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Biology (School) > GCSE 1.2-1.7 and 2.1-2.6 > Flashcards

GCSE 1.2-1.7 and 2.1-2.6 Flashcards

1
Q

Describe all parts of a light microscope

A 
Ocular lens
Body tube
Revolving nosepiece 
Low, medium and high power objectives 
Arm
Stage clips
Stage
Diaphragm 
Lightsource
Coarse adjustment knob (big)
Fine adjustment knob (small)
Base
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2
Q

What magnification does the eyepiece lens give

A

X10

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3
Q

What magnification does each objective lens give and what is the total

A

Low - X4 so total = X40
Medium - X10 so total = X100
High - X40 so total = X400

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4
Q

What is the purpose of iodine and methylene blue on your temporary mounts (onion slide)

A

To stain the cells/structures and make them visible under light

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5
Q

Why must the onion tissue be 1 cell thick? What happens if you have more than one layer?

A

If it is more than one cell thick it will be too hard to see an individual cell as the light can’t reach the top layer

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6
Q

Why is it important to only use the fine focus when viewing at high power?

A

As it may resulting in crashing into the slide if coarse is used

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7
Q

What happens to the area of the specimen you can see as you increase magnification

A

You see it closer and therefore more detail

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8
Q

What are the seven process which are common to all living things

A 
Movement 
Respiration
Sensitivity 
Growth 
Reproduction 
Excretion 
Nutrition
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9
Q

What is something made of a large number of cells

A

Multicellular

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10
Q

What are organism described as when only made up of one cell

A

Unicellular

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11
Q

What does a nucleus do

A

Contains all the chemical reactions that take place inside the cell
Contains all the genetic information needed to produce a new living organism. It is bound by a nuclear membrane

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12
Q

What do chromosomes do

A

Found within nucleus
Made of DNA
Consist of many genes which control the organisms characteristics

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13
Q

What is a mitochondria

A

Free in Cytoplasm
The site of cell respiration
The more energy required by a cell, the more mitochondria will be present within it eg muscle and sperm cells

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14
Q

What is cytoplasm

A

A jelly like substance with hundreds of chemicals in it

Lots of chemical reactions take place in it

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15
Q

What is a cell membrane

A

A think skin around the cell, holding the cell together
Provides a barrier, and controls what passes in and out of the cell
As only some substances can cross this membrane it is described as selectively permeable

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16
Q

What is a cell wall

A

Lies outside of cytoplasm
Made of cellulose
Provides a ridged support and so gives the plant cell a particular shape

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17
Q

Name all the parts in a plant cell

A 
Cytoplasm
Cell wall
Cell membrane (2 lines)
Mitochondria 
Vacuole 
Chloroplasts 
Nucleus 
Nuclear membrane
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18
Q

Name all the parts in an animal cell

A 
Cytoplasm 
Mitochondria 
Cell membrane 
Nucleus 
Nuclear membrane
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19
Q

What is a large permeable vacuole

A

Fluid filled space surrounded by a membrane
Contains cell sap, made up of water, minerals and dissolved substances
Keeps the shape of the cell, when full, and keeps the cells rigid giving the plants more support

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20
Q

What are chloroplasts

A

These are present in plant cells which photosynthesise
Contain a green substance called chlorophyll that trap light energy and help the plant make its own food by photosynthesis

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21
Q

Name the parts of a bacterial cell

A 
Cell wall 
Cytoplasm 
Bacterial DNA (chromosomal DNA)
Plasmid DNA
Flagellum
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22
Q

Give the light microscope equation

A

Total magnification = magnification of objective lens x magnification of eyepiece lens

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23
Q

What is the magnification triangle

A

O
M A

O = observed size
A = actual size
M = magnification
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24
Q

A nucleus in a photograph, magnification X400, measures 15mm. What is its actual size in um

A

A=O/M = 15/400 = 37.5 um

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25
Q

How much is 1000 um in mm

A

1mm

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26
Q

How much is 1000mm in m

A

1m

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27
Q

How much is 1m in um

A

1,000,000um

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28
Q

If a cell measures 1.3mm what is its length in um

A

1300

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29
Q

If a cell measures 27.5um what is its length in mm

A

0.0275mm

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30
Q

Give some facts about electron microscopes

A

Use an electron beam instead of light, which is focussed using electromagnets
Specimen has to be specially prepared and held inside vacuum chamber from which the air has been pumped out
Image is formed as photograph (electron micrograph)
Very large pieces of equipment that require special rooms in a laboratory

