration in the buffer calculated as described above.

Compound formula

Molecular mass (in g/mol)

Mass of compound per litre of 10x PBS (in g)

Molar concentration (in mol/l)

NaCl

KCl

Na₂HPO₄

KH₂PO₄

T F 1. Ascites may occur as a consequence of hypoproteinemia. T F 2. Anemia is defined as an insufficient number of RBCs. T F 3. Marathon runners and blood transfusion recipients are subject to hemolytic anemia. T F 4. Aplastic anemia may result from malaria. T F 5. Pernicious anemia results from a vitamin B-12 deficiency. T F 6. The sickle cell gene survived in the gene pool because it conferred resistance to malaria. T F 7. Abnormal clotting, heart attack, and stroke are possible consequences of polycythemia. T F 8. Hemochromatosis could be treated with anticoagulants like aspirin or coumadin. T F 9. Mumps is a type of leukocytosis. T F 10. Leukemia and leukopenia both refer to low WBC counts. T F 11. Leukemias can be categorized by the stem cell line that is involved. T F 12. A pulmonary embolus is a clot that originates in the lungs. T F 13. Aspirin and coumadin can prevent stroke by decreasing the number of RBCs. T F 14. DVT is a type of bleeding disorder. T F 15. DIC could result from an overdose of heparin. T F 16. Thrombocytopenia is a thromboembolytic condition. T F 17. Impaired liver function is likely to result in excessive clotting. T F 18. Hemophilia results from a deficiency of clotting factors. T F 19. Severe transfusion reactions could result in kidney failure. T F 20. HDN may result when an Rh+ mother has an Rh- baby. https://www.coursehero.com/file/79652493/Blood-Disorders-Worksheet-2pdf/ This study resource was shared via CourseH

If the producer level of a pyramid has 12,000 J of energy available, how much would be available to secondary consumers? (HInt: work this out on your scratch sheet of paper on a pyramid)

Evaluate the effectiveness of screening the blood products for one transmissible disease by considering the safety of the products used in blood transfusions and the screening procedures used.

• consider the safety of the products used in blood transfusions by discussing, in general terms, the screening procedures used.

• evaluate the effectiveness of the screening process in relation to one named transmissible disease.

A DNA sequence cut with EcoRI restriction enzyme can be cloned into a plasmid cut with any restriction enzyme. False True

Diagram of structural features of the adipocytes of brown adipose tissue of the newborn children.

What cytoplasmic organelles and inclusions of the brown fat cells are well developed? 

discuss in brief the history / evolution of anesthesia

Look at DNA, a polymer, and nucleotide, a monomer, on the nucleic acid page. There are

sugar molecules within these structures. How many sugar molecules are in DNA and the

nucleotide