Lesson 1 (Macromolecules)

Question 1

What macromolecules act as the major full substances?

Answer 1

Carbohydrates, lipids and proteins

Question 2

Are sugars (carbohydrates) polar/un polar and soluble/ insoluble in water?

Answer 2

They are highly polar because they contain oxygen and therefore soluble in water.

Question 3

How are disaccharides assembled?

Answer 3

From two monosaccharides linked by a dehydration synthesis reaction.

Question 4

What is a dehydration synthesis reaction?

Answer 4

The formation of a covalent bond between two monosaccharides by removing the water molecule between both.

Question 5

What are the two types of covalent bonds in a disaccharide and now can they be broken?

Answer 5

They can either be alpha-linked (parallel) on beta-linked (perpendicular). They require a special enzyme to be broken.

Question 6

What are enzymes?

Answer 6

Molecules with a catalytic activity that favor reactions in living cells. Mostly proteins.

Question 7

What are the two functions of polysaccharides?

Answer 7

The first is to bring support and rigidity. The second is to store fuel.

Question 8

What is the difference between the two types of polysaccharides?

Answer 8

The arrangement of the monosaccharides they are made of (order).

Question 9

What main function of polysaccharides are starch and glycogen part of?

Answer 9

Fuel storage because they are alpha-linked.

Question 10

What main function of polysaccharides are chitin and cellulose part of?

Answer 10

Support and rigidity because they are made of beta-linkage.

Question 11

Are lipids polar/non polar and soluble/insoluble in water?

Answer 11

They are water-insoluble and primary non polar biological molecules.

Question 12

Are lipids polar/non polar and soluble/insoluble in water?

Answer 12

They are water-insoluble and primary non polar biological molecules.

Question 13

What are the three types of lipids?

Answer 13

Fatty acids, steroids and phospholipids.

Question 14

What happens to fatty acids when their chain length increases?

Answer 14

They become progressively less water-soluble and more solid.

Question 15

Are fatty acids polar on non polar?

Answer 15

Non polar.

Question 16

Are steroids polar on non polar?

Answer 16

Non polar.

Question 17

Are steroids polar on non polar?

Answer 17

Non polar.

Question 18

Are phospholipids polar on non polar?

Answer 18

They are both polar (hydrophilic end) and non polar (hydrophobic end).

Question 19

What are the two types of fatty acids?

Answer 19

The unsaturated (liquid at room temperature) and the saturated L solid at room temperature).

Question 20

As what can be used steroids in the body?

Answer 20

As hormones.

Question 21

How do lipid hormones enter a cell?

Answer 21

They can diffuse through the cell membrane which is also made of lipids.

Question 22

What is the main component of a cell membrane?

Answer 22

Phospholipids because of their dual solubility. They form a bi-layer with the hydrophilic end outside the membrane and the hydrophobic and inside the membrane.

Question 23

What are proteins?

Answer 23

They are polymers of amino acids.

Question 24

How are amino acids inside of proteins grouped?

Answer 24

They are grouped by their R chain properties, according to one of the four types.

Question 25

What are proteins used for?

Answer 25

They are used for structure, as enzymes, as hormones, as receptors, etc.

Question 26

What is the generalized structure of an amino acid?

Answer 26

It has a central carbon atom attached to an amino group (NH2), a carboxyl group (COOH) and an hydrogen atom.

Question 27

What is the group attached to the R bond of the central carbon in amino acids?

Answer 27

It is one of 20 different side groups reported in four different types. It is called the side chain.

Question 28

What have the four types of amino acids characteristics?

Answer 28

Non polar, uncharged polar, negatively charged (acidic) polar and positively charged (basic) polar.

Question 29

In a polypeptide, what links each amino acid to one another?

Answer 29

A peptide bond.

Question 30

How is a peptide bond formed?

Answer 30

By a dehydration synthesis between the NH2 group of one amino acid and the COOH group of another amino acid.

Question 31

What is the distinction between a polypeptide and a protein?

Answer 31

A polypeptide is a string of amino acids while a protein is a string of amino acids that has folded into a specific 3-d shape that is required for proteins to be functional.

Question 32

What are nucleic acids?

Answer 32

They are polymers of nucleotides.

Question 33

What is a nucleotide?

Answer 33

It contains a nitrogenous base (rings of carbons and nitrogen atoms), a five-carbon ring shaped sugar, and one to three phosphate group, all linked by a covalent bond.

Question 34

How are nucleotides in RNA and DNA linked?

Answer 34

By a bridging phosphate group between the carbon of one sugar and the carbon of another sugar.

Question 35

What forms the backbone of a nucleic acid?

Answer 35

The arrangement of alternating sugar and phosphate group.

Question 36

What are some characteristics of DNA?

Answer 36

It is made of two strands (double helix) and contains base pairs ( cytosine - guanine, adnine-thymine).

Question 37

What are some characteristics of RNA.

Answer 37

It is made of a single strand, less stable than DNA, and it has base pairs (cytosine-guanine, adenine-uracil).