biomolecules

Question 1

what are the 4 primary metabolites ?

Answer 1

proteins, nucleic acids, carbohydrates and lipids
(living things need all four of these)

Question 2

nucleic acids are biopolymers with … as the monomer and di,tri, oligo-nucleotides in between

Answer 2

nucleotides

Question 3

proteins are biopolymers with … … as the monomers and di, tri, oligopeptides in between

Answer 3

amino acids

Question 4

lipids are not polymers but contain 1-3 … …, usually attached to …

Answer 4

fatty acids
glycerol

Question 5

all the chemical reactions that make up life take place in … as a solvent

Answer 5

water

Question 6

atoms within molecules are held together by … …

Answer 6

covalent bonds

Question 7

molecules attract each other with weaker interactions such as :

Answer 7

hydrogen bonds
electrostatic forces
hydrophobic interactions

Question 9

describe h-bonding

Answer 9

occurs when a hydrogen attached to an electronegative element is attracted to an atom with an available lone pair

Question 10

explain what electrostatic interactions are.

Answer 10

when positively charged and negatively charged species attract one another

Question 11

explain hydrophobic interactions.

Answer 11

hydrophobic/lipophilic molecules will attract one another when placed in water.

Question 12

why do hydrophobic molecules attract one another when placed in water ?

Answer 12

because they break up the h-bonding network in water (this is destabilising for the system), so by clumping together, the hydrophobic molecules reduce the overall damage to the h-bonding network

Question 13

the entire collection of genes is called the …

Answer 13

genome

Question 14

the genome is kept in …

Answer 14

the nucleus of eukaryotes in a number of chromosomes

Question 15

a chromosome is a …

Answer 15

molecule of dna

Question 16

a gene is a stretch of dna which…

Answer 16

codes for a protein

Question 17

dna carries the … … … which effectively makes it an instruction book for creating an organism

Answer 17

code for proteins

Question 18

the dna code is … onto mrna which is another nucleic acid and this leaves the nucleus

Answer 18

transcribed

Question 19

when the dna code in on a molecule of rna, it is … to a new protein

Answer 19

translated

Question 20

how is a double helix formed ?

Answer 20

two strands of the polymer which are held together by hydrogen bonds.

Question 21

what is the polymer backbone made out of ?

Answer 21

is made up of sugar and phosphate

Question 22

inside the helix are the …

Answer 22

bases

Question 23

what do bases do ?

Answer 23

they carry the code for proteins and allow replication and transcription

Question 24

can faulty dna be passsed on through generations ?

Answer 24

yes

Question 25

how can dna be damaged ?

Answer 25

can be damaged during life, either by mistakes in copying, or damage by outside causes

Question 26

if dna is damaged then the gene product (protein) will be ...

Answer 26

missing or malfunctioning. this can lead to ill effects

Question 27

is dna damaged and copied badly all the time ?

Answer 27

yes

Question 28

is there a system of dna repair in place in human cells

Answer 28

yes and it deals with most problems

Question 29

what would happen if the system of dna repair in human cells fails ?

Answer 29

there are tumour-supressor systems and apoptosis to remove mutated cells without cancer happening

Question 30

proteins are polymers of ... ...

Answer 30

amino acids

Question 31

how many levels of structure do proteins have ?

Answer 31

4 primary, secondary, tertiary and quaternary

Question 32

what are the two types of protein ?

Answer 32

structural and functional

Question 33

what are some examples of functional proteins ?

Answer 33

enzymes, hormones/growth factors, antibodies, factors involved in blood coagulation, receptors and ion channels

Question 34

what is the definition of primary structure ?

Answer 34

the amino acid sequence

Question 35

what is the definition of secondary structure ?

Answer 35

local 3d structure

Question 36

what is the definition of tertiary structure ?

Answer 36

global 3d structure

Question 37

what is the definition of quaternary structure ?

Answer 37

association of multiple polypeptides

Question 38

side chains can be ...

Answer 38

glycine hydrophobic h-bonding charged

Question 39

what does it mean if a side chain of an amino acid is glycine ?

Answer 39

this means there is no side chain and hydrophilic

Question 40

what does it mean if the amino acids side chain is hydrophobic ?

Answer 40

a hydrophobic side chain would mean that it is greasy and lipophilic

Question 41

what does it mean if an amino acid side chain has h-bonding ?

Answer 41

a side chain that has h-bonding would be more polar and hydrophilic

Question 42

what does it mean if an amino acids side chain is charged ?

Answer 42

this means it is either negative, positive or polar and hydrophilic

Question 43

what structures do secondary structure proteins form when regular ?

Answer 43

alpha helix and beta sheets

Question 44

what structures do secondary structure proteins form when irregular ?

Answer 44

turns, loops, coils etc.

Question 45

describe in detail what tertiary structure is .

Answer 45

the helices, sheets and loops of a protein can be combined in many ways to give a global 3d structure

Question 46

tertiary structure is ...

