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Biology > Biology Exam: Full iGCSE > Flashcards

Biology Exam: Full iGCSE Flashcards

1
Q

What’s an eukaryotic cell?

A

Contains genetic material in nucleus.
- Complex
- Plant / animals cells

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2
Q

What’s a prokaryotic cell?

A

Don’t contain a nucleus
- Genetic material floats in cytoplasm
- Simple cells
- Bacteria

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3
Q

Animal cell sub cellular structures?

A
  • Nucleus
  • Mitochondria
  • Cell membrane
  • Cytoplasm
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4
Q

Plant cells structures?

A
  • Same as animal (mitochondria, nucleus, cytoplasm, cell membrane)
  • cell wall
  • Chloroplasts
  • Vacuole
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5
Q

What’re bacteria?

A

Smallest living organisms
- Unicellular
- Prokaryotes

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6
Q

Prokaryotic cell sub cellular structures?

A
  • Cytoplasm
  • cell membrane
  • cell wall
  • genetic material (in the cytoplasm)
  • flagella (sometimes)
  • plasmids
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7
Q

What’s a light microscope?

A

A microscope that uses light to observe

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8
Q

What’s the magnification equation?

A

Magnification = image size / actual size

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9
Q

Why stain cells?

A

So they’re easier to observe
- Hihglifhgt subscellular structures

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10
Q

What stain is used to highlight nucleus?

A

Animal Cell: methylene blue
Plant Cell: iodine solution

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11
Q

What’s an electron microscope?

A

Use electrons to observe instesad of light

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12
Q

Advantages of electron microscope?

A
  • Greater resolution
  • Greater detail
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13
Q

Disadvatnages of electron microscopes?

A
  • Expensive
  • Large
  • Specimens have to be dead
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14
Q

Advantages to light microscope?

A
  • Cheap
  • Small/Portable
  • Specimends can be alive
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15
Q

Disadvantages of light microscopes?

A
  • Lower resolution
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16
Q

What does DNA stand for?

A

Deoxyribonucleic acid

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17
Q

What’s a chromosome?

A

Long molecule of DNA

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18
Q

How many chromosomes do we have?

A

46 (23 pairs)

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19
Q

What’s a gene?

A

Short section that codes for a characteristic
- Like eye colour

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20
Q

How are strands of DNA joined together?
What shape does it form?

A
  • Bases
  • Double Helix
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21
Q

What’s a nucleotide?

A

Monomer made up of:
- Deoxyribose sugar
- Phosphate group
- Base

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22
Q

What bonds with Adenine?

A

Thymine (A-T)

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23
Q

What bonds with cytosine?

A

Guanine (C-G)

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24
Q

What’s transcription?

A

Process where mRNA is produced

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25
Q

How does transcription work?

A
  • DNA unzips
  • Bases attach to strand
  • Forms strand of DNA
  • DNA zips
  • mRNA can move out of nucleus -> ribosomes
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26
Q

What is protein made up of?

A

Amino acids

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27
Q

How is protein made?

A

Translation

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28
Q

How does translation work?

A
  • Ribosome “reads” nucleotides in codons
  • Each triplet/codon codes for an amino acid
  • Amino acids join together in a chain
  • Forming a protein
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29
Q

What’re enzymes?

A
  • Made up of protein
  • Biological catalysts
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30
Q

What’s the active site?

A

Where substances bind to the enzyme and the reaction takes place.

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31
Q

How does the lock & key hypothesis work?

A

Enzyme: Lock
Substrate: Key (Binds to enzyme)

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32
Q

What are enzymes used for?

A
  • Used to build large molecules from smaller ones
  • Used to break down large molecules intor smaller ones
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33
Q

What factors affect enzymes?

A
  • Temperature
  • pH
  • Enzyme concentration
  • Substrate concentration
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34
Q

What happens when active site changes?

A
  • Enzymes denature (break down)
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35
Q

What’re carbohydrates?

A

Polymers that are made from sugars.
Carbohydrate example: Strach

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36
Q

What’s a protein?

A

Polymers made up of amino acids
- The order in which they’re organised determines their protein

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37
Q

What’re lipids?

A

Fats & Oils you eat
- Synthesised from fatty accids and glycerol molecule

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38
Q

What’s aerobic respiration?
Word equation?

A

Happens in mitochondria, makes ATP, used by cells.
glucose + oxygen –> carbon dioxide + water

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39
Q

Symbol equation for aerobic respiration?

A

𝐶₆𝐻₁₂𝑂₆+6𝑂₂→6𝐶𝑂₂+6𝐻₂𝑂

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40
Q

What’s ATP used for?

A
  • Synthesise larger molecules
  • For movement
  • Stay warm
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41
Q

What’s anaerobic respiration?

A
  • respiration without oxygen
  • glucose straight to ATP
  • doesn’t completely break down
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42
Q

Word equation for anaerobic respiration?

