Biological molecules

Question 1

+what is a carbohydrate

Answer 1

molecule contains only C,H,O single unit called monosaccharide, 2 disaccharide and polysaccharide

Question 2

What is glucose

Answer 2

Alpha and Beta glucose are hexose sugars
-many OH groups so is soluble in water

Question 3

what is cytosol

Answer 3

fluid part of the cytoplasm

Question 4

how does glucose bond

Answer 4

condensation reaction between 2 glucose molecules 2 OH groups react forming water and joins molecules by the O
1,4 glyosidic bond

Question 5

What are the other sugars

Answer 5

fructose + glucose = sucrose
galactose + glucose = lactose

Question 6

what are the pentose sugars

Answer 6

ribose and deoxyribose

Question 7

what are the two variations of the polysaccharide starch

Answer 7

amylose, amylopectin

Question 8

amylose

Answer 8

1,4 glyosidic bonds
bond angles cause a helix shape to form supported by H bonds
compact and less soluble than glucose

Question 9

amylopectin

Answer 9

1,4 and 1,6 glyosidic
causes branches
more compact
less soluble
1,6 bond every 25 glucose subunits

Question 10

glycogen

Answer 10

animal storage unit
more branches so more compact and less space required to store it
animals are more metabolically active so neccessary
branching allows for glucose to easily be added to removed

Question 11

what is hydrolysis

Answer 11

turned stored nutrients into usable energy
water, enzymes used to break down molecules

Question 12

cellulose

Answer 12

beta glucose
rotates in 180degrees so the OH groups can interact with each other, causes long straight chain molecules

Question 13

how does cellulose make fibres

Answer 13

cellulose chains make H bonds which form microfibrils many of the microfibrils come together to make microfibrils which come together to make fibres which are strong and insoluble

Question 14

what is the test for reducing sugars and why

Answer 14

CU(II)SO4-2 has a blue colour when reducing sugar is added to the solution the CU(II)SO4-2 is reducing causing it to change colour from blue to red .
Heat in copper sulphate solution and red ppt should form as a layer depending on reducing sugar conc

Question 15

Test for non reducing

Answer 15

Boil the solution in HCL to break down the sugars then add an alkali solution to neutralise it. Then do a normal test for reducing sugars red-blue
Disaccharide/ polysaccharide should be broken down into a monosaccharide

Question 16

What is the test for Starch

Answer 16

Add iodine dissolved in potassium iodide solution should go from yellow/brown to purple/black

Question 17

What are lipids

Answer 17

C,O,H mainly
fats are solid lipids RTP
oils are lipids that are liquid RTP

Question 18

What is a triglyceride

Answer 18

1 glycerol group 3 fatty acids, forms ester bonds(esterification)
3 water molecules required to break it down

Question 19

saturated/unsaturated meaning

Answer 19

sat- no double bonds, all bonds possible by H are made
unsat- double bonds

Question 20

Phospholipids

Answer 20

modified triglycerides 2 fatty acids 1 glycerol and one phosphate group( many electrons so it is hydrophilic)

Question 21

What is a sterol

Answer 21

complex alcohols, 4 ring structure with an OH group at the end
amphiphilic

Question 22

cholesterol

Answer 22

made in liver/ intestines
between phospholipids stops them getting rigid at low temps and fluid at high ones

Question 23

roles of lipids

Answer 23

hydrophobic barriers
hormone production
electrical insulation
waterproof

Question 24

roles of triglycerides

Answer 24

long term energy store
cushioning(protects organs)
buoyancy for aquatic animals

Question 25

what is the test for lipids

Answer 25

ethanol + water shake and positive result is white emulsification

Question 26

amino acids

Answer 26

same basic structure with differing R groups

Question 27

types of Amino acid

Answer 27

5 are non essential and are made from other a.a 9 are essential and obtained from what we eat 6 are only needed in early development

Question 28

Peptide bond

Answer 28

H on one of the Amine groups and and OH of the carboxylic groups bond forming peptide bond and water

Question 29

what enzyme catalyses the bonding of peptides

Answer 29

peptidyl transferase(in ribosomes)

Question 30

primary structure of amino acid

Answer 30

sequence of amino acids, directed by DNA. The sequence influences how the chain folds to give it its function and shape.

Question 31

secondary structure of amino acid

Answer 31

O, H, N atoms interact causing H bonds to form in the chain pulling it into a alpha helix shape, peptide chains forming parallel to each other form H bonds forming a beta pleated sheet

Question 32

tertiary structure of amino acid

Answer 32

folding of protein into its final shape, causes R groups to interact with each other hydrophobic/ hydrophilic interactions H bonds weakest bond ionic bonds form from opposite charged R groups disfulide bonds- form between two sulphur atoms

Question 33

quaternary structure of amino acid

Answer 33

Two or more proteins working together(subunits) same interacts but between subunits subunits can be different or identical enzymes have 2 identical subunits

Question 34

polar/ non polar interactions

Answer 34

proteins fold so that the hydrophilic R groups are pointed outwards toward the aqueous environment

Question 35

breakdown of peptides

Answer 35

Protease catalyses reverse reaction of peptides, water molecule used to break peptide bond reforming Amine group and COOH

Question 36

Globular proteins

Answer 36

compact, soluble and spherical polar R groups are on the outside makes it soluble solubility is important for functions

Question 37

insulin

Answer 37

regulation of blood glucose, transported in blood stream so needs to soluble, need to fit on specific receptors so need a specific A,A chain

Question 38

Conjugated proteins

Answer 38

globular proteins with a non protein component(prosthetic group) Haem group in the blood made of Fe2+ which can reversibly bind to O2 to move it around the body from lungs to cells haemoglobin made from 2 alpha and 2 beta units

Question 39

catalase

Answer 39

enzyme with specific reaction type, quaternary with 4 haem groups, Fe2+ react with hydrogen peroxide(metabolism by-product and speed up its breakdown)

Question 40

fibrous proteins

Answer 40

long insoluble molecules, many hydrophobic R groups in primary structure. small range of amino acids and repetitive

Question 41

Elastin

Answer 41

found in elastic fibres, (walls of blood vessels) need to be flexible, return to normal, quaternary protein made of tropoelastin cross links of covalent bonds

Question 42

Keratin

Answer 42

hair , skin, nails large amount of sulphur containing a.a cysteine. forms strong disulphide bridges pending on the amount of bridges the flexibility varies

Question 43

Collagen

Answer 43

skin, tendons and ligaments. 3 polypeptide chain wound in a rope like structure still flexible every third a.a is glycine which makes the allows the protein to form packed helix. H bonds between polypeptide chains long quaternary proteins with staggered ends