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Biology > Entire biology course > Flashcards

Entire biology course Flashcards

1
Q

Question

A

Answer

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2
Q

What is the acronym that all living things must meet to be classed as living?

A

MRS H GREN

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3
Q

What does the ‘M’ in MRS H GREN stand for and what does it mean?

A

Movement and it is the ability of the organism to change location or position

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4
Q

What does the ‘R’ in MRS H GREN stand for and what does it mean?

A

Reproductiion and this is how the organism makes offspring

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5
Q

What does the ‘S’ in MRS H GREN stand for and what does it mean?

A

Sensitivity and it’s the ability of the organism to respond to changes to its environment (stimuli)

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6
Q

What does the ‘H’ in MRS H GREN stand for and what does it mean?

A

Homeostasis and this is its ability to control internal conditions like blood glucose levels

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7
Q

What does the ‘G’ in MRS H GREN stand for and what does it mean?

A

Growth, how an organism increases in mass and/or volume by cellular division

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8
Q

What does the ‘R’ in MRS H GREN stand for and what does it mean?

A

Respiration, how an organism releases energy from food (glucose)

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9
Q

What does the ‘E’ in MRS H GREN stand for and what does it mean?

A

Excretion, how an organisms removes metabolic waste

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10
Q

What does the ‘N’ in MRS H GREN stand for and what does it mean?

A

Nutrition, how an organism obtains the materials they need to carry out process, e.g. saprotrophic nutrition which is used in fungi to obtain glucose to respire

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11
Q

What are the 5 kingdoms?

A

Animals, plants, fungi, protoctista and prokaryotes/bacteria

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12
Q

What does the term eukaryotic mean and what kingdoms are eukaryotic?

A

Eukaryotic means prescence of membrane bound organelles like the nucleus and 4/5 kingdoms are eukaryotic - animals, plants, fungi and protoctista

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13
Q

What does the term prokaryotic mean and what kingdom(s) are prokaryotic

A

Prokaryotic means absence of membrane bound organelles like a nucleus. Only one kingdom is prokaryotic and that is the prokaryotes/bacteria kingdom

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14
Q

What characteristics do/can the organisms in the animal kingdom have?

A

All multicellular, obtain nutrients by eating other organisms, no chloroplasts, no cell wall, have a nervous system to respond to its environment and stores carbohydrates as glycogen

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15
Q

What characteristics do/can the organisms in the plant kingdom have?

A

All multicellular, obtain nutrients by photosynthesizing so also have chloroplasts to do this, have a cell wall made of cellulose and store carbohydrates as starch or sucrose

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16
Q

What characteristics do/can the organisms in the fungi kingdom have?

A

Can be multicellular, made up of threads called the hyphae making up the mycellium, but can also be unicellular (yeast), some have a reproductive structure (mushroom or toadstool), feed by saprotrophic nutrition, cells do not have chloroplasts but do have a cell wall made of chitin and can contain more than one nucleus and store carbohydrates as glycogen

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17
Q

What is saprotrophic nutrition?

A

When decomposers like fungi and some bacteria release enzymes outside of their cells onto dead organisms to break large complex molecules down into smaller more soluble molecules which are absorbed by the decomposer. E.g. proteins are broken down into amino acids

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18
Q

What characteristics can/do the organisms in the protoctista kingdom have?

A

All unicellular (made of a single cell), some photosynthesize, others feed on living or organic remains, cells can have chloroplasts, cell walls and a flagella, lots of variation (dustbin kingdom - the kingdom where single celled organisms are put that done meet all of the characteristics of other kingdoms so are placed here)

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19
Q

What characteristic can/do the organisms in the prokaryotic/bacteria kingdom have?

A

All unicellular and very small, prokaryotic so do not contain membrane bound organelles like a nucleus, genetic material in the cytoplasm as a single circular chromosome, can have a cell wall made of peptidoglycan, can have a slime capsule outside of the cell wall, can have plasmids (circles of DNA containing extra genes), can have a flagellum for movement

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20
Q

What is a pathogen

A

A microorganism that causes harm to its host. All viruses are pathogens and bacteria, protoctista and fungi can be.

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21
Q

Describe the structure of a virus

A

A strand of genetic material, either DNA or RNA, surrounded by a protein coat

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22
Q

Why are viruses not classed as being ‘living’?

A

They do not meet any of the requirements of MRS H GREN, namely they do not respire, they are not cells or made up of cells and cannot reproduce by themselves

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23
Q

How do viruses replicate?

