Section 1 - Biological Molecules Flashcards

Question

What are three distinguishing features of monosaccharide molecules?

Answer 1

- sweet tasting - Soluble - General rule/formula (CH2O)n where n is a number between 3-7 - Eg. Hexose - Glucose - 6 - C6H12O6

Answer 2

- Carbon - Oxygen - Hydrogen

Answer 3

ONLY IN PLANTS - chains on alpha - Forms close spirals packed tightly into cells. - chains branched or unbranched (tight coil very compact)

Answer 4

PLANTS in forms of small grains - Large amounts in seeds and storage organs eg. potato tubers

Answer 5

suited for energy storage: - insoluble - large (doesn't diffused out) - compact (lots in a small place) - when hydralysed a-glucose is easily transported and used in reparation - branched can be acted on by enzymes simultaneously. so monomers are released rapidly. Not as quick as glycogen

Answer 6

For energy storage in plants.

Answer 7

IN ANIMALS AND BACTERIA NOT PLANTS - a-glucose monosaccharides - shorter chains than starch but more highly branched - sometimes called animal starch - stored as small granules - Mainly in liver and muscles

Answer 8

IN ANIMALS AND BACTERIA NOT IN PLANTS - Mainly in the liver and muscles

Answer 9

- insoluble (so doesn't draw water into the cells by osmosis) (low osmotic potential) - Doesn't diffuse - compact (lots stored in small place) - more highly branched - more rapidly breaks down glucose monomers - means animals have a quicker metabolism and respiratory rate

Answer 10

- B-glucose - straight and unbranched - run parallel to each other so hydrogen bonds can go between (cross-linkages) increasing collective strength - molecules are groups to form microfibrils which in run make groups of fibres. Which in turn increases the over all strength

Answer 11

- turgid - cells are pushed against each other - non-woody parts semi-rigid - Provide max SA for photosynthesis

Answer 12

rigid walls This prevents cells bursting. By exerting an inward pressure to stop influx of water

Answer 13

forms a rigid wall

Answer 14

It is a storage molecule. Of sugar.

Answer 15

The **amount** of **water** that can enter a cell by osmosis to try and balance out the solutes. In the aim to create **equilibrium**

Answer 16

Amylose - Is branched Amylopectin - Is unbranched

Answer 17

Energy storage molecule - help to produce plant seeds and do germination - long term energy storage

Answer 18

By using a **branched polysaccharide** you can increase the amount of **enzymes availabl**e and so the alpha-glucose molecules are broken down more quickly.

Answer 19

Sugar as a term that means monosaccharide and disaccharide are bonded. These can be reducing or non-reducing

Answer 20

Benedict Reagents - an alkaline solution of copper 11 sulfate

Answer 21

1. Add 2cm^3 of food sample to be tested in a test tube. If the sample is not already in liquid form, first grind up into water. 2. Add an equal volume of Benedict reagent (blue) 3. Heat the mixture in a gently boiling water bath for 5 minutes 4. look out for a colour change to see if reducing sugars are present

Answer 22

Particular groups of chemicals that are found in living organisms

Answer 23

A molecule with uneven distribution of change is polarised.

Answer 24

- polysaccharides - polypeptides - polynucleotide

Answer 25

mononucleotide sub-units

Answer 26

Linking together peptides that have amino acids in their basic sub-units

Answer 27

amino acids

Answer 28

All the chemical processes that take place in living organism.

Answer 29

This is a unit for measuring the amount of substance and is abbreviated to mol

Answer 30

The same number of particles as there are in 12g of carbon-12 atoms.

Answer 31

6.022 x 10^23

Answer 32

A solution that contains one mole off solute in each litre of solution.

Answer 33

A mole is the molecular mass expressed as grams (= one gram molecular mass)

Answer 34

- **Covalent** - share a pair of electrons in outer shell a molecule is formed - **Ionic** - lose or gain electron - weaker than covalent - **hydrogen** - when there is an uneven distribution of negative electrons. Making it polarised.

Answer 35

* electrons not evenly distributed * region more negatively charged than the rest of the molecule. * Said to be polarised, in other words it has a polar molecule. * The negative region of one polarised molecule and the positively charges region of another attract each other. * A weak electrostatic bond is formed. * individually weak collectively form important forces that alter the physical properties of molecules. * This is equally true for water.

