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AQA GCSE Biology > B1 (Cell structure and transport) > Flashcards

B1 (Cell structure and transport) Flashcards

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1
Q

How does a light microscope work?

A

Light microscopes use a beam of light to form an image of the object.

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2
Q

How does an electron microscope work?

A

Electron microscopes use a beam of electrons to form an image of the object.

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3
Q

Give some advantages and disadvantages of light and electron microscopes…

A

Light microscopes are relatively cheap and can be used almost anywhere, however the have much lower magnification and resolution compared to the electron microscope. The electron microscope is extremely expensive and must be kept in temperature, pressure and humidity controlled rooms to operate.

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4
Q

What is the equation for magnification?

A

Magnification = size of image / size of actual object

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5
Q

Why do we always use the lower power objective lens first?

A

So we can have a larger field view of the cells. This makes it easier to find what you are looking for.

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6
Q

What is resolution?

A

Resolution is the distance between two visible points on a picture. It is the amount of detail in an image.

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7
Q

What is a slide?

A

A slide is a thin piece of glass where you place your specimen on.

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8
Q

What is a cover slip?

A

A cover slip is a thin piece of glass which you use to cover your specimen to protect it.

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9
Q

What are cells?

A

Cells are the building blocks of life.

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10
Q

What is a tissue?

A

A group of cells.

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11
Q

What is an organ?

A

A group of tissues.

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12
Q

What is an organ system?

A

A group of organs.

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13
Q

What is an organism?

A

A group of organ systems.

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14
Q

Define a nucleus?

A

A nucleus controls the activity of the cell. It contains genetic information about the cell.

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15
Q

What is a cytoplasm?

A

A cytoplasm is a jelly-like structure. This is where most chemical reactions. Made of cellulose.

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16
Q

What is a cell membrane?

A

The cell membrane controls what enters and leaves the cell. It is a partially permeable substance.

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17
Q

What is mitochondria?

A

Mitochondria releases energy from glucose for aerobic respiration.

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18
Q

What are ribosomes?

A

Ribosomes provide protein to the cell, in order for the cell to grow.

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19
Q

What are chloroplasts?

A

Chloroplasts contain chlorophyll which traps sunlight for photosynthesis to occur.

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20
Q

What is a permanent vacuole?

A

The vacuole is a space filled with a solution of sugars and ions called cell sap. This keeps the cell turgid.

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21
Q

What is a cell wall?

A

The cell wall strengthens and supports the cell. Made of cellulose.

22
Q

What is a plasmid?

A

A plasmid is an extra loop of genetic information.

23
Q

State some similarities and differences between animal and plants cells…

A

Both animal and plant cells have a nucleus, cytoplasm and cell membrane. However, animal cells do not have chloroplasts, a permanent vacuole and a cell wall.

24
Q

State similarities and differences between prokaryotic and eukaryotic cells…

A

Both eukaryotes and prokaryotes have a cell membrane, cytoplasm and ribosomes. Eukaryotes have an enclosed nucleus however prokaryotic cells have genetic information stored in loops.

25
Q

State some adaptions of the nerve cell…

A
  • The nerve cell has lots of dendrites to make connections to other nerve cells.
  • It has a large axon for the nerve impulse to pass through.
  • The synapse is adapted to pass on nerve impulses to other parts of the body.
26
Q

State some adaptions of the muscle cell…

A
  • It has special fibres that slide over each other, making it easier to contract and relax.
  • It has many mitochondria to release the energy need to contract.
  • There is a special chemical called glycon, which can be broken down and used by the mitochondria.
27
Q

State some adaptions of the sperm cell…

A
  • It has a long tail for swimming though the female reproductive system.
  • It has a dynamic head to making it easier to swim.
  • It has a large nucleus for the information to be passed on.
28
Q

State some adaptions of the root hair cell…

A
  • They greatly increase the surface area available for water to move into the cell.
  • They have a large permanent vacuole that speeds up the movement of water by osmosis.
  • They have many mitochondria needed for the active transport of minerals and ions into the root hair cell.
29
Q

State some adaptions of the photosynthetic cell…

A
  • They contain a special green structure called chloroplasts containing chlorophyll which traps sunlight for photosynthesis.
  • They are positioned in continuous layers of leaves for maximum light intake for photosynthesis.
  • They have a large permanent vacuole that keeps the cell rigid as a result of osmosis.
30
Q

State some adaptions for the xylem cell…

A
  • When xylem cells are first formed, they are alive but a special chemical called lignin building up in the cell wall. This kills the cell and forms a long hollow tube that allows easy flowing of water and mineral ions.
  • The spirals and rings of lignin strengthens the cell, enabling it to handle high pressures of water moving up the plant.
31
Q

State some adaptions for the phloem cell…

A

-Phloem cells loose a lot of their internal structures but they are supported by companion cells.

32
Q

What is diffusion?

A

Diffusion is the net movement of particles from a high to low concentration through a partially permeable membrane.

33
Q

What factors affect diffusion?

A

Difference in concentrations, the temperature, available surface area.

34
Q

What is active transport?

A

Active transport is the net movement from a low to high concentration though a partially permeable membranes. Requires energy.

35
Q

What is osmosis?

A

Osmosis is the net movement of water from a high to low water potential though a partially permeable membrane.

36
Q

What is a hypotonic solution?

A

Low concentration of sugar and ions on the outside of the cell.

37
Q

What is a hypertonic solution?

A

High concentration of sugars and ions on the outside of the cell.

37
Q

What is cytolysis?

A

Occurs when a cell bursts due to an osmotic imbalance that has excess water to diffuse into the cell.

39
Q

What is an isotonic solution?

A

When the solution has the same amount of particles on the inside and on the outside of the cell. There is no net movement of particles because there is no concentration gradient.

39
Q

What is plasmolysis?

A

The process in which cells loose water in a hypertonic solution.

40
Q

Why is it better to work out percentage change in mass rather that change in mass?

A

Because it makes the investigation of the samples of cubes more accurate.

42
Q

Suggest why epithelial cells have many mitochondria…

A

Because active transport requires energy from respiration.

43
Q

What is a transmission electron microscope?

A

Gives 2D image with high magnification and resolution.

44
Q

What is a scanning electron microscope?

A

Gives dramatic 3D images with lower magnification.

45
Q

Name one food molecule absorbed into epithelial cells by active transport.

A

Glucose/sugar.

46
Q

In the osmosis practical, why did cube A increase more in mass compared to cube B?

A

More water was taken in because cube A had a larger surface area to volume ratio which allowed more osmosis to happen.

47
Q

Explain the advantages of red blood cells passing through a capillary one at a time…

A

More oxygen is released to tissues, more surface area is exposed and shorter distance for gas exchange because cells are more closer to capillary wall.

48
Q

Why is it necessary to absorb some food molecules by active transport?

A

If the food is against a concentration gradient.

49
Q

Why is diffusion important in human?

A

In humans we use the process of diffusion in our alveoli, where our red blood cells get diffuses with oxygen through this process.

50
Q

Why is diffusion important in animals?

A

In plants, the root hair cells use diffusion to get sugars and ions from the soil in order to live.

51
Q

As the organism gets larger…

A

The surface area to volume ratio gets smaller. This makes it for difficult to exchange materials.

52
Q

How have larger organisms adapted in performing diffusion?

A

Larger surface area (more diffusion surface), thin walls (short distance), efficient blood supply (maintains a steep concentration gradient)

AQA GCSE Biology (4 decks)

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