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31
Q

Resolution of a light microscope

A

0.20um

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32
Q

Resolution of an electron microscope

A

0.25x10 to the power of -3um

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33
Q

Magnification using light microscope

A

Up to X1500

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34
Q

Magnification using electron microscope

A

Up to X500,000

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35
Q

Give some specialised animal cells

A

Sperm cell
Ciliates epithelial cells
Nerve cells

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36
Q

Give some specialised plant cells

A

Root hair cells
Onion epidermical cells
Plant leaf palisade mesophyll cells

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37
Q

Cells to organism flow chart

A

Cells -> tissue -> organ -> organ system -> organism

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38
Q

What forms a tissue

A

Group of specialised cells working together

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39
Q

What forms an organ

A

Tissues working together

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40
Q

What forms an organ system

A

Organs working together

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41
Q

What forms an organism

A

Organ systems working together

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42
Q

Define diffusion

A

The random movement of molecules from an area of high concentration to an area of low concentration, down a concentration gradient

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43
Q

What is net movement

A

Overall movement

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44
Q

Give an example of diffusion of gases

A

Oxygen required for respiration passes through gas exchange surfaces eg alveoli by diffusion. The carbon dioxide produced by respiration diffuses in the opposite direction

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45
Q

Why is smoke visible coming out of a chimney but becomes invisible very quickly

A

It disperses in air. High concentration of soot particles which diffuse into surrounding air becoming dispersed and appearing invisible

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46
Q

What are stem cells

A

Cells which are undifferentiated and have not yet become specialised

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47
Q

What are the 2 important abilities stem cells have

A

To continue dividing by cell division to produce more stem cells
To differentiate into a wide variety of specialised cells

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48
Q

Where can stem cells be harvested from

A

Umbilical comes of babies immediate after birth
Placenta of babies immediately after birth
Early human embryos that are not used in fertility treatments

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49
Q

Give an example of stem cells being used in medicine

A

Bone marrow transplants in treating Leukaemia

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50
Q

Digestive organs

A

Mouth, stomach, small + large intestines

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51
Q

Respiratory organs

A

Trachea, bronchi, lungs

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52
Q

Skeletal organs

A

Ribs and bones

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53
Q

Circulatory organs

A

Heart + blood vessels

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54
Q

Excretory organs

A

Liver, kidneys, + bladder

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55
Q

Nervous organs

A

Brain + spinal cord

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56
Q

Reproductive organs

A

Testes + ovaries

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57
Q

Main organs in plants

A

The root
The stem
The leaves
The flower

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58
Q

Describe where stem cells occur in plants

A

In the meristems of plants

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59
Q

Word equation for photosynthesis

A

Carbon dioxide + water -light energy-chlorophyll-> glucose + oxygen

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60
Q

Balanced chemical equation for photosynthesis

A

6CO(2) + 6H(2)O -light energy-chlorophyll-> G(6)H(12)O(6) + 6O(2)

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61
Q

Describe the parts of a leaf

A 
Very top - wax cuticle 
Top chunk - upper epidermis 
Middle chunk - mesophyll 
Upper middle - palisade mesophyll 
Lower middle - spongy mesophyll 
Bottom chunk - lower epidermis 
Gap - stoma 
Bits before gap - guard cell
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62
Q

Give some adaptations of the leaf for light absorption

A 
Thin leaves 
Learned surface area 
Cuticle 
Upper epidermis
Palisade mesophyll layer
Chloroplasts
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63
Q

What are endothermic reactions

A

reactions which require or absorbs energy from its surrounding, usually in the form of heat

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64
Q

What is a better way of measuring the rate of photosynthesis than counting bubbles

A

Bubbles could be different sizes so should measure volume of oxygen produced

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65
Q

What happens in the light intensity graph of rate of photosynthesis

A

It goes up and plateaus

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66
Q

What happens in the time of day graph of rate of photosynthesis

A

At 00:00 it start going up

At 12:00 it peak and dips down again for 24:00

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67
Q

What happens in the carbon dioxide concentration graph of rate of photosynthesis

A

Goes up and then keeps going up very vey slightly

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68
Q

What happens in the termperature graph of rate of photosynthesis

A

Goes up really high then goes all the way down

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69
Q

What are the limiting factors in the light intensity graph of rate of photosynthesis which has the letters A, B and C and 2 lines based on higher and lower CO2

A

A - Light intensity
B - carbon dioxide
C - Temperature

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70
Q

How is maximum heat achieved in a green house

A

Paraffin heaters
Artificial light
Water sprinklers
Fertilisers

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71
Q

Give the word equation for respiration

A

Glucose + oxygen -> water + carbon dioxide + energy

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72
Q

Whenever both respiration and photosynthesis are equal what is it called

A

Compensation point

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73
Q

Explain why raising light intensity increases the rate of photosynthesis

A

As light is an essential part of photosynthesis

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74
Q

What is a heat shield

A

A heat shield means there is only one source of heat.

