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Biology Year 1 > 2.2 Biological Molecules > Flashcards

2.2 Biological Molecules Flashcards

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1
Q

What is a hydrogen bond.
When does this happen

A

Bond between atoms due to the interactions between positive + negative regions. This happens when an atom in a molecule has greater number of protons which exert strong attraction on electrons pulling them towards itself giving it a slightly negative charge while the other atoms has a slightly positive charge

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2
Q

what is polar

A

when there is uneven distribution of electrons causing atoms to having regions of charges

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3
Q

what is the strength of Hydrogen bonds

A

They are weak but many of them provide collective strength

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4
Q

what are monomers

A

Individual molecules that bind to their identical molecules to form a polymer

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5
Q

What are polymers

A

large molecules and chains that are made from smaller molecules called monomers

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6
Q

Condensation reaction

A

Reaction that occurs when 2 molecules are joined together with the removal of water

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7
Q

Hydrolysis Reaction

A

Reaction that occurs when a molecule is split into 2 smaller molecules with the addition of water

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8
Q

Why is water liquid at room temperature

A

Due to many hydrogen bonds between water molecules which make it difficult for it become a gas

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9
Q

What is the viscosity of water like

A

Has a low viscosity which allows it to flow around

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10
Q

How does this help wildlife

A
  • provides habitats for living things in rivers and lakes
  • Forms a major component of tissue in living organism
  • Provide reaction meduim for chemical reaction
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11
Q

What is the density of any liquid like then compared to water

A

As liquid get colder the density increases. Water does the same until the temperature reaches 4 degrees at which the density stays the same

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12
Q

Why is this

A

Due to the polar nature of water to allow water molecules to allign themselves in a less dense structure with more gaps

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13
Q

How is this helpful

A
  • Aquatic organisms have a stable environment in which to live in water
  • Ponds and other bodies of water are insulated against extreme cold. The layers of ice reduces the rate of heat loss
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14
Q

Why is water a good solvent

A

Due to the polarity of water the positive and negative parts of the water are attracted to positive and negative parts of the solute. The water molecules cluster around them and seperate them and keep them apart to allow it to dissolve

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15
Q

How is this helpful

A
  • Molecules and ions can be transported around living things whilst dissolved in water
  • Molecules and ions can move around and react together. many such reactions happen in cytoplasm which is 70% water
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16
Q

What is LHOV

A

Helps the molecules break away from each other to become gas

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17
Q

Why does water have high LHOV

A

many hydrogen bonds

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18
Q

How is this helpful

A

-keeps the temperature stable
-Sweat evaporating cools living things

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19
Q

What is SHC

A

The energy needed to raise the temperature of 1kg of substance by 1 degree

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20
Q

What is waters SHC

A

4.2Ki

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21
Q

How is this helpful

A
  • Living Organisms require a controlled temperature and stable environment for enzymes controlled reactions
  • Aquatic organisms need a stable environment in which to live in
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22
Q

how is water a good reactant

A

it is involved in many important reactions

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23
Q

For example

A

Digestion + Synthesising large biological molecules

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24
Q

what is cohesion

A

The hydrogen bonds between molecules are strong which pulls them together when you pour water on the surface it doesn’t spread instead it gathers together

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25
Q

where is cohesion used

A

collumns of water in plant vascular tissue are pulled up by the xylem tissue from the roots

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26
Q

what is surface tension

A

The water molecules at surface of water are bonded to those beneath making them more attracted to the water molecules beneath than the molecules in the air. This means that surface of water contracts ( due to molecules being pulled inwards ) which gives the surface of the water the ability to resist force applied due to surface tension

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27
Q

where is surface tension used

A

Insects like pond-skaters can walk on water

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28
Q

what elements are found in carbohydrates

A

C , H , O

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29
Q

3 uses of carbohydrates

A

1.Acts as a source of energy (glucose)
2. Acts as a store of energy (Starch & Glycogen)
3. Acts as a structural unit (Cellulose)