A

glucose –> lactic acid

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43
Q

What happens when anaerobic respiration occurs?

A
  • Lactic acid is produced
  • Can cause cramps
  • Have oxygen debt
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44
Q

What’s fermentation?
word equation?
symbol equation?

A

Anaerobic respiration in yeast
glucose –> ethanol + carbon dioxide
C ₆ H₁₂O6 –> 2C₂H₅OH + 2CO₂

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45
Q

What’s photosynthesis?
Word equation?
Symbol equation?

A

turns light, water and CO2 to glucose to be used for respiration
carbon dioxide + water –> glucose + oxygen
6CO₂ + 6H₂0 –> C₆H₁₂O₆ + 6O₂

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46
Q

What’s formula for glucose?

A

C₆H₁₂O₆

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47
Q

Where does photosynthesis occur?

A

Inside the chloroplasts

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48
Q

How can you prove chlorophyll is used in photosynthesis?

A

Variegated plants
- Have more starch in green areas
- Prove green areas do more photosynthesis
- Green areas contain chlorophyll

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49
Q

How can you prove light is needed for photosynthesis?

A

Compare the starch contents of:
- Plant with light
- Plant without light
- Plant with light will contain starch

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50
Q

How can you prove oxygen is given off during photosynthesis?

A

Use pondweed:
- Bubbles will go up
- Trapped bubbles
- Then test for oxygen with glowing splint

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51
Q

Which factors affect the rate of photosynthesis?

A
  • Light intensity
  • Carbon dioxide
  • Temperature
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52
Q

How can you test for rate of photosynthesis?

A

Measure volume of O2 given off

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53
Q

How do you calculate light intensity?

A

relative light intensity = 1 / (distance from light source)^2

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54
Q

What’s diffusion?

A

Net movement of particles from a region of hight concentration to low concentration down the concentration gradient

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55
Q

What factors affect the rate of diffusion?

A
  • Distance needed to travel
  • Concentration gradient
  • Surface area
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56
Q

How is diffusion useful in our bodies?

A

Particles enter and leave cells through diffusion

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57
Q

What’s osmosis?

A

Type of diffusion: diffusion of water molecules through a selectively permeable membrane

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58
Q

Where does osmosis occur in plant cells?

A

Enters or leaves plant cells

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59
Q

Where does osmosis occur in animal cells?

A

enters or leaves animal cells, can burst the cells

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60
Q

What’s active transport?

A

Movement of particles from a low concentration to hgih concentration
Not passive, needs energy

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61
Q

Examples of active transport?

A

Plants use active transport to take in minerals from the soil, that’s why they have high surface area

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62
Q

What’s mitosis?

A

Process by which body cells divide?

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63
Q

How is DNA replicated in mitosis?

A
  • DNA unzips
  • complementary base paris attach
  • Form 2 different strands of DNA
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64
Q

How do chromosomes move?

A
  • Replicate
  • Line up middle of cell
  • Move to poles
  • Then cell divides
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65
Q

What’s a cycle?

A

Cycle of cells replicating and splitting forming 2 individual cells.

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66
Q

What’s a specialized cell?

A
  • Cell used to do a particular thing
  • Differentiate into different types of cell
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67
Q

What’s a sperm cell?

A
  • Has flagellum, lots of mitochondria
  • Has digestive enzymes to break down layers of ovum
  • To transfer genetic material
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68
Q

What’s a fat cell?

A

Usd to store fat

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69
Q

What’re stem cells?

A

Undifferentiated cells
- Can differentiate into different types of cells

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70
Q

Difference between embryonic stem cell & adult stem cell

A
  • Embryonic stem cells can differentiate into anything
  • Adult stem cell can only differentiate into some things
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71
Q

Why are transport systems needed?

A

Big organisms have a low S.A:V ratio, so they can’t use diffusion to transport substances
- Animals have a circulatory system
- Plants have a transport system (with xylems and phloems)

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72
Q

What’s the circulatory system?

A
  • Made up of heart and blood vessels
  • transports oxygen & glucose around body
  • Humans have a double circulatory system
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73
Q

What are the three blood vessels?

A

Artery: Carry blood away from the heart (high pressure)
Vein: Return blood to the heart (have valves)
Capillaries: Link arteries and veins in tissues and organs

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74
Q

What’s inside your heart?

A

Atria & ventricles

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75
Q

What bring deoxygenated blood to the heart?

A

Vena cava

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76
Q

What carried oxygenated blood around the body?

A

Aorta

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77
Q

What does the pulmonary artery do?

A

Takes deoxygenated blood to lungs

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78
Q

What does pulmonary vein do?

A

Brings oxygenated blood from the lungs into the heart

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79
Q

What does the xylem do?

A

Transports water and minerals from roots to the stem, leaves & flowers.

