Module 2.2 Biological Molecules Flashcards
1
Q
Calcium (Ca2+)
A
- Increases rigidity of bones, teeth and cartilage
- Component of the exoskeleton of crustaceans
- Clotting blood and muscle contractions
- Activator for enzymes e.g. lipase, ATPase and cholinesterase
- Stimulates muscle contractions
- Regulates transmission of nerve impulses
- Regulates permeability of cell membranes
- Important for cell wall development (in plants) and formation of middle lamellar between cell walls
2
Q
Sodium (Na+)
A
- Helps regulate osmotic pressure
- Helps control water levels in body fluid
- Helps maintaining pH
- Affects absorption of carbohydrates in intestine
- Affects absorption of water in the kidney
- Contributes to nervous transmission and muscle contractions
- Present in vacuole which helps maintain turgidity
3
Q
Potassium (K+)
A
- Helps control water levels in body fluid
- Helps maintain pH
- Assists active transport
- Involved in synthesis of glycogen and protein, and breakdown of glucose
- Helps keep leaves and flowers healthy
- Involved w nervous transmission and muscle contraction
- Present in vacuoles to help maintain turgidity
4
Q
Hydrogen (H+)
A
- Involved in photosynthesis
- Involved in respiration
- Involved in transport of oxygen and carbon dioxide in the blood
- Involved in regulation of blood pH
5
Q
Ammonium (NH4+)
A
- Component of amino acids, proteins, vitamins and chlorophyll
- Essential component of nuclei acids
- Involved in maintaining pH in the body
- Component in the nitrogen cycle
6
Q
Nitrate (NO3-)
A
- Component of amino acids, proteins, vitamins and chlorophyll
- Essential component of nucleic acids
- Some hormones are made out of proteins which contain nitrogen e.g. insulin
- Component in nitrogen cycle
7
Q
Hydrogencarbonate (HCO3-)
A
- Regulates blood pH
- Involved in transport of carbon dioxide in and out of the blood
8
Q
Hydroxide (OH-)
A
-Regulates blood pH
9
Q
Chloride (Cl-)
A
- Helps production of urine in the kidneys and maintaining water balance
- Involved in transport of carbon dioxide in and out of the blood
- Regulates affinity of haemoglobin to oxygen through allosteric effects on the haemoglobin molecule
- Involved in blood pH regulation
- Used to produce HCl in the stomach
10
Q
Phosphate (PO4 3-)
A
- Increases rigidity of bones, teeth and cartilage
- Component of the exoskeleton of crustaceans
- Component of phospholipids, ATP, nuclei acids + several important enzymes
- Involved in blood pH regulation
- Helps roots grow in plants
11
Q
Phospholipids
A
- Composed of glycerol and a phosphate head w 2 fatty acid tails
- Soluble head and insoluble tail in water
- Part hydrophilic, part hydrophobic
- Make up cell surface membranes
- Made up of C, H and O
- Fatty acid chains joined to glycerol w ester bonds
- Phosphate group + carbohydrate = glycolipid (used for cell signalling)
12
Q
Triglycerides
A
- Composed of a glycerol molecule and 3 fatty acid tails
- Fatty acid chains joined to glycerol w ester bonds in a condensation reaction
- The ester bonds form at 3 OH groups on glycerol - 3 water molecules released
- Made up of C, H and O
- Hydrophobic molecule (evenly distributed charge)
- Insoluble in water (means doesn’t effect water potential of cells)
- Used as energy stores by hydrolysing ester bonds breaking down CO2 and H2O to release energy
13
Q
Cholesterol
A
- Made up of C, H and O
- Make up cell surface membranes
- Hydrophobic molecule (evenly distributed charge)
- Insoluble in water
- Made up of a 4 carbon ring structure
- Vital to organisms - made by many cells
- Helps regulate fluidity
- Can build up causing heart disease and can clog arteries etc. It can be deposited in blood vessels causing atherosclerosis
- Produce steroid hormones e.g testosterone and oestrogen which can pass straight through membranes to target cells
14
Q
Lipids
A
- Solid lipid = fat
- Liquid lipid = oil
- Lipids dissolve in organic solvents e.g. alcohol but not in water
15
Q
Roles of lipids in organisms
A
- Energy source
- Energy store (lipids stored in adipose cells)
- Phospholipid bilayer
- Insulation
- Myelin sheath of neurones - electrical insulation
- Steroid hormones
- Waxy cuticle of leaves
16
Q
Glycerol
A
- C3H8O3
- Glycerol and fatty acids are both found in 2 major groups of lipids - glycerolipids (energy store/source) and glycerophospholipids
17
Q
Fatty acids
A
- All have an acid group at one end joined to a hydrocarbon chain (2-20 carbons long)
- Fatty acids are used to make up lipids
- An essential fatty acid is one that we can’t assemble ourselves
- 3 types - palmitic, stearic and oleic
18
Q
Saturated fats
A
- No double bonds in the hydrocarbon chain
- Raise cholesterol
19
Q
Monounsaturated fats
A
One C=C bond
20
Q
Polyunsaturated fats
A
2+ C=C bonds
21
Q
Are unsaturated fats more or less permeable?
