Unit Three

Question 1

Fluid-mosaic model, fluid

Answer 1

Double bonds in the fatty acid tails of phospholipid prevents tight packing
Cholesterol resists changes in membrane fluidity that is caused by temperature changes

Question 2

Fluid mosaic model, mosaic

Answer 2

Refers to the position and various functions of proteins in the phospholipid bilayer

Question 3

Phospholipids in the plasma membrane

Answer 3

Polar heads face out and nonpolar tails face in
Properties of the lipid bilayer make it permeable to certain substances
Nonpolar molecules can easily pass through the hydrophobic interior

Question 4

Amphipathic molecules

Answer 4

Both hydrophilic and hydrophobic regions

Question 5

Proteins of the plasma membrane

Answer 5

Integrins, receptor proteins, enzymatic proteins, glycoproteins, intercellular junction proteins, transport proteins

Question 6

Integrins

Answer 6

Structure

Question 7

Receptor proteins

Answer 7

Receive signals

Question 8

Enzymatic proteins

Answer 8

Enzymes

Question 9

Glycoproteins

Answer 9

Cell recognition, allows cell to recognize other cell by a sugar

Question 10

Intercellular junction proteins

Answer 10

Connects one cell to another

Question 11

Transport proteins

Answer 11

Transport

Question 12

How do materials move in and out of the cell

Answer 12

Membranes are selectively permeable

Question 13

Materials that can move easily between the phospholipids

Answer 13

Nonpolar, hydrophobic molecules

Tails hydrophobic as well, can move through because most of the membrane is hydrophobic

Question 14

Some materials move through…

Which ones

Answer 14

Transport proteins

Polar molecules and ions

Question 15

Molecules move across the plasma membrane by

Answer 15

Passive transport and active transport

Question 16

Passive transport

Answer 16

Energy is not needed to move molecules across the membrane

Question 17

Three types of passive transport

Answer 17

Diffusion
Facilitated diffusion
Osmosis (diffusion of water)

Question 18

Diffusion

Answer 18

Molecules can move directly through the phospholipids of the plasma membrane
The net movement of molecules from a high concentration to a low concentration until equally distributed
Gases, water molecules, small, uncharged molecules, lipids (steroid hormones), and lipid soluble molecules (hydrocarbons, alcohols, some vitamins)

Question 19

Why is diffusion important to cells and humans

Answer 19

Alveoli in the lungs
O2 that we breath in diffuses out of cell membranes of the alveoli, into our blood stream
CO2 waste diffuses through the epithelial cells of the blood vessels, to alveoli

Question 20

Facilitated diffusion

Answer 20

Large, polar molecules cannot diffuse freely across the cell membrane
They need the help of transport proteins
Facilitated diffusion is the net movement of molecules from a high concentration to a low concentration with the aid of transport proteins
Ions, sugars (glucose), amino acids, water (faster rate) through aquaporins

Question 21

How do molecules move through the plasma membrane by facilitated diffusion

Answer 21

Channel and carrier proteins are specific
Channel proteins allow ions, small so lutes, and water to pass
Carrier proteins move glucose and amino acids
Facilitated diffusion is rate limited, by the number of proteins channels/carriers present in the membrane

Question 22

Why is facilitated diffusion important to cells and humans

Answer 22

Cells obtain food for cell respiration (glucose and amino acids)
Neurons communicate
Small intestine cells transport food to bloodstream
Muscle cells contract

Question 23

Osmosis

Answer 23

Water molecules can move directly through the phospholipids of the plasma membrane
Osmosis is the movement of free water through a semipermeable membrane when solutes can’t move through
Called water potential: tendency of water to move through a membrane
Moves from high to low
Depends on partial pressure of water and solute potential

Question 24

Movement of water

Answer 24

Water moves from side with greater water potential to lower water potential
Movement stops when partial pressure is equal on both sides

Question 25

How does osmosis help plants

Answer 25

There is a higher solute concentration inside the plant cell Water moves into the cell (vacuole) When the partial pressure of water equals the partial pressure of solutes then it creates TURGOR PRESSURE

