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A level Biology > unit 1 > Flashcards

unit 1 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what is a polymer

A

polymers are long repeating chains made of of molecular subunits called monomers. polymers are macromolecules

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2
Q

what is a monomer

A

monomers are basic single molecular units

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3
Q

give two examples of a monomer

A

monosaccharides and amino acids

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4
Q

give 2 examples of a polymer

A

proteins

carbohydrates

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5
Q

explain what happens in a condensation reaction between two monomers

A

condensation reaction between two monomers causes a chemical bond and also releases a molecule of water

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6
Q

what type of reaction causes the breakage of bonds in a polymer using water

A

hydrolysis, you add water to break them apart

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7
Q

what are carbohydrates made from

A

carbohydrates are polymers. they are always made from the same three chemical elements. carbon hydrogen and oxygen. for every carbon is two hydrogens are one oxygen

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8
Q

what are the monomers that make up carbohydrates called

A

monosaccharides The simplest sugars are the monosaccharides. A monosaccharide is a monomer (single unit). One of the most common
monosaccharide is glucose.

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9
Q

what is a disaccharide

A

when two monosaccharides join together

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10
Q

what is a glycosidic bond

A

Glycosidic bonds are the covalent chemical bonds that link r sugar molecules to other molecules. They form by a condensation reaction (releasing a molecule of water)

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11
Q

what are the differences between alpha and beta glucose

A

when alpha-glucose molecules are joined chemically to form a polymer starch is formed. …
When beta-glucose molecules are joined to form a polymer cellulose is formed.
Alpha glucose has an -OH [hydroxyl] group that points “downwards”, away from the ring,
whereas the -OH on carbon 1 of beta glucose is above the ring.

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12
Q

maltose

A

type of molecule- carbohydrae
monomer- 2 alpha glucose
bonds- glycosydic bonds
–reducing

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13
Q

sucrose

A

type of molecule- carbohydrate
monomers- ghlucose and fructose
glycosidic bondage
-non reducing

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14
Q

Polymer: dna

A
  • dna is a nueclic acid and its monomers are nucleotides and its bonds are phosphodiester
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15
Q

polymer: insulin

A

is a protien and its monomers are amino acids and bonded by peptides

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16
Q

What type of molecule are triglycerides and phospholipids

A

Lipids

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17
Q

What are the bonds In triglycerides and phospholipids

A

Ester bonds (condensation reaction)

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18
Q

What’s is the name of the test we have to use for reducing sugars

A

Benedict test / solution - blue

Positive: orange/ red

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19
Q

What is the name of the test we have to use for non reducing sugars

A

Benidicts test- blue
Positive: Orange
Add dilute hydrochloric acid to the sample and heat in a water bath that has been brought to the boil
Neutralise the solution with sodium hydrogencarbonate
Use a suitable indicator (such as red litmus paper) to identify when the solution has been neutralised, and then add a little more sodium hydrogencarbonate as the conditions need to be slightly alkaline for the Benedict’s test to work
Then carry out Benedict’s test as normal; add Benedict’s reagent to the sample and heat in a water bath that has been boiled – if a colour change occurs (orange-red precipitate), a non-reducing sugar is present

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20
Q

How do you test for starch

A

Idione solution. - yellow/ orange

Positive: blue

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21
Q

How do you test for lipids

A

Lipids are nonpolar molecules that do not dissolve in water but will dissolve in organic solvents such as ethanol
Add ethanol to the sample to be tested, shake to mix and then add the mixture to a test tube of water
If lipids are present, a milky emulsion will form (the solution appears ‘cloudy’); the more lipid present, the more obvious the milky colour of the solution
If no lipid is present, the solution remains clear

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22
Q

How do you test for proteins

A

Burets regent- pale blue

Positive- lilac

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23
Q

what is a triglyceride

A

a triglyceride is a lipid which has one glycerol molecule bonded to three fatty acids

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24
Q

two key features of a fatty acid

A
  • contains a hydroxyl group

- and a long chain of carbon and hydrogen

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25
Q

what bonds are lipids formed by

A

ester bonds which form by condensation reaction releasing three molecules of water

