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OCR BIOLOGY (MODULE 2) > BIOLOGICAL MOLECULES > Flashcards

BIOLOGICAL MOLECULES Flashcards

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1
Q

What kind of data does colorimeter provide?

A

Quantitative- determining conc.

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2
Q

Basic method of a colorimeter

A

1) Colorimeter shines light through sample
2) PHOTOELECTRIC CELL picks up reading from light and gives absorption/transmission based on this
3) Sample to be tested put in cuvette
4) More copper sulphate in original sample= more light transmitted
5) Tells you how much Benedicts used

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3
Q

Qualitative measure using benedicts

A
  1. Add 3cm3 of B solution to 3cm3 of sample
  2. Test tube-> boiling water- 5 mins
  3. Filter through fine grade filter paper (or twice)
  4. Low concs of reducing sugar= Unreacted copper sulphate left (read absorbance on RED light)
  5. High concs= increasing amount of red copper oxide in the filtrate (read on BLUE light)
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4
Q

What does a biosensor do

A

Component that takes biological or chemical variable that cannot be easily measured and converts it into an electrical signal

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5
Q

What does a transducer convert

A

One form of energy to another

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6
Q

What are lipids

A

Large complex molecules (macromolecules) with a few oxygen atoms and a lot of carbon and hydrogen atoms

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7
Q

Three important groups in lipids

A

Triglycerides (fats and oils)
Phospholipids
Sterols (eg cholesterol)

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8
Q

What are the functions of lipids

A

Energy storage
Structural (40% phospholipids in cell membrane)
Insolation
Protection
Waterproofing
Buoyancy (fat less dense than water-aquatic animals)
Hormones

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9
Q

What do each group of lipids contain

A

Hydrocarbons
All soluble in organic solvents for example alcohol
All insoluble in water

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10
Q

What is the test for lipids

A

Crushed material with ethanol and decant the suspension to remove any solid particles
Pour the ethanol mixture onto water in another test tube
Do not mix
A milky emulsion forming in the water indicates a lipid is present

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11
Q

What are triglycerides made up of and what bond holds them together

A

One molecule of glycerol attached the three fatty acid bonded by an ester bond

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12
Q

What are the fatty acid tails

A

Hydrocarbons and hydrophobic making them insoluble in water

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13
Q

What are triglycerides used for

A

Energy stores because they are rich in energy

1 g of triglyceride can release twice as much energy as 1 g of carbohydrate

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14
Q

What do you fatty acids always have on one end

A

Carboxyl acid group

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15
Q

What does having more than one double bond in the hydrocarbon section make the fatty acid

A

Poly unsaturated

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16
Q

How does the double bonding affect the melting point of the triglyceride molecule

A

More double bonds equals a lower melting point

Hence why most vegetable lipids are oils

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17
Q

What is esterification

A

The formation of a triglyceride from glycerol and three fatty acid in a condensation reaction

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18
Q

How do you make a phospholipid

A

By replacing one of the fatty acids with a phosphate group and allowing it to ionise making it attract water molecules

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19
Q

In a phospholipid is is the head hydrophilic or hydrophobic

A

Hydrophilic head
Hydrophobic tail
Making them essential in cell membranes

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20
Q

In which direction of the hydrophobic tails pointing towards in a phospholipid bilayer

A

They face inwards towards the centre of the sheet away from the water

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21
Q

What do you phospholipid in the cell membrane give

A

Stability because the hydrophobic tails will never move into a position where they are exposed to water

Selective permeability because only a small and nonpolar substances for example oxygen and carbon dioxide can move through the tails into the bilayer

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22
Q

What is the bond formation when making a phospholipid

A

Condensation reaction

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23
Q

What are the advantages of lipid respiration

A

1 g of lipid gives out twice the amount of energy during respiration compared to 1 g of carbohydrates

Lipids are insoluble in water and so can be stored in a compact way without affecting water potential

Lipids give out more water than carbohydrates which helps with metabolic reactions in organisms

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24
Q

What are sterols and what are they based on

A

Complex alcohol molecules that are based on four carbon based rings with a hydroxyl group at one end

