Grade 12 Biochem Unit

What are the CHNOPS elements?

Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur

What is a protons charge and location?

Positive, inside nucleus

What is a neutrons charge and location?

Neutral, Inside Nucleus

What is an electrons charge and location?

Negative, Outside Nucleus

What is an isotope?

Atoms of the same element that differ in number of neutrons

What determines the chemical behaviour of an atom?

It’s electron configuration

What are intramolecular bonds?

Bonds formed when electrons are transferred or shared

Compare and contrast a cation and an anion

A cation is a positive ion that results when an atom/group of atoms loses electrons

An anion is a negative ion that results when an atom or group of atoms gains electrons

Both are ions and went through the process of ionic bonds.

Compare and contrast ionic bonds to covalent bonds

Ionic Bonds are when an atom gives up one or more electrons and a Covalent Bond is when the electron shells of two non-metal atoms overlap so that the valence electrons of each atom are shared between each other. Both of the bonds benefit atoms that need to gain or lose electrons.

What is electronegativity?

Measure of the tendency of an atom to attract a bonding pair of electrons

Compare and contrast polar and nonpolar covalent bonds

Polar Covalent bonds are when the electrons are shared unequally while Non-polar is when they are shared equally. They are both different types of Covalent bonds since atoms are sharing electrons

Electronegativity of Ionic Bond

> 1.7

Electronegativity of polar covalent bonds

0.5-1.7

Electronegativity of Nonpolar covalent bonds

<0.5

What are two factors that determine the polarity of a molecule?

Whether a molecule is polar or nonpolar

What is a dipole?

A partial charge due to unequal sharing of electrons

What are intermolecular bonds?

Bonding betwee molecules

Compare hydrophilic and hydrophobic molecules and provide an example.

Hydrophilic molecules water loving and dissolve in water because they form intermolecular bonds. Ex. Sugar and Water

Hydrophobic molecules are not water loving and do not dissolve in water sincethey are non-polar and can’t bind to it. Ex. Oil and Water

What is a hydrogen bond? Are hydrogen bonds intermolecular or intramolecular bonds?

Weak association between an atom with a partial negative charge and a hydrogen atom with a partial positive charge. They are intermolecular bonds.

What is the difference between adhesion and cohesion?

Adhesion is when something sticks onto another substance while cohesion is when they mix together

What atom is the backbone of life?

Carbon

What is the difference between a molecular formula and a structural formula?

Molecular Formula is written and Structural Formula is drawn

What is a functional group?

Groups of atoms attached to a molecule that gives the molecule particular chemical and physical properties

What is this functional group, it’s polarity, and an example of where is found in?

Carbonyl

Polar

Found in: Aldehyde, Ketone, Acetone

What is this functional group, it’s polarity, and an example of where is found in?

Carboxyl

Polar

Found in: Proteins, Lipids

What is this functional group, it’s polarity, and an example of where is found in?

Hydroxyl

Polar

Found in: Alcohols

What is this functional group, it’s polarity, and an example of where is found in?

Amino

Polar

Found in: Proteins, Nucleic Acid

What is this functional group, it’s polarity, and an example of where is found in?

Phosphate

Polar

Found in: Nucleic Acids

What is this functional group, it’s polarity, and an example of where is found in?

Sulfhydrl

Slightly Polar

Found in: Proteins

What are macromolecules?

Large Complex molecules usually composed of repeating units of smaller molecules linked by covalent bonds

What is the difference between a monomer and a polymer?

Polymers are the long chain-like substances of macromolecules that are made up of small molecules known as monomers

What are the four main types of biological macromolecules?

Carbohydrates, Nucleic Acids, Proteins, and Lipids

What three elements make up carbohydrates?

Carbon Hydrogen Oxygen

Are carbohydrate molecules usually polar, or non-polar?

polar

What do sugars and starches do in the body?

Store energy in a way thats easily accessible by the body

What is a monosaccharide?

