Summary 8.2

• Sunlight is a form of electromagnetic energy that is basically energy that can travel in waves.
• The difference between two adjacent waves is called a wavelength.
• The range of types of electromagnetic energy is known as the electromagnetic spectrum.
• A substance's color is due to its pigments
• Pigments can be discovered by using a technique known as paper chromatography
• Within the thylakoid membrane, chlorophyll and other molecules are arranged in clusters
• Two systems are involved in light reactions; Water-splitting Photosystem and the NADPH-producing photosystem.

1) Explain why a leaf appears green.

A leaf appears green because green light is not absorbed, as chloroplast pigments do not absorb green light well.

2) Describe what happens a molecule of chlorophyll a absorbs light.

Each time a pigment molecule absorbs light energy, one of the pigment's electrons gains energy. Because the state is very unstable, the excited electron falls back to the ground state and transfers the energy to a neighbouring molecule. It keeps jumping until it arrives at the reaction center of the photosystem. The primary electron acceptor traps the excited electron from the chlorophyll a molecule.

3) Besides oxygen, what two molecules are produced by the light reactions?

The two other molecules are ATP and NADH.

4) Where in the chloroplast do the light reactions take place?

They take place in the thylakoid.

Vocabulary:

Wavelength: The distance between two adjacent waves.
Electromagnetic spectrum: The range of types of electromagnetic energy.
Pigments: Chemical compounds that make a substance a certain color.
Paper chromatography: A laboratory technique in which one can observe the different pigments in a green leaf.
Photosystems: Clusters that consists of chlorophyll and other molecules within the thylakoid molecule.

Summary 8.1

• The organelle in which photosynthesis takes place in is called a chloroplast. They contain chemical compounds called chlorophylls that give the organelles a green colour.
  
• A chloroplasts has an inner and an outer membrane. Inside the inner membrane is a thick fluid called stroma that suspend disk-shaped sacs called thylakoids inside it. Photosynthesis' general equation can be written out as:

6 CO2 + 6 H2O ->->-> C6H12O6 + 6 O2

• Photosynthesis occurs in two main stages, the light reactions and the Calvin cycle.
  
• The light reactions convert the energy from sunlight into chemical energy.
  
• The Calvin cycle makes sugar from the atoms in carbon dioxide plus the hydrogen ions and high-energy electrons carried out by NADPH.

Concept Check 8.1

1. Draw and label a simple diagram of a chloroplast that includes the following structures: outer and inner membranes, stroma, thylakoids.
   

2) What are the reactants for photosynthesis? What are the products?

The reactants for photosynthesis is carbon dioxide and water. The products are glucose and oxygen.

3) Name the two main stages of photosynthesis. How are the two stages related?

The two main stages of photosynthesis are light reactions and the Calvin cycle and they are related because both are needed in photosynthesis, and both transform a compound into another, and they both interact by giving each other certain molecules. Both are also rather complex in the number of steps.

Vocabulary:
Chloroplast: The cellular organelle where photosynthesis takes place.
Chlorophylls: Chemical compounds found in chloroplasts that give chloroplasts their color.
Stroma: The thick fluid found in the inner membrane of the chloroplast.
Thylakoids: Disk-shaped sacs that are suspended in the stroma.
Light Reactions: One of the two main stages of photosynthesis that convert the energy in sunlight to chemical energy.
Calvin cycle: One of the two main stages of photosynthesis that makes sugar from the atoms in carbon dioxide plus the hydrogen ions and high-energy electrons carried by NADPH.

HW 106 Q1-12,14,15

1) b
2) b
3) c
4) b
5) b
6) d
7) b
8) It consists of carbohydrates, that allows for energy to be stored.
9) Glucose, sucrose and starch are related because they are all carbohydrates and sugars.
10) Steroids are lipid molecules in which the carbon skeleton forms four fused rings. They circulate in one's body as chemical signals as well as acting as membranes that surround one's cells.
11) Polypeptide are related to proteins because they link amino acids together in a change and proteins consists of such polypeptide chains.
12) Denaturation affects the ability of a protein to function because it causes the protein to unravel and lose its natural shape because of an unfavorable change in the environment.

Summary 5.5

To start a chemical reaction, one needs to weaken the chemical bonds found in the reactants. This process requires that the molecules be able to absorb energy and it is known as activation energy. One way to weaken the chemical bonds is to heat it up, some cellular reactions use something known as catalysts, which speed up the chemical reaction. The main catalysts of chemical reactions are known as enzymes which are specialized proteins. An enzyme catalyzes only one type of reaction by specific reactions only allow enzyme of a certain shape and a specific reactant acted upon by an enzyme is called the enzyme's substrate. The substrate only fits into a certain region of an enzyme known as the active site.

Images:
http://waynesword.palomar.edu/images/enzyme5.gif
(Enzyme connecting to a substrate)
http://www.accessexcellence.org/RC/VL/GG/images/enzyme.gif
(Enzyme activity)

Concept Check
Explain the role of activation energy in a reaction. How does an enzyme affect activation energy?
Activation energy is the start-up energy for a reaction. An enzyme can affect activation energy by acting as a catalysts that speed up the chemical reactions.
Describe how a substrate interacts with an enzyme.
A substrate interacts with an enzyme by the enzyme acting upon a specific reactant, and the substrate then fits into a particular location of the enzyme known as the active site.

