Topic 4: structure + function of macromolecules Flashcards
1
Q
Give the 4 biological macromolecules
A
1) Carbohydrates
2) Lipids
3) Protiens
4) Nucleic acids
2
Q
Define biomolecule
A
- Chemical molecule = structural/functional component of living organism
- Synthesis of biomolecules mostly = C + H
- Also O + N + S + P
3
Q
Define polymer
A
- Long molecule consisting of small building block = monomers
- 3/4 classes = polymers = Carbs + Proteins + Nucleic acid
4
Q
What are the subunits of the macromolecules?
A
- Monosaccharides > Carbohydrates
- Fatty acids > Lipids
- Amino acids > Proteins
- Nucleotides > Nucleic acid
5
Q
Describe the condensation reaction
A
- Dehydration reaction
- 2 monomers bond through loss of H2O = Form polymers
- Enzymes speed up dehydration
6
Q
Describe the hydrolysis reaction
A
- Reverse of condensation
- Disassembles polymer > monomer by adding H2O
7
Q
Describe carbohydrates
A
- (CH2O)n
- AKA sugars
- Monosaccharides = simple sugars
1) Glucose
2) Fructose
3) Galactose - Disaccharides = 2 monosaccharides
1) Maltose
2) Sucrose
3) Lactose - Oligosaccharides = 20-30 monosaccharides
- Polysaccharides = carb polymer
1) Starch
2) Glycogen
3) Cellulose
8
Q
Describe monosaccharides
A
- Glucose = C6H12O6 = most common
- Fuel for cells + raw material for building
- Classified by = location of carbonyl group + number of carbons in skeleton
- If C=O at end of sugar = aldose
- If C=O middle of sugar = ketose
- Linear but may form rings in aqueous solution
9
Q
Describe disaccharides
A
- Formed by condensation reaction to join 2 monosaccharides = covalent bond = glycosidic linkage
- Glucose + glucose = maltose
- Glucose + galactose = lactose
- Glucose + fructose = sucrose
10
Q
Describe polysaccharides
A
- Have storage + structural roles
- These are determined by monomers + position of glycosidic linkages
- Starch + Glycogen = made of glucose + for storage
- Cellulose + Chitin = structural
11
Q
What are the 2 glycosidic linkages?
A
1) α-linkage = OH group of C2 same side as OH group on C1
2) β-glucose = OH group on C2 different side than C1
- α = helical
- β = linear
12
Q
Describe starch
A
- Storage of glucose in plants
- Plants store excess starch in chloroplasts + amyloplasts
- 2 polysaccharides = amylose + amylopectin
- Amylose = 1-4 glycosidic linkage = unbranched
- Helical due to α-linkage
- Amylopectin = 1-4 + 1-6 glycosidic linkage = branched
13
Q
Describe glycogen
A
- Storage of glucose in animals
- Animals/humans store glycogen in liver + muscle cells = cytosolic granules
- α-glucose = helical
- Has 1-4 + 1-6 glycosidic linkage = branched = enzyme accessible
14
Q
Describe cellulose
A
- Component of plant cell wall
- Unbranched β-glucose polymer = linear
- Humans can not digest = passes through digestive tract as insoluble fiber
- Herbivores = symbiotic relationship with microbes in stomach to break down cellulose
15
Q
Describe chitin
A
- Component of exoskeleton of arthropods + fungal cell walls
- Used to make surgical thread
- β - glucose = linear
16
Q
Describe lipids
A
- Doesn’t have polymers
- Hydrophobic = consist if hydrocarbons = non-polar covenant bonds
- Fats + Phospholipids + Steroids
17
Q
Describe fats
A
- Triglycerides = storage = 1 glycerol 3 fatty acids
- Hydrophobic
- Condensation reaction between glycerol + each fatty acid= ester linkage
- Function = energy storage
- Humans store fat in adipose cells = adipose tissue cushions vital organs + insulates body
18
Q
Describe fatty acids
A
- Structure = R-COOH
- R = long hydrocarbon chain
- Fatty acids differ in length + number/location of double bonds
- Saturated > no =
- Unsaturated > 1 or more =
SATURATED: - Max amount of H
- CH3(CH2)nCOOH
- Mostly found in animals
- Solid at room temp = butter
- Diet rich in saturated fats = contribute to CVD = plaque deposits
- Directly increase LDL bound bad cholesterol
UNSATURATED: - Found in plants + fish
- Liquid at room temp = oil
- Signals liver = take up cholesterol from blood = improve cholesterol levels
- Reduce LDL bound bad cholesterol + maintain HDL good cholesterol
19
Q
Describe phospholipids
A
- Have phosphate group instead of 3rd fatty acid
1) Phosphoglyceride = glycerol + 2 fatty acid + phosphate + organic molecule
2) Phosphospingolipids = sphingosine + 1 fatty acid + phosphate + organic molecule - Function = components of biological membranes
- Amphipathic molecule = hydrophilic head + hydrophobic tail
20
Q
Give some common membrane phospholipids
A
- Phosphatidyl-choline = glycerol + choline