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75
Q

When are compensation points

A

Dawn and dusk

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76
Q

Describe photosynthesis and respiration during the day

A

Both photosynthesis and respiration occur
At high light intensity (midday) - the rate of photosynthesis is greater than the rate of respiration
Therefore the net movement is CO2 enters and O2 exits the leaf

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77
Q

Describe photosynthesis and respiration at night

A

There is no light for photosynthesis
Respiration still occurs
So O2 enters the leaf and CO2 leaves it

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78
Q

Describe photosynthesis and respiration at low light intensity (dawn and dusk)

A

The rate of photosynthesis slows down and is equal to the rate of respiration. This is the compensation point. Therefore overall there is no gas exchange as:
The CO2 produced in respiration is used for photosynthesis
the O2 produced in photosynthesis is used for respiration

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79
Q

How can the movement of carbon dioxide and oxygen into and out of plants be determined

A

Using hydrogen carbonate indicator

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80
Q

Give the three colours of hydrogen carbonate indicator and why

A

Red in normal atmospheric carbon dioxide levels
Yellow in increased carbon dioxide levels
Purple in decreased carbon dioxide levels

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81
Q

What are the main factors of photosynthesis and crop production

A 
Temperature 
Carbon dioxide levels 
Light intensity 
Mineral availability 
Water availability
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82
Q

Which factor limits photosynthesis on a bright winter afternoon in a British grassland

A

There will be enough light and carbon dioxide therefore temperature is likely to be limiting

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83
Q

What factor is limiting photosynthesis in a cornfield in mid summer sunshine in southern France

A

There will be enough light and temperatures will be high. Carbon dioxide is likely to be the limiting factor

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84
Q

On a graph with Y axis (rate of photosynthesis) what are the limiting factors at A, B and C

A

A - light intensity
B - temperature
C - carbon dioxide

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85
Q

Why do thin leaves help light absorption

A

The short distance from the top of a leaf (cuticle) to the bottom (lower epidermis) allows all the cells to receive light

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86
Q

Why does a large surface area help light absorption

A

Enables the leaf to absorb maximum sunlight onto its surface

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87
Q

Why do cuticles help light absorption

A

This is thin and transparent so doesn’t prevent light entering, but is also a waxy layer so also reduces water loss by evaporation. It is a physical defence mechanism

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88
Q

Why does a palisade mesophyll layer help light absorption

A

Contains many tightly packed and regular shaped palisade cells that are rich in chloroplasts near the surface of the leaf to obtain maximum sunlight

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89
Q

What does the upper epidermis do to help light absorption

A

Cell walls are a physical defence for leaf against microbes, and are transparent to allow light to pass through

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90
Q

What do chloroplasts do to help light absorption

A

Contain the pigment chlorophyll to absorb sunlight

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91
Q

What does a spongy mesophyll layer do to help gas exchange

A

The cells have fewer chloroplasts and are irregularly shaped resulting in a large surface area for gas exchange. There are many air spaces within this layer

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92
Q

What do intercellular air spaces do to help gas exchange

A

These occur in the spongy mesophyll and allow the movement of oxygen and carbon dioxide through the leaf

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93
Q

What do guard cells and stomata do to help gas exchange

A

Carbon dioxide and oxygen can enter and leave through the stomata. Stomata are small pores that occur between the guard cells. These guard cells regulate the opening and closing of stomata. There are more stomata non the underside of a mesophytic leaf to prevent water loss. In many plants stomata are open during the day but closes at night

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94
Q

How did the leaf change when placed in boiling water - what has happened and why

A

When placed I’m boiling water the plant was softened and killed as the temperature was so high. It also allows chemicals to enter

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95
Q

How did the leaf change when it was placed in boiling ethanol - why is this an important step

A

When placed in boiling ethanol all of the chlorophyll came out

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96
Q

In the experiment finding out if chlorophyll is needed for photosynthesis what colour changes occur to the leaf and why

A

Only the green parts of the variegated leaf contained chlorophyll and so they reacted with the iodine and turned blueblack. The areas without chlorophyll are unable to produce starch so they do not turn blueblack

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97
Q

How is a plant destarched

A

Leave in a dark place for a period of time

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98
Q

Why is a plant destarched

A

To prevent photosynthesis

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99
Q

How much starch can be stored in a plant

A

Unlimited as it is insoluble and so doesn’t upset the water balance of the cells.

