biomolecules

Question 1

What elements make up carbohydrates, lipids, proteins?

Answer 1

All: C, H, O (carbon, hydrogen, oxygen)

Protein (extra, in addition to CHO): N, S (nitrogen, sulfur)

Question 2

State 2 things that are synthesized from glucose.

Answer 2

Glycogen and starch

Question 3

State 1 thing synthesized from amino acids.

Answer 3

Polypeptides

Question 4

State 1 thing synthesized from fatty acids and glycerol.

Answer 4

Lipids (e.g. fats)

Question 5

What is the structure of starch?

Answer 5

A mixture of 2 polysaccharides (amylose and amylopectin), consisting of glucose molecules

Question 6

What is the role of starch?

Answer 6

Major storage carbohydrate of most plants as an important energy source

Question 7

Starch is a _____ (soluble / insoluble?). It is built from many ____ molecules condensed together.

Answer 7

Starch is a polysaccharide (insoluble). It is built from many monosaccharide molecules condensed together.

Question 8

What is the structure of a triglyceride?

Answer 8

3 fatty acid molecules + 1 glycerol molecule

Question 9

How are triglycerides formed?

Answer 9

Formed by condensation reactions (removal of water) between fatty acids and glycerol

Question 10

What are the bonds formed in triglycerides called?

Answer 10

Ester bonds

Question 11

Triglycerides are ____ molecules, but ___ when compared to glycogen and starch. Because of their ___, ___ properties, triglyceride molecules clump together into huge ___ (appear as macromolecules).

Answer 11

Triglycerides are large molecules, but small when compared to glycogen and starch. Because of their non-polar, hydrophobic properties, triglyceride molecules clump together into huge globules (appear as macromolecules).

Question 12

What are the 2 types of triglycerides and what distinguishes them?

Answer 12

Saturated triglycerides: No double bonds in fatty acid tails (solid)
Unsaturated triglycerides: One or more double bonds present in fatty acid tails (kinks/bends, cannot be compacted –> liquid)

Question 13

What is the difference in structure between phospholipids and triglycerides?

Answer 13

Phospholipids have a similar chemical structure to triglycerides except one of the fatty acids is replaced by a phosphate group

Question 14

Is the phosphate group hydrophilic or hydrophobic?

Answer 14

The phosphate group is ionised and therefore water-soluble (hydrophilic).

Question 15

What are the 4 structures of proteins?

Answer 15

Primary structure, secondary structure, tertiary structure, quaternary structure

Question 16

The ____ structure of a protein is the long chain of ____ ____.

Answer 16

The primary structure of a protein is the long chain of amino acids.

Question 17

The ____ structure of a protein develops when either part or all of the ___ chain becomes ___ to produce an a-helix or it becomes ___ to b-sheets.

Answer 17

The secondary structure of a protein develops when either part or all of the polypeptide chain becomes coiled to produce an a-helix or it becomes folded to b-sheets.

Question 18

The ___ structure is the precise, compact structure, ___ to the protein that arises when the molecule is further folded and held in a particular ___ shape.

Answer 18

The tertiary structure is the precise, compact structure, unique to the protein that arises when the molecule is further folded and held in a particular complex shape.

Question 19

The ___ structure of a protein arises when 2 or more polypeptides become ___ ____, forming a complex, biologically active molecule.

Answer 19

The quaternary structure of a protein arises when 2 or more polypeptides become held together, forming a complex, biologically active molecule.

Question 20

What is denaturation? When does denaturation occur?

Answer 20

Denaturation is the loss of the three-dimensional structure of a protein. It happens when the bonds that maintain the 3D shape of the protein are changed.

Question 21

Name 2 factors that change/disrupt bonds.

Answer 21

Exposure to heat disrupts hydrogen and ionic bonds, pH changes alter ionic bonds. (enzymes! structure determines function)

Question 22

Name 4 properties of water.

Answer 22

• Has high specific heat capacity (much thermal energy required to raise water temperature)
• High latent heat of vapourisation (allows cooling by evaporation)
• Universal solvent in biological systems, a key component of tissues
• Water molecules are highly cohesive (xylem vessels)