Biological Molecules Flashcards

Question

What are lipids?

Answer 1

Contain C, H and O Insoluble in water Soluble in organic solvents, such as acetone and alcohol Fats solid at room temperature, oils liquid at room temp (triglycerides)

Answer 2

**Energy source-** oxidised to release more than twice the energy stored in carbohydrates **Insulation-** poor conduction of heat to insulate heat and also to insulate electrical impulses in nerve cells (myelin sheath) **Protection-** physical protection around certain organs **Waterproofing-** insoluble property used in plant waxy cuticles and animal sebaceous glands

Answer 3

One glycerol molecule bonded to three fatty acid molecules Ester bond (forms between an alcohol and an acid) forms from a condensation reaction also forming a water molecule from each bond (total of 3)

Answer 4

Glycerol molecule is always the same in a triglycerid3 Over 70 different fatty acids You can form 3 of the same fatty acids forming a simple trig. Varying properties of trig are a result of the combination of fatty acids

Answer 5

No double carbon bonds, bonded to as many H atoms as possible already

Answer 6

One double bond between carbons

Answer 7

Multiple double bonds between the carbons

Answer 8

-high energy source High ratio of C-H bonds to C atoms -good storage molecule Low mass compared to energy stores in bonds means more energy can be stored in a small volume, most beneficial to animals carrying mass. -insoluble molecules Large and non-polar, doesn't affect water potential of cells or osmosis -important source of water High ratio of H to O atoms, releasing water when oxidised, especially important for animals in hot environments

Answer 9

A glycerol backbone attached to only 2 fatty acids with phosphate group bonded to the other end of the glycerol Hydrophilic head- phosphate and glycerol, is attracted to water, does mix with fat. Hydrophobic tail- fatty acids, orientates away from water, can mix with fats. This is a polar molecule (2 poles behave differently`) and wil position themselves relative to water Triglycerides are extremely hydrophobic

Answer 10

Polar molecules interacting with water -hydrophilic and hydrophobic ends of molecules allow a bilayer to form as the cell membrane, the polarity causes a barrier between the inside and outside of the cell Can form glycolipids Sugar can bond to the phospholipid molecule to form a glycolipid on the outside of the cell membrane- helps maintain membrane stability and used in cell recognition

Answer 11

1. Label the test tubes suitably for the foods to be tested 2. Chop solid food on a tile or grind with a pestle and mortar 3. Add the food to a labelled test tube to a depth of about 1cm. For olive oil add 2 drops. 4. Add 3cm^3 of ethanol to each test tube 5. Put a clean bung into each test tube and shake carefully at least 10 times. This will help nah lipids deissolve in the ethanol 6. Allow time for food particles to settle. You may proceed when the ethanol above the food has cleared. 7. Use the wash bottle to dispense about 3cm of distilled water into the test tubes. 8. Observe and note any changes

Answer 12

Small units which are components of larger molecules

Answer 13

Molecules made from many monomers joined together

Answer 14

Carbohydrates Lipids Proteins Nucleic acids

Answer 15

-Order of amino acids in the polypeptide -20 amino acids and polypeptides contain usually 100s of them- countless combinations -determined by DNA -peptide bond between each amino acid

Answer 16

-the amine group has a positive charge and the O from C=O has a negative charge -they attract one another from a weak hydrogen bond -bonds form the first part of the 3D structure of a polypeptide

Answer 17

Looping backwards and forwards

Answer 18

- alpha helices can be further twisted to give a more specific and 3 dimensional shape -held together with many bonds -location and type of bonds depends on the primary structure

Answer 19

-hydrogen bonds, weak but plentiful -ionic bonds, between carboxylate and amino groups, easily broken by PH change -disulphide bridges, ionic bonds specifically between sulphur atoms from the R group of a specific amino acids and polypeptides

Answer 20

Roughly circular Irregular and wide range of R groups Physiological/ functional, metabolically Examples: haemoglobin, enzymes, insulin, immunoglobulin Generally soluble in water

