Cell Membrane and Transport / Transport in Humans (Biology H)

Cell membrane/ Plasma Membrane

a lipid bilayer made up of phospholipids

A phospholipid is made up of ______ heads and ____ tails.

hydrophillic, hydrophobic

Cell membrane’s function is to _____ what enters and leaves the cells, while ___ and ___ the cell.

regulate, protecting, supporting

What are examples of what the cell membrane lets in vs. what it lets out?

food in water goes in, waste goes out

The cell membrane is vital to helping maintain _____.

homeostasis

Homeostasis is having a relatively constant internal ___ and ____ conditions (happy and balanced)

physical, chemical

The cell membrane is _______, meaning that some substances can pass and others cannot,

selectively permeable

Example of cell membrane being selectively permeable? (particles that can enter, others that cannot)

**Small molecules (water, O2, CO2) can pass through freely but large charged particles such as proteins, sugars, and ions cannot

Membrane has ______ embbeded and ___ sometimes attached. These can move or float within the membrane, so the membrane is said to be a __________.

proteins, carbohydrates, fluid mosaic model

What does Fluid Mosaic Model mean? Proteins embbeded in the __________ move around and “float” among the lipids - _____. Many different kinds of ____ make up the cell membrane - ____.

lipid bilayer, fluid, molecules, mosaic

___ will help some ____ or ___ molecules pass through the membrane.

proteins, larger, charge

Integral proteins: __________ proteins; some function in ____ (facilitated diffusion or active transport), or ____ like ATP synthase, receptors, or cell to cell contact/communication like forming ____ and ______.

transmembrane, transport, enzymes, tissues, organs

Peripheral proteins:____ the membrane at the surface - often ____, some play a role in cell ____.

bind, enzymes, shape

Glycoproteins: sugars attached to ____ in ____. Some are ____, or cell to cell communication.

proteins, membranes, receptors

Carbohydrates act as ____________ - help cells identify each other

chemical identification cards

Cholesterol (lipid) is used to keep the membrane ____ - ***at some temperatures, the fatty acids of the phospholipid can __________, so the cholesterol prevents them from packing too tightly so molecules can still ____.

fluid, pack together, pass

Glycolipids: sugar molecules attached to _________ - usually _______ -signaling other cells, or ___________ like cholesterol.

phospholipids, outer surface, chemical messengers

Molecules need to be _________ in and out of the cell

transported

Passive transport: molecules that can pass ____ through the _____ from areas of higher concentration to lower concentration

freely, membrane

Concentration is the amount of solute vs solvent

High concentration = more ____

Low concentration = less _____

solute

____ IS REQUIRED in passive transport - just ____

NO ENERGY, happens

3 types of passive transport

___, _______, ______

Diffusion, Facilitated Diffusion, Osmosis

Diffusion: process by which particles move from areas of higher concentration to lower concentration, ____ needed. Once particles reach _______, particles will move in ______.

NO ENERGY, equilibrium, BOTH directions

_________ forms when there are ____ amounts of molecules on either side of a membrane

Concentration gradient, differing

In a mixture, molecules move _____________ towards equilibrium

down its own gradient

 A Larger gradient = _____ diffusion!

Creates ____________

___________ can form when ions diffuse (like nerve impulses!)

faster, potential energy, electrical energy

Facilitated Diffusion: diffusion in which __________ molecules need assistance from a _________ to move down its concentration gradient. HIGH TO LOW, ________ NEEDED. ***Still passive transport, molecules move from an area of high concentration to low concentration, but they need some assistance to pass the selective cell membrane

large or charged, protein channel, NO ENERGY,

Osmosis: movement of_____ across a membrane by _________ (uses protein aquaporin)

water, facilitated diffusion

Osmosis is moving ____, not _____

water, solute

Osmosis: _____ NEEDED (still _____transport!)

no energy, passive

Hypertonic solution: many ____, little ____ (Cell SHRIVELS/SHRINKS)

solutes, water

Hypotonic solution: little ___, lots of ____ (Cell SWELLS (can burst))

solutes, water

Osmosis: Water will move from a _____solution to _____ solution

Water moves from a greater concentration, to where there is a lesser concentration

HYPOtonic, HYPERtonic

Isotonic solution: equal concentration of __ and _ on both sides of the membrane (— of osmosis!!!)

water, solutes, end goal

Water moves in the direction where there is ___ (salt, sugar), and therefore a _____ amount of water. A simple rule to remember: SALT SUCKS!!

solute, lesser

Salt is a _____, so when it is _____ inside or outside the cell, it will draw the water in its direction – i.e. “suck” the water in or out. This is also why you get thirsty after eating something salty.

solute, concentrated,

Pressure is exerted on the _______ side of the solution (___ solute)

hypertonic, more

Cells are filled with salts, sugars, proteins, so it will be ____ to freshwater

hypertonic

When a cell is placed into water (_____ solution), water moves into the cell and could cause it to ___ (cytolysis)

hypotonic, burst

When the cell is placed into a ______ solution, water leaves the cell and it will ____ (plasmolysis)

hypertonic, shrivel

Plant cells have ____ to prevent ______

cell walls, plasmolysis

Active transport: movement of substance ____ its concentration gradient. Moving from an area of LOW concentration to HIGH concentration. REQUIRES ______. Usually need the help of a _____ or a ______ to cross the membrane

against, ENERGY, transport protein, protein pump

Naturally, our cells contain ___ concentrations of sodium and ____ concentrations of potassium

low, high

Sodium-Potassium Pump moves sodium ______ cell and takes _____ into the cell

out of the, potassium

Endocytosis:

process of taking materials into the cell through infoldings, or pockets, in the cell membrane

Endocytosis: Cells _______ to do this - ____ transport!

USE ENERGY, active

How does Endocytosis occur in cells? The pocket will _____ inside the cell and _________.

break free, form a vacuole/vesicle

Phagocytosis

cell engulfs large solid particles and pinches into cell forming food vacuole (CELL EATING)

Pinocytosis

tiny pockets form along the cell membrane, fill with liquid, and pinch off to form vacuoles filled with liquid (CELL DRINKING)

Exocytosis

release of large amounts of material out of the cell

Exocytosis: Cells _______ to do this - ____ transport!

USE ENERGY, active

Exocytosis: How does it occur in cells?

The membrane of a vesicle/vacuole will fuse with the cell membrane and release its contents outside of the cell.

Diffusion occurs in many places in the body: Some examples are diffusion of ____ in ______ system and diffusion of ____ from ___ to _____ in digestive system

gases, respiratory
nutrients, intestines, bloodstream