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26
Q

describe the structure of a phospholipid

A

it contains glycerol and two fatty acids and one phosphate group

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27
Q

describe the polarity in a phospholipid

A

it has a hydrophobic tail and a hydrophilic head and this is because the phosphate group is negatively charged which makes it hydrophilic

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28
Q

describe the general structure of a protein

A

it has an amino grp and a carboxyl group and an r grp

  • carbon
  • oxygen
  • nitrogen
  • hydrogen
  • sometimes sulphur
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29
Q

what elements are in proteins s

A
  • carbon
  • hydrogen
  • nitrogen
  • oxygen-and sometimes sulphur
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30
Q

what joins proteins together

A

peptide bond via condensation reaction

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31
Q

how many amino acids are there are how much are essential

A

20n and 9 are essential

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32
Q

what does it mean when an amino acid is essential

A

it means that it comes from yoyur diet, ypur body cant synthesise these protiens fast enough ti meet itsdemand

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33
Q

fiboruous protiens

A 
are proteins which are long fibers formed by amino acids
insoluble in water
cartine in hair and nails 
collagen 
-hydrophobic r groups
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34
Q

what is starch made from

A

-starch is a carbohydrate and is made up from alpha glucoses it has a glycosidic linkage

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35
Q

properties of a triglyceride

A
  • hydrophobic
  • insoluble
  • nonpolar
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36
Q

sat vs unsat fatty acids

A

with fully saturated tails can pack tightly against one another because the single bonds result in straight molecules. This tight packing generates fats that are solid at room temperature, for example, butter.

Unsaturated fatty acids have bent tails. This means they are not able to be tightly packed and results in oils that are liquid at room temperature.

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37
Q

reducing vs non reducing sugars

A

reducing= donates electrons

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38
Q

is glucose triose pentose or hexose

A

hexose

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39
Q

function of phospholipids

A

forms cell membranes

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40
Q

what is an R group

A

the R group is different in every amino acid

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41
Q

what is two amino acids

A

dipeptide

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42
Q

what is more then two amino acids

A

polypeptide

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43
Q

what is the difference between a polypeptide and a protein

A

in order to be classed as a protein the polypeptide needs to fold into a complex 3D shape in order to carry out is function as an enzyme or hormone

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44
Q

globular proteins

A
  • roughly circular
  • soluble in water
  • it has hydrophilic amino acids on its surface
  • it has hydrophobic amino acids in its center
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45
Q

primary structure

A

Primary Structure: The unique sequence of amino acids that makes up a protein or polypeptide chain.

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46
Q

secondary structure

A

The way in which the primary structure of a polypeptide chain folds.
alpha Helices and Beta Pleated Sheets. Secondary structure is held together by many Hydrogen bonds,

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47
Q

tertiary strcuture

A

Tertiary Structure: The final 3D structure of a protein
tertiary structure is held together by four different bonds and interactions:
Disulphide Bonds
Ionic Bonds
Hydrogen Bonds

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48
Q

quaternary structure

A

The structure formed when two or more polypeptide chains join together, sometimes with an inorganic component, to form a protein.

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49
Q

what is starch made out of

A

alpha glucose

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50
Q

what is glycogen made out of

A

alpha glucose

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51
Q

what is cellulose made out of

A

beta glucose. every two beta glucoses need to flip

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52
Q

why do plants store glucose as starch

A

-plants store glucose as starch because glucose is highly soluble in water because it contains hydroxyl groups which are hydrophilic so it stores it as as starch

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53
Q

what two molecules do starch contain

A

amylose and amylopectin

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54
Q

how does the structure of starch help with its function

A
  • helical shape helps it to be compact so its a well suited energy source
  • because starch is insoluble in water it means it doesn’t affect the water potential
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55
Q

where is cellulose found

A

plant cell walls

56
Q

structure of cellulose

A
  • unbranched

- straight chain

57
Q

how does the structure help for its function - cellulose

A

because it’s a straight chain without any branches this allows the molecules to be close together
-hydrogen bonds can form between neighboring chains
-because there’s a lot of hydrogen bonds it makes it strong
- cellulose chains grouped together acre called microfibrils
a lot of microfibrils are called macrofibril
-

