Biological Molecules and Metabolic Pathways
water
Water consists of one oxygen molecule attached to two hydrogen atoms via a polar covalent bond. Water molecules are held
together by intermolecular hydrogen bonds. The structure is not straight, rather bent because oxygen atom carries two pairs of
unshared electrons. All the electron pairs repel, causing water molecules to attract. The positive end of a hydrogen atom
attaches to the minus end of an oxygen atom. These attractions are known as hydrogen bonds, which are weak interactions
that are formed between a hydrogen with a partial positive charge and a negatively charged electron atom, such as oxygen.
Water molecules have strong cohesive forces because of their ability to form hydrogen bonds with each other. The structure of
water, allows it to maintain molecular polarity, which is an electrical charge that attracts other atoms.
Water is fundamental for many reasons; it keeps us alive along with enriching and growing our food and crops which are a
means for survival. Water covers about 70% of the earth, and makes up over 65% of our bodies.
Water has a high specific heat, meaning it can absorb heat without a change temperature or state. Water loses heat slower
than air, resulting in water temperature being colder earlier in summer and heating up towards the end. The boiling point of
water is 100 degrees, in which it starts to evaporate, and the freezing point is 0 degrees.
Carbohydrates
Carbohydrates are molecules made of carbon, hydrogen, and oxygen. they are made up of carbon plus water atoms. They may
contain a chain of carbons, a ketone, and hydroxyl group, or an aldehyde Every carbon atom is attached to one oxygen atom.
There are multiple different carbohydrates, but they all consist of smaller units called monosaccharides. carbohydrates belong
to three categories: monosaccharides, disaccharides, and polysaccharides. Monosaccharides can be a ring-shaped or linear
, chain molecule. The ratio of a carbohydrate is carbon: hydrogen: oxygen in 1:2:1 ratio.
A polysaccharide is a large molecule made of many small monosaccharide units. Monosaccharides are simple sugars, an
example of this is glucose. Special enzymes join these small monomers together producing polysaccharides. The main functions
of these polysaccharides are structural support, an energy storage, and cellular communication. Polysaccharides are formed
when monosaccharides are connected which are done via glycosidic bonds.
small hydrogen bonds hold glucose molecules together. Even though hydrogen bonds are very weak, when a lot of them form
between two cellulose molecules they become extremely strong and very stable. A condensation reaction takes place releasing
water, which is a process that requires energy. A glycosidic bond forms and holds two monosaccharides together. There are
three important disaccharides, these are sucrose, lactose, and maltose. The covalent bond that is formed between a
carbohydrate molecule and another molecule is known as a glycosidic bond. Glycosidic bonds can be alpha or beta type.
glycogen contains branches of glucose molecules and undertakes the role of a storage of energy. Due to it being widely
branched, glucose can be cut off from many of the branches continuously instead of one at a time, so our bodies can produce
more energy faster.
Proteins
The structure of proteins determines protein function for example, enzymes must have precise shape for substrate