Answer 21

Long strands Repetitive with a limited range of R groups Structural Examples: collagen, keratin, myosin, actin, fibrin Generally insoluble in water

Answer 22

-repeating sequence of amino acids in primary structure -Tightly wound alpha- helix in secondary structure -tertiary structure is another wound helix -quaternary structure is three fibres (some in opposing directions) wound together. - collagen molecules are then bundled together to form stronger fibres

Answer 23

More than one amino acid chain

Answer 24

Haem "prosthetic group" 4 iron Prosthetic group= non protein groups

Answer 25

- biuret reagent (sodium hydroxide and dilute copper sulfate) -can be done in test tubes or dimple tiles -protein= purple -no protein= blue

Answer 26

1. Collision, the reactants must collide 2. Orientation, the reactants must align properly to break and form bonds 3. Energy, the reactants must have enough activation energy

Answer 27

They reduce the amount of activation energy required for a reaction to take place meaning they can take place at a lower temperature (37°) otherwise these reactions would occur too slowly to sustain life

Answer 28

Digestion Photosynthesis Metabolic reactions

Answer 29

-when the substrate binds to the enzymes active site it is held to place briefly by temporary bonds between the two molecules -when the reaction is over those temporary bonds are broken and the products are released from the active site

Answer 30

-one key= one lock -one substrate will fit one enzyme -supported by evidence that enzymes are specific to the reactions they catalyse -enzymes are not rigid like a lock, molecules have been viewed bonding to an area of an enzyme that isn't an active site which causes enzyme action to change

Answer 31

-an enzyme-substrate complex is still formed but a change of shape in the enzyme and substrate us required. -the distortion of the substrate puts a strain on one/some of the bonds in the molecule and lowers the activation energy required to break it

Answer 32

Extracellular

Answer 33

Intracellular

Answer 34

How long foes it take for a certain amount of product to be formed or reactants to be used up

Answer 35

- rising temp= increased kinetic energy and more collisions - optimum temperature gives highest rate of reaction - continues temp rise can break hydrogen bonds and others amongst the polypeptide chains - active site can be altered in shape so substrate no longer fits -human enzymes start this at 45° and are completely denatured by 60°

Answer 36

-each enzyme has its own optimum pH -narrow bell curve on graph -subtle changes to pH can alter changes on amino acids in the active site due to concentration of H atoms- can prevent enzyme- substrate complex forming -bonds of tertiary structure may break= enzyme changes shape and denature it

Answer 37

1. Low enzyme concentration -lots of excess substrate with no enzymes to collide and reactive with so low rate of reaction. 2. Medium enzyme concentration -more available active sites to built to substrates and break them down so increased rate of reaction. 3. Excess enzymes when all available substrates are already binding/ reacting. Rate of reaction limited by concentration of substrate

Answer 38

-similar shape to substrate -occupy active site but not permanently bound -low conc- little impact -high conc- more likely that multiple inhibitors will collide and inhibit enzyme in a low before the substrate binds so activity can be greatly reduced Examples- penicillin, active site inhibitor as it disrupts the ability for cell walls to be built in bacteria

Answer 39

-different shape to substrate -binds to different place on enzyme but induces a change in shape to the active site so substrate no longer fits -increasing the substrate conc. does not decrease the effect of the inhibitor as they are not competing for the same place

Answer 40

Cytosine Guanine Adenine Thymine Uracil

Answer 41

PHOSPHODIESTER BONDS - between the phosphate of one nucleotide and the deoxyribose sugar of another - strong covalent - protects the more reactive bases in the centre of the molecule HYDROGEN BONDS - between bases - 2 between A-T - 3 between C-G - higher the proportion of C-G pairings the more stable the molecules

Answer 42

STABLE - resistant to mutations, most are repaired, persistent mutations are rare HYDROGEN BONDS - easy to break in DNA replication LARGE -ability to encode enormous amounts of information BASE PAIRS WITHIN HELIX - somewhat protected from chemical interactions CORRESPONDING BASE PAIRS - mRNA still an effective molecule to communicate the code

