lecture 4 - plasma membrane and organelles Flashcards
What organelles are found in plant & animal cells?
nucleus, mitochondrion, endoplasmic reticulum, golgi apparatus
What organelles are only found in plant cells?
chloroplast, central vacuole
What organelles are only found in animal cells?
lysosomes
What are all cellular membranes composed of ?
phospholipid bilayer
What are cells bounded by?
plasma membrane
What effects membrane fluidity?
Saturation and temperature
Saturated tails pack together (vicous)/Unsaturated tails prevent packing (fluid)
Warmer lipids are more fluid/colder lipids are more viscous
What stabilises membrane fluidity
cholesterol
List three reasons why organelles are important to cells.
for harvesting energy, making new proteins, getting rid of waste
What is the difference between diffusion and facilitated diffusion?
facilitated diffusion use channels and carriers to aid movement of substances across the membrane
Give examples of substances that move via normal diffusion.
steroid hormones and gases
Name the channel required for osmosis
aquaporin
Describe co-transport.
when one substance uses active transport to create a concentration gradient across the membrane, a second substance attaches to that substance and uses the concentration gradient to move across the membrane (against its own concentration gradient)
What is the difference between passive and active transport?
passive transport is movement of a substance down their concentration gradient so no energy is required, active transport is movement of a substance against its concentration or electrochemical gradient and requires ATP energy
What do cells do to prevent swelling or shrinking under various conditions?
osmoregulation
Name the key functions of membrane proteins.
signal transduction, cell recognition, intercellular joining, linking cytoskeleton & extracellular matix
