2. water carbs and proteins continued

Question 1

What is a glycosidic bond?

Answer 1

-Bond between sugar molecules to form carbs

Question 2

What is an Ester bond? 4

Answer 2

found in lipids

links fatty acids to glycerol

Triglycerides have 3 Ester bonds

phospholipids have 2 ester bonds

Question 3

What is a peptide bond?

Answer 3

joins amino acids together to form proteins

Question 4

What is collagen? 3

Answer 4

-Most common protein in animals
-insoluble
- fibrous

Question 5

What elements make up proteins? 4

Answer 5

Carbon, oxygen, hydrogen, nitrogen

Question 6

How is shape of polypeptide chain maintained when coiled into an alpha helix?

Answer 6

hydrogen bonds

Question 7

What is secondary protein structure? 4

Answer 7

-Formed when hydrogen bonding occurs between Oxy of C=O group on one amino acid
-And hydrogen-NH group on another amino acid further along the chain
-Result is formation of alpha helix & beta pleated sheets
-some areas of polypeptide will have neither structures & remain random coils depending on R groups present

Question 8

Describe tertiary structure 5

Answer 8

-Caused by bonds forming between R-groups on amino acids that lie close to each other
-happens when chain starts to coil
-Creates 3D structures
-held firmly in place by bonds (must name in exam)
- tertiary structure gives active site its precise shape in enzymes

Question 9

What bonds hold the 3D tertiary protein structure together? 4

Answer 9

hydrogen, disulfide, ionic bonds & weak hydrophobic interactions

Question 10

What does high specific heat capacity do in body?

Answer 10

prevents wide variations in body temperature

Question 11

What does strong cohesive forces between water molecules do 2

Answer 11

-creates surface for insects to walk on

-transpiration pull in xylem

Question 12

What is high heat of vaporisation?

Answer 12

the amount of energy needed to change one gram of a liquid substance to a gas at constant temperature

Question 13

What does high heat of vaporization in water do to help sustain life

Answer 13

major component
of sweat used in
heat loss

Question 14

Water is solvent for polar molecules and ions, what does that do to sustain life?

Answer 14

transport medium in blood plasma and phloem

Question 15

22 What is bond at X

Answer 15

alpha 1,6 glycosydic bond

Question 16

What are advantages of mammals having highly branched storage molecules? 3

Answer 16

-many ends for attachment & removal of glucose
-means glucose can be stored more quickly & accessed faster
-Good for when energy requirements lead to higher respiration demands

Question 17

features of starch? 3

Answer 17

-glycosidic bonds between monomers

-stored within chloroplasts

-exists in two forms - branched and unbranched chains

Question 18

describe how the structure of glycogen differs from the structure of amylose 3

Answer 18

-glycogen is branched molecule
- glycogen has 1,6 and 1,4 glycosidic bonds
-glycogen not coiled into helical shape

Question 19

describe the advantages for organisms in storing polysaccharides, such as glycogen, rather than storing glucose 3

Answer 19

• Storage polysaccharides are compact so lots of glucose can be stored
  -Storage polysaccharides are unreactive (unlike glucose)
  -have osmotic effect on cell bc insoluble

Question 20

Draw annotated diagram to explain how a glucose molecule is formed from the free end of the glycogen molecule

Answer 20

pg 15 model answer

Question 21

Explain what is meant by the term primary structure .

Answer 21

sequence of amino acids in polypeptide chain

Question 22

pg 17 The molecular structure of the first two amino acids of lysozyme, lysine and valine, is shown below.
Use the space to show how these amino acids become linked in a condensation reaction.

Answer 22

pg 17

Question 23

What breaks a peptide bond?

Answer 23

hydrolysis- addition of water

Question 24

Describe disulphide bonds 4

Answer 24

-broken by reducing agents
-formed between sulphur atoms
-Form between cysteine R groups in proteins
-strong covalent bond

Question 25

Describe hydrophobic interactions 3

Answer 25

-formed between non-polar molecules
-Non-polar try to avoid contact with polar molecules like water
-very weak

Question 26

describe ionic bonds 2

Answer 26

• formed when atoms donate or receive electrons
• electrostatic attraction

Question 27

Describe a hydrogen bond 4

Answer 27

-Formed by electrostatic attraction
-between a proton & electronegative atom
-quick to form and break
-somewhat weak

Question 28

What is a covalent bond? 4

Answer 28

-Bond between 2 non-metal atoms
-that share at least 1 pair of electrons
-found as single, double or triple bonds depending on electron number
-very strong

Question 29

Describe weak hydrophobic interactions IN PROTEINS 3

Answer 29

-occur between non-polar R-groups (makes them hydrophobic)
-Found in centre of protein shielded by other amino acids
-Stay together bc they’re repelled by water around them

Question 30

Describe ionic bonds IN PROTEINS

Answer 30

Form between ionised amine groups & ionised carboxylic groups

Question 31

Draw a diagram of bond numbers on a ring structure

Answer 31

paperclip in carbs section on file

Question 32

Why does pH change break ionic bonds?2

Answer 32

It’s charge based, so broken by anything that interferes with charge

pH changes H+ concentration

Question 33

Describe a hydrogen bond 4

Answer 33

-Formed by electrostatic attraction
-between a proton & electronegative atom
-quick to form and break
-somewhat weak