6 Flashcards
(30 cards)
Why don’t lipids have a classic monomer-to-polymer construction?
Lipids do not have a classic monomer-to-polymer construction due to their unique structural characteristics
What characteristic places molecules in the lipid category?
Molecules are categorized as lipids based on their hydrophobic nature
Distinguish a hydrocarbon chain from a fatty-acid chain.
A hydrocarbon chain consists solely of carbon and hydrogen, while a fatty-acid chain has a carboxyl group at one end
Illustrate the structure of a triglyceride including any functional groups.
A triglyceride is composed of a glycerol backbone and three fatty acids linked by ester bonds
Explain the process by which triglycerides are formed and the names of the linkages.
Triglycerides are formed through dehydration synthesis, creating ester linkages between glycerol and fatty acids
Describe the chemical and functional differences between saturated and unsaturated fats.
Saturated fats have no double bonds and are solid at room temperature; unsaturated fats have one or more double bonds and are liquid
Draw examples of both saturated and unsaturated fats.
Saturated fat: palmitic acid; Unsaturated fat: oleic acid
Describe the phosphate head structurally and functionally.
The phosphate head is hydrophilic and polar, allowing interaction with water
Describe the fatty-acid tails structurally and functionally.
The fatty-acid tails are hydrophobic and non-polar, repelling water
Explain the primary functions of phospholipids.
Phospholipids form cellular membranes and create a barrier between the cell and its environment
Why are phospholipids considered amphipathic molecules?
Phospholipids are amphipathic because they have both hydrophilic heads and hydrophobic tails
Describe the structure of cholesterol.
Cholesterol has a four-ring carbon structure with a hydroxyl group
Explain the primary functions of sterols.
Sterols help to maintain membrane fluidity and serve as precursors for hormones
Why are sterols considered amphipathic molecules?
Sterols are amphipathic because they have a hydrophilic hydroxyl group and a hydrophobic hydrocarbon tail
Why is the cell membrane referred to as having a ‘fluid mosaic model’?
The fluid mosaic model describes the cell membrane’s flexibility and the diverse arrangement of proteins within the lipid bilayer
Describe the 3 main molecules found in the plasma membrane and explain their functions.
The three main molecules are:
* Phospholipids - form the bilayer
* Proteins - assist in transport and signaling
* Cholesterol - maintains fluidity
What are the various functions of proteins in the plasma membrane?
Proteins function in transport, signaling, and acting as enzymes
What factors affect membrane fluidity?
Factors include temperature, fatty acid saturation, and cholesterol content
What factors affect the permeability of a membrane?
Factors include lipid composition, temperature, and presence of specific proteins
What is meant by the membrane being ‘semi-permeable’?
A semi-permeable membrane allows certain molecules to pass while restricting others
Explain the process of simple diffusion.
Simple diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration
Illustrate what is meant by facilitated diffusion.
Facilitated diffusion involves transport proteins helping molecules cross the membrane without energy input
What is osmosis?
Osmosis is the diffusion of water across a semi-permeable membrane
What happens to the volume of the cell in a hypertonic solution?
The cell shrinks due to water leaving the cell