A single carbon based monomer structure

What are three common examples of monosaccharides? How are they similar? How are they different?

Glucose, fructose, and galactose they are similar since they are all isomers (have same molecular formula but different structure) but different because their atoms are arranged to form different molecules

What are disaccharides composed of?

Two monosaccharides joined by a glycosidic linkage

List 3 examples of disaccharides

Sucrose, Lactose, and Maltose

How do polysaccharides differ from monosaccharides and disaccharides?

Polysaccharides are carbohydrate polymers of monosaccharides (usually glucose) joined covalently.

Compare the structure of glycogen with the structure of starch

Starch has a three dimensional structure that is more linear than the highly branched structure of glycogen

Where is glycogen found and what does it do?

Found in animals and helps regulate blood sugar (glucose) levels

Where is starch found and what does it do?

Found in plant and is the main source of carbohydrates

Can humans break down cellulose? Explain.

No because we lack the enzymes to break it down

What is the primary function of triglycerides?

Store unused calories and provide your body with energy

Describe the structure of a triglyceride molecule

Can either be saturated (no double bonds) between carbon atoms or unsaturated with one (monounsaturated) or more (polyunsaturated) double bonds between carbon atoms

What functional group is found at the end of the fatty acid hydrocarbon chains? How does this relate to the acidity of fatty acids?

Carboxyl group is at the end and it’s what makes it acidic

What is the difference between a saturated and unsaturated triglyceride?

Whether there is none or 1+ double bond between carbon atoms

Where are phospholipids found and what do they do?

Main component of cell membranes and is found attached to an R group of various atoms and is polar and hydrophilic

How do phospholipids differ from triglycerides?

Their structure

Describe the structure of lipid steroids.

Four attached carbon based rings

What are three examples of lipid steroids?

Cholesterol, Testosterone, Estrogen

What is spermaceti?

Liquid wax at internal body temperature

What are the monomers of a protein called?

Amino Acids

Describe the structure of an amino acid.

Composed of a central carbon atom bonded to the amino group, carboxyl group and a hydrogen atom

There are 20 amino acids. What part of an amino acid gives it its unique identity?

It has a variable R group bonded to the central carbon atom

Proteins have a variety of functions. List the 6 key functions of proteins and provide an example protein that carries out each function.

1. Catalyzing chemical reactions

• Enzymes

2. Providing structural support

• Keratin

3. Transporting substances

• Channel and carrier proteins

4. Enabling organisms to move

• AntiFreeze Protein

5. Regulating cellular process

• Proteins

6. Provided defence against disease

• Antibodies

How are polypeptides formed?

Amino acids are joined together by peptide bonds

What type of bonding contributes to the secondary structure of proteins?

Hydrogen bonding contributes to alpha helix or beta pleated structure

What dictates the tertiary structure of proteins?

Folding based on hydrophobic and hydrophilic interactions

Describe the quaternary structure of a protein

Multiple polypeptides joining more than one polymer chain of amino acids

Do all proteins have quaternary structure?

Some do but not all

What is protein denaturation and how does it occur?

Protein denaturation occurs when proteins comoletely unfold and loses it’s normal three-dimensional shape because of extreme hot or cold

What are the two nucleic acids?

DNA and RNA

What is the monomer of a nucleic acid called?

Nucleotides

Describe the structure of a nucleotide

Nucleotides have three components covalently bonded (phosphate group, sugar with five carbon atoms, and a nitrogen-containing base)

In what ways is DNA different from RNA?

DNA’s sugar is deoxyribose with RNA’s sugar is ribose. Their four nitogren containing bases are different to with DNA having thymine instead of uracil that’s in RNA

What is the function of DNA?

Contains the genetic information of the cell

What is the function of RNA?

Assists the process of decoding DNA information into the amino acid sequences of proteins

 What is the activation energy of a chemical reaction?

The energy required to begin any chemical reaction

What are catalysts?

