M2- Chapter 3 - Biological Molecules Flashcards
What is an ion
It forms positive and negative ions that are held together by the attraction of the opposite charges.
What is a carbohydrate
Molecule that contains carbon, hydrogen and oxygen.
In what ratio is a carbohydrate made?
Cx(H20)x
What is a lipid (elements)
Molecule that contains carbon, hydrogen and oxygen.
What are proteins made of (elements)
Carbon, hydrogen, oxygen, nitrogen and sulfur
What are nucleic acids made of (elements)
Carbon, hydrogen, oxygen, nitrogen and phosphorus
Explain what polarity is
Covalent bonds occur when 2 or more atoms share an electron. Sometimes, the electron may be closer to one atom than another. This means that one atom becomes slightly negative and the other slightly positive.
Being polar is to have regions of negativity and regions of positivity.
Give an example of polarity
Oxygen and hydrogen dont share an electron equally in an OH bond. The oxygen has a much greater share of the electron than the hydrogen. Therefore, any molecules that contain the OH bond are slightly polar too.
How do hydrogen bonds occur?
It is a weak interaction between molecules containing a slightly negatively charge atom bonded to a slightly positively charged hydrogen atom.
Name water’s characteristics
- high boiling point
- it becomes less dense as a solid
- Cohesive and adhesive properties
Explain why water has a high boiling point
Due to the many hydrogen bonds in water, it takes a lot of energy to break the bonds.
When it evaporates, it takes a lot of heat with it too, because of its high latent heat of vaporisation.
Explain why water is less dense as a solid
When water reaches 4 degrees Celsius, the hydrogen bonds change their positions of the polar molecules slightly further apart. This pushes the oxygen atom towards the centre, meaning it becomes less dense.
As a liquid, the hydrogen bonds are constantly being broken and remade.
As a solid, it forms a crystal-like lattice where molecules are set at fixed distances.
Another name for sugar
Saccharides
Examples of a monosaccharide
Glucose, fructose, ribose
Example of a polysaccharide
Glycogen, cellulose, starch
Examples of a disaccharide
Lactose and sucrose
What type of sugar is glucose
A hexose monosaccharide (has 6 carbon atoms)
Explain water’s cohesiveness
This means that water will move as one mass because the molecules of water are physically attracted to each other. This creates surface tension
Explain water’s adhesivenss
This means that water is also attracted to other surfaces.
Explain the Capillary Action
This uses water’s adhesiveness to travel against gravity. An example is how water moves up a plant. Also how water is in a beaker. It creates a meniscus , where it curves around the edges. This is because it is attracted to the sides of the glass.
Name 4 reasons why water is so important
- Acts as a solvent to carry dissolved material
- Very efficient transport medium. It’s adhesive properties allows it to work against gravity.
- Acts as a coolant
- Stable
How does water act as a coolant
It lessens the effects of temperature changes during chemical reactions. This way any fishes that live in the sea don’t need to adapt to different weathers because the water slows down the impact of temperature changes.
How is water stable
It doesn’t change temperature or state too easily, meaning it creates a safe environment. An example is that ice floats and is made from the top down. Therefore animals in the sea actually get a thermal layer on top.
What is the difference between alpha- glucose and beta-glucose
Alpha glucose molecules have the OH functional group at the bottom at 1, and it stays that way on 4 too.
Beta glucose molecules have the OH functional group at the top at 1, and then the bottom at 4.