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80
Q

What does the phloem do?

A

Transports dissolved sugars from photosynthesis from leaves to others areas of the plant.

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81
Q

What direction does xylem flow?

A

One way only

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82
Q

What direction does phloem flow?

A

Two-way flow

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83
Q

What’s transpiration?

A

Transpiration is the movement of water in plants that eventually leaves cells

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84
Q

How is water lost from the leaves?

A

With stomata
- They control the evaporation of water

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85
Q

How do stomata work?

A
  • Guard cells control state of stomata
  • Stomata Open: Allow water to evaporate
  • Stomata Close: to prevent loss of water
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86
Q

What’s a potometer?

A

Used to measure how quickly plant shoots take up and lose water.

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87
Q

What factors affect the rate of transpiration?

A
  • Light intensity
  • Temperature
  • Air movement (wind)
  • Humidity
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88
Q

What’s a:
- stimulus?
- receptors?
- effectors?

A
  • Stimulus: Change in environment
  • Receptors: Cells that detect stimulus
  • Effectors: Muscles or glands that produce a response
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89
Q

What do sensory receptors detect?

A
  • light
  • chemical
  • pressure
  • heat
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90
Q

What’re sensory neurones?

A

Carry electrical impulses from recepptors —> CNS

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91
Q

What’re relay neurones?

A

Carry electrical impulses from sensory neurones —> motor neurones (through CNS)

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92
Q

What’re motor neurones?

A

carry electrical impulses from CNS —> effectors

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93
Q

Flow diagram in a nervous reaction?

A

Stimulus –> Receptor cells –> Sensory neurone –> Spinal cord –> Brain –> Spinal cord –> Motor neurone –> Effector –> Response

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94
Q

What’s a reflex action?

A

A involuntary response, it happens automatic (doesn’t go through brain)
Only takes 0.2 seconds!

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95
Q

Flow diagram of a reflex arc?

A

Stimulus –> Receptor cells –> Sensory neurone –> Spinal cord –> Motor neurone –> Effector –> Response

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96
Q

What’s the cornea?

A

Coating in front of eye
- protects eye
- Refracts light

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97
Q

What’s the pupil?

A

Central hole in iris
- Allows eye to enter eye

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98
Q

What’s the iris?

A

coloured ring of muscle tissue
- Alters pupil size by contracting or relaxing

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99
Q

What’s the lens?

A

Transparent lens
- Focuses light onto the retina

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100
Q

What’s the ciliary body?

A

Ring of muscle tissue
- Alters shape of lense

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101
Q

What’‘re the suspensory ligaments?

A
  • Connects ciliary muscle to lens
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102
Q

What’s the optic nerve?

A

nervous tisse
- Carries nerve impulses to brain

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103
Q

What happens when your ciliary muscle contracts?

A

Lens becomes more convesx (fatter)
- You can focus on nearby objects

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104
Q

What happens when your ciliary muscle relaxes?

A

Lens becomes less convex (thinner)
- You can focus on distant objects

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105
Q

What causes short sightedness?

A

Lens being too strong or eyeball being to long

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106
Q

What causes long sightedness?

A

Lense being too weak or eyeball being too short

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107
Q

What’s color blindness?

A

When you can’t make out different colours (or can’t see colours at all)
- It’s genetically inherited

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108
Q

What’re rods?

A

Respond to light, allow you to see in low light levels

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109
Q

What’re cones?

A

Respond to different colours

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110
Q

What does the brain do?

A
  • Processes info by receptor cells
  • Produces a response
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111
Q

What’s the cerebrum?

A

Controls complex behaviour such as:
- learning
- memory
- personality
- concious thought

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112
Q

What’s the cerebellum?

A

Controls posture, balance & involuntary movements

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113
Q

What’s the medulla?

A

Controls automatic actions suhc as heart rate & breathing rate

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114
Q

What’s the hypothalamus?

A

regulates water balance & temperature

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115
Q

What’s the pituitary gland?

A

Stores and releases hormones that regulate many functions

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116
Q

What’s the CNS?

A

Consists of your brain & spinal cord?

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117
Q

What’s the peripheral nervous system?

A

All neurones that connect the CNS to the rest of the body

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118
Q

Why’s it and to repair CNS damage?

A

Very thin nerve fibres
- Repairing damage to one without damagin others is difficult

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119
Q

What’re hormones?

A
  • Chemical messengers
  • Made in endocrine glands
  • Have target cells
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120
Q

What’s the endocrine system?

A

All the endocrine glands and hormones form part of the endocrine system.

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121
Q

What’s the different between nervous system & endocrine system?

A

Nerves: Fast, electrical impulse, short duration, precise
Hormones: Slow, blood, long duration, large area

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122
Q

What’s thyroxine?

A

Controls metabolic rate

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123
Q

What’s adrenaline?

