Biology Test ( first)

Explain why the hydrogen and oxygen atoms don't share electrons equally in a water molecule. Use the term "electronegativity" in your answer.

. So the hydrogen is attracted to oxygen because it has a higher electronegativity.

Define polar compound and give an example other than water.

A polar compound is a molecule with a geometric arrangement with one side having a positive charge and the other side a negative charge. Sulfur dioxide is an example other than water.

What are the monomers of polypeptides

Amino Acids

Why is water such an important molecule to living things?

Because without water, we wouldn't have the important hydrogen/oxygen bonds for processes such as dehydration synthesis and hydrolysis, and the combination of two amino acids.

Define POLAR COVALENT BOND

Bonds that are partly ionic are called polar covalent bonds. In a polar covalent bond, the electrons spend more time, closer to the Oxygen nucleus than the Hydrogen nucleus.

What is the general name given to carbohydrates such as sucrose and lactose?

Disaccharides, which are made of two sugar units.

What type of bonding holds 2 or more water molecules together?

Hydrogen bond

Are hydrogen bonds strong or weak bonds? Can they be easily broken?

Hydrogen bonds are weak bonds because they are easily and quickly formed and broken under normal biological conditions.

What are the monomers that starch is composed of?

Hydrogen, Oxygen, and Carbon

What is the name of the process by which starch is broken down into the smaller units?

Hydrolysis

By what process does the peptide bond form? What is the byproduct of this process?

The bond forms when a carboxylic group of one molecule reacts with the amino group of the other molecule, linking the two molecules and releasing a water molecule. The byproduct is a Polypeptide

What is the chemical formula of water? What type of bonding is found in water molecules? What are these bonds made of?

The chemical formula for water is H20. The type of bonding found in water molecules is hydrogen bonding. It has hydrogen in it, and is made of hydrogen and oxygen. Another component is heat capacity, it uses the energy to break hydrogen apart.

List and explain 5 functions of proteins?

Transport Molecules: Proteins transport molecules to different places in the body. For example, Hemoglobin transfers O and CO2 Muscle Contraction: Proteins make up Actin and Myosin, which weave in between each other to contract muscles Differentiate Cells: Proteins are many different shapes and sizes. The different shapes makes the cell have a certain function or job. Messenger Proteins: They go around the body to tell it to produce more enzymes Structure: They make up bones, tendons, cartilage, skin, feathers, hair, horns, hooves, scales (keratin and collagen)

How are starch and glycogen different? List at least 2 ways.

Starch isn't branched but glycogen is (slide 15 + 16 for visual) Glycogen is used in animals and plants use Starch

Which elements are present in amino acids that were not present carbohydrates?

Carbon, Oxygen, Nitrogen, and Hydrogen

What is the name of the process by which starch is assembled from its smaller units (monomers)? What compound is also formed when a bond between monomers is formed?

Polymerization is when monomers join together to form polymers. A compound that is also formed is a polysaccharide.

What is the biologic function of these fats?

Saturated Fats are needed for energy, hormone production, and cellular membranes. But on the down side, saturated fats seem to increase blood cholesterol levels. Saturated Fats are solid at room temperature. Unsaturated Fats come from plant foods. Unsaturated Fats do not raise blood cholesterol levels. Unsaturated Fats are liquid at room temperature.

Describe how saturated fats are different than unsaturated fats. Circle the bonds in the drawings that make this difference.

Saturated fats means that each carbon has the maximum number of hydrogens, there is no double bond in the carbon chains either. Unsaturated fats means that there is a DOUBLE bond between two carbons somewhere in the chain. (Also doesn't have the MAXIMUM number of carbons possible.

What is the overall charge on a water molecule? Explain why.

So a molecule of water has a total of 10 protons and 10 electrons giving it an overall neutral charge.

By what process do glucose and fructose bond together to form sucrose? What is the byproduct of this reaction?

The process is called dehydration, when a fructose and glucose bond together to form sucrose. The product of this reaction is sucrose and water.

What is the effect of this uneven sharing of electrons in water molecules on the physical properties of water?

The unequal sharing of electrons gives the water molecule a slight negative charge near its oxygen atom and a slight positive charge near its hydrogen atoms.

Define NONPOLAR COVALENT BOND

These covalent bonds are called nonpolar covalent bonds because the electrons shared by the atoms in the bonds are shared equally.

Use your notes from class to describe how cellulose is similar to starch and how the two are different. Include a sketch or at least a description of the shape of the molecules.

They are both made from the same monomer, which is glucose, and are both polysaccharides. But, starch you can eat, but cellulose you cannot digest. We can eat starch because our body has enzymes that break down the starch into glucose to create energy to fuel our body. But we don't have enzymes that can break down cellulose.

How are fructose and glucose different from one another?

They are the same amount (C6H12O6) BUT fructose has a different shape compared to glucose: Fructose only has 4 carbons in a ring whereas glucose has 5 carbons in a ring!

Water molecules are ___________ to other water molecules

attracted