Biologically Important Molecules Flashcards
ALL LECTURES
What are the 4 molecules of life?
- carbohydrates
- lipids
- proteins
- nucleic acids
What are the most prevalent naturally occurring elements in the human body?
- oxygen
- carbon
- hydrogen
- nitrogen
What is the name of the most important carbohydrates in biochemistry?
saccharides
What is the ratio of carbon, hydrogen and oxygen in organic molecules?
generally 1:2:1
What are the key roles of carbohydrates?
- energy source
- energy storage
- structural support
- cell recognition/signalling
- present in ribose/deoxyribose sugars
What are carbohydrates built from?
monosaccharides
What variation in monosaccharides can be present?
- variation in number of carbons
- variation in position of carbonyl group
- variation in orientation of carbons
Why does glucose predominantly exist in acyclic form (rings)?
linear structure is less stable
When does glucose become acyclic?
when it is introduced to an aqueous solution
Define disaccharide.
2 monosaccharides joined together
What are some examples of disaccharides?
- sucrose (glucose + fructose)
- lactose (glucose + galactose)
- maltose (glucose + glucose)
What reaction occurs when a disaccharide is formed?
condensation reaction (water produced)
What bond joins disaccharides together?
glycosidic bond
What is the benefit of having a highly branched polysaccharide?
branching increases the solubility of the molecule, providing multiple terminal ends for enzymatic action
Define heteropolysaccharide
carbohydrate composed of 2 or more different types of monosaccharide
What are the benefits of a heteropolysaccharide?
opens up different structural and functional possibilities
Give an example of a heteropolysaccharide
hyaluronic acid
What is hyaluronic acid composed of?
repeating disaccharide units of N-acetylglucosamine and glucoronic acid
What is the function of hyluronic acid?
- ecm
- synovial fluid
- vitrous humour
- supports tissue hydration
- contributes to wound healing
True or False: Carbohydrates are the 3rd major component of plasma membranes?
True
What are carbohydrates in the cell membrane attached to?
- lipids (glycolipids)
- proteins (glycoproteins)
What is the function of membrane carbohydrates?
act as molecular tags that allow cells to recognise and communicate with each other
List some examples of membrane carbohydrates and their function.
- blood group antigens
- cell adhesion
- selectins mediate adhesion of white blood cells
List the functions of lipids (triglycerides)
- structural component of cell membrane
- energy sources
- cell signalling pathways
- hormone
- vitamins A,D,E and K
Describe the structure of a phospholipid
resembles lipid with one of the fatty acids being replaces by a phosphate
Where would you find sphingolipids?
- abundant in cell membranes of lipids
- abundant in the myelin sheath
What is the function of sphingolipids?
- essential for nerve function/signalling
Why is the regulation of sphingolipids important?
- regulation underpins cell growth differentiation and apoptosis
- regulation plays important roles in neurodegenerative diseases, cancer and inflammatory conditions