A

Stress secretes adrenaline, makes fight or flight response:
- Increases heartbeat rate
- Increase breathing rate
- This makes cells respire quicker
- Directs blood to muscles

124
Q

What’s negative feedback?

A

Cycle that helps keep internal conditions constant
- Change is detected
- Effectors work to change that
- Conditions balanced

125
Q

What’s the menstrual cycle?

A

Monthly cycle during whcih a woman gets ready for pregnancy
- Lasts 28 days
- Eggs mature
- Ovulation
- If eggs fertilised than pregnant
- Otherwise cycle starts again

126
Q

What’s FSH?

A
  • Secreted by pituitary gland
  • Causes eggs to mature
127
Q

What’s oestrogen?

A
  • Secreted by ovaries
  • Causes lining in uterus to build up
128
Q

What’s LH?

A
  • Triggers ovulation
129
Q

What’s progesterone?

A
  • Maintains uterus lining
  • Remains high throughout pregnancy
130
Q

What methods of contraception are there?

A
  • Condom
  • Cervical cap
  • IUD
  • oestrogen & progesterone pill
  • progesterone pill
  • IUS
131
Q

What’s a non-hormonal contraceptive?

A
  • Acts as a barrier
  • Prevents sperm from contacting the egg
132
Q

What’s a hormonal contraceptive?

A

Uses hormones to disrupt female repdocutive cycle

133
Q

What’re the most effective contraceptives?

A
  • IUS: >99%
  • Pills (Both): >99%
  • IUD: >99%
  • Condoms: 98%
  • Diaphragm: 92-96%
134
Q

Why is IVF useful for?

A

To get pregrant if you have problems like:
- blocked sperm ducts
- not enough sperm
- lack of mature eggs
- faile of ovaries to release egg

135
Q

How does IVF work?

A
  • Collects eggs from ovaries
  • Fertilises them with sperm of father
  • FSH & LH are given to mother to endure many eggs mature
136
Q

Why is IVF not reliable?

A
  • no pregnancy
  • multiple pregnancies
137
Q

What’s tropism?

A
  • Plants detect stimuli
  • They can respond by moving in a direction
  • This is tropism
138
Q

What’s phototropism?

A
  • Stem growing towards light
139
Q

What’s gravitropism?

A
  • Growing roots downwards toward gravity to get more soil
140
Q

What hormones does tropism?

A
  • Auxin
  • Travels to specific part of plant
  • Encourages that part’s cells to grow more
  • Bending the shoot/root
141
Q

Other hormones for plant?
(Apart from auxin)

A

Ethene: causes plants to ripen
Gibberellins: promote growth (stem)

142
Q

What’s the normal body temperature?

A

37ºC

143
Q

How is body temperature controlled

A
  • Thermoregulatory centre in brain reponsible for regulating body temperature
144
Q

What happens when you get too hot?

A
  • Body hairs lower, prevents insulating layer of air beign trapped around body
  • Sweat: removes body heat when water evaporates to surroundings
  • Blood vessels widen (vasodilation), increases blood flow, increasing heat loss
145
Q

What happens when you get too cold?

A
  • Body hairs rise, trapping air, making insulation
  • Blood vessels narrow (vasoconstriction), reduces heat loss
  • Shivering, makes cells respire more quickly, transferring energy by heating
146
Q

What’s insulin?

A

If blood sugar levels are too high:
- Releases insulin
- Travels to liver
- turns glucose to glycogen
- Glycogen stored in liver
- Less glucose in blood
- Glycogen can be turned back into glucose if needed

147
Q

What’s diabetes?

A

Can’t controll blood sugar levels

148
Q

What’s type 1 diabetes?

A
  • Cannot produce insulin
  • destroyed pancreatic cells
  • Begins in Childhood
149
Q

What’s Type 2 diabetes?

A
  • Cannot use insulin
  • Body doesn’t properly respond to insulin
  • Occurs later in life
150
Q

What’s isotonic?

A

Equal amounts of water potential

151
Q

What’s hypertonic?

A

High solute concentration
Low water concentration

152
Q

What’s hypotonic?

A

Low solute concentration
High water concentration

153
Q

What’s the loop of Henle?

A

Long U shaped tubule
Recovers water and salts form urine

154
Q

What’s an ecosystem?

A

All the living organisms, and physical conditions in an area.

155
Q

What’s the community and habitat?

A

Community: Organisms within the ecosystem

Habitat: Area where the organisms live

156
Q

What are the 3 main groups of organisms in a community?

A

Producers: Make their own food
Consumers: Eat other organisms for food
Decomposers: Feed on dead/decaying material

157
Q

What’s a trophic level?

A

Step in the food chain

158
Q

What factors are there in an ecosystem?

A

Biotic factors: Living factors, such as organisms present

Abiotic factors: Physical factors, such as the rainfall received

159
Q

What abiotic factors are there?

