Unit 2 Ch. 5

Question 1

Fluid-mosaic-model-

Answer 1

fluid phospholipid bilayer with embedded protein molecules

• phospholipids are arranged so that the hydrophilic heads face the intracellular and extracellular fluids and hydrophobic tails face each other in the middle

Question 2

Glycolipids-

Answer 2

• similar to phospholipid but hydrophilic head is a variety of sugars
  Glyco- sugar
  lipid-protein

Question 3

Cholesterol-

Answer 3

• found in animal plasma membranes
• reduces permeability of membrane (rate liquid can pass through)

Question 4

Glycoproteins-

Answer 4

proteins with sugars attached (protecting the outside of the cell)

Question 5

What would happen if the membrane was stiff/hard?

Answer 5

the cell membrane is fluid, would limit mobility

Question 6

Proteins of the plasma membrane: (5)

Answer 6

Channel proteins- allows a particular molecule or ion to cross the plasma membrane freely.

Carrier protein- selectively interact with a specific molecule or ion so that it can cross the plasma membrane.

Cell recognition protein- allow the cells of an organism to identify other cells of that organism as well as invading cells

Receptor protein- is shaped in such a way that a specific molecule can bind to it.

Enzymatic proteins- catalyzes a specific reaction ( cause to speed up or happen faster)

Question 7

Permeability of the plasma membrane:

Answer 7

Selectively permeable membrane

Allows some substances to pass but not others
Based on size and charge

• large molecules and molecules with charges do not cross cell membranes without help of a transport protein
• non-charged molecules and water can pass

  - follow concentration gradient: a change in the concentration of a substance over a distance

• substances move from high to low concentration

Question 8

Diffusion:
Solution:

Answer 8

Diffusion: movement of molecules from a higher concentration to a lower concentration (down a concentration gradient) until equilibrium is reached

Solution: contains both solute and solvent

Question 9

Solute:
Solvent:

Answer 9

Solute: substance dissolved in a solvent

Solvent: liquid portion of a solution

Question 10

Osmosis:
Osmotic pressure:

Answer 10

Osmosis: the diffusion of water across a selectively permeable membrane

Osmotic pressure: pressure that develops in a system due to osmosis
- The greater the osmotic pressure, the more likely water will diffuse in that direction

Question 11

Tonicity:
what happens when you put a cell in hypo, hyper, and iso solutions?

Answer 11

Tonicity: the relative concentration of solutes in two fluids

Question 12

Isotonic solution:

Hypotonic solution:

hyper tonic solution:

Answer 12

Isotonic solution: solute concentrations are the same
- No net movement

Hypotonic solution: lower concentration of solutes and a higher concentration of water
Net movement of h2o into cell
Creates turgor pressure in plants

hyper tonic solution: higher concentration of solutes and a higher concentration of water
Net movement of h2o out of cell
Causes crenation-shrinking of animal cell or, plasmolysis-shrinking of plant cell cytoplasm

Question 13

Name the two laws of thermodynamics:

Answer 13

1. energy cannot be created or destroyed (can change forms. Ex. when you drop an object, potential to kinetic energy)
2. when energy is converted/transformed from one form of quality to another, some of the useful energy is always lost in the form of (heat)

Question 14

Metabolism:
Reactant:
Product:

Answer 14

the sum of all the reactions that occur in a cell

substances that participate in a reaction

substances that form as a result of a reaction

Question 15

carrier proteins

Answer 15

combines with and transports a molecule or ion across the plasma membrane

Question 16

passive transport

Answer 16

movement of molecules or ions down a concentration gradient through transport proteins in a cell membrane
no outside energy is required for the process
example is facilitated diffusion (transport)

Question 17

active transport

Answer 17

movement of molecules or ions against a concentration gradient
causes solute to become more concentrated on one side
requires outside energy
examples include sodium potassium pump in nerve and muscle cells, iodine collecting in thyroid, sodium being withdrawn urine by kidneys

Question 18

Membrane assisted transport:
Exocytosis:
exo=
cyto=

Answer 18

vesicles (sacks with stuff in it) formed by golgi bodys (packages things with a phospholipid bilayer aka plasma membrane) and carrying a specific molecule fuse with the plasma membrane resulting in secreting (what happens when chemicals made inside the cell get dumped outside of the cell)
exo=outside
cyto=cell

