Cells: amoeba sisters videos

Question 1

Cell surface area and the volume video one

Answer 1

• Cells are very small to allow a large surface area to volume ratio
• cells will have a larger surface area the smaller they are

•The fluid mosaic model is used when determining cell membrane

• Phospholipids are amphiphilic
• Phospholipids move around
• Cholesterol can work to keep phospholipids apart or together during changing temperatures

REMEMBER: Integral proteins go through the proteins and peripheral go on the exterior

• Integral proteins help put macromolecules move through the proteins and phospholipids
• CD4 is on many immune system cells

Question 2

Cell transport video two

Answer 2

• cells need to keep homeostasis. The cell membrane controls what goes in and out, keeping homeostasis
• small non polar molecules have an easier time passing through the bilayer like gases and oxygen
• this is called simple diffusion which requires no energy (passive transport!)
• high to low concentration
• transport proteins can change their size and close.
• facilitated diffusion is when the molecules are too large or polar remember!
• the movement of molecules from low to high requires energy (atp energy) it forced active transport by energizing it
• Endocytosis: Endocytosis is a type of active transport that moves particles, such as large molecules, parts of cells, and even whole cells, into a cell. There are different variations of endocytosis, but all share a common characteristic: the plasma membrane of the cell invaginates, forming a pocket around the target particle.
• cell membrane fuses
• there are three types: phagocytosis (amoebas), receptor-meditated endocytosis (cells are very picky about what’s coming in), and pinocytosis (take in fluids)
• Exocytosis is the reverse, used to get rid of cell waste and getting materials out that cells have made

Question 3

Diffusion video three

Answer 3

Diffusion is when the net movement of a substance traveling down its concentration gradient (remember!)

-high to low

Net movement means overall movement

Diffusion is a passive transport

• The longer the distance the slower the diffuse rate
• hotter temperatures lead to the molecules the move faster, meaning diffusion is increased
• high density can slow the molecules down as characteristic of the solvent
• larger mass will mean slower diffusion rate
• characters of the harrier; the size of the barrier will change the diffusion rate such as if it’s large it will be slower

-