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Unit 1 - Key Concepts In Biology Flashcards

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
What do digestive enzymes do in humans?
They turn large molecules into smaller subunits which are small enough to be absorbed by the small intestine
26
What are polymers?
Molecules made up of monomers that are joined as a chain
27
Why does synthesis happen very slowly?
The sub units rarely collide with enough force to form a bond
28
Why does the break down of large molecules happen very slowly?
The smaller subunits need enough energy to break the bonds
29
What is a biological catalyst?
An enzyme that increases the rate of reactions
30
What are substrates?
The substances that enzymes work on
31
What are the substances that are produced by enzymes?
Products
32
Where is amylase found and what reaction is catalysed
In the salvia and small intestine | Breaks down starch into small sugars
33
Where is catalase found and what reaction is catalysed?
Most cells, especially liver | Break down hydrogen peroxide to water and oxygen
34
Where is starch synthase found and what reaction is catalysed
In plants | Synthesis of starch from glucose
35
Where is DNA polymerase found and what reaction is catalysed
Nucleus | Synthesis of DNA from its monomers
36
What are chemical reagents?
Substances used to identify certain changes
37
What does iodine solution show and what happens
Identifies starch and turned from yellow to black
38
What are reducing sugars
All of the smallest sugars e.g glucose and fructose
39
What does Benedictus coalition show and what happens
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
What is the buried test (what does it show and how)
Shows protein | Potassium hydroxide solution is mixed with food, two drops of copper sulphate is added, turns from blue to purple
41
What is the ethanol emulsion test? (What does it show and how)
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
What is a calorimeter used for
To measure the amount of energy in a food by burning it
43
How is the amount of energy in a food calculate using a calorimeter?
From the temperature of the water
44
What types of sugars does the Benedictus test react with?
Reducing sugars
45
Explain the core practical - testing foods
Carry out different investigations using the solutions and food samples to see what is in it E.g iodine solution to find starch
46
What are qualitative food tests?
They only show if a substance is present or not
47
What is quantitative information
Data that shows values such as the mass
48
What is the structure of a protein
A 3D molecule formed from a folding chain of amino acids
49
What is the active site of an enzyme
Where the substrate of the enzyme fits at the start of the reaction
50
Why can only certain enzymes work for specific substrates
The active sites are all different shapes
51
What is the lock-and-key model?
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
What can affect how he protein folds up? (2)
Changes in pH or temperature
53
What happens when a protein is denatured
The enzymes has been changes affecting the shape of the active site so the substrates no longer fit
54
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
100/ minutes ( it equals how much was broken down per minute)
55
Why does the enzyme react faster at a higher temperature?
There is more energy so the molecules move faster, making it a higher chance of slotting into the active site
56
What is the optimum temperature
The temperature in which the reaction happens the fastest
57
What can affect the rate of enzyme-controlled reactions? (3)
Concentration of substance pH Temperature
58
Why is the change of concentration in the substance cause a different change in the enzyme reaction than the other factors
It has an optimum concentration but any higher won’t make the rate less
59
Explain the core practical - pH and enzymes
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
What causes body odour?
Bacteria living on your body
61
What is a concentration gradient formed from
A difference between two concentration
62
What is diffusion
The spread of particles
63
Which direction do particles diffuse on a concentration gradient
Down
64
What causes a faster diffusion
A larger difference between the two concentrations
65
What is a semi-permeable membrane?
A membrane that allows some particles through it but not all
66
What type of membranes are cell membranes?
Semi-permeable
67
What molecules can diffuse through cell membranes?
Water molecules
68
What is osmosis
The diffusion of water molecules through semi-permeable cell membranes
69
When does the overall movement of particles down a concentration gradient stop
When the concentration of solutes is the same on both sides
70
What does osmosis cause to tissues
To gain or loss mass
71
What is the word equation for a percentage change he in mass
Final mass - initial mass / initial mass x 100
72
What does active transport allow? (2)
Molecules to be transported against a concentration gradient or molecules that are too large for the cell membrane
73
What part of a cell is used for active transport?
Transporter protein
74
What happens in active transport?
The proteins capture the molecules that fit and carry them across the membrane
75
What are passive processes?
Processes that do not require energy
76
Explain the core practical - osmosis in potato slices
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
Why are different sucrose concentrations used for osmosis practical?
Higher sucrose concentration means less water molecules which means slower osmosis
78
Why is a sucrose solution used for osmosis practical?
The sucrose molecules are too big for the cell membrane so only the water is let in

Biology (9 decks)

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