Answer 43

Relatively short

Answer 44

- original complete DNA strand -DNA helicase breaks hydrogen bonds between base pairs, separating the 2 strands - free nucleotides found in the cytoplasm bond to their complementary base pairs - DNA polymerase forms phosphodiester bonds between nucleotide backbones, bonding the backbones of the nucleotides together - 2 polynucleotides are formed, each one with a parent (original) strand and one new strand

Answer 45

Adenosine Triphosphate

Answer 46

Adenosine monophosphate One adenine, one ribose, one phosphate

Answer 47

Adenosine diphosphate One adenine, one ribose, 2 phosphates

Answer 48

Adenosine triphosphate One adenine, one ribose, 3 phosphates

Answer 49

A large, complex molecule that includes phosphate groups

Answer 50

Reversible reaction With the help of ATP synthase during the condensation reaction ADP turns into ATP while water is being emitted from respiration With the help of ATP hydrolase during the hydrolysis reaction, the addition of water causes the ATP to break into ADP

Answer 51

Great as an immediate energy source - unsuitable molecule for long term storage due to instability of phosphate bonds Hydrolysis of ATP is a single reaction - breakdown of glucose involves a series of reactions which take longer to complete

Answer 52

Releases less energy than a glucose molecule so sustains energy levels in constant small amounts - more manageable than a large increases when glucose is broken down Cannot be stored - has to be continuously made within mitochondria of class that require energy

Answer 53

Metabolic processes - building macromolecules via condensation reactions Contraction of muscle fibres for movement - filaments slide past one another Active transport - changes shape of carrier proteins in membranes Secretion - forms lysosomes that break things down in cells Activation of molecules - phosphorylating other molecules to destabilise and reduce activation energy

Answer 54

One adenine One ribose 3 phosphate groups

Answer 55

Two hydrogen atoms bonded to an oxygen atom No overall charge but slight negative charge to oxygen and slight positive to hydrogen so dipole r molecule Attraction between poles of molecules forms hydrogen bonds, weak but plentiful

Answer 56

Due to adhesion of molecules through hydrogen bonds

Answer 57

Requires more energy than expected to increase the temperature, acts as a temperature buffer for aquatic animals, making the environment more stable, water in cells also buffer organisms

Answer 58

Requires more energy than expected to evaporate- use in sweating, lots of heat from body used to evaporate sweat and cool down so thermal energy is released

Answer 59

Hydrogen bonds Large cohesive forces- water pulled through xylem in transpiration steam

Answer 60

When water molecules interact with air, they pull back towards the other water molecules due to the forces of attraction

Answer 61

Metabolism - breakdown of molecules through hydrolysis reactions -many chemical reactions take place in aqueous solutions - reactant of photosynthesis As a solvent An effective solvent that dissolves the following... - gases, O2, CO2 - water products, urea and ammonia - inorganic ions, hydrogen, sodium, potassium - small hydrophobic molecules, amino acids, ATP - enzymes Evaporation cools organisms to help with thermoregulation Not easily compressed, turgor pressures in non-woody plants, hydrostatic skeleton of invertebrates Transparent, aquatic plants can still photosynthesise, light can transmit through eyeball

Answer 62

Ions that do not contain carbon or carbon is in very small amounts

Answer 63

In solution in the cytoplasm Bodily fluids of organisms In high or low concentrations In living things In non living situations

Answer 64

Haemoglobin, red blood cell Binds to oxygen so can be transported

Answer 65

Components of nucleic acids DNA, RNA, ATP and phospholipids in cell membrane

Answer 66

Involved in co-transport of glucose and amino acids

Answer 67

Maintaining pH More H+ ions, lower pH, more acidic

Answer 68

-DNA helicase breaks hydrogen bonds between base pairs, making helix unwind and separating the two strands. -free nucleotides in the cytoplasm bond to their complementary base pairs -enzyme DNA polymerase forms phosphodiester bonds , bonding backbone of nucleotides together. - 2 polynucleotides formed, each with one parent (original) strand and one new strand.