A
More permeable
22
Q
What bond joins glycerol to a fatty acid?
A
An ester bond
23
Q
Haemoglobin
A
- Conjugated protein
- 4 polypeptides
- 2 alpha, 2 beta
- Prosthetic haem groups have an affinity for oxygen (each one can attract 1 oxygen molecule)
- Fe2+ ions
- Function - to carry oxygen from the lungs to tissues for aerobic respiration
- Globular - for metabolic reactions
- Primary structure - amino acids
- Secondary structure - mostly alpha helices
- Tertiary structure - alpha chains and beta chains
- Quaternary structure - 2 alpha and 2 beta chains
24
Q
Collagen
A
- Structural protein
- Fibrous
- Quaternary structure - 3 polypeptide chains tightly wound around each other
- H bonds give strength
- Every 3rd amino acid on each peptide chain is glycine - small - tiny R group - allows close packing
- Covalent bonds across peptide chains (cross linkage) helps to form a collagen fibril - staggered cross linkage adds strength
- Many fibrils make up a fibre
25
Functions of collagen (protein)
- Lines arteriole walls - prevents bursting at high pressure
- Tendons allow movement
- Bones - collagen reinforced to make them hard
- Cartilage and connective tissue
- Used in cosmetic treatments
26
Properties of collagen (protein)
- High tensile strength
- NOT elastic
- Flexible
- Insoluble
27
Comparing collagen and haemoglobin (both proteins)
Collagen:
- Fibrous
- Insoluble
- No prosthetic group
- Structural
Haemoglobin:
- Globular
- Soluble
- Prosthetic haem group
- For transporting oxygen
28
Secondary structure of proteins
- As polypeptides form, to stabilise them, they are coiled (a-helix) or pleated (ß-pleated sheets)
- These are held in place by H bonds
29
Why is the secondary structure of proteins dependant on the primary structure?
- Primary structure = unique sequence of amino acids in the protein
- Different proteins have different combinations of amino acids which each have different R groups and different properties
- Different proteins have H bonds formed in different places in the pleats/coils meaning some are more or less pleated/coiled than others
30
Tertiary structure
- 3D shape
- When coils/sheets are folded into their final shape
- Tertiary structure is 🔑 to the protein's function
31
Tertiary structure - disulfide bonds
- The amino acid cysteine contains sulfur
| - Where 2 cysteines are found close to each other, a covalent bond forms
32
Tertiary structure - ionic bonds
- The strongest 💪🏻
- R groups sometimes carry a charge (either +ve or -ve)
- When oppositely charged amino acidsare found close to each other, an ionic bond forms
33
Tertiary structure - Hydrogen bonds
-Form when slightly positively charged groups are found close to slightly negatively charged groups
34
Tertiary structure - Hydrophilic and hydrophobic interactions
- In a water-based environment, hydrophobic amino acids are most stable if they are held together w water excluded
- Hydrophilic amino acids tend to be found on the outside in globular proteins w hydrophobic amino acids in the centre
35
Globular proteins
- Ball shaped
- Soluble - the hydrophobic groups are found in the centre of the ball w hydrophilic on the outside
- For metabolic reactions
- E.g. enzymes, plasma proteins, antibodies, haemoglobin
36
Fibrous proteins
- Looks like fibres
- Insoluble
- Structural
- E.g. collagen and keratin
37
Denaturation
- Heat energy gives molecules KE
- KE makes molecules vibrate and can break bonds
- Heating proteins can break bonds in the tertiary structure
- Once the tertiary structure is lost, the protein is no longer properly functional
38
Which bond joins a glucose and a fructose unit to make sucrose?
1,4 glycosidic
39
General formula for carbohydrates
Cx(H2O)y
40
Elements that carbohydrates contain
C, H and O
41
3 types of sugar
- Hexose
- Pentose (in DNA - ribose)
- Triose
42
Maltose
a + a
43
Lactose
a + ß galactose
44
Sucrose
a + fructose
45
Cellubiose
ß + ß
46
Amylose
a + a + a and so on...
47
Cellulose
ß + ß + ß etc
48
2 sugars are joined by a what bond?
