Biochemistry Flashcards
Key elements present in living organisms as inorganic ions
Magnesium (Mg^2+) Iron (Fe^2+) Calcium (Ca^2+) Phosphate (PO4^3-) Nitrate (NO^3-)
Magnesium
Constituent of chlorophyll (needed for photosynthesis)
Iron
Constituent of haemoglobin (needed for O2 transport in blood)
Calcium
Hardens bones and teeth
Component of plant cell walls
Phosphate
Make nucleotides (ATP, RNA, DNA)
Constituent of phospholipids
Hardens bones
Nitrate
Nitrogen from nitrate makes nucleotides (ATP, RNA, DNA)
Amino acid formation
Water (polarity, H bonds, surface tension, solvent, thermal properties, metabolite)
- Dipolar molecule
- Hydrogen bonds between water molecules
- Water molecules join together to form skin of water at skin tension
- Water is a solvent for polar molecules like salts
- Water used for transport
- Water has a high latent heat of vaporisation (requires lots of heat to change state e.g. Perspiration)
- Water has a high specific heat capacity (requires a lot of energy to raise temperature) water is stable
- anomalous expansion of water (ice less dense than water)
- chemical reactions occur in water due to transport of ions and polar molecules when particles meet
Water - What happens when sweating/perspiring?
Water has a high latent heat of vaporisation
Liquid water –energy–> water vapour
Requires a lot of energy to change state
Respiration equation
Glucose + water ==> carbon dioxide + water
Photosynthesis equation
Water + carbon dioxide ==> oxygen + glucose
Elements in Lipids
Carbon, Hydrogen, Oxygen
What happens in a condensation reaction?
Water is formed
What happens in a hydrolysis reaction?
Water is used
What is a condensation reaction?
Water is chemically removed to form a bond between adjacent monomers
What is a hydrolysis reaction?
Water chemically added to break a bond between two monomers
Elements in Phospholipids
Carbon, Hydrogen, Oxygen, Phosphorus
Elements in Amino Acids and Proteins
Carbon, Hydrogen, Oxygen, Nitrogen, (Sulphur)
Elements in Carbohydrates
Carbon, Hydrogen, Oxygen
Elements in Nucleic Acids
Carbon, Hydrogen, Oxygen, Phosphorus, Nitrogen
What are trioses?
3 Carbon sugars
What are pentoses?
5 Carbon sugars
What are hexoses?
6 Carbon sugars
What is a polymer?
A large molecule comprising of repeated, identical units (monomers) bonded together
Examples of carbohydrates
Glucose, fructose, sucrose, ribose, lactose, starch/amylose, glycogen
Monomer
Single unit sugar
Monosaccharides
1 sugar
Disaccharide
2 sugars
Polysaccharide
2+ sugars
Carbohydrates/monosaccharides rules
All Carbons in a straight line
One Carbon will have a =O bond
All other Carbons will have a -OH bond
Gaps filled with Hydrogens
Isomer
Same formula, different structure
3 types of monosaccharides
Trioses, Pentoses, Hexoses
Triose
C3H6O3
Important in metabolism
Intermediates of respiration and photosynthesis
Pentoses
C5H10O12
Constituents of nucleotides (deoxyribose in DNA, ribose in RNA,ATP,ADP)
Hexose
C6H12O6
Source of energy in respiration (e.g. Glucose)
C-H and C-C bonds broken to release energy to make ATP
Monosaccharides that make Maltose
Glucose + Glucose
Monosaccharides that make Lactose
Glucose + Galactose
Monosaccharides that make Sucrose
Glucose + Fructose
Maltose
Sugar transported in seeds
Used in beer
Lactose
Milk sugar (found in mammalian milk) Transports energy from mother to baby
Sucrose
Transported in phloem of plants
Product of photosynthesis
A hydrolysis reaction of Maltose plus water would make…
2 alpha glucose molecules
Monosaccharides used for…
Energy in respiration
To build larger carbohydrates
Disaccharides used in…
Transport of energy
Polysaccharides used in…
Structural support or storage
Starch is made of..
Alpha glucose polymerised together (same way up)
2 polymers
Amylose, a component if starch (1,4 bonds) is a helix with smaller helixes off it called amylopectin (1,6 bonds) which is also a component of starch
[alpha-glucose units joined together + 2 polymers, amylose and amylopectin]
Starch allows…
Plants to store glucose
Amylose is..
A component of starch
Amylose made of…
Helix of starch, has chains of amylopectin
Glycogen is made of…
Alpha glucose with short 1,4 and many 1,6 bonds
Has chains of amylopectin
Glycogen is…
The main storage product in animals
Found in liver (sometimes muscles)
Similar to starch but has more side chains for enzymes to attack and digest more quickly
Cellulose is..