Answer 36

It very **rapidly forms bonds** with other **carbon** atoms allowing a sequence of carbon atoms of various lengths to be built up which forms a backbone along which other atoms can attach

Answer 37

- carbon - hydrogen - oxygen - nitogen

Answer 38

a chemical reaction involving the gain of electrons of hydrogen

Answer 39

a sugar that can donate electrons to another chemical

Answer 40

An alkaline solution of copper (11) sulphate

Answer 41

Insoluble red precipitate of copper (1) oxide

Answer 42

a semi-quantitative test

Answer 43

It means it can be used to estimate the approximate amount of reducing sugar in a sample

Answer 44

no Reducing Sugar - Blue very low RS - green low RS - yellow Medium RS - orange high RS - bricky red

Answer 45

1. if not a liquid then ground in water 2. add 2cm^3 of food sample to cm^3 of **Benedict reagent** in a test tube and filter 3. into gently boiling **water bath** for 5 mins if it does not change colour then a reducing sugar is not present 4. add another 2cm^3 of food sample to 2cm^3 **dilute hydrochloric acid** in a test tube and place test tube in gently boiling water for 5 mins. 5. The dilute HCl will **hydrolyse** any **disaccharide** present into its monosaccharides 6. slowly add **sodium hydrocarbonate** solution to **neutralise** the acid. 7. Test solution is **alkaline**. 8. re-test for **reducing sugar**s 9. If a non-reducing sugar was present in the original sample the Benedict solution will now turn **orange-brown**

Answer 46

That they are insoluble

Answer 47

Joining between 200 - 100000 alpha glucose molecules by glycosidic bonds in a series of condensation molecules

Answer 48

1. place 2cm^3 of a **sample** in test tube 2. **or add two drops** of the sample into a **depression** on a spotting tile 3. add **two drops of iodine solution** and **shake of stir** - The presence of starch is indicated by a **blue-black** colouration

Answer 49

**iodine** in a potassium iodide solution from **yellow to blue-black**

Answer 50

* contain carbon, hydrogen and oxygen atoms * the proportion of oxgyen to carbon and hydrogen is smaller than in carbohydrates * they are insoluble in water * they are soluable in organic solvents such as alcohols and acetone

Answer 51

- Triglycerides - Phosopholids

Answer 52

triglyceride

Answer 53

* **flexibility** * **transfer** of lipid-soluable substances **across** them

Answer 54

- cell membranes - source of energy - waterproofing - insulation - protection

Answer 55

When oxidised twice the energy as the same mass of carbohydrates and release valuable water

Answer 56

Lipids are **insoluble** in water. Both plants and insects are **wavy, lipid cuticles** that conserve water, while mammals produce an oily secretion from the sebaceous glands in the skin

Answer 57

fats are **slow conductors of heat** and when stored beneath the body surface help to retain body heat. They also act as electrical insulators in the myelin sheath around the nerve cells

Answer 58

fat is often stored **around** **delicate organs**, such as the kidney

Answer 59

* - a lipid * - three fatty acids combined with glycerol * - each fatty acid forms an ester bond with glycerol in a condensation reaction * - hydrolysis of a triglyceride therefore produces glycerol and three fatty acids

Answer 60

- the glycerol molecule in triglycerides is the same - differences in the **fatty acids**

Answer 61

chain between the carboxyl and hydrocarbon has **no carbon-carbon double bonds**. As the carbon atoms are linked to the maximum possible number of hydrogen atoms

Answer 62

When the carbon atoms are linked to the maximum possible number of hydrogen atoms

Answer 63

mono-unsaturated

Answer 64

Polyunsaturated

Answer 65

- **High ratio of energy** - storing carbon - hydrogen bonds to carbon atoms - **low mass to energy ratio** - storage of molecules energy in a small volume - **Reduces the mass** - large, non-polar molecules and insoluble in water - **not affect osmosis** or the water potential of them - high ratio hydrogen to oxygen atoms - **release water** when **oxidised -** important source of water especially for organisms living in dry deserts

Answer 66

This means they release water when oxidised and provide important source of water especially for organisms living in dry deserts

Answer 67

This helps storing carbon - hydrogen bonds to carbon atoms and therefore an excellent source of energy

Answer 68

This makes it good at storage of molecules because much energy can be stored in a small volume - especially benefits animals as reduces the mass they have to carry as they move around

Answer 69

This means there storage does not affect osmosis in cells or the water potential of them