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30
Q

What are monosaccharides

A

Simplest carbohydrates and act as monomer for larger structures

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31
Q

3 monosaccharides

A

Fructose
Glucose
Galactose

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32
Q

what is the difference between alpha and beta glucose

A

in alpha glucose on the 1st carbon hydrogen in at the top while OH is at the bottom

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33
Q

What is a dissacharide

A

Formed when 2 monosaccharides join together by condensation

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34
Q

What does a condensation reaction form

A

1-4 Glycosidic Bond

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35
Q

A glucose + A glucose

A

maltose

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36
Q

A glucose + Fructose

A

sucrose

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37
Q

B Galactose + A glucose

A

Lactose

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38
Q

B Glucose + B glucose

A

cellobiose

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39
Q

What is a polysaccharide

A

polymers of monosaccharides bonded together using a condensation reaction

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40
Q

Homopolysaccharide

A

Polysaccharide that’s made from 1 type of monosaccharide

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41
Q

Hetropolysaccharide

A

polysaccharide that’s made from from different types of monosaccharide

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42
Q

what polymers are starch made from

A

2 alpha glucose
( Amylopectin , Amylose )

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43
Q

what bonds are there in starch

A

1,4 in amylose
1,4 + 1,6 in amylopectin

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44
Q

what is the function of starch

A

storing glucose

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45
Q

location of starch

A

plant cells

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46
Q

how does structure of starch lead to its function

A
  • helix is compact to fit a lot of space
  • Branched structure increase surface area for rapid hydrolysis back to glucose
  • Insoluble ( won’t affect water potential )
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47
Q

what is the structure of amylose like

A
  • unbranched chain coils to form helix
  • The hydrogen bonds keep it in place
  • The hydroxyl on carbon-2 is situated on the inside of coil making it less soluble and allowing it to maintain the coil structure due to h-bonds
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48
Q

what is the structure of amylopectin like

A
  • Coils up to form spirals
  • Held together by hydrogen bonds
  • Branches emerge from the spiral
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49
Q

what monomers are glycogen made from

A

a glucose

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50
Q

what bonds are there

A

1,4
1,6

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51
Q

why does the structure coil less

A

the 1,4 bond chains are smaller

52
Q

what is the function of glycogen

A

storing glucose

53
Q

Where is it found

A

found in animal cells ( mainly muscle + liver cells )

54
Q

How does the structure of glycogen lead to its function

A
  • More branched than starch meaning it has higher S.A for rapid hydrolysis back to glucose
  • Insoluble ( won’t affect water potential )
55
Q

what monomers are cellulose made from

A

B glucose

56
Q

what bonds do they contain

A

1,4 glycosidic bonds and hydrogen bonds to form a fibril

57
Q

what is the function of cellulose

A

strengthen the cell wall

58
Q

where is it found

A

in plants

59
Q

what is the structure like

A

long straight chains that are parallel to one another and have hydrogen bonds holding them together to form a fibril

60
Q

how does structure lead to function

A

insoluble ( won’t affect water potential )

61
Q

what needs to happen for 2 cellulose molecules to combine through condensation reaction

A

the 2nd cellulose must rotate 180 degrees

62
Q

Why does the 2nd cellulose rotate?

A

the OH groups are on different sides so they need to rotate 180 degrees to align them together

63
Q

how is a microfibril formed

A

when 60-70 cellulose chains bond together

64
Q

how is macrofibril formed

A

formed when 300 microfibrils join together

65
Q

How does the macrofibril provide extra strength

A

run in all directions + criss-cross for extra strength

66
Q

what are 2 adaptations

A
  • There is space between macrofibril to allow water + mineral ions to pass through making the cell-permeable
  • Due to high tensile strength cell doesn’t burst
67
Q

what are lipids

A

Group of substances that contain high number of carbon + hydrogen atoms but a low number of oxygen. They are insoluble in water as they are non-polar but are soluble in alcohol

