Carbohydrates and Lipids

Question 1

where are the H atoms that are attached to the double bonded carbons in cis fatty acids

Answer 1

on the same side of the molecule which causes a bend in the molecule and makes it liquid at room temperature

Question 2

where are the H atoms that are attached to the double bonded carbons in a trans fatty acid

Answer 2

opposite sides of the molecule which doesn’t create a kink so the fatty acid is packed tightly and is solid at room temperature
trans fatty acids are produced artificially by partial hydrogenation of fish oils

Question 3

what is the structure and function of cellulose

Answer 3

B-glucoses at 180 degrees to each other which makes the molecule straight
molecules form bundles which have high tensile strength and prevents plant cells from bursting

Question 4

what is the structure and function of starch

Answer 4

A-glucose all pointing downwards to form curved molecules
- amylose (helix)
- amylopectin (globular)
too large to be soluble in water and it is useful in cells when glucose needs to be stored

Question 5

what is the structure and function of glycogen

Answer 5

similar to starch but more compact (made by animals and some fungi)
it acts as a store of energy in form of glucose in cells where large stores of glucose would cause osmosis problems
molecules do not have a fixed size and number of glucose molecules can be increased or decreased form either end of the molecule

Question 6

why are lipids more suitable for long term energy storage in humans than carbohydrates

Answer 6

fats located beneath skin and around some organs
amount of energy released/grams of lipids is twice amount released/grams of carbs
lipids have less water so is capable of storing more energy
can protect the skin by insulating heat and act as shock absorbers in the area around the kidneys

Question 7

how to determine someone’s BMI

Answer 7

bmi = mass in kg / (height in metres) * 2

Question 8

how are polymers formed

Answer 8

monomers linked together by condensation reactions to form polymers (glucose + glucose = maltose)

Question 9

what are monosaccharides

Answer 9

sweet-tasting and function as an immediate energy source for cells

• > glucose
• > galactose
• > fructose

Question 10

what are disaccharides

Answer 10

small enough to be soluble in water and commonly function as a transport form

• > lactose
• > maltose
• > sucrose

Question 11

what are polysaccharides

Answer 11

used for energy storage or cell structure
play a role in cell recognition
-> cellulose
-> glycogen
-> starch

Question 12

what are cis fatty acids

Answer 12

naturally curved fatty acids

- hydrogens on the same side at double bonded carbons causing a bend in the fatty acid chain and loosely packed

Question 13

what are trans fatty acids

Answer 13

hydrogenated and straightened fatty acids

• hydrogens on opposite sides of double bonded carbons so they do not have a bend in the hydrocarbon chain at the double bonded carbons
• tightly packed

Question 14

what are the functions of lipids

Answer 14

storage of energy for long term use
hormonal roles
insulation
protection of internal organs
structural components of cells

Question 15

what are the types of lipids

Answer 15

triglycerides: long term energy source
phospholipids: structural component of cell membranes
steroids: plant and animal hormones
waxes: protective layer against water loss and animal skin

Question 16

what are some lipid health risks

Answer 16

saturated and trans fats raise blood cholesterol levels while cis unsaturated fats lower blood cholesterol levels
fats and cholesterol are insoluble in blood and are packaged with proteins to form lipoproteins for transport
- ldls raise blood cholesterol levels while hdls lowers