A
  • Light intensity
  • Temperature
  • Moisture level
  • soil pH
160
Q

What is competition?

A

Organisms competing for resources to survive, and strongest survive.

161
Q

What’re the 3 ecological relationships?

A
  • Predation
  • Mutualism
  • Parasitism
162
Q

What’s predation?

A

Predation is one animal hunting, killing, and eating another animal (prey) for food.

163
Q

What’s mutualism?

A

Mutualism is when two organisms both benefit from each other and the relationship.

164
Q

What’s parasitism?

A

Only one organism (parasite) gains while harming the host.

165
Q

What’s a pyramid of biomass?

A

Graphical representation that shows the amount of biomass present at each trophic level in an ecosystem.

166
Q

How do you calculate biomass?

A

Multiply average dry mass of organism by the population.

167
Q

Why does biomass decrease at each trophic level?

A

Biomass is lost as:
- Not all organism is eaten
- Biomass used in respiration
- Some parts cannot be digested (e.g. teeth)
- Waste products are lost through excretion

168
Q

What’s nutrient cycling?

A

Cycling of nutrients through soil-> plants -> animals -> decomposers -> soil

169
Q

What materials are cycled?

A
  • Carbon
  • Nitrogen
  • Water
170
Q

Nitrogen cycle

A

Nitrogen in soil as nitrates –> plants –> animals –> decompose and go to soil as ammonia –> nitrogen-fixing bacteria form nitrates in the soil

171
Q

What’s nitrogen fixing bacteria?

A

Bacteria that live in roots and combine nitrogen with air to make nitrates. Then used by plants.

172
Q

Water cycle

A

Sun causes water to evaporate –> Condense into clouds –> Precipitation water rains down –> Goes into soil, rivers, sea –> Cycle repeats

173
Q

Carbon cycle

A
  • Carbon is taken in through photosynthesis
  • Plants can respire carbon out
  • Animals eat plants and respire carbon out
  • When they die, microbial respiration decays the animals and carbon released
  • Turned to fossil fuels, which are burned by humans releasing CO2
174
Q

What’s a decomposer?

A

Microorganism such as bacteria or fungi which break down (decay) dead organic material.

175
Q

What’s a detritivore?

A

Small animal that speed up decomposition by shredding organic material into small pieces.

176
Q

What factors affect the rate of decomposition?

A
  • Temperature
  • Moist environments
  • Aerobic conditions
177
Q

What’s variation?

A

Differences within a species.

178
Q

What’s the phenotype?

A

The appearance of an organism.

179
Q

What two types of variation are there?

A
  • Genetic variation
  • Environmental variation
180
Q

What’s discontinuous variation?

A

Distinct groups such as blood group.
- One (or few genes)
- Bar chart

181
Q

What’s continuous variation?

A

Characteristic can be any value in a range.
- E.g. Skin colour
- Multiple genes
- Histrograms or line graphs

182
Q

What’s asexual reproduction?

A
  • Produces clone
  • Genetic material duplicated
  • Only one organism needed
183
Q

What’s sexual reproduction?

A
  • Offspring with variation
  • Fertilisation
  • Two organisms needed
184
Q

How does sexual reproduction happen?

A

Gametes fuse together, sperm fuse with the ova in animals, and pollen cell fuses with egg cell in ovule in plants.

185
Q

What’s a diploid cell?

A
  • Two sets of each chromosome
  • 23 pairs, 46 chromosomes in total (human)
186
Q

What happens in fertilization?

A
  • 2 haploid gamete cells fuse
  • Forming a diploid cell called zygote
  • The zygote then divides to produce a new organism
187
Q

What’s the genome?

A

Entire genetic material of an organism

188
Q

How are gametes made?

A
  • Meiosis
189
Q

First stage of meiosis

A
  1. Chromosomes are copied
  2. Line up middle of cell in pairs
  3. Each member gets pullde to opposite ends (poles)
  4. Cell divides in two diploid cells
190
Q

Second stage of meiosis

A
  1. Chromosomes line up in middle of cell
  2. Each chromosome is pulled in half.
  3. Each cell then divides in two. Making 4 haploid cells
191
Q

What does meiosis cells result in genetically?

A
  • Genetically different and creates genetic variation
192
Q

What’s an allele?

A

A different form of a gene

193
Q

How is the dominant and recessive alleles represented?

A

Dominant: Capital letter: e.g. B
Recessive: Lower case letter: e.g. b

194
Q

What does homozygous mean?

A

Two copies of the same allelle. Can be:
- Homozygous dominant: BB
- Homozygous recessive: bb

195
Q

What’s a Punnett square?

A

A square that is used to predict a genetic cross and all the possible combinations.

196
Q

What does XX mean in humans?

A

Chromosomes for female

197
Q

What does XY mean in humans?