58
Q

glycogen

A
  • it is highly branched
  • which means that enzymes can convert glycogen into glucose very rapidly with it having a lot of free ends
  • insoluble in water
  • cannot diffuse out of a cell which makes it the ideal glucose storage molecule in cells
59
Q

describe the structure of enzymes

A

contains active site which attaches to the substrate and forms an enzyme substrate complex

60
Q

why enzymes are specific

A

the teritary structure of the enzyme is complementary to the substrate. the enzyme is specific to the substrate it binds to

61
Q

describe the effect of enzymes on the activation energy of a reaction

A

its lowers the activation energy providing a pathway for a lower activation energy barrier. so in the presence of the enzyme the rate of reaction increases

62
Q

lock and key model

A

the tertiary structure is fixed and does not change shape and the substrate fits perfectly into the active site

63
Q

the induced fit model

A

as the substrate approaches the enzyme the tertiary structure of the active site changes shape

64
Q

the induced fit model

A

as the substrate approaches the enzyme the tertiary structure of the active site changes shape. as it starts to form bonds it adjusts so its moulds itself tightly around the substrate

65
Q

anabolic

A

requires energy and utilizes energy to synthesize larger molecules from smaller ones

66
Q

catabolic

A

releases energy and breaks down larger molecules into smaller units

67
Q

how does temperature affect enzyme action

A

temperature dictates the speed in which enzymes collide
-the increase of temperature means that there will be an increase of kinetic energy
means more successful collisions,
and now more likely to form enzyme substrate complexes.

denatured enzymes: increase of kinetic energy too far van disrupt the intermolecular bonds within the tertiary structure. mainly disrupts the ionic and hydrogen bonds

68
Q

how does PH effect enzyme action

A

optimum ph

  • the ph is dictated by the concentration of h+ ions in a solution
  • charged ions will interact with the charged r groups in the polypeptide
  • hydrogen ions will break or form ijn the incorrect places and so the tertiary structure changes there for not being able to function
69
Q

how does substrate concentration effect enzyme action

A

.enzymes are working at maximum rate. they have reached saturation point
-any further increase of substrate concentration will not increase enzyme activity.
its plateaus

70
Q

how does enzyme concentration affect enzyme action

A

more enzymes mean more enzyme substrate complexes

increase rate of reactions

71
Q

Activation energy

A

the minimum amount of energy in order to start up a reaction or form successful collisions

72
Q

Catalyst

A

speeds u[p a reaction and is never used up

73
Q

Active site

A

what the substrate binds to the tertiary structure

74
Q

Complementary

A

.the active site is complementary to the substrate. the shape is specific for it to bind to

75
Q

Denaturation

A

change of the tertiary structure in enzyme and can no long work as it looses its complementary shape

76
Q

Lock & key

A

the enzyme is complementary to the active site

77
Q

Induced fit

A

initially the active site is not complementary but as the substrate approaches the tertiary structure of the active site moulds to fit with the substrate

78
Q

Competitive

inhibitor

A

A competitive inhibitor is any compound which closely resembles the chemical structure and molecular geometry of the substrate.
The inhibitor competes for the same active site as the substrate molecule.
The inhibitor may interact with the enzyme at the active site, but no reaction takes place.
decreases the rate of enzyme substrate complexes

79
Q

Non-competitive inhibitor

A

.A noncompetitive inhibitor is a substance that interacts with the enzyme, but usually not at the active site. …
The net effect of a noncompetitive inhibitor is to change the shape of the enzyme
and thus the active site so that the substrate can no longer interact with the enzyme to give a reaction.
binds to the allosteric site

80
Q

intracellular enzyme

A

Enzymes that are present inside the cell membrane are called intracellular enzymes