Answer 70

Phospholipids only have two fatty acid tails and the has a phosphate molecule instead

Answer 71

the fatty acid tails - repel water

Answer 72

The phosphate molecules - attract water

Answer 73

This means it interacts with water (or is attracted to it) but does not interact with fat eg. the head of the phospholipids

Answer 74

This means it orients itself away from water but mixes readily with fat eg. the tail of the phospholipids

Answer 75

As it has a molecule with two ends (poles) that behave differently

Answer 76

position so hydrophilic heads are close to water and the hydrophobic tails are as far away from the water as possible. Eg. in a circle with the tails inwards or creating a phospholipid bilayer

Answer 77

When in water and a ball is created. As this gets larger it squashes out to make a bilayer which is in a fluid mosaic model

Answer 78

molecules of phospholipid easily move and float around so things can float in and out for example proteins

Answer 79

- **polar molecules** - in an aqueous environment form a bilayer within cell-surface membranes. - help to hold at the surface of the cell surface membrane - form **glycolipids -** combine with carbohydrates within the cell-surface membrane. These glycolipids are important in cell recognition

Answer 80

**emulsion test** 1. take a completely **dry and grease-free** test tube 2. to 2cm^3 of the **sample** being tested, add 5cm^3 of **ethanol** 3. **shake** the tube thoroughly to **dissolve** any liquid in the sample 4. add 5cm^3 of **water** and shake gently 5. a **cloudy-white colour** indicates the presence of a lipid 6. as a **control** repeat the procedures using water instead of the sample; the final solution should remain clear

Answer 81

Due to any **lipid** finely dispersed in the water to form an emulsion. Light passing through this emulsion is **refracted** as it passes from **oil** **droplets** to water droplets, making it appear cloudy

Answer 82

- Catalysts **lowering activation energy** - Globular proteins that act as catalysts. speed up reactions

Answer 83

Alter the **rate of a chemical reaction** without undergoing permanent changes to themselves. They can be used repeatedly and are therefore effective in small amounts.

Answer 84

- **collide** with **sufficient** **energy** to alter the arrangement of their atoms. - the **free energy** of the **products** must be **less** than that of the **substrates**. - **initial** amount of **energy** to start. Minimum called activation energy

Answer 85

The minimum amount of energy needed to activate the reaction in this way

Answer 86

* The activation energy must be initially overcome before the reaction can proceed. * allows the reaction to take place at a lower temperature than normal. * This enables some metabolic processes to occur rapidly at the human body temperature of 37\*C which is relatively low in terms of chemical reactions. * This speeds up a very slow and inefficient reaction

Answer 87

- 3D sequence of amino acids (primary protein structure) - functional group/ active site specific. - n enzyme-substrate complex.

Answer 88

* The proximity of the substrate leads to a **change** in the enzyme that forms the **functional active site.** * As the enzyme is **flexible** mould around substrate * The enzyme has a certain **general shape** but this **alters** in the presence of the substrate. * **strain on the substrate molecule** distorts a particular **bond** lowers the activation energy needed to break the bond.

Answer 89

A basic monomer unit which combine to make up a polymer called a polypeptide

Answer 90

When amino acid units combine to make up a polymer called a polypeptide. These can be combined to form proteins.

Answer 91

20 - Out of 100 amino acids identified

Answer 92

20 Amino acids occur in all living organisms providing indirect evidence for evolution.

Answer 93

* - The central carbon atoms are attached to four different chemical groups. - * Amino group (-NH2) * - Carboxyl group (-COOH) * - acidic group * - Hydrogen atom (-H) * - R (side) group

Answer 94

AKA a variable group different chemical groups. Each amino acid has a different R group.

Answer 95

A dipeptide

Answer 96

**Condensation reaction** The water is made by combining an -OH from the carboxyl group of the amino acid and a -H from the amino group of another amino acid.

Answer 97

**Peptide** bond - between the carbon atom of one amino acid and the nitrogen atom of the other.

Answer 98

**Hydrolysis** reaction peptide bond of a dipeptide can also be broken by hydrolysis to give its constituent amino acids.

