plasma membrane & organelles (lecture 3)

Question 1

define the structure of the plasma membrane and its function

Answer 1

it is made of double layer semi permeable phospholipid bilayer, with various embedded or attached proteins. it maintains the inside of a cell, like a cell wall and allows things to pass like oxygen nutrients and waste

Question 2

outline the roles of membrane proteins

Answer 2

• signal transduction
• cell recognition
• intercellular joining
• membrane transport
• linking cytoskeleton & extracellular matrix

Question 3

how do substances enter the cell through the plasma membrane

Answer 3

passive transport protein carriers do not require energy and therefore freely allow molecules to cross down their concentration gradient
active transport requires energy in the form of ATP per transfer of molecules against/up their concentration gradient
co-transport protein carriers require multiple types of molecules to be transported at once to allow for one of the substances to be pumped against its concentration gradient

Question 4

name the types of transport across membranes

Answer 4

diffusion
facilitated diffusion,
osmosis,
active transport,
co-transport

Question 5

outline the important cellular organelles bound by membranes themselves

Answer 5

endoplasmic reticulum,
lysosomes,
mitochondria (2 membranes),
nucleus (envelope 2 membranes)

Question 6

which organelles are common between plant and animal cells

Answer 6

Endoplasmic reticulum,
Nucleus,
Golgi apparatus,
Mitochondrion

Question 7

which organelle is unique to animal cells

Answer 7

lysosomes

Question 8

which organelles are unique to plant cells

Answer 8

central vacuole,
chloroplast