Review Questions Chapter 2 PDF

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Chapter 2: Chemistry and Molecules of Life Mission to Mars: Prospecting for life on the red planet Driving Question 1: How is matter organized into molecules of living organisms? Why should you care? We literally are what we eat—matter can not be created or destroyed, so every atom of every element in us was once part of some other living organism or the atmosphere or the earth. The atoms of most elements never change because the particles that comprise them do not change. There’s a good chance that right now you may be breathing an oxygen molecule that was once breathed by Julius Caesar. You could have carbon atoms in you that were once part of a Tyrannosaurus. What should you know? To fully answer this Driving Question, you should be able to: 1. Understand where subatomic particles are located in an atom and what their characteristics are. 2. Explain why carbon is an essential chemical component of living organisms. 3. Determine if a molecule is organic or inorganic. 4. Differentiate between the four classes of molecules of life and when pertinent, the subunits that comprise them. Infographic Focus: The infographics most pertinent to the Driving Question are 2.3, 2.4 and 2.8 and Up Close: Molecules of Life. Test Your Vocabulary: Match the following definitions to the terms they describe: • [ELEMENT] : substances that cannot be chemically broken down • [MATTER]: is anything that takes up space and has mass • [ATOM]: The smallest unit of an element that still retains the property of that element • [PROTON]: positively charged subatomic particles found in the nucleus of an atom • [ELECTRON]: negatively charged subatomic particles that orbit the nucleus w negligible mass • [NEUTRON]: electrically uncharged subatomic particles found in the nucleus of an atom • [NUCLEUS]: the dense core of an atom • [COVALENT BOND]: the sharing of a pair of electrons between two atoms • [MOLECULE]: form when atoms are linked by covalent bonds • [ORGANIC]: have carbon-based backbones and at least one C-H bond • [INORGANIC]: lack carbon-based backbones and C-H bonds • [CARBOHYDRATE]: are made up of sugar monomers

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[PROTEIN]: made up of amino acid monomers [LIPIDS]: are not made of repeating monomers [NUCLEIC ACIDS]: are made up of nucleotides monomers [MACROMOLECULES]: large organic molecules composed of subunits called monomers which link together to form polymer chains [MONOMER]: organic subunits of a macromolecule [POLYMER]: multiple monomers linked up [MONOSACCHARIDE]: simple sugars that make up carbohydrates [AMINO ACID]: make up proteins [NUCLEOTIDE]: make up nucleic acids

1. Understand where subatomic particles are located in an atom and what their characteristics are. Draw an atom (it does not need to be of a particular element), including the subatomic particles. 

Use different shapes or colors for each kind of particle, so that you can tell them apart.

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Make sure to put the particles in the proper region of the atom.

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Add the symbols +, –, or  next to the name of each particle to indicate which are positively charged, negatively charged, or neutral.

electron Red= Neutrons  Blue= Proton + Orange= Nucleus

2. Explain why carbon is an essential chemical component of living organisms. It can form multiple covalent bonds and one of the six elements that make up most by humans What makes carbon such an important part of life’s molecules? It can form multiple covalent bonds

What kind of chemical bonds does a carbon atom typically make with other atoms? Covalent Up to how many bonds can a carbon atom form? 4 3. Determine if a molecule is organic or inorganic. Organic molecules have carbon based backbones and at least one c-h bond Inorganic molecules lack carbon based backbones and a C-H bond What characterizes organic molecules? They have chains of carbon atoms covalently bound to other carbon& hydrogen atoms Is the compound methane (4 hydrogen attached to a central carbon) organic? Yes because it has a c-h bond 4. Differentiate between the four classes of molecules of life and when pertinent, the subunits that comprise them. Carbohydrates: made up by sugar monomers Proteins: made up by amino acid monomers Nucleic Acid: nucleotides monomers Lipids: not made up of repeating monomers What is the structural difference between carbohydrates, proteins, lipids, and nucleic acids, and what are they made of? CARB: with monosaccharides in straight or branching chains - glucose PROTIENS: “core” structure long train like folded – aminoacid NUCELIC ACID: nucleotides monomers (RNA & DNA) DNA: SPIRAL rna: one linear chain (sail on a boat) LIPIDS: hydrophobic molecules (worm)