68
Q

why aren’t they polymers

A

made from different compounds

69
Q

What are triglycerides

A

Type of lipid that’s made up of glycerol and 3 fatty acids that are bonded to the glycerol

70
Q

what is glycerol

A

alcohol that contains 3 carbon atoms and has 3 -OH groups

71
Q

what are fatty acids

A

chains of hydrocarbons with (COOH) attached to one end. Carbon atoms are even number

72
Q

why is the structure of fatty acids acidic

A

The carboxyl group is ionised into the H+ and COO- group. The release of H+ makes it acidic

73
Q

What happens if a fatty acid is monounsaturated or polyunsaturated

A

produces a kink wherever the double bond is

74
Q

What does the kink do

A

The kink pushes the molecules apart which makes them more fluid

75
Q

What is an ester bond

A

A covalent bond formed by a condensation reaction between the -OH of the carboxyl group and -OH group of the alcohol

76
Q

5 functions of triglycerides

A
  1. Energy Source: Can be broken down in respiration to release energy + generate ATP. The first step is to hydrolyse the ester bond and then fatty acid + glycerol can be broken into CO2 and H20
  2. Energy Store: insoluble in water so they can store energy without affecting water potential
  3. Insulation: Adipose tissue is a storage location for lipids in whales acting as a thermal insulator. Lipids in nerve cells can act as electrical insulators
  4. Buyancy: As fat is less dense than water it’s used by aqautic mammals to keep them afloat
  5. Protection: Humans have fat around delicate + important organs to act as shock absorbers. The peptidoglycan cell wall of some bacteria is covered in lipid rich outer coat
77
Q

What is a phospholipid

A

Type of lipid which contains a glycerol that’s bonded to 2 fatty acids as well as a phosphate group

78
Q

What is a phosphate ester bond

A

When a condensation reaction takes place between glycerol and phosphate group

79
Q

What happens to phospholipid when reacting with water

A

When surrounded by water hydrogen atoms disassociate themselves from phosphate group

80
Q

what is the head of phospholipid

A

phosphate group + glycerol

81
Q

what is the tail of phospholipid

A

the fatty acids

82
Q

what does hydrophilic mean and which part is it

A

A hydrophilic is a molecule that is attracted to water due to it having a charge . The head is hydrophilic

83
Q

what does hydrophobic mean and which part is it

A

molecule that’s repelled by water due to it not having a charge. The tail is hydrophobic

84
Q

what does amphipathic mean

A

molecule that has both polar & non-polar regions. (head=polar while the tail=non-polar)

85
Q

what is a phospholipd bilayer

A

a bilayer is formed when 2 layers of phospholipid tails (hydrophobic) point each other inwards while 2 rows of phopholipid heads (hydrophilic) are outwards and pointed away from each other.

86
Q

how is the membrane selectively permeable

A

only allows small + non-polar molecules to move through the tail bilayer

87
Q

what is cholesterol and structure

A

-comes from sterol family ( type of lipid which isn’t made from glycerol or fatty acids)
- consists of 4 carbon based rings
- contains hydroxyl group making it hydrophobic which allows it to sit between hydrophobic section

88
Q

role of cholesterol

A
  • regulates fluidity of membrane to prevent it becoming too stiff or too fluid
  • Cholesterol creates testosteron, oestrogen and vitamin D
89
Q

why can they pass through the bilayer and other membranes

A
  • Since they are small + hydrophobic they can pass through bilayer and other membranes of the cell
90
Q

what is a protein

A

large polymer comprised with f ping chain of amino acids

91
Q

what are 3 roles of proteins

A

1 they form structural components of animals e.g muscle, tendons, bones

2 they adapt specific shapes as enzymes

3 membranes have proteins constituents that’s act as corner + pores for active transport across membranes + facilitated diffusion

