end of y9 cover COPY Flashcards

need to add- transpiration and miscopies and magnification

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1
Q

What factors affect the rate of diffusion?

A

The temperature, the concentration gradient, the surface area, the molecule size.

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2
Q

What is diffusion?

A

The movement of molecules from an area of higher concentration to an area of lower concentration.

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3
Q

How does temperature affect the rate of diffusion?

A

The higher the temperature, the more kinetic energy the particles will have, so they will move and mix more quickly.

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4
Q

How does concentration gradient affect the rate of diffusion?

A

The greater the difference in concentration, the quicker the rate of diffusion.

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5
Q

How does the surface area of the cell membrane separating the different regions affect the rate of diffusion?

A

The greater the surface area, the faster the rate of diffusion.

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6
Q

How does the size of the molecules affect the rate of diffusion?

A

heavy molecules move slower there for diffusion is slowed down.

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7
Q

In a potassium magnate and water solution what is the solute and solvent?

A

solute - the potassium magnate

solvent - the water

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8
Q

In general,(in terms of diffusion) do particles move to a higher or lower concentration?

A

particles move down the concentration gradient. particles will move away from where there is a high concentration to where there is a low concentration.

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9
Q

What are the formulas of surface area and volume for cubes?

A
SA= length x hight x No of sides 
volume= leght x hight x with
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10
Q

Name three natural examples of where diffusion takes place?

A

in a leaf, in the lungs, in the liver

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11
Q

Do you know how the leaf use diffusion?

A

talk through it

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12
Q

Do you know how the lungs use diffusion?

A

talk through it

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13
Q

Do you know how the liver use diffusion?

A

talk it through it

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14
Q

What is osmosis?

A

Osmosis is the diffusion of water molecules, from a region where the water molecules are in higher concentration, to a region where they are in lower concentration, through a partially permeable membrane.

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15
Q

Does a diluted solution or a concentrated solution have a higher concentration of water molecules?

A

diluted solution- has a higher concentration of water concentrated solution -has a lower concentration of water

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16
Q

In terms of osmosis, what is the movement of water molecules like in solution with an even concentration throughout it?

A

When the concentration of water is the same on both sides of the membrane, the movement of water molecules will be the same in both directions. There will be no net movement of water molecules.

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17
Q

Inside a cell how does water pass in and out?

A

The cell membrane is partially permeable.

Water will move into and out of cells by osmosis.

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18
Q

When will an alive leaf not lose water through its stoma?

A

When its raining or humid outside?

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19
Q

How does the cell wall support the cell in terms of osmosis?

A

The cell wall is fully permeable to all molecules and supports the cell. It also stops it bursting when it gains water by osmosis.

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20
Q

If plant cells are placed in solutions of increasing solute concentration how will they react in. Pure water

A

In pure water, the cell contents (the cytoplasm and vacuole) push against the cell wall and the cell becomes turgid.

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21
Q

What happens in an animal cell is it absorbs to much water?

A

In animals, the concentration of body fluids – blood plasma and tissue fluid – must be kept within strict limits – if cells lose or gain too much water by osmosis, they do not function efficiently.

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22
Q

What has to be in place for osmosis to take place?

A

there must be water molecules and a semi/selectively permiable membrane

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23
Q

What is a semi-permeable membrane?

A

A semi-membrane will allow certain molecules or ions to pass through it, but now others.

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24
Q

What is meant by net movement?

A

Net movement men that molecules will be moving in all directions but as a whole, there will be an overall movement to a certain place.

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25
Q

What is active transport?

A

active transport is a process that is required to move molecules against a concentration gradient. The process requires energy.

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26
Q

In terms of active transport which way will molecules move along the concentration gradient?

A

from a low to a high concentration

this is against the natural flow so it requires energy.

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27
Q

How is active transport carried out in cells?

A

active transport is carried out by protein carriers in the cell membrane.

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28
Q

Give three examples of active transport?

A

Root hair cells, kidney and, the small intestine.

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29
Q

how does active transport take place in roots?

A

For plants to take up mineral ions, ions are moved into root hairs, where they are in a higher concentration than in the dilute solutions in the soil. Active transport then occurs across the root so that the plant takes in the ions it needs from the soil around it.

30
Q

how does active transport take place in the small intestine?

A

All the glucose in the gut needs to be absorbed. When the glucose concentration in the intestine is lower than in the intestinal cells, movement of glucose involves active transport. The process requires energy produced by respiration.

31
Q

What is an independent variable?

A

a variable (often denoted by x) whose variation does not depend on that of another.

32
Q

What is a dependent variable?

A

a variable (often denoted by y ) whose value depends on that of another.

33
Q

What are control variables?

A

The control variable is not part of an experiment, but it is important because it can have an effect on the results.

34
Q

What does xylem transport?

A

The xylem transports water and minerals from the roots up the plant stem and into the leaves. this is a one-way movement, up.

35
Q

In a mature flowering plant or tree, what are most of the cells that make up the xylem called?

A

In a mature flowering plant or tree, most of the cells that make up the xylem are specialised cells called vessels.

36
Q

What do vessels do?

A
  • Lose their end walls so the xylem forms a continuous, hollow tube.
  • Become strengthened by a chemical called lignin. The cells are no longer alive. Lignin gives strength and support to the plant. We call lignified cells wood.
37
Q

Does transport in the xylem need energy?

A

Transport in the xylem is a physical process. It does not require energy.

