Membrane Structure and Function

Question 1

Cholesterol

Answer 1

Stiffens and strengthens the membrane, therefore helping to regulate its fluidity

Question 2

Plasma membrane structure

Answer 2

Membrane is composed of phospholipid bilayer (where proteins are embedded)
Hydrophobic tails face inwards to make up the interior of the membrane, hydrophilic heads face outwards
Carbohydrate chains are attached to the outside surface
Cytoskeleton filaments are attached to the side surface

Question 3

Integral Proteins

Answer 3

Have specific functions inside of the membrane

Question 4

Channel Protein

Answer 4

Allows particular molecules to cross the membrane freely

Cystic fibrosis is cause by a faulty chloride channel

Question 5

Carrier Protein

Answer 5

Selectively interacts with specific molecule or ion to freely pass
Inability to transport (NA+-K+) can be the cause of their obesity
Selective

Question 6

Cell Recognition Protein

Answer 6

The MHC glycoproteins are different for each person, which is why finding matching transplants are difficult
Cells with foreign MHC are attacked by white blood cells

Question 7

Receptor Proteins

Answer 7

Shaped in such a way that specific molecules can bind to it

Some types of dwarfism are the result of faulty hormone receptors

Question 8

Enzymatic Proteins

Answer 8

Catalyzes a specific reaction

Cholrea because releases a toxin that interferes with adenylate cyclase, which leads to severe diarrhea

Question 9

Differentially permeable

Answer 9

Certain substances can move across the membrane while others can’t

Question 10

Concentration gradient

Answer 10

Molecules move from an area of high concentration to an area of low concentration

Question 11

Permeability of the plasma membrane

Answer 11

Differentially permeable

Molecules that can’t be transported freely are moved through channel proteins or vesicle formation

Question 12

Vesicle formation

Answer 12

Another way molecules can enter (endocytosis) or exit a cell (exocytosis)

Question 13

Diffusion

Answer 13

Movement of molecules from a higher concentration to an area of low concentration

Question 14

Factors influcening the rate of diffusion

Answer 14

Temperature
Pressure
Electrical currents
Molecular size

Question 15

Osmosis

Answer 15

Diffusion of water across a differentially permeable membrane

Question 16

Isotonic solutions

Answer 16

Solute concentration and water concentration both inside and outside the cell are equal and therefore there is no net gain or loss of water

Question 17

Hypotonic solution

Answer 17

Solutions that cause cells to swell or even burst, due to intake of water

Question 18

Turgor pressure

Answer 18

Pressure inside of a cell

Question 19

Hypertonic solution

Answer 19

Causes cells to shrink or shrivel due to the loss of water

Question 20

Plasmolysis

Answer 20

Shrinking of cytoplasm due to osmosis

Question 21

Facilitated Transport

Answer 21

The passage of some molecules across the plasma membrane even though they aren’t lipid-soluble, moving with their concentration gradient

Question 22

Active transport

Answer 22

Small molecules and ions move against their concentration gradient
Proteins in active transport are often called pumps because proteins use energy to move a substance against its concentration gradient

Question 23

Exocytosis

Answer 23

Vesicle fuses with the plasma membrane as secretion occurs. Substances are secreted from a cell via exocytosis

Question 24

Endocytosis

Answer 24

Substances enter a cell through endocytosis

Receptor mediated endocytosis allows calls to take up specific kinds of molecules

Question 25

Pinocytosis

Answer 25

Occurs when vesicles form around a liquid or around very small particles

Question 26

Phagocytosis

Answer 26

When material is taken in by endocytosis is large, such as food particles or another cell

Question 27

Three methods of endocytosis

Answer 27

Phagocytosis Pinocytosis Receptor-mediated endocytosis

Question 28

Receptor-Mediated Endocytosis

Answer 28

A form of pinocytosis Uses receptor protein shaped so that a specific molecule, such as a vitamin, peptide hormone, or a lipoprotein, can bind to it Only found at one location on the plasma membrane, called a "coated pit" bc there is a layer of protein on the cytoplasmic side of the pit

Question 29

The mosaic part of the fluid-mosaic model refers to the...

Answer 29

Phospholipids

Question 30

Accumulation in cholesterol can lead to

Answer 30

Heart attack clogged arteries high blood pressure

Question 31

Two lipid molecules that are vital to an animals plasma membrane

Answer 31

Cholesterol | Phospholipids

Question 32

Consists of:

Answer 32

Phospholipids and proteins "mosaic" refers to proteins Proteins are embedded in phospholipid bilayer

Question 33

Cell cytoplasm

Answer 33

Site of cell metabolism Breaking down complex molecules for energy synthesizes new cell structures

Question 34

Ribosomes

Answer 34

Sites of protein synthesis, where an RNA strand is translated into an amino acid sequence

Question 35

Prokaryotic cells

Answer 35

Lack a nucleus | concentrated in the region called the cells nucleoid

Question 36

Eukaryotic cells

Answer 36

Cytoskeleton gives cell shape and stability Housed in nucleus Large in size

Question 37

Nucleolus

Answer 37

Present inside of the nucleus as distinct region consist of ribosomal RNA, protein, ribosomes and DNA Nucleoli are the sites of ribosomal synthesis in the cell

Question 38

Endoplasmic Reticulum

Answer 38

Complex system of membranes present within the cytoplasm Continuous within the nuclear envelope and the plasma membrane internal transport system for the cell

Question 39

Smooth ER

Answer 39

Lacks ribosomes on the surface. Involved with lipid synthesis

Question 40

Rough ER

Answer 40

Has ribosomes on surface, involved with protein synthesis

Question 41

Golgi Complex

Answer 41

Special set of membranes derived from the ER Looks like a set of flattened sacs or vesicles Recieves contents from the ER, modifies them and packages them for transport out of the cell

Question 42

Lysosome

Answer 42

Membranous sac (or vesicle) containing digestive enzymes Used to breakdown the complex of the cell lysosome enzymes derived from the Rough ER lysosomes sac derived from golgi complex

Question 43

Peroxisome

Answer 43

Similar to lysosome Contains enzymes Breakdown toxic substances to hydrogen peroxide HP is then broken down by catalase to produce water and oxygen