Biology topic 4

what acts as a barrier between the cell and its environment to control which substances enter and leave the cell

what do you call a membrane that lets some molecules through, but not others

What is the name of the 1972 model used to describe cell membrane structure

why are Cell membranes described as fluid

why are cell membranes described as mosaic

Name five components of cell-surface membranes

Can most water-soluble substances pass through the phospholipid bilayer

Which substances can pass through the phospholipid bilayer

What is the role of cholesterol in the cell-surface membrane

Describe the roles of channel and carrier proteins in the cell-surface membrane.

what are intrinsic proteins attached to carbohydrates

what are lipids attached to carbohydrates

Give three roles of glycoproteins and glycolipids

what's described as The net movement of particles, from an area of higher concentration to an area of lower concentration

Is diffusion an active or passive process

Name two types of diffusion

what is the process in which molecules diffuse directly across membranes

_____ can enter cells via simple diffusion because it is a small and non-polar molecule

Some large molecules can attach to ______, which causes them to change shape.the _____ release the molecules on the opposite side of the membrane

Explain how ions enter cells via facilitated diffusion

Name 5 factors that affect the rate of diffusion across a membrane

Higher _____ means particles have more kinetic energy.so particles move around more quickly, and can diffuse more quickly

The more carrier proteins, the ______the rate of facilitated diffusion

what is a measure of the pressure exerted by water molecules on the membrane or container surrounding a solution

How does adding a solute to water affect the water potential

what is the movement of water molecules from a higher water potential to a lower water potential through a partially permeable membrane

A hypertonic solution has a lower water potential than the animal cell, so water molecules move out of the cell, causing the cell to _____

A hypotonic solution has a higher water potential than the animal cell, so water molecules move into the cell, causing the cell to swell and ____

An _____ solution has the same water potential as the animal cell, so there is no net movement of water and the cell stays the same size

Is osmosis an active or passive process

If you add sugars and salts to a beaker of water, what will happen to the water potential

What are some factors affecting the rate of osmosis

Plant cells have a strong cell wall made of cellulose, which prevents them from ______

what is the movement of molecules across a membrane, from a region of lower concentration to a region of higher concentration

'______ the concentration gradient' means that substances are moving from an area of lower concentration to an area of higher concentration

Is active transport an active or passive process

What type of protein is used in active transport

Name a factor that affects the rate of active transport

the more carrier proteins, the _____ the rate of active transport

what is the simultaneous transport of two substances across a membrane

Name the three proteins involved in the co-transport of sodium and glucose

what actively transports sodium ions out of epithelial cells into the blood

What is the role of sodium in co-transport

which proteins move sodium ions from a high concentration in the lumen of the ileum to a low concentration in the ileum epithelial cells

Where does co-transport of sodium and glucose occur in digestion

Co-transport allows glucose to be transported against its concentration gradient,______ its uptake efficiency

how do glucose molecules move from the epithelial cells into the bloodstream