Answer 99

* polypeptides * Amino acid monomers join in **polymerisation**. * This results in a **polypeptide**. * determined by DNA. * any sequence of the 20 naturally occurring amino acids * determines ultimate shape and function - A change can lead to a change in the function

Answer 100

* The linked amino acids that mark a polypeptide possess both * -NH (H is positive) and -C=0 (O is negative). * These r**eadily form weak hydrogen bonds.** * This caused the long polypeptide chains to be twisted into a **3D shape such as a coil of alpha-helix**

Answer 101

* twisted and folded to give the complex, and specific, 3D structure. * maintained by a number of bonds that occur depending on the primary structure of the protein * - **Disulfide bonds** - fairly strong and not easily broken * - **ionic bonds** - carboxyl and amino groups not involved in peptide bonds. Weaker than DB and easily broken by changes in pH * - **hydrogen bonds** - numerous but easily broken Its this shape that is important to its function making proteins distinctive and recognisable to other molecules. * It can then interact with them in a very specific way.

Answer 102

* - Only in large proteins * number of individual polypeptide chains that are links in various ways * - This may include **non-protein** groups associated with the molecules, such as the iron-containing haem group in haemoglobin

Answer 103

prosthetic

Answer 104

1. Place a **sample** in a test tube 2. add an **equal** volume of **sodium hydroxide** solution at **room** temperature 3. Add a few **drops** of very **dilute (0.05%) copper(11) sulfate** solution and mix gently 4. A **purple coloration** indicates the presence of peptide bonds and hence a protein. If no protein is present, the solution **remains blue**

Answer 105

The biuret test - detecting peptide bonds

Answer 106

This detects peptide bonds

Answer 107

A **purple** colouration If no protein is present, the solution remains blue.

Answer 108

- **Fibrous proteins** - such as collagen which have structural functions. - **Globular proteins** - such as enzymes and haemoglobin which carries out metabolic function

Answer 109

- Form **long chains** which run **parallel** to one another. - The chains are linked by **cross-bridges** and so form very stable molecules eg. Collagen

Answer 110

- Primary sturcure is an **unbranched** polypeptide chain - Secondary structure - polypeptide chain is very **tightly wound** - Lots of amino acid, **glycine** helps close packing - Tertiary structure is twisted into a **double helix** - Quaternary structure is made of **three polypeptide** chains wound together in the same way as individual fibres are wound together in a rope.

Answer 111

**tendons** - joining **muscle to bone**. When a muscle contracts the bone is pulled in the direction of the contraction

Answer 112

Held by bonds between amino acids of adjacent chains

Answer 113

1. - They must come into physical contact with its substrate 2. - It must have an active site which fits the substrate

Answer 114

How long it takes for a particular event to run its course.

Answer 115

- **The formation of the products of the reaction** - **The disappearance of the substrate**,

Answer 116

- We can measure at any point on the **curve of a graph.** - **gradient** of at the chosen point - We have to accurately draw the tangent to a curve

Answer 117

It **increases** the **kinetic energy** of molecules. As a result the molecules move around more rapidly and collide with each other more often.

Answer 118

The enzyme and substrate molecules come together more often in a given time. There are more effective collisions resulting in more enzyme-substrate complexes being formed and so the rate of reaction increases.

Answer 119

It begins to cause the hydrogen and other bonds in the enzyme to break. This results in the enzyme, including its active site, changing shape. At first the substrate will fit less easily and the rate of reaction will be reduced. Then the enzyme will be so disrupted that it stops working altogether.

Answer 120

Around 60\*C

Answer 121

A permanent change and, once it has occurred, the enzyme does not function again.

Answer 122

- increase the metabolic rate slightly, the advantaged are offset by the additional energy (food) needed to maintain the higher temperature - Other proteins, apart from enzymes, may be denatured at higher temperatures - At higher temperatures, any further ruse in temperature, for example, during illness, might denature the enzymes

Answer 123

around 40oC As they have a high metabolic rate for the high energy requirement of flight

Answer 124

The pH of a solution is a measure of its hydrogen ion concentration.

Answer 125

**Away from the optimum** affects the **rate of enzyme action.** An increase or decrease in pH reduces the rate of enzyme action. If it is more extreme then, beyond a certain pH, the enzyme becomes denatured

Answer 126

* A change in pH alters the charges on the amino acids that make up the active site of the enzyme. * substrate can no longer become attached to the active site * enzyme-substrate complex cannot be formed - * The active site therefore changes shape

Answer 127

- repeat the procedure on another substrate molecule - enzymes are not used up in the reaction and therefore work efficiently at very low concentrations.

