Biology // Module 2 // Biological Molecules

Question 1

Why do atoms form bonds?

Answer 1

Atoms form bonds to become stable. This is by filling out their outermost shell. This is why noble gases are so stable.

Question 2

What is a covalent bond?

Answer 2

Non-metal elements which join to share electrons.

Question 4

What are the important cations and some of their uses?

Answer 4

-Calcium (Ca2+), Nerve impulse, Muscle contractions
-Sodium (Na+), Nerve impulse and kidney function
-Hydrogen (H+), Nerve impulse, Stomata
-Ammonia (NH4+), Needed to make nitrate ions

Question 5

What are the important anions and some of their functions?

Answer 5

-Nitrate (NO3-), Amino acid formation
-Hydrogen Carbonate (HCO3-), Maintains blood pH
-Chloride (Cl-), Balance sodium and potassium ions in cells
-Phosphate (PO4 3-), Cell membranes, Nucleic Acids and ATP formation, Bone formation
-Hydroxide (OH-), Catalysts, pH determination

Question 6

What is a polymer?

Answer 6

Long chain molecules made up by the linking of multiple monomers in a repeating pattern.

Question 7

What are the three structures of Carbohydrates and what are they?

Answer 7

-Monosaccharides, simple sugars with general formula (CH2O)n, where n can be 3-7.
Disaccharides, Double sugars formed with two monosaccharides.
Polysaccharides, large molecules formed from many monosaccharides.

Question 8

What are example molecules of Monosaccharides?

Answer 8

Glucose, Fructose and Ribose

Question 9

What are example molecules of Disaccharides?

Answer 9

Lactose and Sucrose

Question 10

What are example molecules of Polysaccharides?

Answer 10

Glycogen, Cellulose, and Starch

Question 11

What is the general formula for Carbohydrates?

Answer 11

Cx(H2O)y

Question 12

What are some facts about monosaccharides?

Answer 12

-Simplest sugar type
-Same number of C and O atoms. E.g C6H12O6
-General formula of (CH20)n, where n is 3-7
-Straight lines or forms rings
-White crystalline solid
-Dissolves into water to form sweet-tasting solutions
-Insoluble in non-polar solvents
-Energy source

Question 13

What is glucose?

Answer 13

Hexose sugar which has a general formula of C6H12O6.

Question 14

What is glucose used for?

Answer 14

Glucose is the major energy source for most cells. It is highly soluble and is the main form in which carbohydrates are transported around the body of animals.

Question 15

What is different about Alpha glucose and Beta glucose?

Answer 15

The main difference is the position of the Hydroxide which is attached to Carbon 1. In Alpha glucose, the hydroxide is below the carbon, and in Beta glucose, the hydroxide is above the carbon.
Alpha= Down, Down, Up, Down
Beta= Up, Down, Up, Down (regular beat)

Question 16

How are disaccharides formed?

Answer 16

Formed by the condensation of two monosaccharides with a 1-4 glycosidic bond.

Question 17

What is Maltose and how is it formed?

Answer 17

Maltose makes malt sugar and is formed from two glucose molecules joined by an alpha 1-4 glycosidic bond.

Question 18

What is Sucrose and how is it formed?

Answer 18

Sucrose makes table sugar and is formed from glucose and fructose joined by an alpha 1-4 glycosidic bond.

Question 19

What is Lactose and how is it formed?

Answer 19

Lactose makes milk sugar and is formed from galactose and glucose joined by a beta 1-4 glycosidic bond.

Question 20

What are polysaccharides?

Answer 20

Polymer containing many monosaccharides linked by glycosidic bonds. They are formed by condensation reactions. The main polysaccharides are starch, cellulose, and glycogen.

Question 21

What are polysaccharides used for?

Answer 21

Used as an energy store and as structural components of cells.

Question 22

What is the sugar found in DNA?

Answer 22

Deoxyribose sugar (Deoxyribonucleic acid)

Question 23

What is the sugar found in RNA?

Answer 23

Ribose.

Question 24

What is the difference between the sugars found in RNA and DNA?

Answer 24

Ribose has one Hydrogen atom and one Hydroxide group attached to Carbon 2, whereas Deoxiribose has 2 Hydrogen atoms and no Hydroxide groups.

Question 25

What is starch?

Answer 25

Storage molecule in plants which are stored in plastids and amyloplasts. It is produced from glucose made during photosynthesis and is broken down during respiration to provide energy.

Question 26

What are some facts about Starch?

Answer 26

-The alpha helical structure makes it good for storage as it is compact.
-It is stored in Amyloplasts.
-Starch is insoluble. Therefore the hydroxyl group on Carbon 2 are hidden inside the helix so they cant bond with water. This means it will not affect osmosis.
-Main plant storage sugar

Question 27

What is Amylose?

Answer 27

Unbranched chain of glucose molecules joined by 1-4 glycosidic bonds. It is very coiled and therefore very compact.

Question 28

What is amylopectin?

Answer 28

Branched and made of glucose molecules joined by 1-4 and 1-6 glycosidic bonds.

Question 29

What is glycogen?

Answer 29

-Made of alpha glucose, joiend by 1-4 glycosidic bonds.
-Has branched which are formed by 1-6 glycosidic bonds.
-Storage sugar found in animals
-Made mostly by the liver in muscles.
-Stored as granules in the cytoplasms of cells
-Can be quickly hydrolysed when energy supply is needed.

Question 30

What is Cellulose?

Answer 30

-Another polysaccharide and is the main part of cell walls.
-It is the most abundant organic polymer
-Cellulose is very strong and prevents cells from bursting when they take in excess water.

Question 31

What is the structure of Cellulose and what is the function?

Answer 31

Long chains of beta glucose molecules joined by beta 1-4 glycosidic bonds. Glucose chains form microfibrils. Hydrogen bonding between the chains gives cellulose tensile strength which supports the structure.

Question 32

What are some facts about Cellulose?

Answer 32

-Polymer of beta glucose.
-Forms chains which run parallel with hydrogen bonds between the chains to form microfibrils. Microfibrils are strong and being fibrous, cellulose is important for the plants cell walls.

Question 33

What is the structure of water?

Answer 33

-One slightly negative Oxygen atom is bonded to two slightly positive Hydrogen atoms.
-Slightly negatively-charged oxygen atoms attract the slightly positively-charged hydrogen atoms. This makes water a polar molecule.
-Oxygen is more electronegative than hydrogen so it is more able to attract electrons.