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Biology AQA Alevel > 3.1 Biological Molecules > Flashcards

3.1 Biological Molecules Flashcards

(59 cards)

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1
Q

What is an isomer?

A

Same chemical formulae, different arrangement

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2
Q

Monomers making Maltese?

A

2 glucose

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3
Q

Monomers making Sucrose?

A

Glucose + Fructose

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4
Q

Monomers making Lactose?

A

Glucose + Galactose

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5
Q

Bonds between sugars

A

Glycosidic

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6
Q

Isomers of glucose

A

Alpha glucose

Beta glucose- flip on carbon 1, alternating directions when in chain

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7
Q

Starch

A

Alpha glucose (stored on plants)

  • mostly unbrancged and tight helix shape
  • insoluble, compact, easily hydrolized, large molecule
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8
Q

Glycogen

A

Alpha glucose (stored in animals)

  • short and branched, tight helix shape
  • insoluble, compact, lots of ends for hydrolysis, large molecule
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9
Q

Cellulose

A

Beta glucose (cel walls)

  • straight and unvranched, parrelel chains connected by hydrogen bonds
  • Cross links so collectively strong, microfibrels and fiberals for more stregnth
  • stops cell from wilting
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10
Q

Test for reducing sugar

A

2cm³ of food sample +Benedicts solution+ heat

Colour change blue to red (shows concentration by colour)

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11
Q

Testing for non reducing sugars

A

2cm³ of food sample + 2cm³ of HCl (hydrolize into monomers)
+ NaHCO3 (neutralize)
Then perform reducing sugars test

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12
Q

Test for Starch

A

Drops of iodine on 2cm³ of food sample

Colour change brown to blue/black

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13
Q

Colorimeter in test for sugars

A

tests solutions absorbance of light

  • more intence the colour more absorbant it is
  • need to caliberate device with water and known concentrations glucose (Quantative Data)
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14
Q

7 Functions of protiens with examples

A
  • contractile (actin+myosin, cilia+flagellum)
  • storage (ovalbumin (egg white) and in seeds)
  • receptor and hormonal (nerve membrane and insulin)
  • transport (haemoglobin)
  • enzymatic (digestive enzymes)
  • structural (silk fibers for webs, collagen and elastin, keratin for hair/feathers/horns)
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15
Q

Amino acid structure and properties of R groups

A

NH2-CHR-COOH (amine and carboxly group)
-20 natural occurring amino acids

R groups can be:
hydrophilic (charged) or hydrophobic
-acidic, basic or amphoteric (acid and base so used as buffers)

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16
Q

Simple protien

A

Made if only amino acids

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17
Q

Conjuncted protiens

A

Contain amino acids and a non-Amino acid part called “prosthetic group”

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18
Q

Primary structure of protiens

A

The sequence of amino acids joined by peptide bonds

-change to primary structure due to mutations in DNA

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19
Q

Secondary structure of protien

A

The way the polypeptide chain is folded into ALPHA HELIX or BETA PLEATED SHEETS
-joined by weak Hydrogen bonds

-chain can have some regions coiled and others folded

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20
Q

Tertiary structure of protiens

A

Protien folds further to give molecule a globular shape

  • forms specific 3D shapes
  • important for enzymes and antibodies
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21
Q

Types of bonds in tertiary structure of protien

A

Ionic- NH2 • • •COOH, broken by pH change
Hydrogen- strong in number, broke by temp or pH change
Disulphide- strongest bond in structure (S‐S)

Hydrophobic interactions- hydrophobic R group cluster together in presence of water (not a bond)

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22
Q

Structure of DNA

A
  • nucleotide (phosphate group, deoxyribose pentosugar, nitrogeonous base)
  • joined by PHOSPHODIESTER BONDS
  • double helix
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23
Q

Bases and Base interactions

A 
Adenine Guanine (purine)
Thymine Cytosine (pyrimidines)
A--T
C---G 
Hydrogen Bonds
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24
Q

Structure of DNA to its functions

Study These Flashcards
A

double stranded- template for semi conservative replication
weak h-bonds- can be broken for easy replication
many h bonds- overall strong
complementary base pair- accurate replication
sugar phosphate backbone- protects from corruption
large molecule- store lots of info
double helix- compact