Summary 5.4

Protein is a polymer that is constructed from a set of just 20 different monomers known as amino acids. Each amino acid monomer consists of a central carbon atom attached to four other atoms or molecules through covalent bonds. Polypeptide is a chain that creates proteins by linking amino acids. These chains are at least 100 amino acids in length. A protein in the simple form of amino acids are connected together can not use its functions. Denaturation is a proccess in which an unfavorable change in the quality of the environment that causes a protein to unravel and lose its normal shape.

Images:
http://www.bio.mtu.edu/campbell/bl4820/lectures/lec1/protein1.gif
(Scientific representation of a kind of protein molecule)
http://plantandsoil.unl.edu/croptechnology2005/UserFiles/Image/siteImages/AminoAcidLG.gif
(Representation of a kind of amino acid)
http://web.siumed.edu/~bbartholomew/images/chapter5/F05-14.jpg
(Representation of denaturation of DNA, a kind of protein)

Concept Check:
Give at least two example of proteins you can "see" in the world around you. What are their functions?
Two examples of proteins that you can "see" in the world around you is hair and muscles. Hair keeps one warm and makes one have a better sense of touch. Muscles help you move and they keep you alive in the case of the heart muscle.
Relate amino acids, polypeptides, and proteins.
Amino acids is a central carbon atom attached to four partners through covalent bonds, polypeptides are consisted of amino acids and proteins are a polymers also made of amino acids.
Explain how heat can destroy a protein.
It can destroy a protein by unravelling and losing its normal shapes, because it breaks some forces that bond two molecules or atoms together.
Which parts of an amino acid's structure are the same in all amino acids? Which part is unique?
Amino acid's carbon partners and the hydrogen atoms are the same in all amino acids. However,f the "side group" that attaches to the fourth bond of the central carbon is unique.

Summary 5.3

Some liquids' inability to mix with water is similar to many other water-avoiding compounds to be called lipids. Molecules that avoid water is known as hydrophobic, a property that is evident in the boundary that surrounds and contains the aqueous contents of your cells. Fat consists of a three-carbon backbone attached to three fatty acids. Saturated fat is a fat in which all three fatty acid chains contain the maximum possible number of hydrogen atoms. Unsaturated fat contains less than the maximum numer of hydrogen atoms in in one or more of its fatty acid chains. Cholesterol is an essential molecule found in the membrame that is around your cells.

Images:
http://fig.cox.miami.edu/~cmallery/255/255chem/p2x2x3.jpg
(A brief overview and diagram of hydrophilic molecules.)

For more information:
http://en.wikipedia.org/wiki/Hydrophilic
(Information about the hydrophilic property)
http://www.dietobio.com/dossiers/en/fatty_acids/molecule.html
(A brief introduction to a Fat Molecule and its Components)

Content Check:
What property do lipids share?
Lipids are hydropholic that allows them to avoid water molecules.
What are the parts of a fat molecule?
A fat molecule consists of a three-carbon backbone called glycerol attached to three fatty acids.
Desribe two ways that steroids differ from fats.
Two ways that steroids differ from fats are that have different structures and functions.
What does the term unsaturated fat on a food label mean?
The term unsaturated fat on a food label mean that they might be healthy and can build up deposits of lipid known as plaques.

Summary 5.2

This is based on the Prentice Hall Biology Textbook known as "Exploring Life".

Chapter 5.2 talks about carbohydrates that provide fuel and building materials. Carbohydrates are organic compounds that are made of sugar molecules and there are different kinds of sugars. One kind of a sugar are the simple sugars also known as monosaccharides, such as glucose and frutose, others are disaccharides, which is basically two monosaccharides joined together. There are also a kind of long polymer chains that are composed of simple sugar monomers are called polysaccharides. One example of a polysaccharide is known as starch that is found in plant cells that acts as sugar stockpiles. Animal cells on the other hand, do not contain starch and they store excess sugar in the form of a polysaccharide known as glycogen. There are other kinds of polysaccharides, such as cellulose that acts as building materials. All the carbohydrates are hydrophilic, due to the many hydroxyl groups in their sugar units.

Images:
http://www.mun.ca/biology/scarr/Ribose_sugar.html
(Displays the structure of sugar atoms particularly Ribose)
http://www.mcb.mcgill.ca/~hallett/GEP/Lecture1/Image6.gif
(Displays the structure of Glucose)

For more information:
http://en.wikipedia.org/wiki/Sugar under the Chemistry section

Concept Check:
Explain the differences between a monosaccharide and a disaccharide. Give an example of each.
An example of a monosaccharide is glucose and an example of disaccharide is sucrose.
Compare and contrast starch, glycogen, and cellulose.
Starch is a polysaccharide found in plant cells that consists entirely of glucose monomers, glycogen is a polysaccharide that has a chain that is more highly branched than a starch polymers. Cellulose is a polysaccharide that can be linked together with hydrogen bonds, forming cable-like fibers in the tough walls that enclose plant cells.
How do animals store excess glucose molecules?
Animals store excess glucose molecules in the glycogen.