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Biology > Unit 1 - Key Concepts In Biology > Flashcards

Unit 1 - Key Concepts In Biology Flashcards

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1
Q

What does a magnification on x30 mean?

A

It appears 30 times bigger

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2
Q

How do you work out a microscopes magnification

A

You multiple the magnifications of the two lenses together

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3
Q

What does resolution mean

A

The smallest distance between two points that can still be seen as two points

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4
Q

What is the highest magnification and resolution that today’s best light microscopes can produce

A

x1500 with resolution of 0.0001 mm

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5
Q

What is different about an electron microscope compared to a light microscope

A

Beams of electrons pass through a specimen to build up an image

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6
Q

What do electron microscopes allow

A

Better magnification and resolution

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7
Q

Between each prefix, what is the multiplayer?

A

X1000

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8
Q

What is the order of prefixes starting from millimetres?

A

Milli, micro, nano, pico

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9
Q

What is a cell with a nucleus called?

A

Eukaryotic

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10
Q

What is the role of a cell membrane? (2)

A

To control what enters and leaves the cell, separates each cell

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11
Q

What is the role of the nucleus

A

To control the cells activities and contains the DNA

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12
Q

What is the role of cytoplasm

A

A watery jelly where most of the cells activities occur

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13
Q

What is the role of Mitochondria

A

Where aerobic respiration occurs

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14
Q

What is the role of ribosomes

A

To make new proteins.

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15
Q

What is the field of view

A

The circular area you see in a light microscope

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16
Q

What is the role of a cell wall

A

It supports and protects the cell

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17
Q

What is the role of a vacuole

A

It stores sap and helps keep the cell rigid

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18
Q

What is the role of the chloroplasts

A

They contain chlorophyll used for photosynthesis

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19
Q

Explain the core practical - using microscopes

A

Understand how to use a microscope
Collect a small specimen of your choice e.g cheek cells or onion tissue
Add a drop of stain to your microscope slide
Place the specimen on the stain
Lower a coverslip using a toothpick
Examine under a microscope starting with the lowest magnification
Draw and annotate a cell diagram

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20
Q

Why are bacteria difficult to see with light microscopes

A

They are small and mostly colourless

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21
Q

What is a flagellum

A

Part of a bacteria cell that spins, allowing it to move

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22
Q

What is the name for cells that do not have a nuclei

A

Projaryotic

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23
Q

In prokaryotic cells, where is the DNA stored (2)

A

In a large loopsof chromosomal DNA or smaller loops called plasmids

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24
Q

How do bacteria get their energy?

A

They release digestive enzymes into their surrounding and absorb the digested food into their cells

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25
Q

What do digestive enzymes do in humans?

A

They turn large molecules into smaller subunits which are small enough to be absorbed by the small intestine

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26
Q

What are polymers?

A

Molecules made up of monomers that are joined as a chain

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27
Q

Why does synthesis happen very slowly?

A

The sub units rarely collide with enough force to form a bond

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28
Q

Why does the break down of large molecules happen very slowly?

A

The smaller subunits need enough energy to break the bonds

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29
Q

What is a biological catalyst?

A

An enzyme that increases the rate of reactions

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30
Q

What are substrates?

A

The substances that enzymes work on

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31
Q

What are the substances that are produced by enzymes?

A

Products

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32
Q

Where is amylase found and what reaction is catalysed

A

In the salvia and small intestine

Breaks down starch into small sugars

33
Q

Where is catalase found and what reaction is catalysed?

A

Most cells, especially liver

Break down hydrogen peroxide to water and oxygen

34
Q

Where is starch synthase found and what reaction is catalysed

A

In plants

Synthesis of starch from glucose

35
Q

Where is DNA polymerase found and what reaction is catalysed

A

Nucleus

Synthesis of DNA from its monomers

36
Q

What are chemical reagents?

A

Substances used to identify certain changes

37
Q

What does iodine solution show and what happens

A

Identifies starch and turned from yellow to black

38
Q

What are reducing sugars

A

All of the smallest sugars e.g glucose and fructose

39
Q

What does Benedictus coalition show and what happens

A

It shows reducing sugars

Equal amount of food as solution is placed in hot water bath. Turns from blue to red (lots of sugars)

40
Q

What is the buried test (what does it show and how)

A

Shows protein

Potassium hydroxide solution is mixed with food, two drops of copper sulphate is added, turns from blue to purple

41
Q

What is the ethanol emulsion test? (What does it show and how)

A

It shows fats and oils (lipids)
Food is mixed with ethanol and shaken, some is poured into water and shaken again, the fats and oils will form a cloudy foam on top

42
Q

What is a calorimeter used for

A

To measure the amount of energy in a food by burning it

43
Q

How is the amount of energy in a food calculate using a calorimeter?