81
Q

extracellular enzyme

A

the extracellular enzymes are those which are present outside the cell

82
Q

dna full name

A

deoxyribose nucleic acid

83
Q

rna full name

A

ribonucleic acid

84
Q

dna: sugar

A

deoxyribose -pentose sugar with one less oxygen the ribose

85
Q

rna: sugar

A

ribose pentose sugar

86
Q

dna:bases

A

guanine
cytosine
adenine
thymine

87
Q

rna:bases

A

guanine
adenine cytosine and uracil
DOES NOT CONTAIN THYMINE

88
Q

dna: strand length

A

anti parallel and it is very long

89
Q

rna: syttrand length

A

short

90
Q

dna: number of strands

A

2 polynucleotide strands

sugar phosphate backbone on the outside with nases in the middle connected through hydrogen bonds

91
Q

rna: number of strands

A

only one polynucleotide strand

92
Q

how many types of dna

A

4

93
Q

how many types of rna

A

3

94
Q

location of dna

A

cell nucleus

95
Q

location of rna

A

cytoplasm

96
Q

function of dna

A

it stores instructions of how to make proteins and distributed in chromosomes

97
Q

function of rna

A

protein synthesis

98
Q

hydrogen ions

A

ph is calculated by the amount of hydrogen ions present
more h+ lower the ph
enzyme controlled reactions are all effected by ph

99
Q

sodium ions

A

amino acids and glucose need help getting across cell membranes so sodium ions help them to transport
can be transported into a cell with the help of sodium ions

100
Q

iron ions

A

hemoglobin is a large protein containing iron ions which bond with oxygen so it can then be carried around the whole body

101
Q

phosphate ions

A

when a phosphate is attached to a molecule it is known as a phosphate group
atp dna and rna all contain phosphate ions

102
Q

dna replication

A
  1. dna helicase attached to the dna molecule and breaks apart the hydrogen bonds between the bases
  2. the polynucleotides separate from each other and free nucleotides line up with their complementary bases
  3. now dna polymerase moves down the activated nucleotides and catalyses a reaction for phosphodiester bonds
103
Q

structure of water

A

one atom of oxygen chemically bonded to two molecules of hydrogen
oxygen is a polar molecule with a slight negative charge and hydrogen with a small positive charge
water molecules are attached to each other and from hydrogen bonds
hydrogen bonds are very weak

104
Q

5 properties of water

A
  • high latent heat of vaporation
  • it acts as a temperature buffer
  • it is an important metabolite
  • it has cohesion
  • a good solvent
105
Q

water is an important metabolite

A

water is a reactant in many different reactions

for example hydrolysis and photosynthesis

106
Q

water has high latent heat vaporization

A

takes a large amount of heat energy for water to evaporate

allows organisms to cool themselves without loosing alot of water

107
Q

water is a good solvent

A

a lot of substances can dissolve in water
prokaryotes and eukaryotes contain a lot of dissolved substances enzymes
bodys of water contain dissolved oxygen. living in water can carry out respiration
transports substances in blood plasma like carbon dioxide mineral ion glucose and amino acids
xylem vessels contain a lot of dissolved mineral ions
-

108
Q

water is a good temperature buffer

A

allows aquatic organisms to live by acting like a temperature buffer as the temperature of water does not tend to change so rapidly
increase of temperature in water tends not to increase kinetic energy but rather weakened or breaks hydrogen bonds

109
Q

water is cohesive

A

hydrogen bonds make the water stick together
cohesion allows long columns of water to travel in the xylem tubes
cohesion causes surface tension which can act as a habitat for insects and other creatures

110
Q

describe atp

A

adenine ribose and three phosphate groups

111
Q

what are the two main functions of atp

A

,ATP can transfer energy and phosphorylate
stores energy briefly and transport it within cells to support endergonic reactions
ATP is the immediate source of energy in a cell

112
Q

which biological processes carry out atp

A

-active transport
-formation of proteins
-muscle contraction
phosphorylation
making glycogen

113
Q

why is atp suited for it function

A

Why is ATP a suitable source of energy in biological processes?
ATP is a suitable energy source because it is soluble which allows it to diffuse freely throughout the cell so that it can move within the various organelles to power the reactions

ATP is described as energy intermediate or an immediate energy source because it
released energy rapidly in a single step hydrolysis.

