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Biology A level (aqa) > biological molecules > Flashcards

biological molecules Flashcards

1
Q

can you explain that all living things have a similar biochemical basis

A

All living things contain carbohydrates, lipids, protein and nucleic acids. Carbohydrates and lipids are mostly used by cells as respiratory substrates. Lipids are consisted in the bilayer of plasma membrane and in hormones. Proteins form many cell structures and nucleic acids carry the genetic code for the production of proteins.

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2
Q

can you describe what a monomer and polymer is and name examples of monomers.

A

monomers are the smaller units from which larger molecules are made, examples of monomers are monosaccharides, amino acids and nucleotides. Polymers are molecules that are made from a large number of monomers joined together

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3
Q

what is a condensation reaction.

A

A condensation reaction joins two molecules together with the formation of a chemical bond and involves the elimination of a molecule of water

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4
Q

what is a hydrolysis reaction

A

A hydrolysis reaction breaks a chemical bond between two molecule and involves the use of a water molecule

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5
Q

describe how carbohydrates are made from monosaccharides, names examples of monosaccharides.

A

monosaccharides are the monomers from which larger carbohydrates are made. Examples of monosaccharides are fructose, galactose and glucose

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6
Q

a condensation reaction between two monosaccharides form what bond

A

glycosidic bond

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7
Q

how are disaccharides formed

A

Disaccharides are formed by the condensation of two monosaccharides

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8
Q

name all the disaccharides

A

sucrose, maltose and lactose

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9
Q

how is sucrose, lactose and maltose formed

A

sucrose is formed by the condensation of a glucose molecule and a fructose molecule.

lactose is formed by the condensation of a glucose molecule and a galactose molecule.

maltose is formed by the condensation of two glucose molecules.

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10
Q

name two glucose isomers and draw the structure both

A

Alpha glucose and beta glucose.

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11
Q

describe what a polysaccharide is

A

a polysaccharide are formed by the condensation of many glucose units

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12
Q

what type of glucose are cellulose, starch and glycogen made of

A

starch and glycogen is formed by the condensation of alpha glucose.
cellulose is formed by the condensation of beta glucose.

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13
Q

describe the structure and function of starch

A

starch is a energy storage in plants.
1) hydrolysis of the glycosidic bond release glucose for respiration to release energy
2)has a compact helical shape which is good for storage
3)branched amplopectic- has lots of ends so has a large SA for enzymes to act on so glucose can release more rapidly for respiration.
4)starch is insoluble so no osmotic effect or doesn’t effect the water potential of the cell

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14
Q

describe the function and structure of glycogen

A

glycogen is an energy storage in animals and bacteria.
1)branched amplopectic- has more branches then starch. which allows it to have a large SA for enzymes to work on and release glucose for respiration rapidly.
2)has a compact helical shape wich give it a good storage.
3)insoluble so no osmotic effect

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15
Q

describe the function and structure of cellulose.

A

cellulose is in plant cells and are there for structral support.
1)have no branches and have a staright chain which allows cellulose molecules to get closer together.
2)many h bonds form between neighboring chains which makes it strong
3)cellulose chains grouped together are called microfibrils and microfibrils grouped together are called macrofinrils and macrofibrils grouped together are called cellulose fibre
3)in order for beta glucose to form 1,4 glycosidic bonds every other glucose molecule needs to rotate 180 degress.

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16
Q

test for protein

A

add food solution in test tube
and biuret reagent solution
if present lilac if not blue

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17
Q

test for starch

A

food solution in test tube
add iodine and potassium iodide.
if blue black its present if orange negative

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18
Q

test for lipids

A

unfiltered food solution in test tube
add same volume of ethonal and waer then shake
if whit cloydy emultion forms lipid is present
if clear no present

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19
Q

test for reducing sugers

A

food sample in test tube add benedict solution and boil for 5 mins
if orange brown its present

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20
Q

test for non reducing

A

boil with acid and neutrilise it, hydrolise the sucrose to break the glycosidic bond and remain fructose and glucose, then add benedics and boil if lilac present.

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21
Q

name the two groups of lipids

A

triglycerides and phospholipids.

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22
Q

how is a triglyceride made what bonds are involved

A

it is formed by the condensation of one molecule of glycerol and three molecules of fatty acids. a condensation between a glycerol and a fatty acids forms an ester bond

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23
Q

r groups can be saturated and unsaturated how can u tell

A

r groups that are saturated only contain single covalent bonds between the carbon atoms. unsaturated r groups contain at 1 double bond with the carbon atoms

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24
Q

describe phospholipids

A

one of the fatty acids in the triglycerol is substituted into a phosphate containing group

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25
Q

describe the properties of triglycerdies related to its structed

A

has a long term storage form of energy due to the long carbon chains
nonpoler so doesnt dissolve in water this makes it have an effective enegry storage

26
Q

phospholipids structure

A

have a hydrophilip head and hydrophobic tails
when in water they position themselves so that the hydrophilic heads are facing the water and the hydrphobic tails are clusted together away from the water, this is called a phospholipid biyaler which are in cell membranes

27
Q

structure of amino acid and which is the amine group and carboxyl group

A

R
I
H2N —–C—– COOH
I
H

28
Q

what is a peptide bond
what are dipeptides and polypeptides

A

peptide bond- a condensation reaction between two amino acids

Dipeptides- are formed by the condensation of two amino acids

polypeptides- are formed by the condensation of many amino acid

29
Q

describe the role of hydrogen and ionic bonds and disulfide bridges in the structure of protein. How are they formed and broken.

