Lipids and membranes Flashcards
(21 cards)
What are the properties of lipids?
Made up of carbon hydrogen and oxygen, macro molecules, insoluble in water, dissolves enough, poor conductor of heat and electricity, good source of energy
What are the functions of lipids?
Storing improvise energy, chemical messengers, cholesterol formation, regulates the body temperature and insulate
How would you test for the presence of lipids?
- Add a sample in a test tube
- Add approx 2cm3 of ethanol to the sample and mix well.
- Add approx 2cm3 of distilled water into another test tube, then pipette the ethanol from the first tube to the new test tube and add water
- If a white emulsion forms a lipid is present
What is meant by qualitative test?
The results are not expressed in numerical terms they’re given as either positive or negative
What is the difference between a saturated and unsaturated fatty acids?
Saturated don’t have any double bonds between their carbon atoms in the hydrocarbon tail and unsaturated have at least one double bomb between the carbon atoms causing a kink
What does a triglyceride look like?
What bond is formed to make a triglyceride?
Ester bond
What is the difference between a triglyceride and a phospholipid?
A triglyceride has one glycerol molecule and three fatty acids where is a lipid has one glycerol and two fatty acids and a phosphate group
Why do fossil slippers naturally form a body layer when in contact with water?
The fatty acid chains are hydrophobic and form a hydrophobic core facing away from water B cytoplasm
What is the function of a glycoprotein?
They enable cells to recognize another cell as familiar or foreign, which is called cell-cell recognition
What is the function of a carrier protein?
membrane proteins that move molecules across a cell membrane by changing their shape. They are also known as transporters or permeases
What is the function of glycolipids?
maintain the stability of the cell membrane and to facilitate cellular recognition, which is crucial to the immune response and in the connections that allow cells to connect to one another to form tissues.
What is the function of a channel protein?
transport substances across the cell membrane, such as ions, water, and molecules. They act like pores
Why is the membrane described as a fluid mosaic?
the membrane is fluid with the molecules moving and the membrane itself being able to bend. It is called a mosaic because the membrane is made of multiple macromolecules pieced together like a tile mosaic. The phospholipids and proteins can move around via diffusion. The phospholipids mainly move sideways, within their own layers
What are the functions of the plasma membrane?
- partially permeable membrane
- transport of key molecules
- cell recognition
- cell signalling
Describe how a partially permeable membrane helps the plasma membrane function?
It prevents certain molecules especially large molecules from diffusing across the lipid bilayer
How does the transportation of key molecules help the function of the plasma membrane?
The molecules are transported by carrier proteins which pass into the cell and transport the substances to parts of the cell
How does cell recognition help to function the plasma membrane?
The cells are covered with different proteins so that they can be recognised. This also prevents lymphocytes from destroying your own body cells. Glycoproteins act as receptors and respond to certain substances
How does cell signalling help to function the plasma membrane?
The cells communicate with each other to control processes inside the body and responds to changes in the environment. One cell releases a message molecule which travels to another cell. The messenger is detected and binds to the cells membrane
What are some intracellular membranes?
Lysosomes, outer membrane of chloroplast, mitochondria inner membrane, nuclear envelope and vesicle membrane
What is the function of the nuclear envelope?
Separates the nucleus from the cytoplasm in eukaryotic cells providing a structural frame work of the nucleus
