Question of the DayQuestion of the Day

1.1. Homeostasis = ???Homeostasis = ???

2.2. What kind of solution can cause a cell What kind of solution can cause a cell to burst (explode)? to burst (explode)? isotonic, isotonic, hypotonic, or hypertonic?hypotonic, or hypertonic?

3.3. Water crosses through a ________ Water crosses through a ________ ____________ __________ during ____________ __________ during osmosis.osmosis.

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ReviewReview

Lab

Pages 6 and 7 questions

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Question of the DayQuestion of the DayGet out a clean piece of paper you can turn inGet out a clean piece of paper you can turn in

QuestionsQuestions::

1.1. What is osmosis?What is osmosis?

2.2. What is a hypertonic solution? What What is a hypertonic solution? What happens to the cell in this type of solution?happens to the cell in this type of solution?

3.3. What is a hypotonic solution? What happens What is a hypotonic solution? What happens to the cell in this type of solution?to the cell in this type of solution?

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Control egg – day 1 = 56.5 Control egg – day 1 = 56.5 gramsgrams

Control egg – day 3 = 56.4 Control egg – day 3 = 56.4 gramsgrams

Control egg – day 4 = Control egg – day 4 = 56.4 grams56.4 grams

Lab

Notes Page 8

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Contractile VacuolesContractile Vacuoles – – Organelle that excretes excess water from Organelle that excretes excess water from

cellscellsUses ATPUses ATPUsually found in unicellular freshwater organisms.Usually found in unicellular freshwater organisms.This prevents them from bursting in a hypotonic This prevents them from bursting in a hypotonic

solution.solution.

Contractile vacuoleContractile vacuole

PlasmolysisPlasmolysis – –loss of turgor pressure in plant cell loss of turgor pressure in plant cell

due to loss of waterdue to loss of waterWhat happens to a plant during What happens to a plant during

plasmolysis? plasmolysis? The plant wiltsThe plant wiltsThe plants plasma membrane and cytoplasm The plants plasma membrane and cytoplasm

will shrink away from the cell wallwill shrink away from the cell wall

REVIEW:REVIEW:What will happen to an Elodea Leaf in a What will happen to an Elodea Leaf in a

hypertonic solution?hypertonic solution?Water will leave the cell…Water will leave the cell…

……which is called playsmolsis, which will cause the which is called playsmolsis, which will cause the plant leaves to wiltplant leaves to wilt

ReviewReview If we put Elodea leaves in a hypotonic If we put Elodea leaves in a hypotonic

solution, what happens? solution, what happens? Water will move into the cell….Water will move into the cell….

…….which will cause the cell to swell. If it’s an .which will cause the cell to swell. If it’s an animal cell it will….animal cell it will….

……burst, UNLESS the cell has a burst, UNLESS the cell has a Contractile vacuole to pump the water out. toContractile vacuole to pump the water out. to

Summary of Hypo/Hypertonic solution Summary of Hypo/Hypertonic solution changes on a RBC.changes on a RBC.

ReviewReview If the cell shrinks, it is in what type of solution?If the cell shrinks, it is in what type of solution? If the cell is at equilibrium with it’s If the cell is at equilibrium with it’s

environment, its in what type of solution?environment, its in what type of solution? If the cell swells, it’s in what type of solution?If the cell swells, it’s in what type of solution?

Water –90%

Salt – 10%

Water 95%

Salt 5%

Water 50%

Salt 50%

Water 50%

Salt 50%

Water 64%

Salt 36%

Water 44%

Salt 56%

Question of the Day

Question of the Day

1. What is passive transport (notes page 2)?

2. What’s an example?

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HOMEWORK

my.hrw.com – Chapter # 5 Self Check Quiz # 1 – 4 of these questions will appear on quiz (ignore #s 7 and 8)

Username = dhe5n

Password = p5e8n

Question of the DayQuestion of the Day12-1012-10Tell me everything you know

about passive transport keep a numbered list.

In Lab:

1. What was the purpose of the vinegar?

2. What hypertonic solution did you put the egg in?

3. What did you use for a hypotonic solution?

Question of the DayQuestion of the Day12-1312-13

ObjectivesObjectivesDescribe how the structure of the Describe how the structure of the

plasma membrane allows it to function plasma membrane allows it to function as a regulatory structure and/or as a regulatory structure and/or protective barrier for a cell.protective barrier for a cell.

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Selective PermeabilitySelective Permeability – – plasma membrane to allow some materials to plasma membrane to allow some materials to

pass while keeping others outpass while keeping others out

Why is selective permeability important?Why is selective permeability important?So the cell can allow important substances in So the cell can allow important substances in

(water, oxygen, glucose) and keep harmful (water, oxygen, glucose) and keep harmful substances out (bacteria).substances out (bacteria).

Passive TransportPassive Transport Passive TransportPassive Transport – –

movement of particles across membranes by movement of particles across membranes by diffusiondiffusion

This process uses NO ATPThis process uses NO ATP Molecules moving from hi concentration Molecules moving from hi concentration low low

concentrationconcentration

Facilitated DiffusionFacilitated Diffusion – – name for passive transport using proteins name for passive transport using proteins Does not use energy!!!Does not use energy!!!

Example:Example:Glucose going from high concentration outside Glucose going from high concentration outside

cell low concentration inside the cellcell low concentration inside the cell Why doesn’t this need energy?Why doesn’t this need energy?

Because it’s still along the concentration Because it’s still along the concentration gradientgradient

LAB

HOMEWORK

Homeostasis and Transport guided reading 5.1