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99
Q

What can glucose be turned into in a plant

A
  1. Sucrose and carried to other parts of the plant
  2. Glucose for respiration or active transport
  3. Starch and stored
  4. Glucose combines with nitrates to become amino acids which are made into protein - a vital building block for plant cells involved in growth and repair
  5. Lipids for storage in seeds
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99
Q

Why is glucose turned into lipids in seeds

A

Lipids are insoluble and contain twice as much energy as the same weight of starch, thus enabling storage of more energy in a small space.

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99
Q

How do you adapt the elodea test to show how light intensity, carbon dioxide and temperature affects the rate of photosynthesis

A

Light intensity- by moving a desk lamp further away at pre determined intervals from the pond weed
Carbon dioxide - by adding more spatulas of hydrogen carbonate indicator to the water
Temperature - by adding warm water to the experiment and recording the temperature with a thermometer

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99
Q

Why is it necessary to take 5 minutes before taking measurements in the elodea test

A

Need plant to get ready for new conditions and get used to it (plant needs to equilibrate to new conditions)

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99
Q

How is the rate of photosynthesis calculated in the elodea test

A

Count bubbles given off by plant in set period of time

99
Q

What are the 5 limiting factors of photosynthesis

A
  1. Light
  2. Chlorophyll
  3. Carbon dioxide
  4. Water
  5. A suitable temperature
99
Q

What are the types of carbohydrates

A

Simple carbohydrates are called sugars eg glucose, lactose.

Complex carbohydrates are built from many sugar molecules joined together eg cellulose, starch and glycogen

99
Q

What is starch

A

Starch is a polysaccharide built from a chain of glucose molecules joined together

99
Q

What is a glucose

A

Glucose is a monosaccharide. Respiration provides the body with energy using glucose as a raw material

99
Q

How much energy does 1g of carbohydrate, fat or protein

A

1g of Carbohydrate or protein = 17kJ

1g of fat = 38kJ

99
Q

What are proteins

A

These are the building blocks for the growth and repair of cells. They can be used for energy when stores of carbohydrate and lipids are low. They are made from long chains of amino acids.

100
Q

What breaks down proteins in pot amino acids

A

Protease

101
Q

What breaks down starch into glucose

A

Amylase

102
Q

What breaks down fats (lipids) into glycerol and then fatty acids

A

Lipase

103
Q

What are lipids (fats)

A

Lipids consist of a molecule of glycerol linked to 3 fatty acids. Fats are energy stores. Fat layers are also good insulation

104
Q

What reagent is used with starch and what are the initial and positive final colours

A

Reagent - iodine
Initial colour - yellow/brown
Positive colour - blue/black

105
Q

What reagent is used with sugar and what are the initial and positive final colours

A

Reagent - Benedict’s reagent
Initial colour - blue
Positive colour - green - brick red precipitate

106
Q

What reagent is used with protein and what are the initial and positive final colours

A

Reagent - biuret solution
Initial colour - blue
Positive colour - purple

107
Q

What reagent is used with fat and what are the initial and positive final colours

A

Reagent - ethanol
Initial colour - clear
Positive colour - white emulsion

108
Q

What is the equation used to work out the energy in 1g of food

A

Energy released form food per gram (J) = (mass of water (g) X temperature rise (degrees C) X 4.2) / mass of food sample (g)

109
Q

Name some factors which could affect the amount of energy needed for a person

A

Size, activity, age, gender, pregnancy, growing child

110
Q

Place the following carbohydrates in order of number of units contained starting with the smallest

Glycogen Glucose Lactose

A

Glucose Lactose Glycogen

111
Q

Give one example of a functional protein in a cell

A

Hormones

112
Q

Which 3 elements are in carbohydrates, fats and proteins

A

Carbon, hydrogen and oxygen

113
Q

Which additional element is found on proteins

A

Nitrogen

114
Q

What are the properties of sugars

A

C H O

6 12 6

115
Q

What is an enzyme

A

All enzymes are proteins. Enzymes are biological catalysts which speed up the rate of reactions without being used up in the process

116
Q

What does the statement ‘enzymes are substrate specific’ mean

A

This means that each enzyme will only react with certain substances

117
Q

What is the optimum pH or optimum temperature

A

The pH or temperature at which an enzyme works best at

118
Q

What is denaturation and how does it happen

A

Denaturation is when an enzyme is broken and cannot function properly. An enzyme is denatured at either very Hugh temperatures or extremes of pH

