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AS Biology > Biological Molecules > Flashcards

Biological Molecules Flashcards

(55 cards)

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1
Q

What’s covalent bonding

A

Atoms share a pair of electrons in their outer shells so both of them are filled resulting in a more stable compound being formed called a molecule

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2
Q

What is ionic bonding

A

Ions with opposite charges attract one another through electrostatic attraction

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3
Q

What is hydrogen bonding

A

The electrons within a molecule are not evenly distributed but tend to spend more time at one position. This region is more negatively charged than the rest of the atom so is a polar molecule. The negative region of one atom is attracted to the positive region of another.

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4
Q

What’s a polymer

A

Long chains of monomer sub units bonded together

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5
Q

What are monomers

A

A single uni that can be bonded together to form a polymer

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6
Q

What’s a condensation reaction and examples

A

When monomers are joined together and water is formed. Reactions that produce water in this way are condensation reactions e.g polypeptide from amino acids or polysaccharide from monosaccharides

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7
Q

What’s a hydrolysis reaction

A

A condensation reaction is breaking apart monomers by the addition of water called hydrolysis

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8
Q

What is metabolism

A

All the chemical reactions that take place in living organisms are called metabolism

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9
Q

What is a monosaccaride

A

A single sugar unit

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10
Q

Properties of monosaccharides

A

Sweet tasting
Soluble
General formula of (CH2O)n where n can be between 3 and 7
Made of carbon oxygen and hydrogen only

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11
Q

What is the formula for glucose

A

C6H12O6
Two types alpha and beta
Hexose

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12
Q

What is a reducing sugar

A

All monosaccharides and some disaccharides e.g maltose

A reducing sugar is one that can donate electrons to another chemical e.g Benedicts reagent

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13
Q

Benedicts reagent test

A

Add reagent to sample
Heat
Turns from blue to red/orange/yellow/green

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14
Q

What kind of results does benedicts reagent give and explain the colour changes

A

Semi quantitative

Blue to green yellow orange then red

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15
Q

What are disaccharides

A

Two monosaccharides joined together through a condensation reaction to form a glycosidic bond.
Hydrolysis breaks the bond and the disaccharides into the monosaccharides

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16
Q

What monosaccharides make up maltose

A

Glucose and glucose

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17
Q

What forms sucrose

A

Glucose and fructose

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18
Q

What forms lactose

A

Glucose and galactose

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19
Q

What’s the test for non reducing sugars

A

Add 2cm3 of test subject to 2cm3 benedict reagent
Heat in water bath
If colour doesn’t change it’s a non reducing sugar
Add hydrochloric acid to another fresh 2cm3 of sample to hydrolyse the bonds
Place into water bath for a further 5 minutes
Add sodium hydrogencarbonate to neutralise the solution
Add Benedicts and heat
Should now give a positive result

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20
Q

What’s the test for starch

A

Iodine goes from yellow to blue black

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21
Q

What’s starch made of

A

Alpha glucose molecules formed by condensation reactions and joined by glycosidic bonds

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22
Q

How is starch suitable for energy storage

A

Insoluble doesn’t affect water potential and doesn’t get drawn into cells by osmosis.

Long chain doesn’t diffuse out of cells

Helix shape means its compact so can be stored in a small space

Branched form has many ends so easy for enzymes to break off glucose monomers for respiration

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23
Q

Where is glycogen found

Study These Flashcards
A

Animals and vacteria cells

24
Q

What’s the structure of glycogen

Practice drawing a single molecule

Study These Flashcards
A

Similar to starch but with more branched ends so it can be acted on simultaneously by enzymes so can break off glucose monomers more rapidly used in respiration. Animals have a higher metabolic rate and therefore respirator rate than plants