A

Ionic bonds contributes to folding. Ionic bonds occur due to the electrostatic interactions between the oppositely charged R groups. They are broken by changes in pH.

Hydrogen bonds help to maintain the shape of the protein and prevent it from falling apart. hydrogen bonds form between the oxygen of each c=o strand and every hydrogen in a
n-h group. h bonds are weak they are broken by pH and temp changes

Disulfide bridges help to stabilize the protein. disulfide bridges form a covalent bond between the sulphure atoms of two cysteine amino acids. they are not broken by high temp or pH changes, they are strong.

30
Q

explain the primary structure

A

it is the sequence of amino acids bonded by covalent peptide bonds. The DNA of a cell determines the primary structure and a primary structure is specific for each protein (one change in the sequence can change the function of the protein).

31
Q

explain the secondary structure

A

the secondary structure is maintained by h bonds that are formed between the oxygen of c=o bond in every strand and the hydrogen of each n-h group. which then folds the chains into beta pleated sheets or alpha helix.

32
Q

explain tertiary structure

A

the tertiary sturcture contains h bonds ionuc bonds and disuphine bonds.

33
Q

explain quaternery structure

A

many 3d tertiary structures joined together

34
Q

what does enzymes do to reactions

A

lowers the activation energy

35
Q

describe induced fit model

A

in the induced fit model the enzyme is flexible and can mold itself around the substrate, So as it changes shape the enzyme puts a strain on the complementary substrate molecule. this strain distorts a bond in the substrate which lowers the activation energy. then the substrate is broken down to form the product.

36
Q

enzyme and tertiary link, factors that can change active site?

A

for enzymes the tertiary structure determines the shape of the active site and factors such as pH and temp can change the tertiary structure.

37
Q

describe the effect of enzyme concentration on the rate of enzyme controlled reactions

A

if there is a low enzyme concentration the substrate molecules will collied with the active sites but then the remaining substrates can not collied to any available active site so the rate is low too. if you double the amount of enzyme concen then the frequency of collision will double and rate is doubled. if you continue increasing rate then substartes are litmitied and there wont be enough substartes to form enzyme substrate complex

38
Q

effect of substrate concentraion on enzyme

A
39
Q

effect of pH on enzyme

A
40
Q

effect of tempreture on enzyme

A
41
Q

what is a competitive inhibitor

A

a molecule that has the same shape as the substrate and it binds to the active site to prevent the substrate from colliding with the active side. However, if you continue to add more substrate it will out compete the inhibitor.

42
Q

what is a non competitive inhibitor

A

it binds away from active side. this causes the active site to change and preventing the substrate colliding with the active site. regardless of how much substrate u add

43
Q

name two polymers of nucleotides and what they do.

A

DNA and RNA . DNA holds the genetic information and RNA transfers the genetic information from the DNA to the ribosomes.

44
Q

what are ribosomes made of

A

RNA and protiens

45
Q

descibe the structure of deoxyribonucleic

A

has a deoxyribose and a nitrogen containing base (adenine, guanine, thymine and cytosine) and then a phosphate group

46
Q

describe the structure of ribonucleic.

A

a ribose then a nitrogen containing base (guanine, thymine, adenine, cytosine and uracil) and a phosphate group

47
Q

draw structure of nucleotide.

A

:D i cant draw it on a laptop twat

48
Q

what is a phosphodiester bond

A

the condensation reaction between two nucleotides.

49
Q

describe the structure of DNA.

A

a double helix with two polynucleiotide held by hydrogen bonds between complementary base pairs

50
Q

simple

A
51
Q

describe the semi conservative replication

A

first the double helix unwinds, the enzyme helicase causes the DNA to unwind by breaking the hydrogen bonds between the complementary base pairs. Then free nucleotides are attracted to their complementry bases, then DNA polymerase joins them together.

52
Q

explain the evidence of dna replication

A

first they get a sample of bacteria and extract the DNA then they add the dna in a solution and spun it at high speed in a centrifuge then dna moved down the solution and formed a band

53
Q

A single molecule of adenosine triphosphate(ATP) is a what

A

nucleotide derivative

54
Q

what is ATP made of

A

a molecule of ribose, adenine and three molecules of phosphate

55
Q

draw structure of atp

A
56
Q

what is ATP

A

it is an immediate source of energy for bioloigical processes

57
Q

expplain atp equation

A

ATP is made during respiration from ADP usinf the enzyme ATP synthase. then TP can be hydrolysed to form ADP + Pi using the enzyme ATP hydrolase

58
Q

explain how ATP is an immadiate source of energy

A

by breaking one of the inorganic phosphate group during hydrolyisis reaction a small amount of energy is released, so only one bond needs to be hydrlysed to release energy

59
Q

explain how ATP can transfer energy

A

when the inorganic phosphate group is relesed during hydrolysis of ATP it can bond with other coumpounds to make them more reactive

60
Q
A

Biology A level (aqa) (2 decks)

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