119
Q

What are the 4 things that affect the rate of an anthem controlled reaction

A
  1. The concentration of the enzymes
  2. Th concentration of the substrate
  3. The pH
  4. The temperature
120
Q

What happens to enzymes at low temperatures

A
  1. Decreased kinetic energy
  2. Particles move around less and are less likely to collide
  3. Less collisions means a slower reaction
121
Q

What happens to enzymes when the temperature is increased

A
  1. Increases kinetic energy
  2. They move around faster and are therefore more likely to collide
  3. Move collisions means more reactions as some must fit
  4. Reaches optimum temperature- maximum rate of reaction
122
Q

What happens to enzyme activity when the enzyme concentration is increased

A
  1. Increased number of enzymes
  2. More free active sites to fit into
  3. More likely something will collide and be broken down
  4. Increases rate of reaction
123
Q

What are the 5 important properties of enzymes

A
  1. They’re all proteins
  2. Can be used again and again
  3. Catalyses one reaction
  4. Influenced by temperature
  5. Influenced by temperature
124
Q

What is respiration

A

Respiration is the release of energy from food

125
Q

What is the energy released in respiration used for

A
  1. Growth
  2. Movement
  3. Reproduction
  4. Active transport of materials
  5. Heat
126
Q

What is the aerobic respiration word equation

A

Glucose + oxygen = energy + carbon dioxide + water

127
Q

What is the balanced aerobic respiration equations

A

(C)6(H)12(O)6 + (6O)2 = energy + (6O)2 + (6H)2(O)

128
Q

What are the two types of respiration

A

Aerobic and anaerobic

129
Q

What happens in the muscles when anaerobic exercise occurs

A
  1. Lactic acid is produced

2. Much less energy released

130
Q

What is the word equation for anaerobic respiration

A

Glucose = lactic acid + small amount of energy (150kJ)

131
Q

What is anaerobic respiration

A

The release of energy from food without oxygen

132
Q

Is there a link between level of fitness and breathing rate

A

The fitter you are the less your breathing rate

133
Q

Is there a link between level of fitness and recovery time

A

The fitter you are the faster your recovery time

134
Q

How does the body get rid of lactic acid

A

The oxygen oxidises the lactic acid

135
Q

What is yeast used in

A
  1. Beer and wine

2. Baking

136
Q

What is the word equation for anaerobic respiration in yeast

A

Glucose = alcohol + carbon dioxide + small amount of energy

137
Q

What are the similarities between aerobic and anaerobic respiration

A
  1. Energy is released by breakdown of sugar
  2. ATP made
  3. Some energy lost as heat
  4. CO2 is produced
138
Q

What are the differences between aerobic and anaerobic respiration

A

Aerobic - uses O2, no alcohol/lactic acid made, large amount of energy
Anaerobic- does not use O2, lactic acid in made in humans and alcohol in yeast, small amount of energy

139
Q

What is the path of air in the body

A

Nasal cavity - trachea - 2 bronchi - many bronchioles - many alveoli

140
Q

Why is it better to breathe through your nose

A

It filters and warms the air before it reaches your lungs

141
Q

Why is the trachea held open by a ring of cartilage

A

To stop it from collapsing

142
Q

What is in between the ribs and lungs

A

Pleural fluid

143
Q

What are some respiratory surfaces in the body that are adapted

A

Large surface area in the lungs - many alveoli in each lung and large surface area means more gas exchange
Thin wall with shirt diffusion distances
Moist walls help gases pass through respiratory surfaces because the gases dissolve in the moisture
Permeable surfaces - the moist thin walls make the respiratory surfaces permeable
The alveoli are surrounding by capillaries to ensure any oxygen diffusing is carried around the body
The process of breathing ensures that there is a large diffusion gradient that encourages oxygen to diffuse into the blood and carbon dioxide to diffuse into the alveoli

144
Q

What is ventilation

A

The movement of air into and out of the lungs

145
Q

What happens when you inhale

A

Intercostal muscles contract, rib cage moves up and out, diaphragm contracts and moves down, volume in thorax increases, air pressure in chest decreases and air moves in

146
Q

What happens when you exhale

A

Intercostal muscles relax, rib cage moves down and in, diaphragm relaxes and moves down, volume in throat decreases, air pressure in chest increases and air moves out

147
Q

Name the elements that are in inspired air

A

21% oxygen
0.04% Carbon dioxide
78% nitrogen
A little bit of water vapour

148
Q

Name the elements that are in expired air

A

16% oxygen
4% carbon dioxide
78% nitrogen
A lot of water vapour

149
Q

What colour does bicarbonate indicator and limewater turn when in the presence of carbon dioxide

