2.3 Carbohydrates & lipids

Question 1

Polysaccharides compare - contrast

Answer 1

All from glucose but differ due to H bonds between different side chains

STARCH: E storage, amylose (alpha 1,4) + amylopectin (alpha 1,4/1,6),

GLYCOGEN: E storage, more barnched than amylopectin (alpha 1,4/1,6)

CELLULOSE: structure, unbranched parallel chains, beta

Question 2

Condensation reactions

Answer 2

reaction of anabolism (larger molecules fromed)

Loss of -OH and -H -> H2O forms

Links together monosacch - di/polysacch

Question 3

E storage in organisms

Answer 3

In organisms E stored in lipids or carbohyd:

• Lipids: long-term storage, more efficient because no water associated, adipose tissue - beneath skin/around organs, secondary roles: thermal insulation, protects organs - shock absorber, used only in AEROBIC respiration
• Carbohyd: short-term storage, rapid use, used both in aerobic and anaerobic respiration

Question 4

BMI formula

Answer 4

Question 5

BMI ranges

Answer 5

Question 6

BMI diagram

Answer 6

Question 7

Types of fatty acids

Answer 7

1. Unsaturated (polyunsaturated): more than one double bond - less H than possible
2. Saturated (monosaturated): single bonds between C

Question 8

Types of unsaturated fatty acid

Answer 8

1. CIS isomer: H same side, bent, not as good at packing - LOWER melting temp - liquid at room temp - OILS
2. TRANS isomer: H opposite sides, not bent, better at packing - HIGHER melting temp - solid at room temp - FATS; produced artificially - hydrogenation of oils

Question 9

Health risks of fats

Answer 9

Coronary heart disease (CHD): trans and saturated fats, coronary arteries become partially blosked by fatty deposits - BLOOD CLOT (narrowing of lumen) - HEART ATTACK

Disagree some examples:

• Maasai in Kenya - high in saturated fats but much fibre - no CHD
• Mediterranean diet rich in oils (cis-monosaturated) - low CHD - genetics + tomatoes

Question 10

Evaluation of diets and health claims by

Answer 10

Surveys on large sample sizes - statistics, however, many factos: sex, health, age -> epidemiological studies - measures factors over long periods of time

Question 11

Monosaccharides

Answer 11

1. Pentose (5C): ribose/deoxyribose/fructose -
2. Hexose (6C): galactose/glucose - alpha/beta
3. Other (3C, 4C, 7C) - not found in nature but in metabolsim stages

Question 12

Types of glucose

Answer 12

1. Alpha glucose
2. Beta glucose