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Biology > Unit Test 1 > Flashcards

Unit Test 1 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Cells that stay the same size are called ?

A

Isotonic

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2
Q

Cells swell and may burst are called ?

A

Hypotonic

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3
Q

Cells shrink and become dehydrated are called ?

A

Hypertonic

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4
Q

What is Osmosis?

A

Osmosis is a special kind of diffusion concerned only with the movement of water from an area of high concentration to an area of low concentration passing through a partially or selectively permeable membrane.

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5
Q

What is Diffusion?

A

Diffusion is the movement of particles from a place where they are high in concentration to a place where they are in low concentration down a concentration gradient until they are evenly spread.

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6
Q

What is Active Transport?

A

Active Transport is the uptake of particles by cells from a region of lower concentration to a region of higher concentration against a concentration gradient.

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7
Q

What does active transport need?

A

Active transport needs energy and the assistance of membrane
proteins, such as carrier proteins.

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8
Q

Sometimes cells can keep hold of particles and not let them diffuse out. True or False

A

True

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9
Q

Cells can take in more particles against a concentration gradient. True or False

A

True

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10
Q

What is the water potential of a solution ?

A

The water potential of a solution is a measure of the tendency of water molecules to move from one place to another.

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11
Q

The difference in water potential between two solutions is known as

A

the water potential gradient

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12
Q

Which solution has a higher water potential than a concentrated solution?

A

a dilute solution

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13
Q

In water potential what is a Isotonic solution?

A

When two solutions have the same concentration of solutes.

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14
Q

In water potential what is a Hypotonic solution?

A

A solution with a lower concentration of solutes compared to another solution.

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15
Q

In water potential what is a Hypertonic solution?

A

A solution with a higher concentration of solutes compared to another solution.

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16
Q

Give 2 examples of Osmosis in Animals?

A
  1. The movement of water into the cytoplasm in unicellular organism such as paramecium and Amoeba
  2. Re-absorption of water in the kidney tubules of mammals.
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17
Q

Which substances move by Diffusion?

A

Oxygen, carbon dioxide, food, and waste products.

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18
Q

How do animals diffuse in and out of cells?

A

In animals, the substances are transported in the bloodstream, from where they can diffuse in and out of cells.

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19
Q

Which factors affect the rate of diffusion?

A

Temperature
Area of Interaction
Mass of the particle
The steepness of the concentration gradient
Distance particles have to travel

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20
Q

What is Facilitated Diffusion?

A

Facilitated diffusion is a passive movement of molecules across the cell membrane from a region of higher concentration to a region of lower concentration by means of a carrier molecule.

21
Q

What 5 things happen in Facilitated Diffusion?

A
  1. Particles always move with (down) a concentration gradient.
  2. Uses transport/channel proteins.
  3. Passive transport.
  4. Usually for specific molecules such as glucose.
  5. Facilitated diffusion stops at equilibrium.
22
Q

How does Temperature affect the rate of Diffusion?

A

The hotter the gas or liquid, the faster diffusion happens because the particles have more energy and move faster at higher temperatures.

23
Q

How does Area of Interaction affect the rate of Diffusion?

A

Increased surface area increases the rate of diffusion.

24
Q

How does Mass of the Particle affect the rate of Diffusion?

A

Heavier molecules move more slowly; therefore, they diffuse more slowly.

25
Q

How does the steepness of the concentration gradient affect the rate of Diffusion?

A

The greater the difference in concentration, the more rapid the diffusion. The closer the distribution of the material gets to equilibrium, the slower the rate of diffusion becomes.

26
Q

How do the distance particles have to travel affect the rate of Diffusion?

A

The greater the distance that a substance must travel, the slower the rate of diffusion.

27
Q

Give 2 examples of diffusion in the home

A
  1. Spraying perfume or air freshener at one corner of the room will get diffused into the air then it can be smelled in the entire room.
  2. A tea bag immersed in a cup of hot water will diffuse into the water and change the colour.
28
Q

Give 2 examples of diffusion in the plants

A
  1. The exchange of gases through the stomata of plants is a typical example of diffusion
  2. loss of water vapour from leaves to the atmosphere through the process of transpiration.
29
Q

Give 2 examples of diffusion in the animals

A
  1. Molecules of food and oxygen diffuse out of the blood and into the cells of animals
  2. Carbon dioxide and waste chemicals diffuse out of the cells and into the blood
30
Q

What makes it possible for living organisms to move around?

