Cell Membranes

Front 1

What are the three things cell membranes do?

Back 1

Transport raw materials across the cell, transport certain manufactured products and wastes out of the cell, prevent entry/exit of wanted/unwanted matter into the cell.

Front 2

Each phospholipid molecule has a ___________ and a _____________.

Back 2

Hydrophyllic head, hydrophobic tail.

Front 3

What is a hydrophyllic head made up of?

Back 3

A phosphate group.

Front 4

What is a hydrophobic tail made up of?

Back 4

Fatty acids.

Front 5

What type of molecule is a phospholipid?

Back 5

They are amphipathic molecules. Amphipathic molecules have both a polar and non-polar region.

Front 6

In a phospholipid, what is polar and what is non-polar?

Back 6

The hydrophyllic heads are polar, and the hydrophobic tails are non-polar.

Front 7

What do glycoproteins function in?

Back 7

cell to cell communication.

Front 8

What does cholesterol allow cell membranes to do?

Back 8

Function in a wider range of temperature.

Front 9

At high and low temperatures, what does cholesterol do?

Back 9

High temperatures: maintains membrane rigidity. Low temperatures: keeps membrane fluid and flexible, preventing freezing.

Front 10

How do cells achieve a state of homeostasis.

Back 10

Through selective permeability.

Front 11

What are intracellular and extracellular fluids composed of?

Back 11

Water, salts, sugars, proteins, and many electrical charged molecules and ions.

Front 12

What molecules are small enough to slip between the phospholipid molecules?

Back 12

Oxygen gas and water.

Front 13

What are peripheral proteins?

Back 13

Proteins that are only partially embedded in the cell membrane.

Front 14

What are integral proteins?

Back 14

Proteins that extend across the entire bilayer. Ex. Channel proteins.

Front 15

What are receptor proteins?

Back 15

Proteins that have a particular shape that allows a specific molecule (hormone) to bind to it.

Front 16

What do enzymatic proteins do?

Back 16

enable or increase the rate of certain chemical reactions.

Front 17

The binding of a molecule to a receptor protein can cause what?

Back 17

It can cause the protein to change it's conformation (shape) resulting in a specific cellular response.

Front 18

What is the theory of brownian motion?

Back 18

It is the theory that all particles are in constant, random motion.

Front 19

What is a concentration gradient?

Back 19

A difference in the concentration of particles between two areas.

Front 20

How will particles move to achieve equilibrium?

Back 20

Particles will move from the area of highest concentration to the area of lower concentration.

Front 21

What is passive transport?

Back 21

Movement across the cell membrane that does not require the use of energy.

Front 22

What are three types of passive transport?

Back 22

Diffusion, osmosis, facilitated diffusion.

Front 23

What is diffusion?

Back 23

The net movement of particles from an area of higher concentration to an area of lower concentration.

Front 24

Why does oxygen always diffuse into the cell?

Back 24

Because the concentration of oxygen is always lower within the cell because cells are constantly consuming oxygen.

Front 25

What is osmosis?

Back 25

Diffusion of water molecules across the cell membrane.

Front 26

When a cell is placed into a hypotonic solution, what happens?

Back 26

The water will diffuse into the cell, causing the cell to swell and possibly burst. Hypotonic sol'ns contain a low solute relative to another solution.

Front 27

When a cell is placed into a hypertonic solution, what happens?

Back 27

When a cell is placed in a hypertonic solution, water will diffuse out of the cell causing the cell to shrivel. Hypertonic sol'ns contain a high solute relative to another solution.

Front 28

What are isotonic solutions?

Back 28

Isotonic solutions contain the same concentration of solute as another solution. The fluid that surrounds the body cells is isotonic.

Front 29

What are transport/carrier proteins?

Back 29

Membrane bound proteins that facilitate the transport of molecules across the membrane.

Front 30

Does facilitated diffusion require energy?

Back 30

No, because the molecules are still moving along their concentration gradient.

Front 31

What is active transport?

Back 31

Transport that requires energy, because the molecules and ions need to move against their concentration gradient.

Front 32

What is endocytosis?

Back 32

A process whereby cells may take in larger molecules.

Front 33

What are the three main types of endocytosis?

Back 33

Pinocytosis, phagocytosis, receptor assisted endocytosis.

Front 34

What is phagocytosis?

Back 34

When a cell eats by means of endocytosis.

Front 35

What is pinocytosis?

Back 35

When a cell drinks by means of endocytosis?

Front 36

What is receptor mediated endocytosis?

Back 36

When the membrane bound proteins assist with endocytosis.

Front 37

How are cells infected by HIV?

Back 37

The HIV tricks receptor proteins to bind to the virus, permitting entry to the cell through endocytosis.

Front 38

What is exocytosis?

Back 38

allows materials stored in vesicles or vacuoles to be exported out of the cell.

Front 39

What is a genome?

Back 39

An organism's entire genetic make up.

Front 40

What are diploid and haploid organisms?

Back 40

Diploid organisms contains 2 copies of DNA. Haploids contain only 1.

Front 41

What are chromosomes?

Back 41

Long threads of DNA found within the cell.

Front 42

What are genes?

Back 42

sections of chromosome, each coding for a particular set of instructions.

Front 43

What is nucleotide?

Back 43

Functional unit of DNA, composed of a sugar, phosphate group and 1 of 4 nitrogenous bases.

Front 44

What does mRNA have instead of thymine?

Back 44

Uracil.

Front 45

What happens during transcription?

Back 45

DNA is copied in the form of mRNA.