Question 19

Endocytosis:
endo=
cyto=

Answer 19

cells take in substances by vesicle formation due to plasma membrane invagination ( folding inward, a fold of something= vag)
endo= inside
cyto= cell

Question 20

Phagocytosis:

Pinocytosis:

Answer 20

Phagocytosis: “cell eating”
Large food molecules taken in by endocytosis- forms a food vacuole

Pinocytosis: “cell drinking”
Vesicles form around a liquid or very small particles

Question 21

Receptor-mediated endocytosis:

Answer 21

Receptor-mediated endocytosis: selective uptake of molecules into a cell by vacuole formation after they bind to specific receptor proteins in the plasma membrane

Question 22

Junctions between cells:
Plasmodesmata:

Adhesion junction:

Tight junction:

Gap junction:

Answer 22

Plasmodesmata: channels that pass through plant cell walls and connect cytoplasm of neighboring cells

Question 23

energy:

kinetic energy:

potential energy:

chemical energy:

Answer 23

ability to do work, cause change, or transfer heat

energy of motion

stored energy/energy of position

interactions between atoms in a molecule

Question 24

Exergonic reactions:
Endergonic reactions:

Answer 24

Exergonic reactions: energy is released

Endergonic reactions: products have more free energy than the reactants, require energy input (photosynthesis)

Question 25

What is ATP composed of, what’s it broken down into? What is required for ATP to break down?

Answer 25

ATP- adenosine triphosphate
Nucleotide composed of adenosine (adenine + ribose) and 3 phosphate groups
Energy for cells
Broken down into ADP (adenosine diphosphate)

Question 26

Metabolic Pathways And Enzymes:
Metabolic pathway:

Enzyme:

Answer 26

Metabolic pathway: a series of linked reactions
Begin with reactants (substrates) and terminate with end products

Enzyme: made of amino acids, order determined by DNA. protein moleulce that functions as an organic catalyst to speed a chemical reaction

Question 27

Four features of enzymes:

Answer 27

1. Enzymes do not make anything happen that wouldn’t happen on its own
2. Aren’t permanently altered or used up in a chemical reaction- we can use the same enzymes over and over again
3. Usually work in both forward and reverse directions of a reaction
4. Are highly selective about their substances

Question 28

Factors affecting enzymatic speed: (5)

Answer 28

1. Substrate concentration: enzyme activity increases as substrate concentration increases
2. Temp and ph: as temp increases enzyme activity increases (more collisions)
   Enzyme can become denatured if temp increases too much and will no longer work
   Each enzyme has an optimum pH- a change in ph can also cause denaturation
3. Enzyme concentration:
4. Enzyme cofactors- non proteins which allow enzyme to work (co=together)
5. enzyme inhibition: occurs when the active site on an enzyme becomes altered because too much of an end product was made, or when an active enzyme is prevented from combining with its substrate
6. Enzyme cofactors- non proteins which allow enzyme to work (co=together)

Question 29

Active site-

Answer 29

Region on an enzyme where the substrate binds and the reaction occurs

Question 30

what occurs when an enzyme is induced to undergo a slight alteration to achieve optimum fit

Answer 30

Change in shape of active site facilitates the reaction
After reaction has been completed the products are released and the active site returns to its original state.

Question 31

Electron transport system:

Answer 31

Passage of electrons along a series of membrane-bound carrier molecules releasing energy used to synthesize ATP

Question 32

Coenzymes:
what ae they derived from

Answer 32

Coenzymes: complex organic enzyme helpers
Many are derived from vitamins
Ex. NAD and FAD (accept hydrogens and electrons) known as dumptrucks, move ions from different locations
- vitamins necessary for this

Question 33

ATP production:

Answer 33

ATP production:
H+ (protons) are pumped to one side of membrane, which establishes an electrochemical gradient
H+ flow back across membrane through ATP synthase complexes and this provides energy for ATP production

the production of ATP due to a hydrogen ion gradient across a membrane

Question 34

Electron transport system:

Answer 34

Passage of electrons along a series of membrane-bound carrier molecules releasing energy used to synthesize ATP