Answer 46

vital to function

Question 47

what is denaturation ?

Answer 47

this is when a functional protein changes its tertiary and quaternary structure

Question 48

how do proteins become denatured ?

Answer 48

denaturation can happen through chemical reactions, heat, ph or changes in solvent

Question 49

what is the function of an enzyme ?

Answer 49

enzymes catalyse reactions

Question 50

what is the function of a receptor ?

Answer 50

receptors carry signals across cell membranes

Question 51

functional proteins have ...

Answer 51

ligands

Question 52

what is a ligand ?

Answer 52

a ligand is a molecule which binds to a protein

Question 53

what can a ligand be ?

Answer 53

a ligand can be a substrate, co-factor or inhibitor of an enzyme

Question 54

do enzymes increase of decrease the activation energy of a reaction ?

Answer 54

they lower the activation energy of a reaction which will increase the rate

Question 55

enzymes catalyse reactions. this means ...

Answer 55

they speed up reactions without getting used up themselves

Question 56

how do enzymes lower the activation energy of a reaction ?

Answer 56

they form a complex with the substrate to stabilise the transition state of the reaction

Question 57

inhibition means that the enzyme works ...

Answer 57

less efficiently (the rate of the reaction is reduced )

Question 58

ligands are typically signalling molecules like...

Answer 58

adrenaline, acetyl choline, histamine or seratonin but can be proteins

Question 59

what is an ion channel ?

Answer 59

an ion channel is a type of receptor which can open, and allow ions to pass in or out of the cell, when the signalling molecule binds to it

Question 60

part of the immune system produces antibodies. what are antibodies ?

Answer 60

antibodies are proteins designed to bind to a particular antigen

Question 61

will antibodies bind to molecules which have a similar shape to their antigen ?

Answer 61

no- antibodies are very specific and will ignore molecules which are very similar but not identical

Question 62

antibodies specificity is very useful in ...

Answer 62

biotechnology

Question 63

most of the essential structure and function of a cell is mediated by a ...

Answer 63

protein

Question 64

if the wrong protein is produced by faulty ..., or a protein is underexpressed, a ...

Answer 64

gene expression disease state can occur

Question 65

what is one way disease can be caused ?

Answer 65

by exogenous proteins which cause other proteins to fold badly

Question 66

what are exogenous proteins ?

Answer 66

exogenous proteins cause other proteins to fold badly

Question 67

how is prion disease caused ?

Answer 67

it is caused by the incorrect folding of normal brain proteins called prions. this was due to proteins from infected meat.

Question 68

can a mistake in the proteins primary structure have consequences on the secondary,tertiary and quaternary structure ?

Answer 68

yes and hence it would also affect protein function

Question 69

many kinds of cancer are associated with faulty ... produced from faulty ...

Answer 69

proteins genes

Question 70

what is cml disease ?

Answer 70

this is when an abnormal gene produces a protein which causes blood cell proliferation-too many white blood cells

Question 71

polysaccharides are usually ... or ... molecules

Answer 71

structural storage

Question 72

glucose is an ...

Answer 72

aldohexose

Question 73

is glucose hydrophobic ?

Answer 73

no it is hydrophilic and H-bonds very well

Question 74

what is the body's main energy substrate ?

Answer 74

if available it is glucose and the brain works on almist nothing else

Question 75

how is excess glucose removed from the blood ?

Answer 75

it is removed from the blood by insulin and is stored as glycogen

Question 76

is a lack of insulin in the blood dangerous ?

Answer 76

yes it is, without insulin, the blood level of glucose would reach dangerous levels .

Question 77

what is usually used for a diagnosis of diabetes ?

Answer 77

glucose in urine and high levels of glucose in the blood

Question 78

how do we find out if there is elevated levels of glucose in the urine ?

Answer 78

a simple dipstick will show whether elevated levels of glucose are present

Question 79

to see if there are high levels of glucosse in the blood we would ...

Answer 79

do a diagnostic test which is based on glucose oxidase, an enzyme, but monitoring also utilises hemologin glycation

Question 80

what is the definition of lipids ?

Answer 80

lipids are a heterogeneous, diverse group of molecules typified by their insolubility in water

Question 81

fats and oils are used in

Answer 81

storage

Question 82

phospholipids and cholstrol are found in

Answer 82

membranes and lipoproteins-structural

Question 83

how are triacylglycerols (fats) converted into energy ?

Answer 83

they are broken down into free fatty acids by the enzyme lipase

Question 84

cell membrane lipids have a ... ... at the end

Answer 84

polar group

Question 85

what does cholstrol do ?

Answer 85

it is found in membranes and rigifies the bilayer membranes

Question 86

what does vitamin e do in the cell membranes ?

Answer 86

alpha-tocopherol is the main antioxidant in cell membranes it prevents the peroxidation of polyunsaturated fatty acyl chains in lipids