For each of the below descriptions, write down which of the four molecules of life it is describing:                

when 'complex', they contain many subunits in straight or branching chains CARBS do not have repeating subunits LIPIDS subunits are amino acids PROTIENS some are used to speed up chemical reactions PROTIENS used for storing, transmitting, and executing genetic information NUCLEIC ACID subunits are composed of a nitrogenous base, five-carbon sugar, and phosphate group NUCLEIC ACID subunits are joined to each other with peptide bonds PROTIENS some function as hormones LIPID STEROLS subunits are called monosaccharides CARBS subunits each have the same core structure but they differ in the side chains they contain PROTIEN the three-dimensional shape of the molecule is essential for it to function correctly Protein some are useful as padding or insulation Lipid Trriglicerides subunits usually consist of carbon rings Carbs the two types of molecules in this class differ based on whether they consist of a single chain of subunits or two chains of subunits NUCLEIC ACIDS some of them are a major component of cell membranes lipid phospolipids subunits are nucleotides NUCLEIC ACIDS

Review Questions

1. The simplest kind of carbohydrate molecule is called a _____ . Carbohydrates are primarily important because they can be used to _____. a. monosaccharide / store energy b. amino acid / carry out various cellular functions c. nucleotide / store genetic information d. fatty acid / store energy e. amino acid / store genetic information 2. Which type of biological macromolecule is not made of chains of linked monomers? a. Complex Carbohydrates b. Lipids c. Proteins d. Nucleic Acids e. None of the above; all are made of chains of monomers 3. All of the following are types of lipids except _____. a. Nucleic acids b. Fatty acids c. Triglycerides d. Sterols e. Phospholipids

Driving Question 2: What is the definition of life, and how could Martian life be recognized? Why should you care? What is life? At first, the question of what is alive and what is not seems so elementary that it should not need asking. But, when it gets down to the details of what defines life, the question starts seeming a lot more profound. This chapter ponders the possibility of extraterrestrial life and how we can recognize and find it. Will it fall under the definition of life as we know it? Here on Earth, it is important to understand the nature of life, because it means understanding who we are and how we and all other life forms work. What should you know? To fully answer this Driving Question, you should be able to: 1. List and describe 5 characteristics inherent to all living things. a. Growth Movement Reproduction Response to external stimuli (homeostasis) and metabolism 2. Defend an argument of whether a virus is or is not alive, and how this may relate to life on Mars. a. A virus is not alive, although it moves & reproduces it requires a host Infographic Focus: The infographics most pertinent to the Driving Question are 2.1 and 2.10. Test Your Vocabulary: Match the following definitions to the terms they describe: [HOMEOSTASIS] the maintenance of a relatively constant internal environment [ENERGY] comes from sunlight or food that organisms need to break down food [METABOLISM] the sum of total of all chemical reactions occurring in living things [VIRUS] moves reproduces but requires a host [PRION] 1. List and describe 5 characteristics inherent to all living things. What defines life? Refer to Infographic 2.1 in your textbook if necessary. 

Growth: the process of increasing in size How does the definition of growth differ for unicellular and multicellular organisms? For unicellular organism’s growth is an increase in cell size before reproduction. For multicellular organism’s growth refers to an increase in an organisms size as the number of cells that make up the organism increases. Why would the ability to grow be an essential quality of living organisms? They have to grow before they can reproduce and learn from the parent how to survive

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Reproduction:the process of producing new organisms Why must living organisms be able to reproduce? to produce new organisms to populate the world

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Homeostasis: the maintenance of a relatively constant internal environment How many ways can you think of in which you exhibit homeostasis, the quality of maintaining a stable state? When it’s cold outside my internal body temperature continues to stay the same or regulate itself Why is homeostasis an important characteristic of living things? Organisms maintain a stable internal environment even when the external environment changes (penguin)