A

From the temperature of the water

44
Q

What types of sugars does the Benedictus test react with?

A

Reducing sugars

45
Q

Explain the core practical - testing foods

A

Carry out different investigations using the solutions and food samples to see what is in it
E.g iodine solution to find starch

46
Q

What are qualitative food tests?

A

They only show if a substance is present or not

47
Q

What is quantitative information

A

Data that shows values such as the mass

48
Q

What is the structure of a protein

A

A 3D molecule formed from a folding chain of amino acids

49
Q

What is the active site of an enzyme

A

Where the substrate of the enzyme fits at the start of the reaction

50
Q

Why can only certain enzymes work for specific substrates

A

The active sites are all different shapes

51
Q

What is the lock-and-key model?

A

A model that shows how enzymes work (2 substrates fit onto the active site of an enzyme where they have a bond formed between them making one product molecule)

52
Q

What can affect how he protein folds up? (2)

A

Changes in pH or temperature

53
Q

What happens when a protein is denatured

A

The enzymes has been changes affecting the shape of the active site so the substrates no longer fit

54
Q

For a graph showing the temperature and how long it takes for 100g of a substrate to be broken down, how do you work out the rate of reaction

A

100/ minutes ( it equals how much was broken down per minute)

55
Q

Why does the enzyme react faster at a higher temperature?

A

There is more energy so the molecules move faster, making it a higher chance of slotting into the active site

56
Q

What is the optimum temperature

A

The temperature in which the reaction happens the fastest

57
Q

What can affect the rate of enzyme-controlled reactions? (3)

A

Concentration of substance
pH
Temperature

58
Q

Why is the change of concentration in the substance cause a different change in the enzyme reaction than the other factors

A

It has an optimum concentration but any higher won’t make the rate less

59
Q

Explain the core practical - pH and enzymes

A

Set up a tripod, gauze, heat resistance may, Bunsen burner and beaker with water (40C)
Use the Bunsen burner to keep the water at this temperature
Place a drop of iodine solution in a spotting tile
Measure 2cm^3 of amylase solution 1cm^3 of a solution with a known pH and 2cm^3 of starch solution into a tube and place in water bath
Every 20s put a drop into an iodine solution drop
Repeat with different pHs

60
Q

What causes body odour?

A

Bacteria living on your body

61
Q

What is a concentration gradient formed from

A

A difference between two concentration

62
Q

What is diffusion

A

The spread of particles

63
Q

Which direction do particles diffuse on a concentration gradient

A

Down

64
Q

What causes a faster diffusion

A

A larger difference between the two concentrations

65
Q

What is a semi-permeable membrane?

A

A membrane that allows some particles through it but not all

66
Q

What type of membranes are cell membranes?

A

Semi-permeable

67
Q

What molecules can diffuse through cell membranes?

A

Water molecules

68
Q

What is osmosis

A

The diffusion of water molecules through semi-permeable cell membranes

69
Q

When does the overall movement of particles down a concentration gradient stop

A

When the concentration of solutes is the same on both sides

70
Q

What does osmosis cause to tissues

A

To gain or loss mass

71
Q

What is the word equation for a percentage change he in mass

A

Final mass - initial mass / initial mass x 100

72
Q

What does active transport allow? (2)

A

Molecules to be transported against a concentration gradient or molecules that are too large for the cell membrane

73
Q

What part of a cell is used for active transport?

A

Transporter protein

74
Q

What happens in active transport?

A

The proteins capture the molecules that fit and carry them across the membrane

75
Q

What are passive processes?

A

Processes that do not require energy

76
Q

Explain the core practical - osmosis in potato slices

A

Label different boiling tubes with different concentrations of sucrose solution
Cut similar sized potato slices
Blog each one dry and record its mass
Put one into each boiling tube for 15 mins
Take out, blot and record it’s mass again

77
Q

Why are different sucrose concentrations used for osmosis practical?

A

Higher sucrose concentration means less water molecules which means slower osmosis

78
Q

Why is a sucrose solution used for osmosis practical?

A

The sucrose molecules are too big for the cell membrane so only the water is let in

Biology (9 decks)

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