IB Biology: Level 11 - Lipids 2.3

Question 1

What is a Lipid?

Answer 1

Energy-rich organic compounds, such as fats, oils, waxes, steroids and phospholipids that are made of carbon, hydrogen, and oxygen.

Question 2

What is a triglyceride?

Answer 2

A lipid made of one glycerol with three attached fatty acids

Question 3

What is cholesterol?

Answer 3

A steroid that forms an essential component of animal cell membranes

Question 4

What is a phospholipid?

Answer 4

A molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail.

Question 5

Compare and contrast a phospholipid with a triglyceride

Answer 5

Both have glycerol and fatty acid chains that are joined by condensation reactions. Phospholipids have two fatty acid chains whereas triglycerides have 3 fatty acid chains and phospholipids have a phosphate group attached to the third hydroxyl on the glycerol which causes it to be partially hydrophilic.

Question 6

What is the structure of glycerol? Which molecules does it form part of?

Answer 6

A three-carbon alcohol to which fatty acids are covalently bonded to make fats and oils.A small molecule that forms the head region of a triglyceride fat molecule

Question 7

What is an ester bond?

Answer 7

The covalent bond formed when fatty acid molecules are joined to glycerol molecules in condensation reactions.

Question 8

What is a fatty acid? Can you draw one?

Answer 8

A long carbon skeleton, with usually 16-18 carbons, at the end has a carboxyl group attached to a hydrocarbon

Question 9

How can you identify a saturated fatty acid or fat?

Answer 9

Fats or fatty acids with the maximum number of hydrogens. In other words they do not contain double bonds.

Question 10

How can you identify an unsaturated fatty acid or fat?

Answer 10

Fats or fatty acids with less than the maximum number of hydrogens in one or more of its fatty acid chains. In other words it contains at least one double bond.

Question 11

What does monounsaturated mean?

Answer 11

A fatty acid whose molecular structure includes only ONE double carbon bond.

Question 12

What does polyunsaturated mean?

Answer 12

A fatty acid whose molecular structure includes two or more double carbon bonds.

Question 13

What is a condensation reaction? Can you describe it for the formation of a triglyceride or a phospholipid?

Answer 13

It is the joining of two molecules with the removal of water. For triglyceride it involves the joining of 3 fatty acids to the hydroxyl groups of the glycerol molecule with the removal of 3 water molecules.

Question 14

What is hydrolysis?

Answer 14

It is the breaking of a bond between two molecules with the addition of water

Question 15

What does hydrophillic mean?

Answer 15

water loving

Question 16

What does hydrophobic mean?

Answer 16

water fearing

Question 17

cis-fatty acid

Answer 17

Unsaturated fatty acid with H bonds on the SAME side of the double bonded carbons.

Question 18

trans-fatty acid

Answer 18

Unsaturated fatty acid with hydrogen bonds on opposite sides of the double bonded carbons

Question 19

Implications

Answer 19

determination of whether results of research support the health claim made. (Strongly, moderately, or not at all based on evidence gathered)

Question 20

Limitations

Answer 20

answers the question of whether research methods used were rigorous or if there uncertainties in methodology

Question 21

Correlation

Answer 21

A connection between 2 or more things

Question 22

Positive correlation

Answer 22

When an increase in a variable increases the other, or decrease in a variable decreases the other

Question 23

Negative correlation

Answer 23

Correlation in the opposite direction. When increasing one variable decreases the other, and vice versa

Question 24

Calorimeter

Answer 24

A tool used to measure the energy content in food

Question 25

Atherosclerosis

Answer 25

Build up of plaque in arteries; hardening of arteries that can lead to heart attacks or strokes

Question 26

BMI

Answer 26

method of screening of body mass. Ratio of weight to height squared

Question 27

Energy content in lipids (fats)

Answer 27

9 calories / gram

Question 28

ENergy content in carbohydrates

Answer 28

4 calories / gram

Question 29

Energy content in protein

Answer 29

4 calories / gram

Question 30

LDL (Low density lipoprotein)

Answer 30

“Bad” Cholesterol that carries dietary fats into cells; has been linked to atherosclerosis

Question 31

HDL (High density lipoprotein)

Answer 31

“Good” Cholesterol that carries impurities out of cells

Question 32

Hydrogenation

Answer 32

The process whereby hydrogen atoms are added to the carbon-carbon double bonds making them more saturated. For example, an unsaturated fat like olive oil being made into a solid spread. Turning cis unsaturated fats into trans fats