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Sense and Respond to Stimuli: the process of reacting to their environment What do you think it means to sense and respond to stimuli? To respond to the environment such as if there’s threat What are examples of stimuli? What are the typical responses to them? Food source= jump to get it threatening situation= fight or flight

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Obtain and Use Energy: allowing them to do work What are the possible sources of energy for living organisms? From food, or the sun Why is it essential that living things be able to use energy? The energy that you get from the source you use for things The following entities are not considered alive although they may exhibit some of the characteristics of life. For each item, explain which characteristics of life they exhibit and which ones they lack:

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A rock: growth

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A computer: ability to obtain and use energy

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A computer virus: sense and respond to stimuli reproduction

The following organisms are considered alive, so they meet the five characteristics of living things. It may not be readily apparent, however, how they meet all five characteristics. For each organism below, explain why it isn't readily apparent that they are alive: 

A houseplant don’t reproduce

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A wild mushroom sense and respond to stimuli

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Mildew homeostasis

2. Defend an argument of whether a virus is or is not alive, and how this may relate to life on Mars. A friend asks you about viruses: Specifically she wants to know if they are alive. You explain that viruses consist of genetic material (RNA or DNA) surrounded by a protein coat, which may or may not be enclosed in a small membrane. When a virus infects a cell, the genetic material in the virus 'overwrites' the cell's genetic instructions, and the cell produces more of the components of the virus and assembles the components for it. Then, you realize you have to explain to your friend the characteristics of living organisms and whether or not a virus fits those characteristics:  Does a virus grow? yes  Does a virus reproduce? yes  Does a virus maintain a stable internal environment? no  Does a virus sense and respond to stimuli? no  Does a virus obtain and use energy? yes Keeping these characteristics in mind, what is your answer? Is a virus alive? no How does your argument relate to the potential presence of life on Mars? What if you took the opposing viewpoint about viruses; how would that relate to your classification of life on Mars? Review Questions 1. Which of the following is not a characteristic of all living things? a. growth b. reproduction c. using energy d. breathing e. acquiring energy 2. True or False: Evidence of life on Mars will definitely fit within our definition of life on Earth.

a. f Driving Question 3: What is the basic structural unit of life? Why should you care? All life on earth is made of cells, and all cells have cell membranes to hold in their contents. Cell membranes serve as boundaries, gatekeepers, and communicators. You wouldn’t be able to think, move, or generally function without proper cell membranes. What should you know? To fully answer this Driving Question, you should be able to: 1. Describe the basic structural unit of life. a. They have a water based interior that is separated from a chemically distinct water-based exterior by a cell membrane. It has a lipid bi layer with embedded protiens 2. Identify the different parts of the cell membrane. a. Lipid bi layer: phospholipid bilayer = inside is hydrophobic (tails) while the heads are phospholipids which love water 3. Explain the importance of the cell membrane. a. A lipid bi layer seperates the water based inside from the water based outside of the cell. Infographic Focus: The infographics most pertinent to the Driving Question are 2.5 and 2.10. Test Your Vocabulary: Match the following definitions to the terms they describe: [CELL]: basic structural unit of life [CELL MEMBRANE]: a double bi layer that seperates the contents of a cell from its environment [PHOSPHOLIPID]: water loving heads and water fearing tails (the whole thingy) [HYDROPHOBIC]: water fearing tails (inside) [HYDROPHILIC]: water loving head 1. Describe the basic structural unit of life. In the most basic terms, describe the structure of a single celled organism. - (simple bacteria) complex internal structures like a nuclei that contains organized strands of genetic material. Made up of one single cell In the most basic terms, describe the structure of a multicellular organism. - More than one cell (humans, animals, plants) Based on your answers, why is the cell called the basic structural unit of life? - Because it starts off with that one cell 2. Identify the different parts of the cell membrane. Draw and label the typical lipid bilayer of a cell membrane. Phospholipid! Head: hydrophilic Tails: hydrophobic

