4.1 Carbohydrates, fats and Proteins

Question 1

Carbohydrates

Answer 1

Substances that include sugars, starch, and cellulose contain carbon, hydrogen, and oxygen.

Question 2

sugars

Answer 2

Carbohydrates have relatively small molecules: they are soluble in water, and they taste sweet.

Question 3

glucose

Answer 3

a sugar that is used in respiration to release energy

Question 4

glycogen

Answer 4

a carbohydrate that is used as an energy store in animal cells

Question 5

starch

Answer 5

a carbohydrate that is used as an energy store in plants

Question 6

iodine solution

Answer 6

a solution of iodine in potassium iodide; it is orange-brown, and turns blue-black when mixed with starch

Question 7

Benedict’s solution

Answer 7

a blue liquid that turns orange red when heated with reducing sugars

Question 8

reducing sugars

Answer 8

sugars such as glucose, which tun Benedict’s solution orange-red when heated together

Question 9

fats

Answer 9

lipids that are solid at room temperature

Question 10

oils

Answer 10

lipids that are liquid at room temperature

Question 11

lipids

Answer 11

substances containing carbon, hydrogen, and oxygen; they are insoluble in water and are used as energy stores in organisms

Question 12

emulsion

Answer 12

a liquid containing two substances that do not fully mix; one of them forms tiny droplets dispersed throughout the other

Question 13

protein

Answer 13

a substance whose molecules are made of many amino acids linked together; each different protein has a different sequence of amino acids

Question 14

amino acids

Answer 14

substances with molecules containing carbon, hydrogen, oxygen and nitrogen: there are 20 different amino acids found in organisms

Question 15

antibodies

Answer 15

molecules secreted by white blood cells, which bind to pathogens and help to destroy them

Question 16

pathogens

Answer 16

microorganisms that cause disease, such as bacteria

Question 17

keratin

Answer 17

the protein that forms hair

Question 18

biuret reagent

Answer 18

a blue solution that turns purple whem mixed with amino acids or proteins