A

Chromosomes for male

198
Q

What determines the sex of the offspring?

A

The sperm can have X or Y, but eggs only have X. So sperm determines the sex.

199
Q

What is a mutation?

A

An alteration of the DNA sequences.

200
Q

What can cause mutations?

A
  • Incorrect replication of DNA
  • Alcohols
  • Ionizing radiation
201
Q

Why are mutations harmful?

A
  • They can cause cancer
  • They can cause the production of abnormal protein channels
  • They can cause different shaped protein to be made
202
Q

What is evolution?

A

Gradual change of a species over time.

203
Q

What drives evolution?

A

Natural selection: the organisms that are best suited to that environment survive and pass on their genes (survival of the fittest)

204
Q

What’re fossils?

A

Animal or plant remains that are preserved in rocks.

205
Q

What’s the fossil record?

A

Fossil layers show that organisms have changed over time.

206
Q

What’s the evidence for evolution?

A
  • Fossil record
  • Rapid changes in a species
  • Extinction
  • DNA comparisons and analysis
207
Q

Who made the theory of evolution and how?

A

Darwin and Wallace.
Darwin observed that birds better suited to the environment would reproduce more, passing on their genes.

208
Q

Why was On the origin of species controversial?

A

It contraditcted that God had created all living things.

209
Q

What is classification?

A

Sorting living organisms into groups.

210
Q

Why do scientists classify organisms?

A
  • Identify species
  • Predict characteristics
  • Find or show evolutionary links
211
Q

What are the seven taxonomic levels?

A

Kingdom
Phylum
Class
Order
Family
Genus
Species

212
Q

What’s artificial classification?

A

Classifying organisms on observable characteristics.

213
Q

What’s natural classification?

A

Classifying organisms on their DNA.

214
Q

What is a sampling?

A

Taking observations or measurements from a small area.

215
Q

How can you sample animals?

A
  • Pooters
  • Sweep nets
  • Kick sampling
  • Tree beating
  • Pitfall traps
216
Q

What are identification keys and two types?

A

Series of questions to identify a species.

  • Branched key
  • Numbered key
217
Q

What’s the capture-recapture technique?

A
  1. Capture organisms and mark them
  2. Release back into community and wait
  3. Recapture organisms
  4. Count the number of marked & unmarked
  5. Estimate the population size
218
Q

How can you estimate the population size equation?

A

Estimated population size = (first sample size x second sample size) / number of recaptured marked individuals

219
Q

How can you sample plants?

A

Using a quadrat, record number of organisms in each section. Then you can work out the total per metre squared.

220
Q

What’s two types of plant sampling are there?

A
  • Random sampling
  • Non-random sampling
221
Q

What’s non-random sampling?

A

Used to study how organism varies over distance. Place quadrats on transect line.

222
Q

Why is biodiversity important?

A

Removal of species can affect others and whole ecosystem.

223
Q

How is biodiversity lost?

A
  • Deforestation
  • Agriculture (Pesticides & Herbicides)
  • Hunting & fishing
  • Pollution
224
Q

What is conservation?

A

Protecting natural environment to save habitats and species.

225
Q

What is captive breeding?

A

Breeding animals in human controlled environments.

226
Q

Advantages & Disadvantages of captive breeding?

A

Advantages:
- create a stable population of a species
- reintroduce species back to its natural habitat

Disadvantages:
- low genetic diversity
- captive organisms may not survive in the wild.

227
Q

What’s a seed bank?

A

Preserving seeds to conserve plants for the future. It’s a gene bank.

228
Q

What’s ecotourism?

A

Tourism with minimised impact on environment. Supports conservation.

229
Q

What’re indicator species?

A

Species which its presence (or absence) indicates condition of habitat.

230
Q

What’s food security?

A

Ability to access affordable food of sufficient quality & quantity.

231
Q

What factors threaten food security?

A
  • Increasing human population
  • Changing diets
  • Climate change
  • New pests and pathogens
232
Q

How can we increase food production?

A
  • Maximizing photosynthesis
  • Using fertilisers
  • Removing pests
  • Higher yield crops
233
Q

What’s intensive farming?

A

Produce maximum food possible in minimum area of land. More industrial.

234
Q

What’s organic farming?

A

Produces less yield, high quality, natural, expensive.

235
Q

What’s sustainable food production?

A

Producing food in ways that can be continued indefinitely.

236
Q

What sustainable farming techniques are there?

A
  • Using manute as fertiliser
  • Crop rotation
  • Biological control
237
Q

What’s biological control?

A

Using organisms to kill pests naturally.

238
Q

What’s a hydroponic system?

A

Plants grown in water containing dissolved minerals.

239
Q

What’s selective breeding?

A

Breed specific animals for particular characteristics.

240
Q

Disadvantages of selective breeding?

A
  • Reduces gene pool
  • Increases chance of inheriting genetic disease
241
Q

What is genetic engineering?