92
Q

what elements does it contain

A

Each amino acid contains C,H,N,O and S sometimes

93
Q

what is the structure of an amino acid

A

All protein chains of amino acid contain amine group (NH3) at one and + carboxyl group (-COOH) at the other

-The R group can vary by size polarity and charge

94
Q

what is a peptide bond

A

A covalent bond formed when two amino acids are joined together in a condensation reaction

95
Q

what does protease enzyme do

A

Protease enzymes break down protein peptides bond in digestion

96
Q

what is a dipeptide

A

When two amino acids join they are a dipeptide

97
Q

what is a polypeptide

A

Polypeptide is when many amino acids join together

98
Q

what is the primary structure

A

It is the sequence of amino acid in the polypeptide chain.

99
Q

why it it important

A

The function of protein depends on the structure, which depends on the amino acid order.

100
Q

what is the secondary structure

A

The coiling or folding of the amino acid chains to form either an a-helix or B pleated sheet. This is due to H bonds. (Between C equals O And H in the amine a group) to hold the structure.

101
Q

what is the tertiary structure

A

Further folding of a secondary structure which forms 3D unique shape and is held by; Iconic, Hydrogen, disulphide Bonds.

The iconic + sulphide Form between R groups of different amino acids.

disulphide bonds only sometimes occur as there must be sulphur in R- group.

102
Q

what is the quaternary structure

A

Where proteins consist of more than one polypeptide chain bonded together.

103
Q

what is hydrogen bond in the tertiary structure

A

Form between C = O in carboxyl groups and H in an amine group.

104
Q

what is the ionic bond between tertiary structure

A

Form between carboxyl + amine groups that are part of R groups

105
Q

what are the hydrophobic and hydrophilic interactions in the tertiary structure

A

R groups are hydrophobic + tend to stay in the middle of polypeptide to stay away from H2O.

The hydrophilic parts are found at edge to be close to water.

Hydrophobic + Hydrophilic interactions cause twisting of amino acids which charge shape of the protein.

These interactions can be especially Important influence given that most protein are tube found surrounded by H2O inside a living Organism.

106
Q

what are disulphide bonds

A

Bond formed Between 2 sulphurs in R group and forms a bridge.

These are strong covalent bonds.

Made from Cysteine amino acid (They contain s)

107
Q

What are fibrous proteins

A

They are long thin protein that is insoluble in water.

They are made from repeating sequences of amino acids and are metabolically inactive leading them to have structural roles in an organism

108
Q

3 examples of fibrous proteins

A

Collagen
Elastin
Keratin

109
Q

Collagen

A

Found in the artery wall and a layer of collagen prevents the artery from bursting when withstanding HP

Tendons are made from collagen and connect muscle to bones allowing them to pull bones

Cartilages + Connective tissue are made from collagen

Bones are made from collagen + then reinforced with calcium phosphate which makes them hard

110
Q

Keratin

A

Is found in body parts that need to be hard to provide mechanical protection as well as acting as an impermeable barrier to infection being waterproof and preventing entry of waterborn pollutants

Keratin can be found in nails, claws, hooves, horns, and scales

They are rich in cystine which means they have many disulphide bridges in its polypeptide as well as having many H-bonds to provide additional strength

111
Q

Elastin

A

Due to coiling and cross linking of the elastin molecules its long and extensible (stretchy)

Skin can stretch around bones and muscles due to elastin

Elastin in lungs allow them to deflate and inflate

They are also found in the bladder to help it expand to store urine

Elastin also helps our blood vessels widen and stretch + recoil as blood is pumped through them helping maintain the pressure wave of blood as it passes through

112
Q

what are globular proteins

A

Type of 3d protein that is spherical and soluble in water and having metabolic roles

They have Hydrophobic R groups on the inside the hydrophilic R groups on the outside

