1A - Biological Molecules Flashcards
What are polymers?
- large complex molecules
- long chains of monomers joined together
What are monomers?
- small, basic molecular units
Name 3 examples of monomers
- Monosaccharides
- Amino acids
- Nucleotides
What are Carbohydrates made from and what elements do they contain?
- Monosaccharides
- Carbon (C), Hydrogen (H) and Oxygen (O)
Name 3 main monosaccharides
- Glucose
- Fructose
- Galactose
What is glucose?
- a hexose sugar (contains six carbon atoms)
Alpha and beta glucose are isomers. What are isomers?
- molecules with the same molecular formula as each other but atoms are connected in different ways
What is a condensation reaction?
- two molecules join together by a new chemical bond
- water molecule is released
What type of bond forms in condensation reaction?
- Glycosidic
What is a disaccharide?
- Two monosaccharides joined together
A glucose molecule and a fructose molecule join together to make what?
- Sucrose
A glucose molecule and a galactose molecule join to make what?
- Lactose
Two glucose molecules join to make what?
- Maltose
What is a hydrolysis reaction?
- where polymers are broken down into monomers
- water molecule is added and breaks the chemical bond
What are polysaccharides?
- more than two monosaccharides joined together
Starch is a mixture which two polysaccharides?
- Amylose
- Amylopectin
What is the structure of amylose?
- long, unbranched chain of alpha glucose
- coiled structure
- compact (good for storage)
What is the structure of amylopectin?
- long, branched chain of alpha glucose
- side branches allow enzymes to break down glycosidic bonds easily
What at the properties of starch?
- insoluble in water (hydrophobic)
- doesn’t affect water potential
- they can swell up (good storage)
What do animals store excess glucose as?
- Glycogen
What is the structure of glycogen?
- similar to amylopectin but loads more side branches
- side branches release glucose quickly
- compact molecule
Where would you find cellulose in a plant?
- Cell wall
What is the structure of cellulose?
- long, unbranched chains of beta glucose
- linked together by hydrogen bonds called microfibrils
- microfibrils provide structural support
What is the structure of a triglyceride?
- one molecule of glycerol with 3 fatty acids attached to it
How are triglycerides formed?
- Condensation reactions
(ester bonds form between three glycerol molecules) - water is released each time
What do the terms hydrophobic and hydrophilic mean?
- HydroPHOBIC means it’s insoluble in water
- HydroPHILIC means it’s soluble in water
What is the difference between saturated and unsaturated fats?
- Saturated fats do NOT have any double bonds between carbon atoms
- Unsaturated fats have double bonds between carbon atoms
What is the difference between the structures of triglycerides and phospholipids?
- One of the fatty acid molecules in a triglyceride is replaced by a phosphate group
What are the properties of triglycerides?
- hydrocarbon tails contains a lot of chemical energy
- insoluble (don’t affect water potential)
- causes osmosis
What are the properties of phospholipids?
- make up bilayer of cell membranes
- heads are hydrophilic and tails are hydrophobic - form double layer
- water-soluble substances can’t easily pass through it
What is a dipeptide?
- Two amino acids joined together
What is a polypeptide?
- More than two amino acids joined together
What are the different groups in the structure of amino acids?
- Carboxyl group (COOH)
- Amino group (H2N)
- Variable/carbon containing group (R)
In a condensation reaction, what type of bond is formed between two amino acids?
- peptide bonds
What is the primary structure of a protein?
- sequence of amino acids in the polypeptide chain
What is the secondary structure of a protein?
- hydrogen bonds from between the amino acids
- coil into a helix or fold into a pleated sheet
What is the tertiary structure of a protein?
- coiled or folded further
- more hydrogen and ionic bonds form
- 3D structure
What is the quaternary structure of a protein?
- several different polypeptide chains held together by bonds
- final 3D structure
What are the 4 different functions of proteins?
- Enzymes
- Antibodies
- Transport
- Structural
What are enzymes?
- speed up chemical reactions acting as catalysts
- spherical in shape
- soluble
- have roles in metabolism
What are antibodies?
- immune response
- two light polypeptide chains
What are transport proteins?
- contain hydrophobic and hydrophilic amino acids
- transport molecules and ions across membranes
What are structural proteins?
- physically strong
- long polypeptide chains lying parallel and form cross links
How do enzymes lower the activation energy?
- make reactions happen at lower temperatures
- speeding up the rate of reaction
Why do scientists prefer the ‘induced fit’ model than the ‘lock and key’ model?
- new studies showed the enzyme-substrate complex slightly changed shape to completely fit
What are the properties of an enzyme?
- very specific (only one complementary substrate can fit into an active site)
- tertiary structure of the enzyme determines the active site’s shape
- tertiary is determined by primary structure
- primary structure is determined by a gene
What are the 5 factors that can affect enzyme activity?
- Temperature
- pH
- Enzyme concentration
- Substrate concentration
- Inhibitors (competitive and non-competitive)
How does an enzyme become ‘denatured’?
- active site changes shape
- enzyme and substrate can no longer fit together
How does temperature affect enzyme activity?
- more kinetic energy, so molecules faster
- enzymes are more likely to collide
- heavy vibrations causes bonds in enzyme to break if it’s too high
What is the difference between competitive and non competitive inhibitors?
- competitive bind to the active site
- non competitive bind to the enzyme away from active site, causing it to change shape
