Chapter 2 Bio

Discuss how buffers help prevent drastic swings in pH.

Buffers absorb excess hydrogen and hydroxide ions to prevent increases or decrease in pH. An example is the bicarbonate system in human body.

What property of carbon makes it essential for organic life?

Carbon can form up to four covalent bonds, allowing it to form long chains.

How many neutrons do carbon-12 and carbon-13 have, respectively?

Carbon-12 contains 6 neutrons while carbon-13 contains 7 neutrons.

Why are hydrogen bonds and van der Waals interactions necessary for cells?

Hydrogen bonds and van der Waals interactions form weak associations between molecules, providing the necessary shape and structure of DNA and proteins to function in the body.

Why can some insects walk on water?

Insects can walk on water because of its high surface tension.

What makes ionic bonds different from covalent bonds?

Ionic bond involves the transfer of electrons whereas covalent bond involves the sharing of electrons.

Water takes up 333 million cubic miles on Earth, yet access to drinking water is a critical issue for many communities around the world. Explain why this is so.

Only 4 percent of the total water on earth is freshwater, out of which 68 percent is found in glaciers.

When the temperature of liquid water is reduced, water freezes and becomes less dense. This is a property not seen in most other liquids. Ice floats on liquid water because it is less dense. What molecular property of water allows for this phenomenon?

When water cools, hydrogen bonds between hydrogen atoms push water molecules further apart.

Use the periodic table to describe what a Bohr model of Fluorine (F) would look like and explain why the Bohr model is not an accurate representation of the electron orbitals in fluorine.

A Bohr model would have 2 electron rings, and a Bohr model would not show the sub-shell of second ring

The unique properties of water are important in biological processes. For the following three properties of water, define the property and give one example of how the property affects living organisms: Cohesion Adhesion High heat of vaporization

Cohesion is the attraction between the water molecules, which helps create surface tension. Insects can walk on water because of cohesion. Adhesion is the attraction between water molecules and other molecules. Water moving up from the roots of plants to the leaves as a result of capillary action is because of adhesion. Heat of vaporization is the amount of energy required to convert liquid into gas. This property helps humans maintain homeostasis of body temperature by evaporation.

What are three examples of how the characteristics of water are important in maintaining life?

First, the lower density of water as a solid versus a liquid allows ice to float, forming an insulating surface layer for aquatic life. Second, the high specific heat capacity of water insulates aquatic life or bodily fluids from temperature changes. Third, the high heat of vaporization of water allows animals to cool themselves by sweating.

Describe the pH scale and how it relates to living systems. Give an example of how drastic pH changes are prevented in living systems.

The pH scale ranges from 0 to 14, where anything below 7 is acidic and above 7 is alkaline. The bicarbonate system in the human body buffers the blood.