BI110 Chapter 7: Module 7

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mauveleopard62

23 Jan 2019

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Substances can be grouped into two broad categories based on their interactions with water. Substances that readily interact with water are hydrophilic, or water loving. Polar molecules and ionic compounds are typically hydrophilic. Substances that repel water are hydrophobic, or water fearing. nonpolar molecules are hydrophobic. A solution is a completely homogenous mixture of two or more compounds. In a solution, the substance present in the greatest quantity is called a solvent. All other substances in the mixture are called solutes (can be liquid, solid or gas). The simplest method to calculate the concentration of a solute in a solution involves measuring the mass of solute per volume of solvent. Scientists want to know how many particles of solute are present (may be atoms, molecules, or units of ionic compound). The number of particles can be calculated using the value called the mole (mol). By definition, one mole contains 6. 02 x 1023 particles (avogadro"s number).

Related Questions

Ionic bonds are formed when two opposite charged ions (formed when atoms lose or gain electrons) encounter each other. These bonds can be viewed as âextreme polar covalent bondsâ as one atom is in total control of the otherâs electron(s). Why are ionic bonds so much weaker when they are in water?

A.	Ionic compounds such as salts are hydrophilic, so they prefer to form bonds with water molecules over other compounds.

B.	Water molecules readily form covalent bonds to charged particles and, as these bonds are stronger than ionic bonds, the ionic bonds are pulled apart.

C.	Water molecules shorten the size of covalent bonds and this weakens ionic interactions.

D.	Water molecules readily donate electrons and nullify the positively charged ions.

E.	Polar water molecules can physically interfere with the polar (positive/ negative) charged attraction between ions and thus the ionic bonds are disrupted and weakened.

1,Match the descriptions to the type of transport.

- A. B. C.	Water enters a cell because it is hypertonic compared to the extracellular environment, increasing its turgor pressure
- A. B. C.	Water enters guard cells because the guard cells are hypertonic compared to the surrounding cells
- A. B. C.	Potassium ions are pumped into guard cells
- A. B. C.	The motor cells of a Venus fly trap are hypotonic compared to surrounding cells, causing water to leave the motor cells
- A. B. C.	Sugar is loaded into the phloem

A.	Both active and passive transport
B.	Passive Transport
C.	Active transport

2,Describe what is wrong with the following statement and explain why:

All prokaryotic and eukaryotic cells contain plasma membrane, nucleus, ribosomes, organelles, cytoplasm, and cell walls.

What is short-distance transport?

	a,	The movement of solutes from a region of low concentration to a region of high concentration
		b,The movement of water, nutrients, and other substances between cells
c,		The movement of substances from a region of high concentration to a region of low concentration
d,		The movement of water across a semipermeable membrane from a region of low solute concentration to a region of high solute concentration.

What terms describe the movement of water across a semipermeable membrane from a region of high water concentration towards a region of low water concentration (and high solute concentration.)

What is found in the proptoplasm?

Cell wall, cytoplasm, plasma membrane, nucleus, and other cell organelles

Plasmodesmata, cell wall, and plasma membrane

Cell wall, cytoplasm, and plasma membrane

Cytoplasm, nucleus, and other cell organelles

The channels that allow nutrients and protoplasm to pass between plant cells are called _________________.

What happens when a plant cell is placed in a hypotonic solution?

Water will enter the plant cell and the plasma membrane will swell and cell lysis will occur

Water will leave the plant cell and the plasma membrane will pull away from the cell and plasmolysis will occur

Water will enter the plant cell and the plasma membrane will swell and push against the cell wall

Water will leave the plant cell and the plant cell will lose turgor pressure, causing the plant to wilt

________________ transport uses cellular energy.

What molecules make plasma cell membranes hydrophilic on the outside and hydrophobic on the inside?

What type of cells do plants have?

		Bacterial
		Archaeic
		Eukaryotic
		Prokaryotic

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Question 5

At a constant temperature, if you increase the number of unsaturated fatty acid chains in the phospholipid, the membrane will become......

less fluid

more fluid

fluidity will be unchanged

Question 6

Bacteria in a hot spring at 80 degrees celsius would be expected to have ______________ in their cell membrane

high proportions of saturated phospholipids

high proportions of unsaturated phospholipids

an equal ratio of saturated to unsaturated phospholipid

Question 7

Membrane proteins have an important role in membrane fluidity

True

False

Question 8

The HIV virus can't attach to cells that have a mutation in the CCR5 gene and so such individuals are resistant to HIV. What population of people have a higher incidence of the mutant CCR5 gene and why?

europeans because their ancestors survived the bubonic plague

North Americans because their ancestors survived small pox

europeans because they have a longer evolutionary past with HIV

Africans because they have a longer evolutionary past with HIV

Question 9

Nematode trapping fungi have ______________ molecules called ______________ that recognize specific carbohydrates on the surface of the nematode worms. This is how a fungus can recognize that its prey, the nematode worm, has wriggled into the loop. Write two words on lowercase separated by a space with no other syntax

Question 10

Diffusion requires energy

True

False

Question 11

The net direction of molecule movement when molecules diffuse is

down their concentration gradient

random directions

Question 12

In osmosis, water molecules from a solution of higher solute concentration cross a semi-permeable membrane into a solution of lower solute concentration?

True

False

Question 13

Which best defines osmosis?

In osmosis, water from a solution of lower solute concentration move across a semi-permeable membrane into a solution of higher solute concentration?

In osmosis, water from a solution of higher solute concentration move across a semi-permeable membrane into a solution of lower solute concentration?

Question 14

Animal cells placed into a hypotonic solution would most likely?

lyse (burst)

shrink

remain unchanged in size

Question 15