25
Why does glycogen structure suit storage
Insoluble doesn't draw water into the cells by osmosis and doesn't diffuse out of cells Compacts so can be stored in a small space Alpha glucose
26
What's the structure of cellulose
Made of beta glucose Straight unbranched chains Hydrogen bonds between straight branches Huge quantity of h bonds make the structure very strong
27
What are the cellulose molecules called
Microfibrils
28
What's the purpose of cellulose in plants
Cell walls- provides rigidity Prevents osmotic bursting of the cell Keeps living plant cells turgid and provide maximum surface area for photosynthesis
29
How do fibres and microfibrils link
Microfibrils bunch together to make fibres
30
What are the roles of lipids
Source of energy Lipids are insoluble so used to conserve water in cuticles of plants Insulation- fats are slow conductors of heat so insulate and retain body heat Protection- fat stored around organs
31
What's a triglyceride made of
Glycerol and three fatty acids Esther bond
32
Structure of triglycerides related to their properties
High ratio of energy storing carbon hydrogen bonds so good energy store Low mass to energy ratio so good storage molecules Large and non polar so are insoluble so doesn't affect water potential Release water when oxidised so help organisms living in desert
33
Phospholipid structure
Same as lipid with a phosphate replacing one fatty acid Hydrophobic tail of fatty acid Hydrophilic phosphate Polar molecule
34
How does the structure of phospholipids relate to their fundtuon
Polar molecule (hydro phobic and philic) means in aqueous environment form a bilayer between cell surface membranes
35
Test for lipids
``` Dry test tube Add 2cm3 sample and 5cm3 of ethanol Shake to dissolve any lipid in sample Add 5cm3 of water and shake gently Cloudy white colour indicates presence of lipid ```
36
Structure of an amino acid | Practice drawing it
``` C in centre Amino NH3 H Carboxyl C =O and OH R group ```
37
What's bind between amino acids
peptide
38
Primary structure of proetein
Polypeptide chain | Glycosidic bonds
39
Secondary structure
Alpha helix Or beta pleated sheets Hydrogen bonding
40
Tertiary structure
Alpha helices folded even further Disulphide bond Ionic bond between carboxyl and amino groups Hydrogen bond
41
Quaternary structure
Contains a number of polypeptide chains | Non proteins groups in there associated with the molecule
42
Test for proteins
Biuret test Sample of solution in test tube equal volume of sodium hydroxide in Add few drops dilute copper sulfate solition Purple colour indicates peptide bonds present
43
Enzyme structure
Globular protein Specific 3D shape determined by amino acid order Active site
44
What's the induced fit model
The active site forms as it comes into contact with the substrate. Proximity of substrate leads to a change in enzyme that forms functional active site. Enzyme moulds itself to fit the substrate from original general shape
45
Define competitive and non competitive inhibitors
Competitive- bind to active site of enzyme and can be reversed by adding more substrate Non - bind to enzyme at point other than active site
46
What's a nucleotide made up of
Phosphate | Deoxyribose Pentose sugar backbone and nitrogenous base
47
What bond is between nucleotides
Phosphodiester
48
RNA structure
Single (allow bond to ribosomes) relatively short made of nucleotides Pentose sugar always ribose Uracil instead of thymine
49
DNA structure
``` Double helix Pentose sugar is deoxyribose Long strands joined together by hydrogen bonds between bases Complementary base paring Phosphodiester backbone Antiparallel ```
50
What's atp used for
``` Metabolic processes Movement Active transport Secretion Activation of molecule ```
51
Eukaryotic cell structure - section 3
Needs to be done
52
How does structure of dna help function
Deoxyribose pentose sugar backbone gives strength Cooling of double helix means compact and stable Long large amount of info stored Complementary base pairing allows information to be replicated
53
How mutations effect proteins
Change dna bases Amino acid sequence changed Change in h and ionic bonds Tertiary structure altered so specific 3D shape not same
54
What’s a triplet code in proteins
each amino acid coded for by 3 bases some amino acids have more than one code (degenerate) Code doesn’t overlap and some bases act as stop codons Code is universal
55
What’s semi conservative replication
New molecules formed have one old strand and one new strand

AS Biology (17 decks)

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