A

Bicarbonate indicator: red to yellow

Limewater: clear to cloudy

150
Q

What does the balloons, thin sheet of rubber and plastic tube represent in the model of the lungs

A

Balloons are the lungs
Thin sheet of rubber is the diaphragm
Plastic tubes are the trachea and bronchi

151
Q

Name 3 differences between the model lungs and real lungs

A
  1. In a human the ribs work with the diaphragm to change the volume of the thorax but the model lung only shows the diaphragm
  2. In real lungs the diaphragm is a dome shape not a flat like in the model lungs
  3. The space between the lungs and chest wall is a lot greater in the model
152
Q

What must all respiratory surfaces be/have

A
  1. Be well supplied with air/blood/water
  2. Be moist
  3. Have a large surface area
  4. Be permeable and be thin
  5. Gave a diffusion gradient for gases
153
Q

What is gas exchange

A

Gas exchange is the exchange of gases across a respiratory surface eg oxygen is taken in and carbon dioxide is removed

154
Q

Name the parts of the physical parts of a Central Nervous System diagram

A

Brain
Skull
Vertebrae
Spinal cord

155
Q

What are the two main parts of the central nervous system

A
  1. Brain

2. Spinal cord

156
Q

What are the three main parts of the peripheral nervous system

A
  1. Sensory neurones
  2. Association neurones
  3. Motor neurones
157
Q

Give the flow chart for nerves

A

Stimulus -> receptor -> brain -> effector -> response

158
Q

What are the 3 types of neurone

A
  1. Sensory
  2. Association
  3. Motor
159
Q

What is a nerve impulse also known as

A

An electrical impulse

160
Q

What are synapses

A

Small gaps between neurones à Roos which impulses jump

161
Q

What happens at a synapse

A
  1. A neurotransmitter chemical produced in on neurone, is released from vesicle
  2. The chemical diffuses across the synapse and attaches to receptors on the next neurone
  3. If there is a high enough concentration of neurotransmitters, it will trigger an electrical impulse in the next neurone
162
Q

What are voluntary actions

A

They are responses to stimuli which you can choose to do or not to do

163
Q

What are involuntary actions

A

These happen whether we want them or not. We cannot make them happen or stop happening. They occur in our bodies all the time. We have no conscious control over them

164
Q

What are reflex actions

A

A reflex is an automatic immediate response to a particular stimulus by means of a nervous pathway involving a small number of nerve cells

165
Q

What does the spinal cord contain

A

Dark central grey matter, white matter and the central canal

166
Q

What does the central canal contain

A

Cerebrospinal fluid

167
Q

What does dark central grey matter contain

A

It contains mainly cell bodies and synapses

168
Q

What does white matter contain

A

It Contains long nerve fibres which run up and down the spinal cord, connecting with many reflex arcs and the brain

169
Q

What are effectors

A

They are the structures in the body that carry out the response to a given stimulus eg the elbow joint

170
Q

What are antagonistic muscles

A

Opposing muscles

171
Q

Where is a transmitter substance found in relation to neurones

A

In vesicles

172
Q

Name all the parts of the eye

A

Conjunctiva, cornea, iris, pupil, lens, aqueous humour, ciliary muscle, suspensory ligament, vitreous humour, optic nerve, Sheath of nerve, fovea, retina, sclera

173
Q

What happens to the lens when looking at something distant

A

The lens is made thinner high makes it bend light rays less

174
Q

What happens to the lens when looking at something close

A

The lens is made fatter which makes it bend light rays more

175
Q

How are rays of light bent after they enter the cornea

A

They are bent inwards (refracted) because is a converging lens

176
Q

Where are light rays refracted to in the eye

A

The retina

177
Q

What is the ciliary muscle

A

It is a ring of muscle that surrounds the lens of an eye

178
Q

How is the lens attached to the ciliary muscle

A

By suspensory ligaments

179
Q

What are the ciliary muscle and suspensory ligaments like

A

Ciliary muscles are like an elastic band, while the ligaments are like a piece of string

180
Q

What is ecology

A

Is the study of the interaction between living organisms and their environment

181
Q

What is the environment

A

Means all the conditions that surround any living organism - both the other living things and the non living things or physical surroundings

182
Q

What is a habitat

A

Means a place where plants and animals live

183
Q

What is a population

A

Means all the members of a single species that live in a habitat

184
Q

What is an ecosystem

A

Is a community of plants, animals and micro-organisms, together with the habitat where they live