25
importance of DNA
``` genetic code (for all protiens) mitosis variation ```
26
difference between DNA and RNA
RNA- ribose sugar, smaller, single helix, Uracil instead of Thymine
27
Process of DNA replication
- DNA helicase breaks H bonds, DNA unravel - strands act as templates - free floating activated nucleotides attract to specific complementary base - DNA polymerase joins nucleotides (phosphodiester) - Semi conservative, ensures genetic continuity
28
uses of ATP
- movement - metabolism - maintaining temperature - active transport - PHOSPHORYLATION to change protein shape - cell division - production/secretion of other products (e.g. from lysosomes)
29
Structure of ATP
-adenine -ribose pentose sugar -3 phosphate group (last bond unstable and easily broken) KNOWN AS A NUCLEIC ACID
30
How does ATP release energy? How does it return to ATP? How much energy released?
- last phosphate covalent bond broken by ATP hydrolase - reversible, joined back by ATP synthase - immediate release of energy, in manageable amount (33kJ)
31
What is triglyceride made of?
1 glycerol molecule( 3 hydroxyl groups) and 3 fatty acid molecules (each has 1 carboxyl group) Connected by ester bond
32
Saturated lipid
No carbon-carbon double bonds Straight and closely packed (dense) -so solid at room temp E.g. fats/butter
33
Unsaturated lipids
Has carbon-carbon double bond Causes chain to bend, less dense - liquid at room temp E.g. oil
34
Properties of triglycerides
-good energy store (high proportion of H so provides 2× more energy than respiration and provides water so reduces mass needed to be carried by animals) -non polar (doesn't affect water potential, provides waterproof layer) -thermal and electrical insulation -protect internal organs (as cushioning) - less dense than water (aids in buoyancy)
35
Phospholipid structure
1 phosphate group (PO⁴R) negative ion 1 glycerol (3 hydroxyl groups) 2 fatty acid chains (each has 1 carboxyl group) Head is charged so polar so hydrophilic Tails are unchanged so hydrophobic
36
Shapes formed by phospholipids
- monolayer ontop of water - MICELLES- monolayer ball - BILAYER- fluid membrane but stable shape - barrier and electrical insulation - ions dissolved in water so cant go through membrane (surrounds nerve cells)
37
Test for lipids
EMULSION TEST If sample solid it must be crushed 2cm³ of sample and add 5cm³ of ethanol Shake tube and add 5cm³ of water, reshake WHITE EMULSION
38
Light Microscope | pros and cons
uses light and lenses low mag and resolution for bacteria/tissue simple and cheap
39
Electron Microscope | pros and cons
uses electron and electromagnets high mag and resolution for organelles/organisms complex and expensive
40
Setting sample for Electron microscope
Killed, Dehydrated, stained with heavy metals (which can cause artifact/debris to damage sample), fixed in a vacuum
41
TEM (pros and cons)
- to see organelles inside (stains absorb electron) - has slightly better resolution that SEM - used for cells, cant use it for organisms
42
SEM (pros and cons)
- to see surface of specimen (stain reflects electron) - 3D - can be used to see specimens
43
steps in Differential Centrifugation
- chop and place in ICE COLD ISOTONIC BUFFER - homogenize - spin in centrifuge, remove supernatant - repeat at faster speeds -first pellet: nucleus, 2nd pellet: chloroplast/mitochondria
44
creating temporary mount
-cut thin enough for light to pass through -flatten then stain with Iodine SOLUTION (unless looking at something pigmented) -use mounting needle to lower cover slip at an angle
45
Why is cells placed in ice cold, isotonic, buffer solution? (for centrifugion)
cold-reduce hydrolytic enzyme activity isotonic- so doesn't affect water content of cells buffer- constant pH so structural proteins not changed
46
difference in 2 strands of DNA
-antiparallel strands -phosphate end (5 prime/leading), sugar (3 prime/lagging) DNA POLYMERASE WORKS FROM 5 TO 3 PRIME
47
Experiment for Semi Conservative Replication
bacteria grown in heavy nitrogen, next replications done in light nitrogen for 3 generations -spun in DENCITY GRADIENT CENTRIFUGION
48
what is density gradient centrifugation?
DNA centrifuging in a solution of caesium chloride, DNA separates at its densities compare bands to normal light nitrogen bands
49
Results of Experiment of Semi Conservative Proof
1. all heavy so at bottom 2. half heavy have hybrid 3. half hybrid half light 4 quarter hybrid, rest light
50
structure of ATP
adenine, ribose pentosugar, 3 phosphate groups
51
properties of water
``` cohesion water tension high heat capacity high latent heat of vaporization used in metabolism universal solvent amphoteric low density as solid ```
52
Properties of water- cohesion
attraction between molecules | h20 sticks together so can FLOW (needed in phloem)
53
Properties of water- metabolism
used in HYDROLOSIS and produced in CONDENSATION - many reactions happen in aqueous conditions - needed in photosynthesis
54
Properties of water- as a solvent
H2O has dipole so can dissociate ions in ionic compounds | -gasses waste products, inorganic molecules DISSOLVE in water to be TRANSPORTED
55
Properties of water- Latent heat of vaporization
needs lot of energy to turn water to vapor (COOLANT) | -use as a way for organism to get rid of excess heat SWEATING
56
Properties of water- surface tension
-hydrogen bonds strong at surface molecules, allows insets to walk on water
57
Properties of water- amphoteric
is an acid (H+) and base (OH-) | BUFFER for chemical reactions, keeps constant pH
58
Properties of water- high heat capacity
needs lot of energy for an increase in temperature, allows organisms to MAINTAIN TEMPRATURE, NO SUDDEN CHANGE in temp
59
Properties of water- low density as solid
h-bonds keep molecules further in solid than liquid - ice FLOATS on water - acts as insulator to water and organisms below

Biology AQA Alevel (6 decks)

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