Review Questions 1. The tails of phospholipids are: a. Hydrophobic b. Hydrophilic c. Neutral 2. The heads of phospholipids are: a. Hydrophobic b. Hydrophilic c. Neutral 3. What part of a phospholipid in the cell membrane interacts with the inside environment of the cell? a. Head b. Tail c. Neither

Driving Question 4: Why is water so important for life and living organisms? Why should you care? You might rightly say that a sixth characteristic of living things is the presence of water in them. Your body contains around 60% water by weight. All living and actively growing things are made of cells containing mostly water. . How did water get to be so important to life? It has several unique characteristics that make it a special molecule. Because it is a polar molecule (with unevenly distributed charges across it), water is a good solvent for charged or polar substances. Water can break ionic bonds in solutes like salt, so that its component ions are released into the solution as charged particles. The movement of ions in water solution is essential for your brain and muscles to work. Nearly all of the complex chemical interactions that go on every moment of your life – and which enable you to think, live, and breath– happen in water. The polarity of water molecules is also important in the formation of hydrogen bonds with each other and with other polar biomolecules; this in turn helps keep your DNA together in your cells, and your proteins in their proper shapes. Furthermore, you can’t taste or smell organic molecules like sugar or the scent of lemons until they dissolve in water. What should you know? To fully answer this Driving Question, you should be able to: 1. Diagram a water molecule and label its components. a. h h h o 2. Explain why water is a polar molecule and why this makes it a good solvent for charged or polar substances. a. Because electrons arent shared equally between the oxygen and the hydrogen atoms in each of its polar covalent bonds 3. Explain what hydrogen bonding is and what implications it has to the properties of water. 4. Explain why water is important for life. Infographic Focus: The infographics most pertinent to the Driving Question are 2.5, 2.6, 2.7, 2.8 and 2.9. Test Your Vocabulary: Match the following definitions to the terms they describe: [POLAR MOLECULE] [HYDROGEN BOND] [COHESION] [ADHESION] [SOLVENT [SOLUTE]

[SOLUTION] [IONIC BOND] [ION] [pH] [ACID] [BASE] 1. Explain why water is a polar molecule and why this makes it a good solvent for charged or polar substances. Are the atoms in water covalently or ionically bonded? How do you know? Why is water a polar molecule? What does being polar have to do with being a good solvent? If you dissolve the salt magnesium bromide (MgBr2) in water, the magnesium atoms and the bromine atoms dissociate from each other as positively-charged magnesium ions (Mg2+) and negatively charged bromide ions (Br1-). When water molecules surround the magnesium ions, what side of each water molecule will be directed towards them, the hydrogen or oxygen side? 2. Explain what hydrogen bonding is and what implications it has to the properties of water. What is hydrogen bonding and how does it affect water bonding with itself and other substances? How does hydrogen bonding affect the heat capacity of water? 3. Explain why water is important for life. Based on your answers to the questions above, why is water important for life?

Review Questions 1. Water molecules attracted to each other by hydrogen bonds will be connected by bonds between _____. a. the positive (hydrogen) side of one molecule and the negative (oxygen) side of the other. b. the positive (hydrogen) side of one molecule and the positive (hydrogen) side of the other. c. the negative (oxygen) side of one molecule and the negative (oxygen) side of the other. d. Both b and c e. None of the above

2. Which of the following pairs of terms apply to a single water molecule’s structure? a. polar, covalent bond b. nonpolar, covalent bond c. polar, hydrogen bond d. nonpolar, hydrogen bond 3. Waxes are a kind of lipid. Why does water form beads on wax paper? a. Wax is hydrophobic; water will be attracted to itself by cohesion but not the wax. b. Wax is hydrophilic; water will be attracted to the wax paper by adhesion but not to itself. c. Wax is hydrophobic; water will be attracted to the wax paper by adhesion but not to itself. d. Wax is hydrophilic; water will be attracted to itself by cohesion but not the wax....