- Phosphatidyl-ethanolamine = glycerol + ethanolamine
- Phosphatidyl-serine = glycerol + serine
- Phosphatidyl-inositol = glycerol + inositol
- Sphingomyelin = sphingosine + choline
21
Q
Describe the bilayer
A
- When phospholipids exposed to water = assemble in bilayer = hydrophobic tails interior and hydrophilic heads exterior
- Found in cell membranes = main component
22
Q
Describe steroids
A
- Lipids made of carbon skeleton of 4 fused rings
- Cholesterol = steroid in animal cell membrane + precursor for hormones
- Steroid hormones = androgens + estrogens
23
Q
Describe health risks of cholestrol
A
- High level in blood = CVD
- In blood bound to lipoproteins = low density / high density
- Lipoproteins recognized by receptor on plasma of liver cells = cholesterol released into liver via receptor-mediated endocytosis
- HDL bound cholesterol = good = protein > cholesterol = travels fast in blood + deposited directly to liver
- LDL bound cholesterol = bad = cholesterol > protein = travels slow in blood = leaves pieces around = plaque
24
Q
Describe proteins
A
- 50% dry mass of cells
- Functions= structural support + storage + transport + cellular communication + movement + defense against foreign substances
- Polypeptide = polymer of amino acids
- Protein = 1> polypeptides = each has unique linear sequence of amino acids
- Amino acids linked by covalent bond = peptide bond between carbonyl of 1 + amino of other via condensation reaction
25
Q
Define enzyme
A
- Protein that acts as catalyst = speed up chemical reactions
26
Q
Describe amino acids
A
H
NH3-C-COOH
R
- Have carboxyl group + amino group
- Different properties due to differing R groups
- 3 types = non-polar + polar + electrically charged
27
Q
What are the non-polar amino acids?
A
- Gly
- Ala
- Val
- Leu
- Ile
- Met
- Phe
- Trp
- Pro
28
Q
What are the polar amino acids?
A
- Ser
- Thr
- Cys
- Tyr
- Asn
- Gln
29
Q
What are the electrically charged amino acids?
A
ACIDIC
- Asp
- Glu
BASIC
- Lys
- Arg
- His
30
Q
Describe protein structure + function
A
- Machines can determine structure = X-ray crystallography
- Functional proteins contain more than 1 polypeptide
- Sequence of amino = 3D structure = function
- Primary structure = unique sequence of aminos
- Secondary structure = either coiling / folding of polypeptide chain = α-helices / β-pleated sheets
- Tertiary structure = 3D structure determined by interaction in R group
- Quaternary structure = multiple polypeptides bind
31
Q
What types of interactions take place in the tertiary structure?
A
- Disulphide bonds = between 2 S in S-H groups in R group
- H-bonds
- Van der Waals
- Ionic
- Hydrophobic
32
Q
Explain protein folding chaperones
A
- Proteins go through several intermediate states = stable conformation
- Chaperonins = proteins that assist + maintain folding of proteins
- Location = cytosol + mitochondria + ER
33
Q
Explain sickle cell disease
A
- Slight change in primary structure = affects protein structure + ability to function
- Inherited blood disorder
- Due to substitution of a single amino in haemoglobin in RBC
- Shape deformed = unable to carry oxygen
34
Q
Describe haemoglobin
A
- Globular protein = 4 polypeptides = 2 alpha + 2 beta
35
Q
Explain protein conformation
A
- Conformation depends on physical + chemical environment of protein
- Denature = loss of conformation due to unraveling = loss of function = biologically in active
DENATURE FACTORS - pH change
- Salt concentration change
- Temp change
36
Q
Describe nucleic acids
A
- Store + transmit hereditary info
- Nucleotide structure = phosphate group + pentose sugar + nitrogenous base
- Nitrogenous bases = A G C T/U
- Sugars = deoxyribose/ ribose
- Polymer = polynucleotide = goes from 5’ to 3’
- Connected with a phosphodiester bond = OH 3’ + phosphate 5’
2 TYPES:
1) Deoxyribonucleic acid = DNA - Stores info for protein synthesis
- Directs RNA synthesis
- Directs protein synthesis through mRNA
2) Ribonucleic acid = RNA
37
Q
Define gene
A
- Unit of inheritance
- Amino acid sequence for polypeptide
- Made of DNA = nucleic acid
38
Q
Describe a DNA double helix
A
- 2 anti-parallel polynucleotide strands = double helix
- Strands run in opposite directions = 5’>3’ + 3’>5’
- Held together by H-bonds between bases
- Sugar+phosphate backbone
- Complementary base pairs = AT + CG
39
Q
Explain DNA replication
A
- Copy all DNA molecules into a 2nd set
- Required before cell division
- 2 strands separate = H-bonds break = each stand is template for complementary copy