185
Q

What is a niche

A

Is the role of a living organism within a community

186
Q

What is biodiversity

A

Is the measure of the different types of plant and animal species in an area

187
Q

What does biotic mean

A

This is the term used to describe the living components of the environment

188
Q

What does abiotic mean

A

The non living parts of the environment that might relate to the climatic factors like temperature, light intensity and humidity

189
Q

What name is given to a large range of sampling techniques

A

Field work

190
Q

What are two major aspects of sampling

A

Ensuring the data is reliable and representative

191
Q

How do ensure the data is reliable when sampling

A

Through taking results from many different sampling points and then calculating an average value. The more samples that are taken, the more reliable the results

192
Q

What does representative mean in terms of sampling data and how do you ensure the data is representative

A

This simply means that what is recorded is a true reflection of what is actually in the environment. To ensure results are representative sampling points must be random. This ensures that bias does not influence the results

193
Q

What is a quadrat

A

A quadrat is a simple frame (usually 0.5m x 0.5m) that can be placed on the ground in order to sample a specific area of ground cover

194
Q

When using a quadrat what measurement us used

A

When using a quadrat the percentage cover is often estimated. It is not possible to record specific values of percentage cover so in most cases percentage cover values would be 1%, 10%, 20% and so on up to 100%

195
Q

What is a belt transect

A

A belt transect is a technique used when there is gradual change from one habitat to another

196
Q

How is a belt transect carried out

A

In a belt transect, quadrats are placed along a line end on end allowing a strip of the ground and the species growing on it to be sampled. As the transect progresses from one end to another the numbers of certain species will decrease whilst others will increase

197
Q

Name some abiotic factors that an influence what types of organisms can survive in a habitat

A 
Wind speed 
Water content of soils 
The pH of soils
Light intensity 
Temperature
198
Q

How is wind speed measured and how can it influence what types of organisms can survive in a habitat

A

Wind speed can be recorded using an anemometer. This factor can influence the types of species present for example in sand dunes and also in mountain ranges. The values of wind speed can indicate how exposed a certain habitat is.

199
Q

How is the water content of soils measured and how can it influence what types of organisms can survive in a habitat

A

In ecological investigations soil samples can be collected and returned to the lab. Weighing the soil and then drying out until the mass stays constant which allows the percentage water content to be estimated. The water content of soils can influence what types of organisms can survive in a habitat as plants need a ready supply of water to survive. For this reason sandy soils that don’t retain much water tend only to support a small number of highly adapted plants

200
Q

How is the pH of soils tested and how can it influence what types of organisms can survive in a habitat

A

The pH of a soil can be tested chemically using a soil sample and universal indicator or simply by inserting a pH probe into the ground. The pH of soils can affect what types of plants grow there as some plants prefer acidic soils, whilst others have a preference for alkaline conditions

201
Q

How is light intensity measured and how can it influence what types of organisms can survive in a habitat

A

Light intensity is easily measured using a light meter. Light intensity can greatly affect the distribution of plants. If plants are shaded by taller trees they will probably have adaptations to allow them to absorb a greater amount of the available light

202
Q

How is temperature measured and how can it influence what types of organisms can survive in a habitat

A

Temperature is readily measured using a soil thermometer. Temperature is a further factor that can influence distribution of organisms

203
Q

What is a competition in terms of ecology

A

Competition in ecosystems refers to the need for organisms to obtain resources from the habitat in which they live.

204
Q

Name four things plants compete for

A
  1. Water
  2. Light
  3. Space
  4. Minerals
205
Q

Name four things animals compete

A
  1. Food
  2. Territory
  3. A mate
  4. Shelter
206
Q

Why are animals adapted to their environment

A

Usually there is not enough of the given resource for both organisms and therefore the organism that is better suited will obtain more of that resource and its chances of survival are greater.

207
Q

What is a organism called that makes its own food and makes energy available to the rest of the food

A

A producer eg a plant

208
Q

Where do plants obtain their energy from

A

Plants obtain their energy from the sun during the process of photosynthesis

209
Q

What are all animals

A

Consumers

210
Q

What are the 3 classes of consumers

A
  1. Herbivores
  2. Carnivores
  3. Omnivores
211
Q

What are primary consumers

A

Animals that feed on plants

212
Q

What are secondary consumers

A

Animals that feed on the primary consumer

213
Q

What are tertiary consumers

A

Animals that feed on secondary consumers

214
Q

How is a food chain arranged

A

The organisms involved are assigned to a stage in the chain based on how they obtain their food. These stages are referred to as trophic levels

