2.1 Molecules to Metabolism Do your Socrative quiz!

Highest level of certainty in science corroborated unquestionably The process of science is based on a system of: Making hypotheses Testing them through rigorous collection of empirical evidence (can be measured and recorded) Peer-review of data Statistical analysis Replication Acceptance THEORY! Highest level of certainty in science acceptance corroborated unquestionably repeated corroborated ? hypothesis testing observations hypothesis hypothesis ? not corroborated (evidence does not support hypothesis) “It’s only a theory”

The scientific process

Falsifiability The purpose of science is to explain and predict. A key aspect of this is falsifiability. Falsifiability is the possibility that an assertion could be shown false by a particular observation or physical experiment. This does not mean it is false; rather, it means that if the statement were false, then its falsehood could be demonstrated.

All humans live forever. No human lives forever. All humans live forever. Is this falsifiable? No. Is this falsifiable? Falsifiable It does not seem possible to prove wrong. In theory, one would have to observe a human living forever to falsify that claim. The presentation of just one dead human could prove the statement wrong. This excludes metaphysical assertions about souls, which are not falsifiable. Some statements are only falsifiable in theory, while others are even falsifiable in practice. For example, "it will be raining here in one billion years" is theoretically falsifiable, but not practically so.

Karl Popper and his philosophical analysis of the scientific method A hypothesis, proposition, or theory is "scientific" only if it is, among other things, falsifiable. Unfalsifiable statements are non-scientific. Falsifiability is a special case of the more general notion of criticizability.

Urea was discovered in the 1720’s in urine. For example: Urea was discovered in the 1720’s in urine. In 1828 Friedrich Wohler synthesized urea! Silver isocyanate It was assumed to be a product of the kidneys. Ammonium chloride At the time, it was thought that these compounds could only be made with the help of a “vital principle”. This “vital principle” causes the phenomena of life to happen, rather than chemical or physical forces. If urea had been synthesized without a “vital principle” then other organic compounds could as well.

You must be able to draw and identify molecular diagrams of some basic organic compounds. These can be represented in lots of different ways. Look at the following diagrams, they all represent the same thing. How?

You must be able to draw and identify molecular diagrams of some basic organic compounds. These can be represented in lots of different ways. Look at the following diagrams, they all represent the same thing. How?

Carbohydrates Monosaccharides Disaccharides Can be in a chain or a ring 2× as many H’s as C’s Sucrose = glucose + fructose Glucose Lactose = glucose + galactose Lactose Maltose = glucose + glucose Galatose

Model how monosaccharides combine to form disaccharides through condensation reactions OH + H =

Phospholipids Lipids Triglycerides

Model how fatty acids and glycerol combine to form triglycerides through condensation reactions OH + H =

Amino Acids Serine Glutamine Tyrosine

Model how amino acids combine to form polypeptides through dehydration reactions I think you get the idea! Pick three amino acids bond them through condensation reactions.

Which molecule represents ribose? What is molecule B? Question from Paper 1 Which molecule represents ribose? What is molecule B? What is molecule C?

Which structure represents an amino acid? Question from Paper 1 Which structure represents an amino acid?

ii. Generalized fatty acid ii. Generalized amino acid Question from Paper 1 Which molecule is: i. ribose ii. Generalized fatty acid ii. Generalized amino acid Discuss which two molecules are most similar in structure.

What is the name of this molecule? What are each of the parts called? Biology Journal 8/28/2013 What is the name of this molecule? What are each of the parts called?

Drawing structures Glucose – C6H12O6 6-membered ring with a side chain 5 carbons in the ring, one carbon in the side chain #C’s with 1 on the right, then clockwise Hydroxyl’s (-OH) on C’s 1, 2, 3, 4 point down, down, up, down Ribose – C5H10O5 5-membered ring with side chain 4 carbons in the ring, one carbon in the side chain #C’s with 1 on the right, then clockwise Hydroxyl’s (-OH) on C’s 1, 2, 3, point up, down, down Generalized amino acid C atom in the center is bonded to four things Amine group –NH2 Carboxyl group – COOH Hydrogen atom –H R group Saturated fatty acid C’s form an unbranched chain All single bonds in a saturated fatty acid # of C’s is between 14 and 20 At one end of the chain, the C is part of a carboxyl group At the other end of the chain, the C is bonded to three H atoms All other C’s are bonded to two H atoms