114
Q

how is atp synthesised and broken down

A

atp hydrolase hydrolyzes atp to form adp+pi.
which is a release of energy. exergonic and requires water
atp synthase synthesises atp. endergonic. condensation reaction water is lost

115
Q

explain how Meselson and Stahl proved the semiconservative model.

A

DNA in the N15 environment contained 100% N15 DNA This showed that each new two daughter cells had one strand from the parent cell, which proved that DNA replicated semi conservatively.

116
Q

carbonyl group in an amino acid

A

form hydrogen bonds in secondary structure

117
Q

what are the key categories of sugars

A

1.reducing: reducing sugars can donate an electron
all monosaccharides are reducing sugars and some disaccharides
2. non reducing sugars don’t donate an electron for example sucrose

118
Q

what is the test for reducing sugars

A
  1. grind the food sample in distilled water
  2. filter solid food particles
  3. add 3 cm^3 of food sample into a boiling tube and then add 3 cm^3 of benedict’s solution into the same boiling tube
  4. add the boiling tube into a beaker of boiling water and wait 5 minutes
119
Q

what is benedict’s solution made out of

A

cu 2+ which makes it a blue colour

when a reducing sugar is present it adds an electron making it cu+ giving it a red colour

120
Q

what is the semiconservative model

A

both dna molecules contain one original strand and one new strand

121
Q

structure of nucleic acids

A

pentose sugar with a nitrogenous base and a phosphate group

122
Q

what does dna polymerase do

A

dna polymerase moves down the activated nucleotides and catalyses a reaction for phosphodiester bonds

123
Q

what does dna helicase do

A

dna helicase attached to the dna molecule and breaks apart the hydrogen bonds between the bases

124
Q

complementary base pairing

A

adenine hydrogen bonds with thymine

guanine hydrogen bonds with cytosine

125
Q

Why is atp efficient

A

Relatively small amount of energy (little danger of thermal death of cells )
Energy instaneoulsy requires one hydrolysis reaction
Phospherlates other compounds
Does not leave cells or loose form

126
Q

Why do humans synthesis such large amounts of atp

A

Atp cannot be stored immidieate

Atp only releases a small amount of energy at a time

127
Q

What type of proteins are enzymes

A

Globular proteins contain hydrophilic amino acids on their surface and hydrophobic on their centre

128
Q

Explain how substrate enzyme complex’s are formed

A

Substrate binds to the tertiary structure of the enzyme. The amino acids on the surface of the active site form temporary bonds with the substrate. To form an enzyme substrate complex. catalyses the substrate to form an enzyme product complex. The product is then released from the active site

129
Q

How do enzymes lower the AE

A

Enzymes lower the activation energy by catalysing substrates

130
Q

What’s the induced fit model

A

The active site moulds tightly around the substrate. The amino acids on the surface of the active site form temporary bonds with the substrate and catalyses the product

131
Q

How do you calculate the rate of reaction

A

Draw tangent x/y

132
Q

Explain the substrate conc on rate of reaction

A

At the beginning there is a large amount of substrate molecules. This means there is a high frequency of successful collisions forming more enzyme substrate complexes. The more product formed means there is less substrate meaning less successful collisions and less enzyme substrate complexes. Eventually all the substrates will be formed into product meaning the reaction will have stopped

133
Q

How does temperature effect enzymes

A

Increase of temperature of an enzyme increases the kinetic energy of the enzymes and substrate. Which means they move rapidly which means more enzyme substrate complexes formed. If Tempetire increases beyond optimal temperature the kinetic energy can cause vibrations which disrupt the hydrogen bonds within the protein and tertiary structure changes which means it is no longer complementary to its substrate and can no longer form enzyme substrate complexes and the enzyme is classed as denatured

134
Q

How does ph effect enzymes

A

Ph depends on the concentration of hydrogen ions. Lower the pH higher the h+ conc. hydrogen ions can bond with charged r groups within the amino acid. Which causes ionic bonds to break which changes the tertiary structure of the enzyme thus changing the shape of the active site therefore not being complimentary to its substrate therefore becoming denatured there fore decreasing its rate of reaction

135
Q

How do you calculate PH

A

Ph= -log[h+]

A level Biology (11 decks)

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