B1 Flashcards

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1
Q

Order of units

A

1 km = 1000 m
1 m = 100 cm
1 mm = 1000 micrometers
1 micrometer = 1nm

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2
Q

Light vs electron microscopes

A

Light has lower resolution and magnification
Light is b & w, electron is colour
Light is 2D, electron is 3D
Electron needs specialist training
Light is smaller

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3
Q

How to work out total magnification

A

Multiply the magnification of eyepiece lens by the magnification of the objective lens

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4
Q

Magnification equation

A

Image size = magnification x size of real object

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5
Q

What is resolution

A

The ability to distinguish between two points

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6
Q

What is resolving power

A

Affects how much detail it can show

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7
Q

Structures in animal cell

A

Nucleus, cytoplasm, cell membrane, mitochondria, ribosomes

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8
Q

What does the nucleus do

A

Controls all the activities in the cell and contains the genes on the chromosomes that carry the instructions for making proteins needed to build new cells or organisms

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9
Q

What is the cytoplasm

A

Liquid gel in which organelles are suspended and where chemical reactions for life take place

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10
Q

What is the cell membrane

A

Controls the passage of substances such as glucose and mineral ions into the cell. Controls movement of substances such as urea or hormones out of the cell

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11
Q

What is mitochondria

A

Where aerobic respiration takes place

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12
Q

What are ribosomes

A

Where protein synthesis takes place

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13
Q

What is cell wall

A

Made of cellulose that strengthens the cell and gives it support

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14
Q

What are chloroplasts

A

Contain the substance chlorophyll which absorbs light so the plant can make food by photosynthesis

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15
Q

What is a permanent vacuole

A

Filled with cell sap which keeps the cell rigid to support the plant

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16
Q

What are eukaryotic cells

A

Have a cell membrane, cytoplasm and genetic material enclosed in a nucleus. All animals, plants, fungi and protista are eukaryotes

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17
Q

Example of prokaryote

A

Bacteria

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18
Q

Size of prokaryotic cell vs eukaryotic cell

A

Prokaryotic is much smaller

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19
Q

Structures in prokaryotic cell

A

Cytoplasm, cell membrane, cell wall (no cellulose), genetic material is in a free loop found in cytoplasm, may have plasmids, many have slime capsule, some have flagellum

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20
Q

Adaptations of nerve cells

A
  • lots of dendrites to make connections to other nerve cells
  • axon that carries nerve impulse from one place to another (very long)
  • synapses are adapted to pass the impulses to another cell or between a nerve cell and a muscle using transmitter chemicals
  • contain lots of mitochondria to provide energy needed to make transmitter chemicals
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21
Q

How do striated muscle cells work

A

Striated (striped) muscle cells work together in a muscle tissue, muscles contract and relax in pairs to move skeleton so vertebrates can move

22
Q

How do smooth muscle cells work

A

Form one of the layers of tissue in the digestive system and contract to move gut

23
Q

Adaptations of striated muscle cells

A
  • contain special proteins that slide over each other making the fibres contract
  • contain many mitochondria to transfer energy needed for chemical reactions that take place
  • can store glycogen (broken down and used in cellular respiration)
24
Q

Sperm cell adaptations

A
  • long tail
  • mitochondria
  • digestive enzymes
  • large nucleus with genetic information
25
Q

Adaptations of root hair cells

A
  • big surface area available for water to move into the cell
  • large permanent vacuole which speeds up movement of osmosis from soil to cell
  • many mitochondria for active transport
26
Q

Adaptations of photosynthetic cells

A
  • contain chloroplasts
  • positioned in continuous layers in the leaves and outer stem to absorb as much light as possible
  • large permanent vacuole to keep cell rigid as a result of osmosis (support stem and spread out leaves)
27
Q

Adaptations of xylem cells

A
  • are alive when originally formed by spirals of lignin form and kill cell, results in long hollow tubes
  • spirals and rings of lignin in the xylem make them very strong and able to withstand pressure of water movement
28
Q

Role of xylem cells

A

Carry mineral ions and water from roots across the plant

29
Q

Role of phloem

A

Carries food made by photosynthesis around the plant

30
Q

Adaptations of phloem

A
  • cell walls between the cells break down and form a sieve plates which allow water carrying dissolved food to move freely
  • lose a lot of their internal structures but are supported by companion cells to keep them alive
31
Q

What is diffusion

A

Net movement of particles from an area of high concentration to an area of low concentration down a concentration gradient until equilibrium is reached

32
Q

Relationship between diffusion rate and concentration gradient

A

Higher gradient = faster rate

33
Q

Relationship between temperature and diffusion

A

Higher temperature = faster rate

34
Q

Examples of diffusion in living things

A
  • dissolved substances moving into and out of cells
  • oxygen and carbon dioxide in lungs and red blood cells and body cells
35
Q

What is osmosis

A

Net movement of water molecules form an area of high concentration to low concentration through a partially permeable membrane until equilibrium is reached

36
Q

What is a dilute sugar solution

A

High concentration of water and low concentration of sugar

37
Q

What is a concentrated sugar solution

A

Low concentration of water and high concentration of sugar

38
Q

What does it mean if solution is isotonic to the cell

A

Concentration of solutes in solution outside the cell is the same as the internal concentration so no movement

39
Q

What does it mean if the solution is hypertonic to the cell

A

Concentration of solutes in the solution outside the cell is higher than the internal concentration so water moves out of cell

40
Q

What does it mean if solution is hypotonic to the cell

A

The concentration of solutes in the solution outside the cell is lower than the internal concentration so water moves into cell

41
Q

What happens to cell in animal if it is hypotonic

A

Water moves in by osmosis so the cell swells and may burst

42
Q

What happens to cell in animal if it is hypertonic

A

Water will move out by osmosis and cell will shrivel up and no longer survive

43
Q

What happens when water moves into plant cells by osmosis (hypotonic)

A

Vacuole swells which presses the cytoplasm against the cell wall and the pressure builds up until no more water can physically enter the cell (turgid)

44
Q

What happens if solution is hypertonic to cell contents in plants

A

Water will leave by osmosis and the cells will no longer be firm (become flaccid) so it can no longer support plant tissues, vacuole and cytoplasm shrink and eventually the cell membrane pulls away from the cell wall (plasmolysis)

45
Q

What is active transport

A

When substances move against a concentration gradient

46
Q

What is required for active transport

A

Energy produced during cell respiration so cells in active transport usually have lots of mitochondria

47
Q

Examples of active transport importance

A

Mineral ions from soil into roots
Sugar out of gut and kidney tubules into blood

48
Q

Surface area: volume ratio

A

Bigger organisms have smaller ratios so more difficult to exchange minerals
- gases and food molecules can no longer reach all cells in body
- metabolic waste cannot be removed fast enough

49
Q

Adaptations for exchanging materials

A
  • large surface area
  • thin membrane (short diffusion path)
  • efficient blood supply moves diffusing substances away maintaining steep gradient
  • being ventilated makes gas exchange more efficient by maintaining steep gradient
50
Q

Example of adapted exchange surfaces in humans

A

Alveoli
Villi

51
Q

Examples of adapted exchange surfaces

A
  • large roots
  • flat, thin leaves
52
Q

Example of adapted exchange surfaces in fish

A

Gills exchanging blood and carbon dioxide between blood and water