113
Q

3 examples of globular proteins

A

Haemoglobin
Insulin
Catalase

114
Q

Haemoglobin

A

A globular protein that is found in red blood cells

Made from 4 polypeptide chains making it have a quaternary structure (2 Alpha Globin chains + 2 Beta Globin chains)

At each polypeptide group there is a prosthetic group attached (a non-protein component that forms a permanent part of a functioning protein molecule) making a conjugated protein (protein which has another chemical group)

The 4 prosthetic group in haemoglobin are called haem groups and contain iron ion (Fe2+)

One O2 molecule binds to each haem group allowing for each haemoglobin to transplant 4 O2 molecules

115
Q

Insulin

A

Made from 2 polypeptide chains – the A chain has an alpha helix while the Beta chain has a Beta-pleated sheet

The 2 chains are linked by disulphide links

Amino acids with hydrophilic R groups are on the outside of molecule making it soluble in water

The shape of insulin allows for it to bind to glycoprotein receptor on the outside of muscle + fat cells to increase its uptake of glucose from blood and to increase the rate of glucose consumption making a lower blood glucose concentration

Since its soluble it dissolves in blood + easily transported around body

116
Q

Catalase

A
  • Quaternary protein consisting of 4 haem prosthetic groups
  • Presence of Fe2+ ion in the prosthetic group & allow it to interact & break down Hydrogen peroxide
  • Hydrogen Peroxide is a by product of metabolism and is harmful to cells if it accumulates
117
Q

role of calcuim ions

A

Increases rigidity of bones, teeth and cartilage and I a component of the exoskeleton

Important for clotting blood and muscle contraction

Activator for several enzymes such as lipase

Stimulates muscle contraction

Regulates permeability of cell membrane

Important for cell wall development in plants and formation of middle lamella between cell walls

118
Q

roles of soduim ions

A

Involved in regulation of osmotic pressure, control of water levels in body fluid and maintenance of pH

Affects absorption of carbohydrates in the intestine & water in the kidney

Contributes to nervous transmission and muscle contraction

Constituent of vacuole in plants which helps maintain turgidity

119
Q

roles of pottassuim ions

A

Involved in control of water levels in bodily fluids and maintenance of pH

Assists active transport of material across the cell membrane

Involved in synthesis of glycogen and protein, and breakdown of glucose

Generates healthy leaves and flowers in flowering plants

Contributes to nervous transmission and muscle contraction

Component of vacuoles in plants helping to maintain turgidity

120
Q

Role of hydrogen ions

A

Involved in photosynthesis and respiration

Involves in transport of oxygen and carbon dioxide in the blood

Involved in regulation of blood pH

121
Q

Role of ammonia ions

A

A component of amino acid, proteins, vitamins, and chlorophyll

Some hormones are made of proteins e.g. insulin

An essential component of nucleic acid

Involved in maintenance of pH in the human body

A component of the nitrogen cycle

122
Q

Role of nitrate ions

A

A component of amino acids, proteins, vitamins, and chlorophyll

An essential component of nucleic acids

Some hormones are made of proteins which contain nitrogen e.g. insulin

A component of nitrogen cycle

123
Q

Role of hydrogen carbonate ion

A

Involved in regulation of blood pH

Involved in transport of carbon dioxide into and out of the blood

124
Q

Role of chlorine ions

A

Helps in production of urine and maintaining water balance

Involved in transport of carbon dioxide into and out of blood

Regulates affinity of haemoglobin to oxygen through allosteric effects on the haemoglobin molecule

Involved in regulation of blood pH

Used to produce hydrochloric acid in the stomach

125
Q

Role of phosphate ion

A

Increases rigidity of bone, teeth and cartilage and is a component of the exoskeleton of crustaceans

Component of phospholipids, ATP, nucleic acids, and several important enzymes

Involved in regulation of blood pH

Helps root growth in plants

126
Q

Role of hydroxide ion

A

Involved in regulation of blood pH

Biology Year 1 (16 decks)

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