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25
Q

In sterols what is the hydroxyl group

A

Polar therefore hydrophilic well the rest of the molecule is non-polar and therefore hydrophobic

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26
Q

What is the structure of cholesterol

A

Has a hydrocarbon ring structure attached to a hydrocarbon tail
This ring has a polar hydroxyl group attached making cholesterol is slightly soluble in water but it is insoluble in blood

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27
Q

What are structural features of cholesterol

A

Short straight molecules
Hydrocarbon tail
4 hydrocarbon rings
One oxygen atom in the hydroxyl group

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28
Q

Where is cholesterol found

A

In the biological membrane

29
Q

What does cholesterol regulate

A

It sits between phospholipid and regulates fluidity at different temperatures

30
Q

Where do we use lipids

A 
Respiration
Energy storage
Thermal insulation 
Protection
Buoyancy
Waterproofing
31
Q

What is the structure main role and other features of triglycerides

A

Three fatty acid plus a glycerol bonded by an ester bond
Compact energy storage and insoluble in water so doesn’t affect cell water potential
Stored as fat which has roles of thermal insulation buoyancy and protection of organs

32
Q

What is the structure main role and other features of phospholipids

A

Glycerol +2 fatty acid and a phosphate group
Form is a stable part hydrophobic and part hydrophilic molecule
-making them good for cell membranes because water-soluble substances can’t easily pass through the bilayer
Phosphate groups may have carbohydrate parts attached these are involved in cell signalling

33
Q

What is the structure main role and other features of cholesterol

A

Four carbon based rings join together
Forms a small molecule that fits into the lipid bilayer giving strength and stability
Used to form the steroid hormones e.g. progesterone and testosterone

34
Q

What is the formula for nitrates and what are they necessary for?

A

NO3-

The component N needed for plants

35
Q

What is the formula for hydrogen carbonate and what is it necessary for?

A

HCO3-
Maintenance of blood pH (breathing rte controlled by blood pH)
CO2 transport

36
Q

What is the formula for hydroxide and what is it necessary for?

A

OH-
Catalysis reactions
pH determination

37
Q

What is the formula for chloride and what is it necessary for?

A

Cl-

Balance positive charge of sodium and potassium ions in cells

38
Q

What is the formula for phosphate and what is it necessary for?

A

PO43-

Cell membrane, bone and nucleic acid formation

39
Q

What are the chemical elements found in

  • carbohydrates
  • lipids
  • proteins
  • nucleic acid
A

C, H & O
C, H & O
C, H, O, N & S
C, H, O, N & P

40
Q

What is the biological name for sugars?

A

Saccharides

41
Q

What is the formula for calcium and what is it necessary for?

A

Ca2+
Nerve impulse transmission
Muscle contractions

42
Q

What is the formula for sodium and what is it necessary for?

A

Na+
Nerve impulse transmission
Kidney function

43
Q

What is the formula for potassium and what is it necessary for?

A

K+
Nerve impulse transmission
Stomatal opening

44
Q

What is the formula for ammonium and what is it necessary for?

A

NH4+

Production of nitrate ions by bacteria

45
Q

What is the formula for hydrogen and what is it necessary for?

A

H+
Catalysis reaction
pH determination

46
Q

Why do sugars dissolve in water?

A

Has an uneven distribution of charges between the O2 and H2 atoms, creates slightly positive and slightly negative area
Allowing sucrose to dissolve

47
Q

What do hydrogen bonds restrict and what over comes them?
What does the water content of cytoplasm help with?
(high specific heat capacity)

A

Restrict movement-large amount of energy required to increase temp of water
Therefore water is quite stable and can withstand large temperature fluctuations making water ideal for aquatic organisms

Help buffer cells against temp change due to heat released during metabolic reactions

48
Q

What is the heat energy required for?
What do lots of H bonds make it hard for water to do?
(high latent heat of vapourisation)

A

Help molecules break away from each other to become a gas

Evaporate

49
Q

Describe hydrogen bonds

A

Weak interactions when a molecule contains a slightly negatively charged atom bonded to a slightly positively charged hydrogen

50
Q

What are properties of water being a liquid at room temperature?

A
  • aquatic habitats for organisms
  • form major components of tissues
  • provide reaction medium for chemical reactions
  • effective transport medium
51
Q

What makes molecules hard to escape and turn into gas?