215
Q

What trophic level are plants always at

A

The first

216
Q

What trophic level is the primary consumer at

A

The second

217
Q

What trophic level are the secondary consumers at

A

The third

218
Q

What trophic level are tertiary consumers at

A

The fourth

219
Q

What do the arrows on a food chain represent

A

The flow of energy

220
Q

What is a food web

A

A collection of food chains

221
Q

Why don’t food chains contain more than 3 or 4 trophic levels usually

A

This is because energy is lost at each stage in the food chain

222
Q

Is photosynthesis efficient for absorption of energy

A

This process is very inefficient with only a small amount of light energy actually hitting the plants gets absorbed by chlorophyll as most is reflected or passes through the leaf

223
Q

How much energy is lost every stage of the food chain

A

Around 90%

224
Q

Name 4 ways energy is lost in the food chain

A
  1. Not all of the available materials is eaten
  2. Much of the food is not digested
  3. The process of excretion
  4. All organisms respire and lose energy as heat
225
Q

What is a pyramid of numbers

A

The numbers of organisms at each trophic level represented in the form of graph

226
Q

Why are pyramids of number not always the best representation of feeding relationship

A

They do not consider the size of the organisms at each trophic level

227
Q

How is the issue of a pyramid of numbers fixed

A

It is inverted then represented in biomass

228
Q

What happens to the nutrients when an organism dies

A

Even if an organism dies, the nutrients it contains will eventually be released back into the ecosystem in the form of various minerals and other nutrients found in the soil

229
Q

Whilst energy _____; nutrients ____

A

whilst energy flows; nutrients cycle

230
Q

What are the two process involved in nutrient cycling

A
  1. Decay

2. Decomposition

231
Q

Give an example of the process of decay

A

Various small animals such as worms and insects break down dead organisms as they feed on them

232
Q

What is referred to as extra cellular digestion

A

The bacteria and fungi digest the materials by releasing (secreting) enzymes from their cells onto the decayed material. These enzymes break the molecules down into a more soluble form that the bacteria and fungi then absorb. This mode of digestion is sometimes referred to as extracellular digestion

233
Q

What is known as saprophytic nutrition

A

When extracellular digestion is used to complete the breakdown of dead material

234
Q

What is a major product of the decay and decomposition process

A

Humus

235
Q

What are the 3 conditions required for a effective decay and decomposition

A
  1. Warm temperature
  2. Moisture
  3. A large surface area
236
Q

What is the carbon cycle

A

A nutrient cycle that shows how carbon is passed from the atmosphere into plants and on to animals as they feed on plants. The cycle also includes the processes of decomposition, combustion and fossilisation.

237
Q

What is combustion

A

When any fuel is burnt it releases carbon in the form of carbon dioxide back into the atmosphere.

238
Q

What is fossilisation

A

under certain circumstances dead organisms do not become fully decomposed. Over millions of years these partially decomposed materials are converted into fossil fuels such as coal, oil and gas.

239
Q

What 3 problems can increasing temperatures cause on the earth

A
  1. Melting ice caps leading to increased sea levels
  2. Climate change
  3. Loss of habitats
240
Q

What does the nitrogen cycle show

A

How nitrogen gas is converted into nitrogen containing compounds in plants and animals and then how the nitrogen these compounds contain is recycled either back into the air or made available to other organisms

241
Q

Why is the nitrogen cycle important

A

It is important as it shows how organisms obtain their amino acids and proteins which are required for growth

242
Q

Where is the Nitrogen fixing bacteria found

A

found living in the soil as well as in the root nodules of a specific group of plants called leguminous plants

243
Q

Why is the Nitrogen fixing bacteria important

A

The nitrogen fixing bacteria in the root nodules provide the plant with all the nitrates required for making amino acids and proteins. In return the plant provides the bacteria with a ready source of carbohydrates - these are required to allow the bacteria to respire

244
Q

What is nitrification

A

A process that converts ammonia and other nitrogen containing ions in the soil into nitrates that can be readily absorbed by plant roots

245
Q

What is Denitrification

A

the process that converts nitrates back into nitrogen gas. This is an undesirable process as it results in less nitrate being available in the soil and therefore reduced plant growth

246
Q

Ow are root hair cells adapted and why are they adapted

A

They are adapted by having an increased surface area due to the presence of an extension of their cell walls. They are adapted in order to absorb minerals and water from the soil

247
Q

What is active uptake

A

This is a process that moves materials from a region of low concentration to a region of higher concentration against the concentration gradient

248
Q

What process is needed to occur for active uptake to happen

A

Respiration

Biology (School) (4 decks)

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