Chapter 1- Biological Molecules Flashcards
What is covalent bonding?
Atoms share a pair of electrons in outer shell
Outer shell of both atoms are filled and more stable
What is ionic bonding?
Ions with opposite charges attract one another
Electrostatic is known as ionic bond
Weaker than covalent bond.
What is hydrogen bonding?
Electrons within a molecule are not evenly distributed but spend more time at one position . This region is more negatively charged than the rest. Molecule with uneven distribution of charge is a polar molecule. Negative region attracts positive region. A weak electrostatic bond is formed . Individually weak but collectively form important forces that alter physical experience.
What is a condensation reaction?
Each time a new sub unit it attached to the polymers a molecule of water is formed.
What is hydrolysis?
Through addition of water, the bonds linking sub units break, thereby splitting molecule into its constituent parts
What is metabolism?
All chemical processes that take place in living organisms
What are most polymers made of?
Carbon
Hydrogen
Oxygen
Nitrogen
What is the basic monomer of carbohydrates?
Sugar known as a saccharide
What is a monosaccharide, and what is it’s general formula?
Examples of monosaccharides?
Sweet tasting soluble substances
(CH2O)n
N =3-7
Glucose galactose fructose
What is glucose?
What is its formula?
How many isomers does glucose have?
Hexose sugar
C6H12O6
Alpha glucose
Beta glucose
What is the difference between alpha glucose and beta glucose?
Alpha - H at top
Beta -OH at top
Glucose joined to glucose forms?
Glucose joined to fructose forms?
Glucose joined to galactose forms?
Maltose
Sucrose
Lactose
What bond is formed when a condensation reaction occurs?
What breaks the glycosidic bond?
Glycosidic bond
Hydrolysis
Why are polysaccharides suitable for storage?
What happens when polysaccharides are hydrolysised ?
Large molecules, that are insoluble
Break down into disaccharides or monosaccharides
Where is starch found in?
Why is it important?
Plants in the form of small grains found in storage organs
Forms major component of food/major energy source
Formation of starch chains?
Made from alpha glucose
Can be branched or unbranched
The unbranched chain is wound into a tight coil and makes a molecule very compact
Why is starch’s structure suited for its function? Give five examples?
- Insoluble doesn’t affect water potential so water is not drawn into the cells by osmosis
- Large insoluble doesn’t diffuse out of cells
- Compact, a lot can be stored in small spaces
- When hydrolysed forms alpha glucose which can easily be transported and used in respiration
- Branch form has many ends can be acted by enzyme simultaneously glucose monomers are released rapidly
Where is starch never found in?
What Is found in the cells instead?
Animal cells
Similar polysaccharide glycogen
Where is glycogen found?
What is the structure of glycogen?
What does it do for animals?
Where is it mainly stored?
Animal bacteria cells
Shorter chains more highly branches
Major carbohydrate storage product
Why is the mass of carbohydrate stored relatively small?
Fat is the main storage molecule in animals
Why does glycogen structure suit its storage?
Give 4 examples?
Insoluble doesn’t draw water in by osmosis
Insoluble doesn’t diffuse out of cells
Compact
More highly branched more ends can be acted on by enzymes releasing of glucose molecules used in respiration
What happens in glycogen when enzymes act on the branches?
Rapidly broken down to form glucose monomers used in respiration. Important to animals which have a higher metabolic rate and respiratory rate than plants
Why is cellulose different to starch and glycogen?
Made of monomers of beta glucose which produces fundamental differences in structure and function,
What is the formation of cellulose?
When cellulose is grouped what does it form?
Straight unbranched that run parallel to one another allowing hydrogen bonds to form cross linkages between adjacent chain.
Overall number of hydrogen bonds strengthens cellulose
Microfibrils arranged in parallel groups called fibres
Why is cellulose a major component of a plant cell?
How the cellulose wall prevent bursting?
Provides rigidity to plant cell, prevents cell from bursting when water enters it by osmosis.
Exerting inward pressure that stops any further influx of water= living plant cells are strong important in maintaining leaves and stems to provide maximum surface area for photosynthesis
How does cellulose suites to its structure?
Beta glucose form long straight unbranched chains
Chains run parallel to each other and are crossed linked by hydrogen. Bonds adds to strength collectively
Grouped to form microfibrils in turn form fibres provides more strength
What do all lipids have ?
-Contain Carbon, hydrogen and water
What is the role of lipids?
What are the two main groups of lipids?
In the cell membrane
Triglycerides and phospholipids
What does phospholipids contribute to the membrane?
They contribute flexibility of membranes and transfer of the lipid-soluble substances across them
Name four roles of lipids?
Source of energy
Waterproofing
Insulation
Protection
How does lipids play a role in energy?
When oxidised lipids provide more than twice the energy as the same mass of carbohydrates and release valuable water
How do you lipids waterproof plants?
Insoluble in water so with plants and insects have waxy lipid cuticles that conserve water
How do you lipids insulate?
Fat are slow conductors of heat and when stored beneath the body surface help to retain body heat
And example is they also act as electrical insulator in the name myelin sheath around nerve cells
What are triglycerides and what is the formation?
They have three fatty acid’s combined with a glycerol. Each fatty acid forms an ester bond with glycerol in a condensation reaction
What is the difference in all triglycerides?
What do you all fatty acids contain?
All glycerol molecules are the same but there is a variation in the fatty acids Carbonyl group (— COOH) with hydrocarbon chain attached
When is the fatty acid described as saturated?
What is it meant by mono-unsaturated?
If the chain has no carbon-carbon double bonds because all the carbon atoms are linked to the maximum number of hydrogen atoms , saturated with hydrogen
When there is a single double bond
Why is triglyceride a good source of energy ?
High ratio of energy storing carbon-hydrogen bonds to carbon atoms
Why are triglycerides good storage molecules?
Low mass to energy ratio, much energy can be stores in a small volume
Beneficial to animals as it reduces the mass they have to carry
Why are triglycerides insoluble?
Large non polar molecules
Storage doesnt affect omosis in cels or water potential of them
What is the difference between phospholipids and triglycerides?
One fatty acid molecule is replaced by a phosphate molecule
Difference between phosphate molecule and a fatty acid?
Fatty acids repel water
Phosphate molecules attract water
What is the scientific name for attracted to water and repels from water?
Hydrophilic head
Hydrophobic tail
Molecules with two ends are called?
When phospholipids are placed in water what happens?
Polar
Are placed in water they position themselves so that hydrophilic heads are closer to the water as possible and hydrophobic tails are far away
What do phospholipids form in an aqueous solution?
A bilayer within cell surface membrane
A hydrophobic barrier is formed between the inside and outside of a cell
What part of the phospholipids help hold the surface of the cell membrane?
The hydrophilic head
How are glycolipids formed by phospholipids?
Phospholipids structure forms glycolipids by combining carbohydrates within the cell surface membrane
