Unit 3: The Chemistry Of Life

Question 0

5 other elements needed in living organisms

Answer 0

Sulfur, calcium, phosphorous, iron, and sodium

Question 1

Most frequently occurring chemical elements in living things

Answer 1

Carbon, hydrogen, oxygen, and nitrogen

Question 2

One role for sulphur

Answer 2

Used in making of amino acids (tertiary structure of proteins with disulphide bridges)

Question 3

One for role for calcium

Answer 3

Used in structure of bones and teeth. It’s ions are used in synaptic transmission

Question 4

One role for phosphorous

Answer 4

Part of a DNA molecule. Used in phosphorylation. Used in ADP and ATP.

Question 5

One role for iron

Answer 5

Used in hemoglobin

Question 6

One role for sodium

Answer 6

Major part of action potentials

Question 7

Oxygen is slightly

Answer 7

Negative

Question 8

Outline the thermal property of water

Answer 8

Water has a high specific heat (it takes a lot of energy to raise one gram of the substance by one degree fare height). This means that it takes a lot higher or lower of a temperature to change the temperature of the water. This allows the water to be a coolant on a hot day. The water will stay cooler that the environment on a hit day. Additionally, it can be warm on a cold day.

Question 9

Outline the cohesive properties of water

Answer 9

Water, due to the high electronegativity difference in oxygen and hydrogen, allows for the hydrogen bonding to occur. This creates dipole-dipole forces between water molecules and gives water it’s cohesive properties. This is useful in xylem and phloem of plants. For example, it allows water to be lifted up the plant despite gravity and transport nutrients.

Question 10

Outline the solvent properties of water

Answer 10

Water is a polar molecule due to the high electronegativity difference between hydrogen and oxygen. This allows it to be a solvent for other polar molecules (like dissolves like; polar-polar and nonpolar-nonpolar). In water, ionic compounds dissociate. Because it is a good solvent, it is a good medium for chemical and metabolic reactions.

Question 11

Explain water’s use in living organisms as a coolant

Answer 11

Due to the thermal properties of water, water is able to be a good coolant. It can maintain a lower temperature I a hit environment because it has a high specific heat (takes a lot of energy to change temperature of water). Sweat is an example of this in nature.

Question 12

Explain water’s use in living organisms as a medium for metabolic reactions

Answer 12

Because water is a good solvent, it is a good medium for metabolic reactions. Ionic compounds dissociate into ions in it and the particles are able to easily collide. This allows for reactions to occur in the body and in labs.

Question 13

Explain water’s use in living organisms as a medium for transport medium

Answer 13

Water has cohesive properties due to its hydrogen bonds. This allows for water to love against gravity in plants, it can carry nutrients to all parts of the plants in the phloem and xylem because of this.

Question 14

Distinguish between organic and inorganic compounds

Answer 14

Organic compounds contain carbon and inorganic do not

Question 15

Exceptions to organic compounds containing compounds

Answer 15

Carbonates, hydrogen carbonates, and carbon dioxide

Question 16

Function of glucose in animals

Answer 16

Small molecules that are easily broken down for energy

Question 17

Function of lactose in animals

Answer 17

Easily broken down into monosaccharide

Question 18

Function of glycogen in animals

Answer 18

Insoluble. Used for storage

Question 19

Function of fructose in plants

Answer 19

Small molecule easily broken down for energy in cell respiration

Question 20

Function in sucrose in plants

Answer 20

Soluble, but up reactive so it can be transported throughout plant

Question 21

Function of cellulose

Answer 21

Insoluble energy molecule

Question 22

Outline the role of condensation and hydrolysis in e relationship between amino acids

Answer 22

Condensation (adding water) reactions are used in order to create chains of monomers. In amino acids two amino acids (monomers) joined other form a dipeptide. Hydrolysis reactions remove a water and break the compound into lower forms such as monomers.