A

Altering an organism’s genome to produce an organisms with desire characteristics.

242
Q

3 examples of genetic engineering?

A
  1. Cotton - increase crop yield
  2. Corn - to produce toxins that kill insects
  3. Bacteria - to produce insulin
243
Q

How does genetic engineering work?

A

Scientists insert foreign genes into the early stages of an organism’s development to create desired characteristics.

244
Q

What are the risks of genetic engineering?

A
  • Eating GM crops may lead to health problems
  • GM crops may cross-pollinate with wild plants and disrupt ecosystem
245
Q

How are organisms genetically engineered?

A
  1. Identify gene that codes for characteristic
  2. Remove gene from donor organism
  3. insert the gene into the host organism
246
Q

What’s a restriction enzyme?

A

Cuts the donor DNA at specific base sequences.

247
Q

What’s a ligase enzyme?

A

Joins the DNA into the sticky ends.

248
Q

Examples of GM crops?

A

Golden rice - extra beta-carotene
Bt corn - produces poison to pests

249
Q

What’s biotechnology?

A

Use of biological processes/living organisms to manufacture products.

250
Q

What’s a disease?

A

Condition that causes part of the body to not function properly.

251
Q

What 2 type of diseases are there?

A
  • Communicable diseases
  • Non-comunicable diseases
252
Q

What’s a communicable disease?

A

Disease that can be spread between organisms. Are caused by pathogens.

253
Q

What’s a non-communicable disease?

A

Disease that cannot be spread between organisms.

254
Q

What’re non-communicable disease caused by?

A
  • Poor diet
  • Obesity
  • Genetic disorders
  • Body processes not operating correctly (i.e. cancer)
255
Q

How do pathogens spread between animals?

A
  • Cuts thrugh skin
  • Through digestive system
  • Through respiratory system
  • Through reproductive system
256
Q

How do pathogens spread between plants?

A
  • Vectors such as insects
  • Direct contact of sap from infected plant
  • Wind carrying fungal spores
257
Q

How do pathogens cause disease?

A

Pathogens invade and replicate in host organism’s cells during incubation.

258
Q

How does a pathogen reproduce?

A
  1. Enters cell
  2. Inserts genes
  3. Cells copies genes, new viruses are made
  4. Cell bursts releasing the viruses
259
Q

How can you prevent the spread of communicable diseases?

A
  • Covering your mouth and nose
  • Not touching infected people or objects
  • Using protection
  • Not sharing needles
  • Washing hands
  • Cooking properly
  • Drinking clean water
  • Prevent animal/insect bites
260
Q

How dod farmers prevent the spread of disease in plants and animals?

A
  • Diseased plants are burned
  • Animals treated or killed
  • Chemicals too kill pathogens
261
Q

What’s athlete’s foot?

A

Caused by fungi in foot. Very contagious

262
Q

What’s food poisoning?
Example

A

Caused by growth of microorganisms in food.
E.g. salmonella

263
Q

What are sexually transmitted infections?

A

STIs passes from person to person through unprotected sex, bodily fluids or contact.

264
Q

What’s the difference between HIV & AIDS?

A

HIV: Virus that weakens immune system
AIDS: Condition caused by HIV infection, weak immune system

265
Q

What are the two types of defences of plants against communicable diseases? Examples?

A

Physical Defences: stop microorganisms entering.
E.g. cuticle, cell wall…

Chemical Defences: substances that kill microorganisms.
E.g. Insect repellent (pine resin), antibacterial & antifungal compounds…

266
Q

What is diagnosis and how does it work?
Field and Lab.

A

Identifying existence of the disease.
Field: Observation, Microscopy
Lab: DNA analysis, Identification of antigens

267
Q

What is diagnosis and how does it work?
Field and Lab.

A

Identifying existence of the disease.
Field: Observation, Microscopy
Lab: DNA analysis, Identification of antigens

268
Q

How does a scab form?

A
  1. Platelets get stuck in the hole
  2. Fibrin fibres and platelets create a mesh
  3. Red blood dells get caught in the mesh
  4. The blood hardens creating a scab
269
Q

What two types of white blood cells are there?

A

Phagocytes: engulf microorganisms, and make enzymes to digest them

Lymphocytes: makes antitoxins and antibodies

270
Q

What’s an antibody?

A

Proteins that bind to antigens on the surface of microorganisms. Then that microorganism can be ingested.

271
Q

Why do you gain immunity after disease has been removes?

A

White blood cells are able to make antibodies quicker. Memory cells that make the immune response quicker.

272
Q

What is monoclonal antibody?

A

Fusion of cancer cells and lymphocytes. Artificially made to neutralise a target cell.

273
Q

How are monoclonal antibodies produced?