A

Diffusion

31
Q

Why can solids not diffuse in solids ?

A

By contrast, solids cannot diffuse because in solids, the particles are tightly packed and can only vibrate; they cannot move from place to place.

32
Q

What are molecules in liquids and gases constantly doing?

A

Moving and bumping into each other

33
Q

Diffusion is the main way in which substances move over short distances in organisms and it is involved in the different life processes. True or False

A

True

34
Q

What is an Isotonic solution in Osmosis?

A

It describes two solutions of the same concentration separated by a partially or selectively permeable membrane. There is no overall (net) movement of water between the two solutions.

35
Q

What is a Hypertonic solution in Osmosis?

A

It describes a solution that is more concentrated than another for a particular substance, e.g. sugar. Note: a strong sugar solution is high in sugar particles but low in water particles.

36
Q

What is a Hypotonic solution in Osmosis?

A

It describes a solution that is less concentrated than another for a particular substance. Note: a weak sugar solution is low in sugar particles but high in water particles.

37
Q

How does Osmosis work?

A

Osmosis diffuses water across a selectively permeable membrane, from a high water potential to a low water potential then the selectively permeable membrane on the side of the water is being continuously bombarded by water molecules which pass through them this causes an increase in the volume of sucrose solution and a decreases in the volume of water.

38
Q

Why is Osmosis crucial for cells?

A

Osmosis is crucial for cells because it helps maintain the balance of water and solutes, which is essential for their proper function.

39
Q

What are the 4 key reasons Osmosis is crucial for cells?

A

Nutrient Absorption
Waste Removal
Cellular Stability
Turgor Pressure in Plants

40
Q

Why is Tugor Pressure a key reason Osmosis is crucial for cells?

A

In plant cells, osmosis helps maintain turgor pressure, which keeps the cells rigid and supports the plant structure2

41
Q

Why is Waste Removal a key reason Osmosis is crucial for cells?

A

It also plays a role in removing waste products from cells. For instance, osmosis helps in the excretion of waste products from the blood through the kidneys.

42
Q

Why is Cellular Stability a key reason Osmosis is crucial for cells?

A

Osmosis helps maintain the right balance of water inside and outside the cell, which is crucial for maintaining cell shape and function. This balance prevents cells from shrinking or swelling excessively.

43
Q

Why is Nutrient Absorption a key reason Osmosis is crucial for cells?

A

Osmosis allows cells to absorb essential nutrients and minerals from their surroundings. For example, in the human body, osmosis helps in the absorption of nutrients from the intestines into the bloodstream.

44
Q

How does Osmosis affect animal cells?

A

The cell membrane is the partially permeable membrane in animal cells and water enters animal cells by osmosis.

45
Q

What is haemolysis?

A

Animal cells have no cell wall to stop them from swelling too much so they burst and we call this haemolysis.

46
Q

How do cells get plasmoysed?

A

When plant cells are placed into a strong sugar or salt solution, water passes out of the cells by osmosis. As water passes out, the sap vacuole starts to shrink. These cells are no longer firm, they are limp. We say that they are flaccid.
As more water leaves the cells their cell membranes start to peel away from their cell walls. These cells are now plasmolysed.

47
Q

Why are Turgid cells important?

A

Turgid cells are important because they give the plant support and they keep the stems of many plants upright. When the cells lose water and are no longer firm and turgid, we consider this as wilting and plant stems will also lose water.

48
Q

How do cells go through Turgidity ?

A

As water enters plant cells it makes the cells swell up. The water pushes against the cell wall and eventually the cell contains as much water as it can hold. It is like a blown up balloon. The strong cell wall stops the cell from bursting but we say that the cell is turgid. The outward pressure which the cell sap exerts against the inside wall of the cell is known as turgor pressure.

Biology (2 decks)

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