A

Water molecules form H bonds, which form networks

  • network constantly shifts, breaking and making new bonds
  • hard to turn into gas (hence 100 degree boiling point)
52
Q

What happens when temperature falls?
What does ice do?
(density)

A

Temperature decreases=molecules having less KE and move less
-more H2 bonds form, and don’t break easily

Starts to solidifies at 4 degrees

  • semi-crystalline structure
  • less dense than water; bonds that hold molecules together are further apart, so ice forms on surface and INSULATES
53
Q

Description of cohesion

A

When water molecules are attracted to each other

-H2 bonds pull molecules in at surface and this cohesion causes surface tension (causes droplets to form)

54
Q

What sort of substances dissolve in water? (and descriptions)

A

Polar substances

  • solute has neg, and positive charges
  • water molecules cluster round slightly charged parts of solutes
  • helps keep the solute molecules apart-water
  • at this point they dissolve and a solution is formed
55
Q

What happens once a solute becomes a solution?

A

Molecules move around and react with other molecules

56
Q

Why does salt dissolve in water?

A

Salt is an ionic compound
+ve ions become surrounded by water molecules with neg. oxygen atoms
–ve ions become surrounded by water molecules- positive hydrogen atoms facing them
Water molecules surround ions, keeping them apart and dissolved a solution

57
Q

What are carbohydrate functions in organisms?

A
  • energy store
  • energy source
  • structure
58
Q

What are monosaccharides, what are the characteristics and what carbon number are the grouped in?

A
  • simplest carbohydrate
  • sweet and soluble
  • triose, pentose and hexose sugars
59
Q

What are disaccharides, what do they form and what are some examples?

A

-two monosaccharides can be joined
-sweet, soluble=crystals
glucose+glucose-maltose
glucose+fructose-sucrose
glucose+galactose-lactose

60
Q

What is a glycosidic bond?

A

Covalent chemical bonds that link ring shaped sugar molecules to other molecules

61
Q

Whats the short and long test for reducing sugar?

A

Reagent strip

Benedicts solution and heat

62
Q

What are polysaccharides and what have the undergone?

A

Polymers of monosaccharides, which have undergone condensation reaction

63
Q

What are properties of polysaccharides and what do they make?

A

-insoluble in water
-not sweet
-cant be crystallised
Properties + compact structure= good for storage

64
Q

What % of amylopectin and amylose are in starch?

A

80% amylopectin

20% amylose

65
Q

AMYLOSE
What kind of reaction, forming bonds between what glucose?
-what does this result in?
Properties?
What colour does it turn potassium iodine solution?

A
  • condensation, (1-4=alpha) meaning straight line that coils
  • compact=good for storage
  • blue/black-iodine molecules become fixed in centre of helix (must be done at room temp others helix will uncoil)
66
Q

AMYLOPECTIN
What kind of reaction, between what kind of glucose?
What number bonds are there more of making the structure more…
What does it have lots of?
What colour does it turn potassium iodine solution?

A
  • condensation (1-4=alpha)
  • more 1-6 bonds=branched
  • ‘ends’ for glucose to attach to
  • red/purple-cannot bind as much iodine because highly branched
67
Q 
GLYCOGON
What kind of glucose?
What no. bonds?
What does it have lots of?
It is more....than starch
Where are high concentrations of glycogen found?
A
  • alpha glucose
  • 1-4 and 1-6
  • ‘ends’ glucose add onto
  • compact
  • liver and skeletal muscle cells
68
Q

CELLULOSE
What bond numbers and type of glucose?
-how to make the bond and what it forms
-what protects chains

A
  • 1-4, beta glucose
  • alternate beta glucose molecules are rooted through 180 degree, straight chains

Straight chains have lots of OH to protect them

  • form hydrogen bonds, with adjacent cellulose molecules
  • cellulose=stronger than starch
69
Q

What. is the function of cellulose?

A
  • plant cell walls, strengthen and support whole plant
  • macrofibrils make the cell wall permeable to water
  • structure/shape of cell to aid function

OCR BIOLOGY (MODULE 2) (6 decks)

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