38
Q

How are the walls of xylem thickened?

A

The walls are thickened with lignin.

39
Q

What does the phloem do?

A

The phloem moves food substances that the plant has produced by photosynthesis to where they are needed

40
Q

What process in plants needs food to be transported by the phloem?

A

for processes such as:
growing parts of the plant for immediate use
storage organs such as bulbs and tubers
developing seeds.

41
Q

What does phloem transport?

A

Phloem is responsible for transporting food produced from photosynthesis. Is therefore both up and down the stem.

42
Q

what is transport in the phloem called?

A

Transport of substances in the phloem is called translocation.

43
Q

Phloem consists of living cells. The cells that make up the phloem are adapted to their function. what is the function of Sieve tubes?

A

Sieve tubes – specialized for transport and have no nuclei. Each sieve tube has a perforated end so its cytoplasm connects one cell to the next.

44
Q

Phloem consists of living cells. The cells that make up the phloem are adapted to their function. what is the function of the Companion cells?

A

Companion cells – transport of substances in the phloem requires energy. One or more companion cells attached to each sieve tube provide this energy. A sieve tube is completely dependent on its companion cell(s).

45
Q

If plant cells are placed in solutions of increasing solute concentration how will they react in a concentrated solution?

A

In a more concentrated solution, the cell contents lose water by osmosis. They shrink and pull away from the cell wall. The cell becomes flaccid. It is becoming plasmolyzed.

46
Q

If plant cells are placed in solutions of increasing solute concentration how will they react in a highly-concentrated solution?

A

In a very concentrated solution, the cell undergoes full plasmolysis as the cells lose more water.

47
Q

What makes trees get rings?

A

mature xylem cells are dead this causes rings to form in wood as another layer matures and dies it creates another ring.

48
Q

why do plants need water?

A
  1. for photosynthesis

2. to keep itself upright

49
Q

why do cells in active transport need mitochondria?

A

Cells involved in active transport usually have lots of mitochondria to provide the energy they need.

50
Q

Explain the process of active transport.

A

A solute molecule needs to be transported inside a cell by a transport protein on the cell membrane. The solute is then recognised by the protein and grabbed. The protein then rotates the membrane and releases the solute inside the cell (using energy). The protein then rotates back again (often using energy).

51
Q

What is aerobic respiration?

A

Image result for What is aerobic respiration?study.com

Aerobic respiration is the process of producing cellular energy involving oxygen.

52
Q

What is the equation for aerobic respiration?

A

Glucose + Oxyen -> Carbon Dioxie + Water + Energy

53
Q

What is a trait of cells that carry out active transport?

A

Cells involved in active transport usually have lots of mitochondria to provide the energy they need.

54
Q

If the area over which diffusion can take place is greatly increased. What will happen to the rate of diffusion?

A

The rate of diffusion will greatly increase.

55
Q

In terms of diffusion, why do so cells have folded membranes along at least one surface?

A

By folding the cell membrane of a cell, or the tissue lining an organ, the area over which diffusion can take place is greatly increased. Therefor the rate of diffusion is also greatly increased.

56
Q

What can increase the effectiveness of an exchange surface?

A
  • having a large surface area
    -having a thin membrane
    (and in animals)
    -having an efficient blood supply
    and - having ventilation
57
Q

How can having a thin membrane increase the effectiveness of an exchange surface?

A

Because in provides a short diffusion path.

58
Q

How can having an efficient blood supply increase the effectiveness of an exchange surface?

A

having an efficient blood supply moves the diffusing substances away from the exchange surfaces and maintaining a steep concentration gradient.

59
Q

How can being ventilaated increase the effectiveness of an exchange surface?

A

In animals being ventilated makes gas exchange more efficent by maintaining a steep concentration gradients.

60
Q

what is transpiration?

A

Transpiration is the process by which plants lose water vapor from the surface of their leaves.

61
Q

What are sports drinks?

A

Drinks that are designed to be used during exercises.

62
Q

What happens during exercise?

A
  • you sweat so you loese water and ions

- you require more energy so sugars are broken down in respiration

63
Q

what is the effect of exercise on the body?

A

your body loses water, ions and sugar

64
Q

What will happen if your body does not have the right concentration of water and ions?

A

if the concentration of water and ions is not maintained the body will now work effectively.

65
Q

What do sports drinks contain?

A

water, sugars and, ions.

66
Q

Where does the transpiration stream move through in plants?

A

root → stem → leaf

67
Q

How is water from the roots able to move up the plant?

A

Transpiration produces tension or ‘pull’ on the water in the xylem vessels by the leaves. Water molecules are cohesive so water is pulled up through the plant.

68
Q

What are the functions of a transpiration stream?

A
  • transporting mineral ions
  • providing water to keep cells turgid in order to support the plant
  • providing water to leaf cells for photosynthesis
  • keeping the leaves cool by evaporation
69
Q

what is a defence mechanism for when a plant is losing too much water ?

A

If plants lose water faster than it is replaced by the roots, the stomata can close to prevent wilting.

70
Q

what are the limitation of the light microscopes?

A

The resolution of a light microscope is around 0.2 μm, or 200 nm. This means that it cannot distinguish two points closer than 200 nm.

71
Q

what are the limitation of the electron microscopes?

A

Living cells cannot be observed using an electron microscope because samples are placed in a vacuum.

72
Q

What is the magnification triangle?

A

magnification= size of image/real size of image