Question 26

Why is osmosis important to cells and humans

Answer 26

The colon absorbs water back into the blood and other stuff that I don't have in my notes but need to get when she posts the slideshow on classroom

Question 27

Tonicity

Answer 27

Refers to the total solute concentration of the solution outside the cell Isotonic, hypotonic, hypertonic

Question 28

Isotonic

Answer 28

Solutions that have equal solute concentrations as the cells they surround NEED OTHER PART THAT DONT HAVE IN NOTES YET No net movement of water, will stay same size

Question 29

Hypotonic

Answer 29

Solutions that have a lower solute concentration than the cells they surround

Question 30

What will happen to a cell placed in a hypotonic solution

Answer 30

The cell will gain water and swell If the cell bursts it's called lysis In plant cells with rigid cell walls, this creates turgor pressure

Question 31

Hypertonic

Answer 31

Solutions that have a higher solute coned train than the cell it surround

Question 32

What will happen to a cell placed in a hypertonic solution

Answer 32

The cell will lose water and shrink In plant cells, the central vacuole will shrink and the plasma membrane will pull away from the cell wall This shrinking is called plasmolysis

Question 33

Phosphorylate

Answer 33

Introduce a phosphate group into (a molecule or compound)

Question 34

Cholesterol

Answer 34

Resists changes in membrane fluidity that are caused by temperature changes

Question 35

Glycolipids

Answer 35

Carbohydrate attached to a phospholipid in the cell membrane

Question 36

Protozoans

Answer 36

A single-celled microscopic animal of a group of phyla of the kingdom Protista, such as an amoeba, flagella, ciliate, or sporozoan

Question 37

Contractile vacuole

Answer 37

A membrane-enveloped cellular organelle, found in many microorganism so that periodically expands, filling with water, then contracts, expelling its contents to the cell exterior, thought to be important in maintaining hydrostatic equilibrium

Question 38

Catalyze

Answer 38

To cause or accelerate a reaction by acting as a catalyst

Question 39

Active transport

Answer 39

Molecules move from areas of low concentration to areas of high concentration with the aid of ATP energy Requires transport proteins called Pumps Against concentration gradient

Question 40

Active transport

Answer 40

Brings in essential molecules; ions, amino acids, glucose, nucleotides Maintains internal conditions different from the environment (life) Vesicle with something attaches to and fuses with cell membrane, releases thing inside out the cell

Question 41

Sodium potassium pump

Answer 41

Three sodium ions move out of the cell, two potassium ions move into the cell Used to establish an electrochemical gradient across neuron cell membranes

Question 42

Exocytosis

Answer 42

Active transport Movement of large molecules bound in vesicles out of the cell with the aid of ATP energy Proteins and polysaccharides, whole cells, hormones, mucus, neurotransmitters, waste

Question 43

Endocytosis

Answer 43

Movement of large molecules into the cell by engulfing them in vesicles, using ATP energy Phagocytosis, pinocytosis, receptor-mediated endocytosis

Question 44

Channel proteins

Answer 44

Chanel for lipid insoluble molecules and ions to pass freely through Ions, small solutes, and water

Question 45

Carrier proteins

Answer 45

Bind to a substance and carry it across membrane, changing shape in process Glucose and amino acids

Question 46

Phagocytosis

Answer 46

Cell eating Engulfing large molecules, whole cells, bacteria Macrophages ingesting bacteria or worn out red blood cells Unicellular organisms engulfing food particles

Question 47

Pinocytosis

Answer 47

Cell drinking Engulfing liquids and small molecules dissolved in liquids, unspecific what enters Intestinal cells, kidney cells, plant root cells

Question 48

Receptor-mediated endocytosis

Answer 48

NEED

Question 49

Receptor-mediated endocytosis

Answer 49

Movement of very specific molecules into the cell with the use of vesicles coated with proteins When specific molecules bind to the receptor proteins, then this stimulates the molecules to be engulfed in a coated vesicle Ex. Uptake of cholesterol (LDL) by animal cells