Cell Structure - Lecture 0.3 Flashcards
describe the structure of the cell membrane
Lipids are proteins makes up the major components. Lipids are arranged in a bilayer with the hydrophilic phosphate heads on the outside and hydrophobic fatty acid chains on the inside.
How does cholesterol play a role in the cell membrane?
Helps maintain cell membrane stability and permeability especially where the transmembrane proteins are located
Cholesterol is amphipathic - what does this mean?
It has both hydrophilic/polar (water loving) and hydrophobic/nonpolar (lipid loving/water fearing) moieties. The polar side hydrogen bond with the phosphorylated heads of the lipid bilayer and the non polar side bind with the phospholipid tails via van Der waal forces.
Explain the functions of the lipid bilayer.
Establishes a chemical gradient - the proteins within the plasma membrane are highly selective and these are moved by transport proteins specific to the substances through channels. The chemicals can then be concentrated on either side of the membrane. Therefore the selective permeability of the lipid bilayer establishes the electrochemical gradient between the inside and outside of cell.
Define nucleolus
where ribosomes are assembled
Define ribosome
translate mRNA into proteins
What is a main function of mitochondria?
Make ATP via oxidative phosphorylation (cellular respiration)
Contrast the smooth and rough ER.
RER - has ribosomes attached and makes proteins that re exported from the cell; makes phospholipids. SER lacks ribosomes; where carb metabolism occurs and makes lipids
What is the importance of the GA?
proteins made in the RER and lipids made in the SER destined for use outside of the cell are transported into the GA and modified as they pass through.
What is a lysosome?
membrane bound vesicle formed from the GA. Contain digestive enzymes that break down old organelles or particles taken up by the cell.
Explain the difference between the cytosol and the cytoplasm.
Cytoplasm is where organelles are located and where ribosomal proteins synthesis (mRNA translation) and cellular respiration take place. Cytosol is where the cytoskeleton filaments are located as well as the bulk of dissolved ions and water. Where glycolysis, fat storage and glycogen storage occur
What are the types of transport mechanisms?
Concentration gradients, facilitated diffusion, active transport (primary and secondary)
What does it mean to say moving along a concentration gradient?
molecule is moving from area of high to low concentration and releasing energy that is being harnessed to run other reactions