A
  1. Mice injected with antigen
  2. Mouse produces antibodies
  3. Lymphocyte producing antigen collected
  4. Fused with myeloma (cancer) cells
  5. Reproduce to form clones which produce the required antibody
274
Q

How are monoclonal antibodies used?

A
  • Pregnancy testing
  • Detecting disease
  • Treating cancers
275
Q

What is a vaccine?

A
  • Small amounts of weak pathogens
  • Immune system produces antibodies
  • Can provide a faster response if infected
  • You are immune
276
Q

How are pathogens killed?

A
  • Antiseptics
  • Antivirals
  • Antibiotics
277
Q

What’s aseptic technique?

A
  • Working with sterile equipment
  • Reduces cross-contamination from microorganisms
278
Q

What’s preclinical testing?

A

Testing drug on cells, bacteria and tissue cultures.

279
Q

How are new drugs developed?

A
  1. Tested on animals (at least 2 species)
  2. Tested on healthy volunteers
  3. Tested on small sample of volunteers with condition
  4. Tested on large number of people with condition
280
Q

What’s the placebo effect?

A

When people feel better because they expect to feel better.

281
Q

What’s a double blind trial?

A
  • Give drug to some patients
  • Give placebo to some patients
  • No one knows which one it is
  • Overcomes placebo effect
282
Q

What does smoking contain and what do those substances do?

A

Tar: collects in lungs, causes cancer
Nicotine: addictive drug
Carbon monoxide: attaches to haemoglobin instead of oxygen
Particulates: weakens walls of alveoli (less oxygen)=
Other substances: paralyse ciliated cells lining, causing bronchitis, or damage to lungs

283
Q

What are the effects of alcohol?

A

Contains the drug ethanol
- Depressant (slows body reactions)
- Change behaviour
- Blurred vision
- loss of balance
- increased reaction times

284
Q

What long term effects does alcohol have?

A

Contains ethanol which:
- Can scar livers (cirrhosis)
- Cause stomach ulcers
- Heart disease
- Brain damage

285
Q

What’s a cardiovascular disease?

A

Disease of heart and blood vessels.

286
Q

What’s atheroclerosis?

A
  • Narrowing of blood arteries, reduced blood flow
287
Q

What’s thrombosis and what can it cause?

A

Blood clot
- Artery supplying heart: heart attack
- Artery supplying brain: stroke

288
Q

What factors increase your risk of CVD?

A
  • Having a poor diet
  • Little exercise
  • Smoking
  • High blood pressure
  • Age
289
Q

How does diet increase CVD?

A
  1. Too much salt, means more water absorbed in blood
  2. Extra water causes high blood pressure
290
Q

How does exercise affect your health?

A
  • Lower fat reduces risk of CVD & Diabetes
  • Joints are healthier, risk of arthirits decreases
  • More muscle, stronger heart
  • Lower cholesterol levels
291
Q

How to reduce risk of CVD?

A
  • Eat less processed food (reduces salt, fat & sugar intake)
  • Exercise regularly
  • Reduce consumption of alcohol & smoking
292
Q

How can CVD be treated surgically?

A
  • Replacing damaged valves
  • Widening blocked arteries with stent
  • Bypassing arteries using other blood vessels
  • Heart transplant
293
Q

What’s organ transplant?

A

Replacing damaged organs with donor organs

294
Q

How is risk of rejection reduced during organ transplant?

A
  • Tissues are matched
  • Immunosuppressant drugs are used
295
Q

How are embryonic stem cells used?

A
  • Testing new drugs
  • Manufacturing new brain cells
  • Rebuilding bones and cartilage
  • Making replacement heat valves cells
296
Q

What’s gene therapy?

A

Replacing a faulty allele of a gene, with a functioning allele for the same gene.

297
Q

How does gene therapy work?

A
  1. Cutting out ‘normal’ Allene of healthy person with restriction enzymes
  2. Producing copies of healthy allele
  3. Inserting copies of allele in person with genetic disorder
  4. This can be done using a virus that infects cells with healthy allele
298
Q

What’re the difficulties in gene therapy?

A
  • Healthy alleles may not go into every target cell
  • Healthy alleles may join chromosomes in the wrong place
299
Q

How do you test for starch?

A

Iodine solution
- Will turn blue-black

300
Q

How do you test for fat (lipids)?

A

Ethanol to substance and then into water
- colourless to cloudy

301
Q

How do you test for protein?

A

Add drops of copper sulfate, then sodium hydroxide
- Will turn purple

302
Q

What’s glucose?

A

Add drops of benedict’s solution
- Will turn orange-red

303
Q

What does amylase do?

A

Breaks down starches into glucose

304
Q

What does protease do?

A

Breaks down proteins into amino acids

305
Q

What does protease do?

A

Breaks down proteins into amino acids.

306
Q

What does lipase do?

A

Breaks down fats into fatty acids and glycerol.

Biology (5 decks)

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