Glycosidic bond
49
Pentose
Ribose (in mRNA)
| Deoxyribose (in DNA)
50
Polysaccharides you need to know
```
Amylose
Cellulose
Amylopectin
Glycogen
Starch (amylose + amylopectin)
```
51
Amylose
1,4 glycosidic bonds
No branches
a-glucose
Spiralled
52
Amylopectin
1,4 glycosidic bonds and 1,6 glycosidic bonds
| Branched
53
Proteases
- Enzymes that break down peptide bonds
- E.g. pepsin in the stomach
- Used in digestion and to break down hormones so that their effect isn't constant
54
Elastin
- Protein
- Coiled and cross linked for strength
- Found in skin, the lungs, the bladder and blood vessels
55
Pepsin
- Single polypeptide chain
- 327 amino acids
- Symmetrical tertiary structure
- Mainly acidic R groups (stable)
56
Insulin
- 2 polypeptide chains
- a-chain begins w alpha helicies
- b-chain ends w beta
- Tertiary structure held together by disulphide links
57
Transcription
1. DNA helicase unwinds the double helix of DNA
2. Free nucleotides attach by comp. base pairing (RNA polymerase joins the nucleotides together)
3. mRNA moves away
4. The 2 strands of DNA are zipped back together
5. mRNA leaves via a nuclear pore and enters the cytoplasm
58
Translation
1. mRNA enters ribosome
2. tRNA enters the ribosome and brings a specific amino acid that corresponds to the codon on the mRNA strand
3. The tRNA anti-codon matches the mRNA codon (complimentary)
4. The amino acids join by peptide bonds
5. Polypeptide chain made
59
Functions of proteins
- Structural e.g. muscle or bones
- Carrier/channel proteins
- All enzymes
- Many hormones
- Antibodies
60
Basic structure of amino acids
- Amine group
- Acid group
- R group
61
Explain why glycogen is referred to as an energy store
- Can be hydrolysed to release a-glucose in aerobic respiration
- Polysaccharide of glucose
- Branched
62
Name the 2 parts of starch
Amylose
| Amylopectin
63
Describe the structure of a cellulose microfibril
- ß-glucose flipped 180*
| - H bonds between chains
64
What bonds hold polysaccharides together?
Glycosidic
65
Formula of pentose sugars
C5H10O5
66
a and ß glucose have different shapes but the same formula - what term is used to describe this?
Isomer
67
3 things that happen in a condensation reaction
Larger molecules form
Covalent bonds form
Water used
68
How do a glucose and b glucose differ?
a : OH below the plane of the ring
| b : OH above the plane of the ring
69
Peptidoglycan (murein)
Bacteria cell walls
70
Chitin
- Exoskeleton of insects
| - Surgical thread (strong and flexible)
71
Starch
- Found in plants
- Polysaccharide of a-glucose
- Mix of unbranched, coiled amylose and branched amylopectin
- Insoluble
- Forms grains
- Energy storage
72
Glycogen
- In animals e.g. liver and muscle cells
- Polysaccharide of a-glucose
- 1,4 and 1,6 glycosidic bonds
- Insoluble
- Forms granules
- V branched
- Shorter chains
- Energy storage
73
Cellulose
- In plants - cell wall
- ß-glucose
- Insoluble
- V strong
- Unbranched, long, straight
- 1,4 glycosidic bonds
- Structural
- Polysaccharide formed in condensation reactions
- Every ß-glucose is flipped 180* from the last to form a glycosidic bond
74
Cell walls
- H bonds form between OH groups of neighbouring chains
- Cellulose chains become cross linked to form a microfibril
- Microfibrils are held together by H bonds to form macrofibrils
75
Macrofibrils
- Embedded in pectin (polysaccharide)
- H bonds
- Criss cross structure allows water through
- Macrofibrils v strong = turgid when too much water
76
Aerobic respiration
C6H12O6 + 6O2 --> 6CO2 + 6H2O
77
Maltose and amylose
- a-glucose + a-glucose = maltose
- The same reaction thousands of times forms amylose - held together by 1,4 glycosidic bonds - spring shape - H bonds - unbranched - compact - insoluble
78
Starch
- Iodine gets caught in the spring like shape of amylose (orange -->blue/black)
- Made up of amylose and amylopectin
- Amylopectin - branches of a-glucose w 1,4 glycosidic bonds joined at the ends to another chain w 1,6 glycosidic bonds
- Store of energy - broken down into a-glucose for resp in hydrolysis reactions
79
Glycogen
- Polysaccharide
- a-glucose
- Hydrolysis reactions are used to break it down to release glucose for respiration
80
Comparing glycogen and starch
- Glycogen - 1,4, shorter, more branched, more compact
- Both insoluble
- Both store glucose in chains
81
Carbohydrates
C,H, O
Monomer- monosaccharides e.g. glucose
Polymer- polysaccharides e.g. starch
82
Proteins
C, H, O, N and S
Monomer- amino acids
Polymer- polypeptides (proteins)
83
Nucleic acids
C, H, O, N and P
Monomer- nucleotides
Polymer- DNA and RNA
84
Condensation reactions
- Link monomers
- Covalent bond forms
- Larger molecules formed
- Water released
- OH group needed
85
Hydrolysis reactions
- Covalent bonds broken
- Smaller molecules formed
- Water used
86
H bonds
- When a slightly positive and slightly negative charge come close
- Weak
- Easily broken
87
Monosaccharides
- Contain 3-6 carbons
- Small
- Soluble in water
- Sweet tasting
- Form crystals