Structural polysaccharide found in plant cell walls
A polymer of Beta Glucose
Cellulose made of…
Beta glucose (1,4 bonds) where every other Beta glucose is rotated 180 degrees resulting in a straight chain microfibre
Chitin contains CHON so is a…
Polysaccharide derivative
Chitin is a…
Structural polysaccharide found in exoskeletons of insects and fungal cell walls
Chitin contains…
CHON
(O and N found in Amide)
Double Hydrogen bonds between Amides
Alpha glucose is when…
H is above C1
Beta glucose is when…
H is below C1
Starch is…
A large molecule (transport difficult)
Insoluble
Good for plants (stays put- plant can break down for growth and energy)
Test for starch
Add iodine to starch and solution will turn from orange/brown to blue/black
Test for reducing sugars and non reducing sugars
Add Benedict’s solution to reducing sugar and heat to 80 degrees. Will turn from blue to red. If done to a non reducing sugar, negative result (stays blue). To achieve positive result, hydroxide with HCl acid then retest
Test for protein
Add Biuret solution to protein. Will turn from blue to lilac (purple)
Test for lipids (fats and oils)
Add ethanol to lipid (oil) then to water. Will turn from clear to cloudy (produces a white emulsion)
All fats are…
Lipids
Lipids contain…
CHO (mostly C and H, some O)
Fats and oils composed of…
Fatty acids and glycerol
Lipids broken down by…
Lipase
3 fatty acids plus 1 glycerol…
Triglyceride
What bond is in a triglyceride?
Ester bonds
What is an Ester bond?
O O
\ //
C
(C double bonded to O and bonded to another O)
Properties of lipids
- used as an energy reserve in plants and animals
- thermal insulator (stored under skin)
- protection (around organs)
- metabolic water source
- waterproof (insoluble- forms waxy cuticle)
- low density helps float
- nerve transmission
- steroids and cholesterol
- used in cell membrane formation (phospholipid bilayer)
Phospholipids contain…
CHOP
Triglyceride with a fatty acid replaced with a phosphate group
Basis of cell membrane
Phospholipid bilayer
Unsaturated fats have…
At least one C=C bond
Unsaturated fats are…
Good for human health (found in plants)
Saturated fats are..
Bad for human health (found in meat)
Diet of saturated fats…
Low density lipoproteins (LDL) build up- increased risk of heart disease
Diet of unsaturated fats…
More High density lipoproteins (HDL)- higher HDL:LDL ratio decreases risk of heart disease
Amino acids contain…
CHON (S)
Basic structure of an amino acid…
Amino group
R group (variable side chain of CHON(S))
Hydrogen atom
Carboxyl group
How many amino acids are in living cells?
20 or 22
Simplest amino acids?
Glycine and Valine
What is a peptide bond?
O H
\ /
C - N
(C double bond to O and bonded to a NH)
Product of amino acids reacting
Dipeptide
What are the levels of protein structure?
Primary
Secondary
Tertiary
Quaternary
What bond forms when Glycine and Valine react?
Peptide bond
What are classifications of proteins?
Globular and fibrous
What are globular proteins used for?
Enzymes, antibodies, hormones
What are fibrous proteins used for?
Keratin in hair
Structural functions
Primary protein structure
Determined by DNA
Gives type, number and sequence of amino acids in polypeptide chain
One gene codes for one polypeptide
Peptide bonds between each amino acid
Bonds in primary protein
Peptide
Secondary structure in proteins
Shape after primary
Peptide and hydrogen bonds
Hydrogen bonds twist and folds polypeptide to form an alpha helix (or a beta pleated sheet)
Bonds in secondary protein
Peptide and hydrogen
Tertiary structure proteins
Shape after secondary
Alpha helix further folded and twisted to give a 3D structure
Peptide, hydrogen, disulphide, ionic (& covalent hydrophobic) bonds
Bonds maintain active site shape
Bonds in tertiary structure
Peptide, hydrogen, disulphide, ionic (& covalent hydrophobic) bonds
Enzymes have a _____ structure
Tertiary
Bonds in tertiary structure are to…
Maintain active site shape
Quaternary structure protein
Combination of 2 or more different polypeptide chains in tertiary structure
Associated with non protein groups and form large complex molecules (e.g haemoglobin)
Haemoglobin
4 polypeptide chains
4 genes needed to code for haemoglobin (each polypeptide molecule different)
Associated with non protein groups (haem group)
Quaternary protein structure
Collagen
3 polypeptide molecules
1 gene needed to code for collagen (each polypeptide molecule the same)
Not associated with non protein groups
Secondary protein structure
Globular proteins suited to function…
Compact, folded into 3D spherical molecules
Soluble in water
Fibrous proteins suited to function…
Polypeptides in chains/sheets with cross linkages to form long fibres
Insoluble in water
Example of globular protein and its function
Haemoglobin - transports O2 to tissues
Example of fibrous protein and its function
Collagen - provided properties needed in tendons