Chapter 3: Molecules of Life

Question 1

what element does an organic compound contain?

Answer 1

carbon

Question 2

what elements are usually found attached to carbons in an organic compound?

Answer 2

hydrogen if making a hydrocarbon chain or most any general carbon skeleton (then oxygen and nitrogen in functional groups)

Question 3

what are the four key types of organic compounds found in living organisms?

Answer 3

carbohydrates, proteins, lipids, nucleic acid

Question 4

what elements make up the organic compounds we relate with food?

Answer 4

carbohydrates: C, H, O
lipids: C, H, O
proteins: C, H, O, N

Question 5

what are the building blocks of carbohydrates

Answer 5

monosaccharides

Question 6

name the three categories of lipids and their building blocks

Answer 6

triglycerides: 3 fatty acids, 1 glycerol
phospholipids: 2 fatty acids, 1 glycerol, a phosphate group
waxes: 1 fatty acids and an alcohol
steroids: 3 six-sided carbon rings connected to 1 five-sided rings

Question 7

what are the building blocks of proteins?

Answer 7

amino acids

Question 8

what are the building blocks of nucleic acids

Answer 8

nucleotides (sugar, phosphate group, nitrogenous base)

Question 9

what is the name for a sugar that is made up of two sugars combined? 3+?

Answer 9

disaccharide, polysaccharide

Question 10

what is the main reason we need carbohydrates in our diet?

Answer 10

primary fuel and energy source

Question 11

name examples of food that contain carbohydrates

Answer 11

whole grain breads and cereals, legumes, and starchy vegetables are all good complex carbohydrate sources. simple carbohydrates include sugars that occur naturally in some vegetables and many fruits, and these naturally sweet foods can make good sweeteners instead of using pure sugar

Question 12

oils and fats are example of what organic compound?

Answer 12

lipids

Question 13

name examples of lipids we can eat

Answer 13

edible animal fats: lard, fish oil, butter. these come from fats in milk, meat, or under skin of animals
plant fat: peanut, soya bean, sun flower, sesame, coconut, olive, vegetable oils

Question 14

if a lipid is solid at room temperature it is which type of fat? what does that mean structurally?

Answer 14

saturated, it wouldn’t contain any double bonds in the hydrocarbon chains of the fatty acid (all of the fatty acids’ carbons would be bonded to four atoms)

Question 15

where do we find proteins in our bodies

Answer 15

in muscles, organs and glands. in every living cell and all bodily fluids except bile and urine. the cells of muscles, tendons and ligaments have protein

Question 16

name things we eat that have protein

Answer 16

fish, poultry, meat, eggs, chess, milk, soya beans, beans, rice, grain

Question 17

most of the energy we get from what we ear is temporarily stored where in our bodies

Answer 17

adenosine triphosphate (ATP)

Question 18

name two types of nucleic acids

Answer 18

1. RNA (ribonucleic acid) 2. DNa (deoxyribonucleic acid)

Question 19

where does DNA get its name from?

Answer 19

deoxyribonucleic acid (contains sugar deoxyribose

Question 20

where does RNA get its name from

Answer 20

ribonucleic acid (contains sugar ribose)

Question 21

one main difference between structure of DNA when compared to that of RNS

Answer 21

DNA is a double stranded (double helix) but RNA is single stranded

Question 22

what is DNA’s main purpose

Answer 22

determines characteristics of an organism (basic unit of heredity, the gene). it also directs all cellular activity

Question 23

what does RNA do

Answer 23

stores and transfers info from DNA that is essential for the manufacture of proteins. some act as enzymes, helping to move along chemical reactions that link together amino acids to from proteins

Question 24

how do enzymes work

Answer 24

Enzymes work as biological catalysts, lowering the activation energy of chemical reactions. Each enzyme has an active site with a very specific shape. A substrate (reactant of the reaction needing to be catalyzed) must bond to the active site of the enzyme for the activation energy of the reaction to be lowered (and therefore a speeding up of the chemical reaction). As long as an enzyme is not denatured, after it helps with one reaction it can help with another, etc., etc., etc. In other words, an enzyme is not destroyed after one use but continues to be used over and over again as it itself remains unchanged.

Question 25

what types of condition cause enzyme to become denatured

Answer 25

Any condition that permanently changes the shape of the enzyme’s active site is said to have denatured the enzyme (making it useless). Example conditions are variations in pH, salinity (salt concentration), and temperature — to denature an enzyme usually requires an extreme of one of these conditions.

Question 26

what does a glycerol molecule look like

Answer 26

H    H   H
        |      |    |
H -- C -- C-- C-- H
        |      |      |
      OH   OH  OH

Question 27

what does a fatty acid look like

Answer 27

O H H H H H H
|| | | | | | |
O – C– C – C– C– C – C– C– H
| | | | | |
H H H H H H