Substances that speed up chemical reactions but are not used up. They lower the activation energy required to begin the reaction

What are enzymes?

Cells manufacture specific proteins to act as catalysts and increase the rate of reactions and these specific proteins are known as enzymes. Almost all chemical creactions in organisms are facilitated by enzymes

Describe the structure of an enzyme

They are proteins made of long chains of amino acids and they exhibit primary, secondary and tertiary and sometimes quaternary structures. In general they have globular shapes with pockets or indentations on the surface known as active sites

What is an induced fit and how does it happen

An induced fit is what happens to the enzyme one the substrate binds to the active site. It changes conformation slightly to have a tighter fit with the substrate. Hydrogen bonds form between the enzyme and the substrate and a slight change in enzyme shape occurs to accommodate the substrate; this change is called an induced fit

What is the difference between a cofactor and a coenzyme?

A cofactor is when additional non-protein partners are required to catalyze a reaction with many of them being metal ions (minerals like iron or zinc). And coenzymes are organic cofactors derived from water-soluble vitamins

What are two key factors that affect enzyme activity?

Change in temperature or pH

How does substrate concentration affect enzyme activity?

If there are few substrate present the the formation of an enzyme-substrate complex will take longer since they’ll encounter each other less often

What is an inhibitor?

Molecules that interact with an enzyme and reduce the activity of the enzyme by interfering with its interaction with the substrate

What is the difference between competitive inhibition and non-competitive inhibition?

Competitive inhibition is when a substance binds to the active site of an enzyme to prevent substrates from binding. A non competitive inhibition like an allosteric inhibition is when an inhibitor prevents the enzyme from working but doesn’t affect the bonding of the substrate to the active site

What is feedback inhibition?

The product of the last reaction of a pathway is a non competitive inhibitor of the enzyme that catalyzes a reaction at the beginning of the pathway. This prevents overproduction of a product

What is the allosteric site of an enzyme?

A part of the enzyme that’s not the active site that a substance can bind to that causes rapid changes in enzyme activity

What do activators do?

Molecules that can bind to an allosteric site (not the active site) to cause an increase in enzyme activity

What are the four main types of biochemical reactions?

Neutralizations, oxidization-reduction, condensation, hydrolysis

What is an acid?

A substance that produces hydrogen ions, H⁺, in solution

What is a base?

A substance that produces hydroxide ions, OH^-, in solution

Write a word equation for a neutralization reaction. (reactants → products)

Element 1 Element 2 + Element 3 + 4→ water + a salt

What is the normal range of blood pH?

7.35-7.45

What happens if the blood pH drops below the normal range?

You could get Acidosis which is an illness caused by your blood pH is too low and if its below 7.0 it could be fatal

What happens if the blood pH rises above the normal range?

You could get Alkalosis which is an illness caused by your blood pH being too high (above 7.5) if it is above 7.8 it could be fatal

What do buffers do in our cells?

Minimize changes in pH by donating hydrogen ions, H⁺, when fluid is basic or accepting H⁺ when fluid is acidic

What happens when a molecule gets oxidized?

It loses electrons

What happens when a molecule gets reduced?

When it accepts the electron 

What does OIL RIG mean?

Oxidation Is Loss of electrons, Reduction Is Gain of electrons

What is a redox reaction?

The entire reaction of a molecule losing an electron while another gains electrons

What process occurs in our cells that involves a series of redox reactions?

cellular respiration

What is another name for a condensation reaction?

Dehydration Synthesis

What happens during a condensation reaction?

A H atom is removed from a functional group on one molecule, and an OH group is removed from a functional group on one molecule. The two molecules bond to form a larger molecule and water

What happens during a hydrolysis reaction?

The breakdown of macromolecules into their monomers

What important inorganic molecule is involved in both hydrolysis and condensation reactions?

Water

Outline the major function of the nucleus

Stores and replicates the genetic information of the cell