Topic 1 biological molecules H2O, Carbs & Lipids

Question 1

what do u call a molecule that is partly positive and partly negative

Answer 1

dipole/polar molecule

Question 2

Nitrate ions formula and use

Answer 2

(NO3-) needed in plants for the formation of amino acids–> proteins–>formation of DNA

Question 3

phosphate ions formula and use

Answer 3

(PO4 -3) formation of ATP ADP and DNA/RNA

Question 4

Chloride ions formula and use

Answer 4

(Cl-) nerve impulses+secretory systems

Question 5

hydrogen carbonate ion formula and use

Answer 5

(HCO3-) Buffer blood preventing it from becoming too acidic

Question 6

sodium ions formula and use

Answer 6

Na+ nerve impulses

Question 7

Properties of water

Answer 7

polar solvent
transport medium-other substances can dissolve in it
slow to absorb and release heat-high specific heat capacity
cannot be compressed
cohesive- stick together due to forces between the molecules
adhesive-attracted to different molecules
high surface tension

Question 8

degree angle between 2 hydrogens in water molecules

Answer 8

104.5

Question 9

general formula for monosaccharides

Answer 9

(CH2O)n

Question 10

how many carbon atoms in triose sugars

Answer 10

n=3

Question 11

how many carbon atoms in pentose sugars+examples

Answer 11

n=5
eg. Ribose, deoxyribose

Question 12

how many carbon atoms in hexose sugars

Answer 12

n=6
glucose galactose and fructose

Question 13

Test for reducing sugars

Answer 13

Benedicts solution –>solution of light blue Cu(2) ions when heated with reducing sugars it reduces Cu(2) to Cu(1) ions turning from blue to orange

Question 14

Test for non-reducing sugars (EG. sucrose)

Answer 14

heat non reducing sugars with a few drops of HCl, allow to cool, add sodium hydrogen carbonate to neutralise glycosidic bonds.
—>monosaccharide forms, you can then use the benedict test

Question 15

what are molecules with 3-10 sugar units known as

Answer 15

oligosaccharides

Question 16

what are molecules containing 11 sugar units or more

Answer 16

Polysaccharides

Question 17

what about the structure of polysaccharides makes them ideal storage molecules within a cell

Answer 17

compact molecules, take up little space
physically and chemically inactive, do not interfere with other functions of cell
not very soluble in water- causes no osmotic water movements

Question 18

examples of where hydrolysis takes place

Answer 18

digestion in the gut
muscle and liver cells-when carbohydrate stores are broken down to release sugars for use in cellular respiration

Question 19

starch is a mixture of which 2 compounds

Answer 19

amylose-unbranched polymer- spirals
amylopectin-branched polymer-terminal glucose molecules that can easily be broken off when energy is needed

Question 20

similarities between amylose and amylopectin

Answer 20

both long chains of alpha glucose molecules

Question 21

differences between amylose and amylopectin

Answer 21

amylose- 1,4 glycosidic bond-long and unbranched
amylopectin- 1,4 glycosidic bonds but also a few 1,6. therefore it has branching chains

Question 22

glycogen properties

Answer 22

made of alpha glucose units.
very compact
more 1,6 glycosidic bonds
—> side branches, glycogen can be broken up quickly for energy

Question 23

describe structure of cellulose

Answer 23

insoluble
its monomers are beta glucose, held together by 1,4 glycosidic bonds.
one monomer unit is inverted, hydroxyl groups stick out.
therefore, hydrogen bonds can form between partially positively charged hydrogen atoms of the hydroxyl groups

cellulose does not coil up, straight long chains.

Question 24

what are lipids made of

Answer 24

carbon, oxygen and hydrogen
fatty acids and glycerol

Question 25

what bonds combine the organic chemicals in lipids??

Answer 25

ester bonds

Question 26

what is the glycerol chemical formula

Answer 26

C3H8O3

Question 27

How can fatty acids vary

Answer 27

length of carbon chain can differ(usually 15-17) can be a saturated or a unsaturated hydrocarbon

Question 28

example of a saturated fatty acid

Answer 28

stearic acid

Question 29

bonds in a saturated fatty acid

Answer 29

single covalent bond

Question 30

bonds in a unsaturated fatty acid

Answer 30

one or more double covalent bonds

Question 31

bonds in a monounsaturated fatty acid

Answer 31

one double bond

Question 32

bonds in a polyunsaturated fatty acid

Answer 32

2 or more double covalent bonds

Question 33

example of polyunsaturated fatty acid

Answer 33

linoleic acid

Question 34

define esterification

Answer 34

the formation of ester bonds condensation reaction between a carboxylic group(COOH-)of the fatty acid and a hydroxyl group(-OH) of the glycerol

Question 35

what is a phospholipid

Answer 35

a chemical in which glycerol bonds with 2 fatty acids and an inorganic phosphate group

Question 36

what do we call molecules that dissolve readily in water

Answer 36

hydrophilic

Question 37

what do we call molecules that do not dissolve in water

Answer 37

hydrophobic

Question 38

define monolayer

Answer 38

single closely packed layer of atoms and molecules hydrophilic head in the water and hydrophobic lipid tails in the air

Question 39

define a micelle

Answer 39

a spherical aggregate of molecules in water with hydrophobic areas in the middle and hydrophilic areas outside

Question 40

what is a bilayer

Answer 40

a double layer of closely packed atoms or molecules

Question 41

phosphate ions formula

Answer 41

PO4 3-

Question 42

cellulose formula

Answer 42

(C6 H10 O5)n

Question 43

how to form a triglyceride

Answer 43

esterification between glycerol and 3 fatty acids

Question 44

Uses of lipids due to their properties

Answer 44

hydrophobic--> waterproofing organisms fatty sheath insulation for nerves so electrical impulses travel faster insulate against heat loss low density- helps mammals float insoluble in water so lipids do not interfere with the many water based reactions that happen in the cytoplasm of a cell

Question 45

How is a phospholipid formed

Answer 45

when a hydroxyl group from glycerol undergoes esterification with a phosphate group instead of a fatty acid

Question 46

describe structure of a phospholipid

Answer 46

Phosphate is polar with a slight negative charge making it hydrophilic the glycerol is hydrophobic and so are the 2 fatty acid tails therefore they do not dissolve in water.

Question 47

difference in cis arrangement vs trans arrangement

Answer 47

Cis- hydrogen on the same side trans-hydrogen on the opposite side