Question

List the following elements in order of highest electronegativity to lowest: silicon, sulphur, argon, chlorine.

Answer the following questions about water: (10 marks total)

In a single molecule of water (H₂O), what kind(s) of bonds(s) are present?

Explain how these bonds contribute to the high surface tension of water.

Explain why water has a high specific heat and explain why this is important to life.

A baking soda solution has a pH of 8. (5 marks total)

Is it acidic, basic, or neutral? Why?

Is it an acid, a base, or neither? Why?

What is the concentration of hydrogen ions in baking soda? (1 mark)

Compare and contrast the following: (4 marks each, total 16 marks)

Starch and glycogen

Phosphodiester bonds and peptide bonds

Chemical energy and heat

Hypothesis and null hypothesis

For the theory of evolution identify the pattern component and the process component.

Read the section in your textbook Canadian Research 1.1: Artificial Selection on Bighorn Sheep in Alberta. Using specific examples from this study, outline the steps of the scientific method. (Note that the reading may not include all the steps. For any “missing” steps, include what would have been the case.)

Answer the following questions about enzymes: (15 marks total)

Briefly describe how enzymes catalyze reactions

List 4 factors that affect enzyme activity. For each factor explain how the factor works to alter reaction rate.

The tertiary structure of proteins involves interactions with the amino acid side chains (the R groups). List the types of interactions and explain the role of the functional groups involved .

Compare and contrast the structure and function of DNA and RNA.

Explain why the components of phospholipids contribute to the formation of lipid bilayers.

Explain why carbohydrates have high free energy.

Discussion

Based on what you have learned so far, consider one of the following questions. Post your ideas to the Discussions area first, and then read and respond to other students’ postings. The Discussions area is in the left-hand navigation menu of this course.

Self-Replicating Molecules

Your textbook states that the ability of molecules to self-replicate is an indicator that these molecules are “living entities”. Should self-replication be the only indicator of life? Why or why not?

Origins of Life

Up to date RNA has been the only molecule directly associated with the origin of life and early evolution of life on Earth.

In your own words explain how researchers came to this conclusion. Do you find their arguments convincing? Why or why not? Prior to answering this question, make sure you read Chapter 4, Section 4.4, The First-Life Form.

Answer 1

Ans1) The electronegativity is defined as the power of an atom to attact electron towards itself.

The electronegativity of the given element from higher electronegativity to lower electronegativity.

Chlorine, Sulphur, Silicon, Argon.

Argon has no electronegativity as it is a noble gas whose outermost electron is in octet and highly stable as all its valence electron are full. Chlorine is a halogen and highest electronegative property than the sulfur and silicon.

Ans 2) A single water molecule is composed of 2 Hydrogen and one oxygen aton. The hydrogen bond is atteched with the Oxygen through a polar covalent bond. Overall water molecules has two types of bonds 1) Hydrogen bond and 2) Covalent bond.

Ans 3) Water has highest surface tension because of its chemical bonds. The water molcules are bonded with each other by hydrogen bond. For this reason the water molecule at the surface are pulled together into the surface by the strong hydrogen bond.

Ans 4) When heat is absorbed hydrogen bonds in the water molecules breakdown to form a single molecule of water which is free. But when hydrogen bonds are formed between the water moelcule then a large amount of energy is released. Wtaer covers 70% of earth surface and the high specific heat of water means it can absorb a huge amount of heat without increasing the temperature. When the temperature decrease, the stored heat is released and the temperature remains same. This combine effect of buffering effect of specific heat water play an important role in the development of life in earth. Thus a constant temperature is observed in the earth which helps in the natural function of different organisms.

Ans 5) Baking soda is basic at pH 8. Baking soda is alkaline and composed of sodium bicarbonate.

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