Biology As Biological Molecules

Front 1

How are biological molecules evidence for evolution

Back 1

Both plants and animal cells have similarities in structure

All organisms share some biochemistry (contain the same carbon based compounds that interact in similar ways) eg both use DNA and RNA as genetic material

Front 2

What are monomers and polymers

Back 2

Monomers are small basic molecular units that can join to other monomers via condensation to make up a polymer

Front 3

Making / breaking a polymer

Back 3

Condensation reaction between monomers. Water is released as a chemical bond is formed

Hydrolysis reaction breaks chemical bonds between monomers using (adding in) h20

Front 4

Sugars are

Back 4

A general term for monosaccharides and disaccharides

Front 5

Name 3 monosaccharides

Back 5

1)glucose (a/b)

2)fructose

3) galactose

Front 6

Draw two isomers of hexose sugar glucose

Back 6

Back (Definition)s

Front 7

Which elements to carbohydrates contain

Back 7

C ,H ,O

Front 8

Disaccharides are

Back 8

Two monosaccharides joined together by a glycosidic bond.

Formed in a condensation reaction (h20 released)

Front 9

Name three disaccharides and the monomers that form them

Back 9

Lactose (glucose + galactose)

Sucrose(glucose+ fructose)

Maltose (glucose +glucose)

Front 10

What is a reducing sugar

Back 10

Any sugar (mono/disaccharides) able to act as a reducing agent (because it has a free aldehyde/ ketone group)

Front 11

Which sugars are reducing

Back 11

All monosaccharides and some disaccharides eg.maltose and lactose

Front 12

What can we use to test for reducing sugars

Back 12

Heat sample in a boiling tube with Benedicts reagent in a water bath that’s boiling . Positive sample will turn from blue to green yellow and brick red finally.

Higher the concentration of the reducing sugar the further the colour change

Front 13

Testing for non-reducing sugars

Back 13

You have to break the non reducing sugar down into monosaccharides (all reducing) . You add dilute HCL heat in boiling water bath and then neutralise using sodium hydrogen carbonate. Then carry out the reducing sugars test (heat with benadicts reagent)

Front 14

Polysaccharides are

Back 14

Carbohydrates made from large numbers of their monomers (two or more) join together via condensation reactions . Can also be broken down by hydrolysis.

Front 15

Starch use

Back 15

Plants store excess glucose as starch for hydrolysis to glucose when it needs

Front 16

Starch is made up of 2 carbohydrates

Back 16

1) amylose - a coiled unbranched (compact for storage) chain of alpha glucose .

2) amylopectin- a highly branched chain of a-glucose that allows a bigger surface area for enzymes to quickly hydrolyse it

Front 17

How is starch adapted to its functikn

Back 17

1) insoluble so doesn’t move out of the cell

2) insoluble so doesn’t effect water potential

3)coiled so it’s compact and takes less space up

4) highly branched (big surface area) so enzymes can work quickly to release glucose when it’s needed

Front 18

Glycogen adaption for function

Back 18

Used as animal store for energy (excess glucose)

1) It’s compact for storage to take up less space

2) it’s even more highly branched to increase surface area for enzymes to act on

Front 19

Cellulose adaption to function

Back 19

Used for structural support in plants eg. Cell wall

Made of long unbranched chains of beta glucose

Different chains are linked to one another using hydrogen bonds to form strong fibres (microfibril)

Front 20

How do you test for starch

Back 20

Add iodine (in potassium iodide) to a sample . It turns from brown/orange to blue/black of starch is present

Front 21

How are lipids different to proteins and carbohydrates

Back 21

They are not polymers made from long chains of monomers . They are made from many different components joined together

Front 22

Triglycerides made of

Back 22

1)one molecule of glycerol

2)Three fatty acids with long hydrocarbon tails (insoluble)

3) joined together by Ester bonds O-C=O

Front 23

Structure of Fatty acids

Back 23

Same basic structure with different hydrocarbon tails (r)

Front 24

Two types of fatty acids

Back 24

Saturated fatty acids don’t have any double bonds between their carbon atoms (saturated with hydrogen)

Unsaturated do have double bonds between carbons in their chain causing a change in the zig zag shape

Front 25

Triglyceride formation how does it happen

Back 25

3 condensation reactions occur , 3 molecules of h20 are released as 3 fatty acids join to glycerol

Front 26

Phospholipids are

Back 26

(Same structure are triglycerides except one fatty acid is swapped for a phosphate group)

-glycerol

-2 fatty acids

-phosphate group

Front 27

Triglycerides adaption for function

Back 27

Used as an energy store

1)more carbon-hydrogen bonds then c-c these release more energy

2) low mass to energy ration (good for storage)

