Biology Unit 1 Booklet 3 Biomolecules, Enzymes and Digestion Flashcards
Monomers to a polymer
Condensation reactions
Atoms made up of carbon, hydrogen, oxygen and sometimes nitrogen ( held together by covalent bonds )
Carbohydrates
Proteins
Lipids
Nucleic acids
Polymer to a monomer
Hydrolysis reaction
Carbohydrate contain the elements
Hydrogen
Carbon
Oxygen
Carbohydrates include sweet tasting soluble sugars such as
Glucose
Sucrose
Lactose
Carbohydrates include large polymers such as
Starch
Cellulose
Glycogen
General formula of a monosaccharide
(CH2O) n
Glucose is a _____________ sugar with the formula _______________
Hexose sugar
C6 H12 O6
Glucose has many isomers but the two most important ones are
Alpha glucose
Beta glucose w
Difference between alpha and beta glucose
The OH and the H atoms on carbon 1 are switched
Alpha glucose polymerises into
Starch
Beta glucose polymerises into
Cellulose
Test for reducing sugars
Benedict’s test
Food sample dissolved in water
Equal volume of Benedict’s reagent
Heat in water bath. If present, solution turns from blue to orange brown
Glucose linked to glucose forms
Maltose
Glucose linked to fructose forms
Sucrose
Glucose linked to galactose forms
Lactose
When water is lost in a condensation reaction a _______________ bond is formed
Glycosidic bond
Test for non reducing sugars
Heat with Benedict’s and see no colour change
Boil fresh sample with dilute HCl and then neutralise with NaHCO3
Reheat with Benedict’s and obverse colour change, blue to orange red
Three common polysaccharides
Starch
Cellulose
Glycogen
Polysaccharides general formula
( C6 H 10 O5) n
Starch is found in
Many parts of plant in the form of grains and granules
Starch consists of
200-100000 alpha glucose molecules joined by glycosidic bonds
Test for starch
Add iodine solution to sample
Look for colour change from brown to blue black
Glycogen is most abundant in
Liver and muscle cells
Glycogen is found as _____________ in the cytoplasm
Insoluble granules in the cytoplasm
Cellulose major component in plant cell walls because
String stable structure
Cellulose consists of thousands of _____________ glucose molecules forming ____________ chains with ____________ bonds forming linkages between them
Beta glucose
Linear chains
Hydrogen bonds
Proteins contain the elements
Carbon Hydrogen Oxygen Nitrogen Sulphur
Protein are polymers of
Amino acids
The number of naturally occurring amino acids
20
Two amino acids join by condensation to form
Di peptide
The bond between amino acids is called a
Peptide bond
A chain of many amino acids is a called
Polypeptide
The primary structure if protein structure
Linear chains of amino acid
Peptide bonds
Mae by ribosomes
Condensation
The secondary structure of protein folding is
Alpha helix and beta pleated sheets
Hydrogen bond between hydrogen and oxygen
Folding depended son type of R group present
The tertiary structure of protein folding
Folds into specific 3D globular structure
Disulphide bonds
Ionic bonds
Fibrous globular
The quaternary structure of protein folding is
More than 1 polypeptide chain joins together
More complex
E.g. Haemoglobin
The three types of proteins are
Fibrous protein which are long rope like structure to build materials such keratin and collagen
Globular protein which are metabolically active molecules such as ligaments and antibodies
A range of proteins are also found in membranes
Several bonds stabilise protein structure
String peptide bonds- linking amino acids chains Weak but numerous hydrogen bonds Ionic bonds Hydrophobic interactions Occasional very strong disulphides bonds
Some types of bond are easily affected by
Heat
PH
Other factors
Test for proteins
Biuret test
Add an equal volume of NaOH to the sample at room temperature and a few drops of CuSO4
Look for colour change from blue to lilac which indicates a peptide bond
Digestion takes place in two stages
Physical breakdown
Chemical digestion main features if the digestive system
Main feature of digestive system
Oesophagus Stomach Small intestines Large intestines Rectum Salivary glands Pancreas
The oesophagus
Tube that takes food from the mouth to the stomach using waves of muscle contractions called peristalsis
Mucus is secreted from tissue in the walls to lubricate the food passage downwards
The stomach
Small sac
Lots of food, allowing stomach to expand
Entrance and exit controlled by the sphincter muscles
Stomach walls produce gastric juices
Gastric juices is hydrochloric acid, pepsin and mucus
Pepsin hydrolysed proteins into smaller polypeptide chains
Peristalsis turns food into chyme
The small intestines
Duodenum and ileum
Chyme moved along by peristalsis
Duodenum, bile and pancreatic juices neutralise the acidity of chyme and breakdown to smaller molecules
Ileum,small soluble molecules are absorbed through villi that line the gut wall
Molecules are absorbed through diffusion - facilitated diffusion and active transport
