3.1 Chapter 1- Biological Molecules Flashcards
(150 cards)
What is indirect evidence for evolution?
- All life on Earth shares a common chemistry. This provides indirect evidence for evolution, as it suggests all life has a common ancestor.
- Despite the extensive variety of life and the great variety of cells, the cells of all living organisms contain only a few groups of carbon-based organic compounds that interact in similar ways.
- The variety of life, both past and present, is extensive, but the biochemical basis of life is similar for all living things.
Why is the biochemical basis of life similar?
- Based on carbon atoms- organic.
- Contain versatile bonds that readily link with each other and form chains or backbones along which other atoms can be added. This permits a large number of different types of molecules based on carbon.
- Few other atoms attach to carbon so life is therefore based on a small number of chemical elements.
What are all molecules made up of?
- Atoms
What are the different types of bonding?
- Covalent bonding- atoms share a pair of electrons in their outer shells- results in the outer shell being filled and more stable compounds- molecules being formed.
- Ionic bonding- ions with opposite charges attract one another- electrostatic attraction.. Weaker than covalent bonds.
- Hydrogen bonding- electrons within a molecule tend to spend more time in one position- more negatively charged than the rest of the molecule. The negative region of one polarised molecule and the positively charged region of another attract each other. Weak electrostatic bonds are formed between the two. Although each bon dis individually weak, they collectively form important forces that alter the physical properties of molecules- especially water.
What is a molecule with an uneven distribution of charge called?
Polarised- it is a polar molecule.
Define a monomer and give examples.
- A smaller repeating unit/ molecule from which larger molecules/ polymers are made.
- Monosaccharides, amino acids and nucleotides.
Define a polymer.
- Polymers are molecules made from a large number of monomers joined together.
- A chain of many monomers joined together by bonds. e.g. amino acids forming proteins with peptide bonds.
How are polymers formed?
- Monomers are linked together into chains of monomers through polymerisation.
- Monomers are usually carbon-based as they readily form chains.
- Some are industrially produced such as polyesters, but some are naturally produced such as polysaccharides, polypeptides and polynucleotides.
Give examples of how polymers are formed by monomers.
- Amino acids- condensation reaction- polypeptide, protein, enzyme, antibody- peptide bond.
- Nucleotide- condensation reaction- polynucleotide- DNA or RNA- phosphodiester bond.
- Alpha glucose- condensation reaction- starch/ glycogen- glycosidic bond.
- **Beta glucose- condensation reaction- cellulose- glycosidic bond. **
- Must specify type of glucose.
- **Must specify bonds formed. **
- **You may have to identify monomer structures and from that the polymers formed e.g. identify an amino acid and that it is a monomer in an enzymes active site- simple box fill activities usually. Just be careful to label as you go through. **
What must you remember to mention when talking about polymers?
The bonds e.g. glycosidic, phosphodiester
Define a condensation reaction.
- The joining of two molecules/ monomers together forming a chemical bond and eliminating or releasing a molecule of water.
- Helps to form polymers in polymerisation.
- Every time a bond is formed water is released.
- You may be asked to draw the structure of a molecule after a condensation reaction has occurred- remember water is lost.
- You may be asked to find the formula of a molecule once a condensation reaction has occurred- look out for hidden condensation reaction- **a water molecule is lost each time a bond is formed so remember to subtract that- may not be obvious. **
Define hydrolysis
- The breaking of a chemical bond between two molecules/ monomers using a water molecule.
- Used to break down polymers into monomers/ molecules.
What is metabolism?
The metabolisim is all the chemical processes that take place in living organisms.
What is a metabolic reaction?
Chemical process that occurs within living organisms to maintain life- transformation of nutrients and other substances to produce energy and build cellular components.
What is the metabolic rate?
Rate at which energy is used in an organism.
What is a metabolic pathway?
Series of small reactions taking place in an organism usually controlled by enzymes.
What are moles?
- The mole is the SI unit for measuring the amount of a substance. Abbreviated to mol.
- One mole contains the same number of particles as there are in 12g of carbon 12 atoms.
- This number is Avogadro’s constant- 6.022 x 1023.
- A molar solution is a solution that contains one mole of solute in each litre of solution.
- Moles are the molecular mass expressed as grams.
- E.g. Sodium has an atomic weight of 23 while chlorine has 35.5. The molecular mass of sodium chloride is therefore 58.5.
- One mole of sodium chloride is therefore 58.5 grams.
- 1 mole of solution of sodium chloride is 58.5 grams in one litre of solution.
What are the monomers of carbohydrates?
- Monosaccharides are monomers from which large carbohydrates are made.
What are the features of monosaccharides?
- Soluable
- Sweet tasting
- General formula (CH2O) n
- Reducing sugars
- Common monosaccharides are glucose, galactose and fructose.
What type of molecules are monosaccharides?
Made from only carbon, oxygen and hydrogen.
What is the general formula of a monosaccharide?
(CH2O) n
What is another name for hexose?
Glucose
Name the each monosaccharides from 3 to 7 carbons.
3- triose
4- tetrose
5- pentose
6- hexose= glucose
7- heptose
What is the name for a bond between a monosaccharide?
Glycosidic bond- formed in a condensation reaction between two monosaccharides.