The Chemical Basis of Life

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Questions and Answers

Which of the following is true about the atomic number of an element?

It is equal to the sum of the number of protons and neutrons.

It can't change or the identity of the element changes.

It can change if the number of neutrons changes.

It is determined by the number of electrons. (correct)

Which of the following is true about the mass number of an atom?

It can change if the number of neutrons changes. (correct)

It is determined by the number of protons.

It is equal to the sum of the number of protons and neutrons.

It can change if the number of protons changes.

Which of the following is true about valence electrons?

They are found in an atom's innermost shell.

They are found in an atom's outermost shell. (correct)

They are the most abundant elements found in organisms.

They determine the atomic number of an element.

Which of the following elements has 4 valence electrons?

Carbon Signup and view all the answers

Which of the following elements is the most abundant in living things?

Carbon Signup and view all the answers

Which of the following particles has a positive charge?

Proton Signup and view all the answers

Which of the following particles is electrically neutral?

Neutron Signup and view all the answers

Which of the following particles has a negligible mass?

Electron Signup and view all the answers

Which of the following is true about covalent bonds?

They result from electron sharing. Signup and view all the answers

Which of the following is true about orbitals?

Each orbital can hold 2 electrons. Signup and view all the answers

Which type of chemical bond involves the complete transfer of electrons from one atom to another?

Ionic bond Signup and view all the answers

Which type of bond is the strongest?

Nonpolar covalent bond Signup and view all the answers

Which form of energy is stored in the chemical bonds that link together atoms to form molecules?

Chemical energy Signup and view all the answers

What is the currency for most of the energy needs of cells?

Adenosine triphosphate (ATP) Signup and view all the answers

Which type of reaction releases energy?

Exergonic Signup and view all the answers

What are the two ways to speed up most reactions?

Increase temperature and decrease concentration of reactants Signup and view all the answers

What is metabolism?

The sum of all the chemical reactions occurring in every cell Signup and view all the answers

Where does energy and matter enter the biosphere?

At the base of the food chain Signup and view all the answers

What property of water allows it to dissolve polar and charged molecules?

Water's polar nature Signup and view all the answers

Why does ice float in water?

Ice is less dense than water Signup and view all the answers

Which force causes the formation of a meniscus at the surface of water when it meets a solid surface?

Adhesion Signup and view all the answers

What property of water prevents light objects from falling through its surface?

Surface tension Signup and view all the answers

What property of water allows it to move in biological systems such as roots and leaves?

Cohesion Signup and view all the answers

What is the term for the concentration of H+ and OH- ions present in a solution?

pH Signup and view all the answers

What do cells use to protect against the damaging effects of pH changes?

Buffers Signup and view all the answers

What determines the functional behavior of a molecule in organic chemistry?

Functional groups Signup and view all the answers

What are the building blocks of proteins?

Amino acids Signup and view all the answers

What type of bonds form between amino acids to create proteins?

Peptide bonds Signup and view all the answers

What property of carbon allows it to form different combinations of bonds and molecular shapes?

Carbon's versatility Signup and view all the answers

What property of water allows it to absorb and retain a high amount of energy?

Heat capacity Signup and view all the answers

Study Notes

Atomic Structure and Electrons

Atomic number refers to the number of protons in the nucleus of an atom, determining the element's identity.
Mass number is the total number of protons and neutrons in an atom’s nucleus.
Valence electrons are the outermost electrons involved in chemical bonding and reactions.
Silicon (Si) and carbon (C) are examples of elements with 4 valence electrons.
Carbon is the most abundant element in living organisms, essential for life's molecular structures.

Subatomic Particles

Protons have a positive charge and are located in the nucleus.
Neutrons are electrically neutral and also found in the nucleus.
Electrons have negligible mass relative to protons and neutrons, found in orbitals outside the nucleus.

Chemical Bonds and Reactions

Covalent bonds involve the sharing of electron pairs between atoms.
Ionic bonds involve the complete transfer of electrons from one atom to another.
Covalent bonds are generally the strongest type of chemical bond.
Chemical potential energy is stored in the bonds linking atoms to form molecules.
Adenosine triphosphate (ATP) is the primary energy currency for cells.

Energy and Metabolism

Exothermic reactions release energy during the process.
Increasing temperature and concentration are two methods to accelerate reaction rates.
Metabolism encompasses the entirety of biochemical processes occurring within a living organism.

Water Properties

Energy and matter primarily enter the biosphere through photosynthesis and nutrient cycling.
Water's polarity allows it to dissolve polar and charged molecules, acting as a solvent.
Ice floats due to its lower density compared to liquid water.
Cohesion leads to the formation of a meniscus when water meets a solid surface.
Surface tension prevents light objects from sinking in water due to cohesive forces among water molecules.
Capillary action enables water to travel in biological systems, such as within plant roots and leaves.

pH and Cellular Response

pH measures the concentration of H+ and OH- ions in a solution, affecting biological and chemical processes.
Buffers help cells maintain stable pH levels, protecting against damaging fluctuations in acidity or alkalinity.

Organic Chemistry

The functional behavior of a molecule in organic chemistry is determined by its structure and functional groups.
Amino acids are the building blocks of proteins, linked by peptide bonds.
Carbon's tetravalency allows it to form diverse molecular shapes and combinations of bonds.
Water's high specific heat capacity allows it to absorb and retain substantial amounts of energy, regulating temperature in environments.

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Description

Test your knowledge of the chemical basis of life with this quiz on water and carbon. Learn about the key elements that make up living things and their roles in structure and function. Explore the properties of matter and understand the significance of protons, neutrons, and electrons.