Chapter 5 - Campbell Essential Biology with Physiology 4th Edition (Simon, Dickey, and Reece)

What are the two types of membrane (cell) transport?

Active and Passive Transport

What does selectively (semi) permeable plasma membrane mean?

Plasma (cellulose fluid) that allows certain substances to pass through but not others.

What is passive transport?

the cell does not expend energy to transport a substance.

What is Active Transport

where the cell expends energy to transport substances.

What are the 3 types of passive transport:

1)Diffusion

2)Osmosis

3)Facilitated Diffusion

What is the Concentration?

The number of molecules of a substance in a specified amount of liquid. Example: 10mg of NaCl per liter of water.

Concentration Gradient

The difference in the number of molecules or ions per unit volume between adjoining regions. Gradient means slope or difference.

What is Diffusion

is the movement of molecules down their concentration gradient, from higher concentration to lower.

What are the 5 factors affecting diffusion?

1)Steep concentration gradient (the steeper the gradient the faster diffusion occurs)

2)Temperature

3)Molecular size

4)Presence of an electric gradient

5)Presence of a pressure gradient

What is Osmosis?

- The passive diffusion of water down its concentration gradient through a semi permeable membrane.

- The passive transport of water molecules from a hypotonic solution to a hypertonic solution through a semi permeable membrane.

What is a Solute?

the substance being dissolved in a medium.

What is a Solvent?

the medium in which the solute is dissolved.

What is an example of a solution?

a salt solution is a solution where salt is the solute dissolved in the solvent water.

What is a Hypertonic solution?

comparing two solutions, it is the solution having the highest concentration of solute.

What is a Hypotonic solution?

when comparing two solutions, it is the one having the lower concentration of solute.

What is an Isotonic solution?

when comparing both solutions, the same concentration of solutes are present in both.

How to plants encourage osmosis?

1)By maintaining high solute concentrations in their vacuoles.

2)This creates hypertonic conditions inside the plant cell encouraging water to move into the cell from the outside.

What type of solution do animal cells operate best in?

an Isotonic solution

What type of solution do plant cells operate best in?

a Turgid solution or Hypotonic solution.

What is Plasmolysis?

The shrinking of the cytoplasm in a plant cell placed in a hypertonic solution.

What is Osmoregulation?

control of water balance. Example: Oceans have 35mg/L; Freshwater has less than 35mg/L

Protein-mediated transport

Transport of substances via a protein on the cell membrane.

Name the two types of protein-mediated transport?

1)Protein-mediated passive transport

2)Protein-mediated active transport

Protein-mediated passive transport

-Also called facilitated diffusion

-Substances move down their concentration gradient

-Cell does not expend energy

- Transport is facilitated by a protein

Protein-mediated active transport

-Substances move against their concentration gradient

-Cell expends energy to transport the substance

-Transport is via a protein

What is the main purpose of Exocytosis (out) and Endocytosis (in)?

Transport of materials in bulk.

What is Exocytosis used for?

To remove waste products from the cell.

What are the three ways that Endocytosis is facilitated?

1)Phagocytosis

2)Pinocytosis

3)Receptor-mediated endocytosis

Phagocytosis (to eat) is?

The uptake of solid matter in bulk (cell-eating)

Pinocytosis (to drink) is?

The uptake of liquid matter in bulk (cell-drinking).

Receptor-mediated endocytosis is?

Endocytosis mediated by a receptor protein.

Signal-Transduction Pathway is?

a series of molecular reactions where a signal on a cell's surface triggers a specific response within the cell.

How can a molecule change a cell without entering it?

It can bind to a membrane protein that triggers a signal transduction pathway.

What is Chemical Energy?

-Is potential energy found in chemical compounds.

-Cellular respiration: the energy releasing chemical breakdown of fuel molecules.

What is Adensoine tri-phosphate (ATP)?

synthesized in the mitochondria (organelle), ATP consists of an organic molecule called adenosine plus a tail of three phosphate groups. The triphosphate tail provides energy for cellular work by transferring a phosphate to other molecules.

What are enzymes?

-are biological catalysts

- are proteins

What is a Catalyst?

A compound that speeds up a reaction without taking part in it.

What is a Substrate?

The molecule an enzyme acts upon.

What is an Active Site?

The region on an enzyme where the substrate attaches.

What is an Induced Fit?

The interaction between a substrate and the active site of an enzyme that changes shape slightly to embrace the substrate more closely.

What is Phosporylation?

The transfer of phosphate groups to molecules that need to do work. ATP-ADP

What are the 3 types of work?

1)Mechanical Work

2)Transport Work

3)Chemical Work

What is Activation Energy?

-Is the energy required to break chemical bonds.

-It lowers the required energy to break the bonds. Enzymes sit on the bond facilitating this process.

What are Enzyme Inhibitors?

-Inhibit an enzyme from speeding up a reaction.

-Inhibitors work by:

a)Attaching to the active site and preventing the substrate from docking

b)Attaching to the enzyme and changing the shape of the active site.

An examples of an enzyme inhibitor is malathion, which is a pesticide used to kill cock roaches.

How can an object at rest have energy?

It can have potential energy because of its location or structure.

Which form of energy is most randomized and difficult to put to work?

Heat

Explain how ATP powers cellular work?

ATP transfers a phosphate group to another molecule, increasing that molecule's energy content.

What is the source of energy for regenerating ATP from ADP?

Chemical energy harvested from sugars and other organic fuels via cellular respiration.

How does an enzyme affect the activation energy of a chemical reaction?

an enzyme lowers activation energy.

How does an enzyme recognize its substrate?

The substrate and the enzyme's active site are complementary in shape and chemistry.

Name two ways that a molecule may inhibit an enzyme?

An inhibitor may bind to an enzyme in its active site, or it may bind in an alternate site that affects the active site.

Why is facilitated diffusion a form of passive transport?

It uses proteins to transport materials down a concentration gradient without expending energy.

An animal cell shrivels when it is ______ compared with its environment?

Hypertonic

The cells of a wilted plant are ________ compared with their environment?

Isotonic

What molecule is the usual energy source for active transport?

ATP