Answer 128

- This leads to a proportionate increase in the rate of reaction. - Because there is more substrate than the enzyme's sit can cope with

Answer 129

- Not sufficient to supply all the enxymes active sites at one time a further increase would not effect the rate of reaction - The ROR is therefore stabilised at a constant level meaning the graph would level off. - As the available substrate is already being used as rapidly as it can be by the existing enzyme molecules.

Answer 130

- Too few enzyme molecules to allow all substrate molecules to find an active site at one time - ROR is only half the maximum possible for the number of substrate molecules availiable

Answer 131

- With enough enzyme molecules for substrate, all active sites can be used at the same time - ROR is at max as all active sites are filled

Answer 132

- The addition of more enzyme molecules than substrates has no more effects as some can not be used - No further increase in the rate of reaction

Answer 133

- Too few substrate molecules to occupy all available active sites. - ROR is less than max possible for the number of enzymes molecules available

Answer 134

- More substrate molecules means all active sites are being used at one time - The ROR is at its maximum as all active sites are filled

Answer 135

- The addition of further substrate molecules has no effect as all active sites are already occupied - No increase in ROR

Answer 136

95\*C and continue past 100\*C

Answer 137

Bacteria that loves hot temperatures

Answer 138

Substances that directly or indirectly interfere with the functioning of the active site of an enzyme and so reduce its activity

Answer 139

- **Competitive** - Bind to active site of enzyme - **Non-competitive** - Bind to enzyme at a position other than the active site

Answer 140

- shape similar to substrate. - occupy the active site of an enzyme - compete with the substrate

Answer 141

The difference between the concentration of the inhibitor and the concentration of the substrate.

Answer 142

* Attach at **allosteric** site * inhibitor alters the shape of the enzyme * so the enzyme cannot function As the substrate and inhibitor are not competing for the same site, an increase in substrate concentration does not decrease the effect of the inhibitor

Answer 143

As the substrate and inhibitor are not competing for the same site, an increase in substrate concentration **doe not decrease the effect of the inhibitor**

Answer 144

A series of reactions in which each step is catalysed by an enzyme.

Answer 145

- many hundreds of different pathways - The **enzymes** that control a pathway are often **attached** to the **membrane** of a cell organelle in a very precise sequence. - Inside each organelle **optimum conditions** for the functioning of particular enzymes may be provided - To keep a **steady concentration of a particular chemical** in a cell, the same chemical often acts as an inhibitor of an enzyme at the start of a reaction.

Answer 146

In the metabolic pathways - If too much or little is produced there is a greater/less inhibition of the enzyme so the concentration returns to normal.

Answer 147

If **too much or little is produced** there is a **greater/less inhibition of the enzyme** so the concentration returns to normal.

Answer 148

No double bond

Answer 149

One double bond

Answer 150

Multiple double bonds

Answer 151

Saturation

Answer 152

Usually saturated

Answer 153

Usually unsaturated

Answer 154

- Glycerol are always the same - The **fatty acid tails cause variation**

Answer 155

**Iodine test** * Collect sample and place on tile. * Add a **drop** of **iodine** to the sample and if colour change then starch is present. * **Orange to blue black**

Answer 156

To produce the optimum pH for the microbe being broken down.

Answer 157

breaks up cellulose

Answer 158

Mitochondria - Aerobic respiration - ATP In cytoplasm - Anaerobic respiration

Answer 159

The different temperatures used

Answer 160

The time taken to first see the X

Answer 161

* Same marker pen * same milk powder * The same concentration of trypsin * Same person checking the visibility of X

Answer 162

1. Marker an ‘X’ halfway down the side of three test tubes. 2. Add 10cm3 of the solution of milk powder to each 3. In three clean - Add 2cm3 of trypsin solution to 2cm3 of pH 7 buffer 4. Stand all tubes in a water bath at 20°C. 5. Leave 10 minutes. 6. Combine one of each tubes content 7. Bung each test tube - invert 5 times to mix thoroughly. 8. Put the test tube back into the water bath. 9. Time how long it takes for the milk to go clear. Stop when seeing X. (Can use colourimeter - trypsin = calibration) 10. Record the time in a suitable table 11. Repeat method at 30°C, 40°C, 50°C, 60°C. 12. Process your data and draw a graph of your processed data.

Section 1 - Biological Molecules Flashcards

(199 cards)