Question 23

3 functions of lipids

Answer 23

Buoyancy, insulation, key component in plasma membranes, shock absorber (protection), hormones, structure

Question 24

Carbs or lipids? Short terms energy, quickly accessed, easy transportation, soluble, low energy per unit, small

Answer 24

Carbohydrates

Question 25

Outline DNA nucleotide structure in terms of sugar (deoxyribose), base, and phosphate.

Answer 25

A DNA nucleotide is composed of deoxyribose (5 carbon) sugar, a base (adenine, guanine, cytosine, or thymine), and a phosphate group

Question 26

State the names I’d the four bases in DNA.

Answer 26

Adenine, guanine, cytosine, thymine

Question 27

Outline how DNA nucleotides are linked together by covalent binds into a single strand

Answer 27

Covalent bonds link the 3’ and 5’ ends of the sugar and create the sugar-phosphate backbone of DNA. This creates a single strand.

Question 28

Define enzyme

Answer 28

Proteins (globular) that act as chemical reactions

Question 29

Define active site

Answer 29

Region on surface of the enzyme where the substrate bonds (this is what is responsible for catalysing reactions with substrates)

Question 30

List three examples of monossaccarides

Answer 30

Glucose, galactose, fructose

Question 31

List three examples of disaccharides

Answer 31

Maltose, lactose, sucrose

Question 32

List three examples of polysaccharides

Answer 32

Starch, glycogen, cellulose

Question 33

Explain enzyme-substrate specificity

Answer 33

According to the lock and key theory, enzymes and substrates are specific to one another, this suggests that one enzyme active site can inky accept one substrate that will fit precisely into its active site

Question 34

Explain the effects if temperature on enzyme activity

Answer 34

Enzymes have an optimum temperature at which they function. If the temperature decreases, the enzyme activity will decrease, but it will not denature the enzyme. As temperature increases so does rate of reaction (enzyme activity) up to a point, and following that point, the rate decreases and will cease due to the denaturation of the enzymes.

Question 35

Explain the effects of pH on enzyme activity

Answer 35

Enzymes have optimum pH at which they operate. As it varies from this direction, the enzyme activity will decrease

Question 36

Explain the effects of substrate concentration on enzyme activity

Answer 36

As substrate concentration increases the rate of reaction will too because more active sites are being occupied during the chemical reaction. Once the substrate gets to a certain point, reaction rate will stay the same (because all of the active sites will be occupied and there will be excess).

Question 37

Define denaturation

Answer 37

Denaturation is the changing of the structure of an enzyme so it can no longer function. This may occur as the result of temperature being increased too high.

Question 38

Explain the use of lactase in the production of lactose-free milk

Answer 38

He enzyme lactase breaks down the sugar lactose into glucose and/ or galactose. Som people do not have this enzyme (lactose intolerant). This is fixed in lactose-free milk by doing one of two things. The first is adding lactase to the milk. The second is to pass the milk over a material that contains lactase (so that the milk ends up not containing lactase).

Question 39

Primary structure

Answer 39

The primary structure of a protein is it’s amino acid sequence. This amino acid sequence is determined by the base sequence of the gene which codes for the protein

Question 40

Secondary structure

Answer 40

Secondary structures have a-helices and b-pleated sheets. These form as a result of hydrogen bonds between the peptide groups of the main chain. Therefore. Proteins that contain secondary structures will have region that are cylindrical (a-helices) and/or regions that are planar (b-pleated sheets)

Question 41

Tertiary structure

Answer 41

The tertiary structure of a protein is it’s three-dimensional conformation which occurs as. Result of the protein folding. This folding is stabilised by hydrogen bonds, hydrophobic interactions, ionic bonds and disulphide bridges. These intermolecular bonds form between the R groups of different amino acids.

Question 42

Quaternary structure

Answer 42

A quaternary structure is formed when two or more polypeptide chains associate to form a single protein. An example is haemoglobin which consists of four polypeptide chains. In some cases, some proteins can have a non-polypeptide structure called a prosthetic group. These proteins are called conjugated proteins. The haem group in haemoglobin is a prosthetic group.