3) insoluble in water so don’t move out of area and don’t affect water potential

4)high ratio of hydrogen to oxygen atoms so water is released

Front 28

Phospholipids adaption to function

Back 28

Make up the bilayer of cell membrane control what enters and leaves a cell

Naturally form bilayer The tails face in and heads out so water soluble substances can’t pass through easily

Long lipid tails release lots of energy if bonds are broken

Front 29

How to conduct the emulsion test for lipids

Back 29

Shake sample with ethanol for 1 minute

Pour into water , milky emulsion is indication of lipids

More milky means more lipids

Front 30

What are Proteins made up of

Back 30

Monomers of proteins are amino acids they join together via peptide bonds in a condensation reaction

Front 31

Di and polypeptides are

Back 31

Two amino acids joined together by a peptide bond in a condensation reaction

More that two amino acids joined together by a peptide bond in a condensation reaction

Front 32

To form a peptide bond what is lost

Back 32

OH from the carboxyl group of one amino acid and the H from the amino group on another amino acid

Front 33

Basic amino acid structur

Back 33

Front 34

What is the primary structure of a protein

Back 34

The sequence of the amino acids in a polypeptide chain

Front 35

Two ways to measure Enzyme activity

Back 35

1) how fast the product is made

2) how quickly substrate is broken fown

Front 36

Temperature effect on enzyme activity

Back 36

1)As temperatures increases more kinetic energy is given to molecules that move faster increasing likelihood of collisions

2)energy is also more likely to reach activation energy.

3)Until you get above the optimum molecules in the enzyme vibrate so much bonds in the structure break

4) the shape (active site) changes so it can no longer fit to substrate and can’t catalyse it (denatured)

Front 37

ph effect on enzymes activity

Back 37

Above and bellow the optimum ph for an enzyme excess h+ and oh- interfere with the hydrogen and ionic bonds holding an enzymes tertiary structure together. The enzyme becomes denatured and the active site changes .

Front 38

Substrate concentration effect on enzyme activity

Back 38

More substrates mean a higher rate of reaction as collision frequency is higher. Up to saturation point when all enzymes active sites are occupied so adding more makes no difference.

Front 39

Enzyme concentration

Back 39

Increasing it increases rate of reaction until there are more than enough enzymes to deal with the amount of limited substrate then increasing enzyme concentration has no further effect

Front 40

What are Enzyme inhibitors

Back 40

Molecules that prevent enzyme activity by binding to the enzymes that they inhibit

Front 41

Competitive inhibitors

Back 41

They have a similar shape to the substrate so bind to the active site (no reaction as it doesn’t cause the change) blocking it .

Increasing the substrate concentration can counteract this as it’s more likely to bind to enzyme than the inhibitor

Front 42

Non competitive inhibitors

Back 42

These bind to an enzyme away from its active site it causes the active site to change shape so the substrate molecules can no longer bind to it

Non competitive inhibitor molecules don’t compete with the substrate so increasing substrate concentration has no effect on rate of reaction

Front 43

Secondary structure

Back 43

This is the way the gain folds , hydrogen bonds form between amino acids making it into an a- coil or a b- pleated sheet

Front 44

Tertiary structure

Back 44

The way in which the polypeptide is further coiled and folded by more hydrogen bonds , ionic bonds and disulphide bridges forming between different parts of the polypeptide.

Front 45

Quaternary structure

Back 45

The way different polypeptide chains are held together in a protein made form more than one chain

Front 46

Biurette test for protein

Back 46

The test needs to be alkaline so add sample to sodium hydroxide the. Add copper sulphate. It will turn from blue o purple if there is a protein

Front 47

Enzymes are ?

Back 47

Biological catalysts

They catalyse metabolic reactions at a cellular level (eg.respiration) or for the whole organism eg. Digestipn

Front 48

What is an active site

Back 48

The part of an enzyme which has a specific shape complementary to substrates . Enzymes are highly specific (catalyse one substrate reaction) due to tertiary structure.

Front 49

How enzymes speed up reactions

Back 49

In a chemical reaction a certain energy is needed before reactions can happen . Enzymes lower this activation energy by forming enzyme substrate complex this can

1)hold to substrates together reducing repulsion and joining them

2)weaken bonds in a substrate so it can break down more easily (less energy required)

Front 50

Lock and key model

Back 50

Early model suggests enzymes active sites are perfectly complementary to their substrate. And the enzyme remain unchanged after reaction

Front 51

The induced fit model

Back 51

shape of Active Sites are not exactly Complementary, but change shape in the presence of a specific substrate to become Complementary.

When a substrate molecule collides with an enzyme, if its composition is specifically correct, the shape of the enzyme's Active Site will change so that the substrate fits into it and an Enzyme-Substrate Complex can form. The reaction is then catalysed and an Enzyme-Product Complex forms.