A

They enter a host cell, take over the cell (hijack it) by making the cells enzymes and ribosomes to make new viruses and then the cell dies, allowing the viruses that have been made by the cell to infect other cells

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24
Q

What is a leguminous plant

A

Plants that can contain mutualistic nitrogen fixing bacteria in nodules on their roots, e.g. beans and peas

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25
Q

What is a mosquito?

A

An animal (insect) that acts as a vector that carries plasmodium (which is a protoctist) that causes malaria

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26
Q

Give two examples of fungi

A

Mucor that has the typical hyphal structure made of mycellium strands and yeast which is unicellular and is used in the production of bread and beer

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27
Q

Give two examples of protoctists

A

Plasmodium - causes malaria and chlorella - has chloroplasts

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28
Q

Give two examples of bacteria

A

Lactobacillus bulgaricus, a rod-shaped bacterium used in the production of yoghurt from milk, and Pneumococcus, a spherical bacterium that acts as the pathogen causing pneumonia.

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29
Q

Give two examples of viruses

A

The tobacco mosaic virus that causes discolouring of the leaves of tobacco plants by preventing the formation of chloroplasts, the influenza virus that causes ‘flu’ and the HIV virus that causes AIDS.

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30
Q

What chemical elements are in carbohydrates?

A

Carbon Hydrogen and Oxygen

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31
Q

What chemical elements are in proteins?

A

Carbon Hydrogen and Oxygen

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32
Q

What chemical elements are in lipids?

A

Carbon Hydrogen, Oxygen and Nitrogen

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33
Q

What is glucose used for?

A

Respiration - releasing energy

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34
Q

Name 3 polysaccharides (polymers of glucose)

A

Cellulose, Starch and Glycogen

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35
Q

Name 3 functions of lipids?

A

Energy storage, part of cell membrane, thermal insulation, electrical insulation, buoyancy

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36
Q

What is a triglyceride made up of?

A

Glycerol and 3 fatty acids

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37
Q

What is the monomer of proteins?

A

Amino acids

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38
Q

Name 3 functions of proteins?

A

Structural (collagen, keratin), enzymes, hormones, antibodies and transport (haemoglobin or cell membrane proteins)

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39
Q

What is the chemical used to test for glucose and what colour does it go?

A

Benedicts - blue to brick red

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40
Q

What is the chemical used to test for starch and what colour does it go?

A

Iodine - yellow to blue/black

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41
Q

What is the chemical used to test for protein and what colour does it go?

A

Biuret - blue to purple

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42
Q

What chemical test is used to test for lipid and what colour does it go?

A

Ethanol emulsion test - clear to milky white

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43
Q

Which food test do you need to heat in a water bath

A

Benedicts test - testing for glucose

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44
Q

Why does an enzyme reaction speed up when heated (to it’s optimum temperature)

A

More kinetic energy = more collisions between substate and enzyme = faster reaction

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45
Q

Why does an enzyme reaction slow down when heated above it’s optimum temperature

A

Enzyme’s active shape changes shape = substrate cannot fit into active site = enzyme denatured

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46
Q

Where does the substrate bind on an enzyme

A

Active site

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47
Q

Give an example of nucleic acid

A

DNA or RNA

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48
Q

Where is DNA stored in a cell

A

Nucleus

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49
Q

What is an organism’s genome?

A

Total DNA In an organism

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50
Q

What is a gene?

A

Section of DNA that codes for a protein

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51
Q

What is a chromosome?

A

Coiled up DNA - there are 46 chromosoems in a human cell

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52
Q

What are the bases in DNA?

A

Adenine, Thymine, Cytosine, Guanine

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53
Q

What are the 3 parts of a nucleotide?

A

Sugar, base and phosphate

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54
Q

Which bases pair with which?

A

T with A and G with C

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55
Q

Define diffusion

A

Movement of particles from a high to a low concentration

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56
Q

Define osmosis

A

Movement of water from a high water potential to a lower water potential across a semi permeable membrane

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57
Q

Define active transport

A

Movement of molecules from a low concentration to a high concentration across a membrane using ATP (energy)

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58
Q

How does temperature speed up diffusion?

A

Molecules have higher kinetic energy so move faster

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59
Q

How does concentration gradient affect the rate of diffusion?

A

A large difference in concentration (high concentration gradient) between areas will speed up diffusion

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60
Q

How does distance affect the rate of diffusion?

A

Short distance means faster diffusion as less distance to travel for molecules

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61
Q

How does surface area to volume ration affect the rate of diffusion?

A

A large SA:V ratio = faster diffusion

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62
Q

What is homeostasis?

A

maintenance of internal conditions in the body in a narrow range

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63
Q

What is the role of a receptor in a coordinated response?

A

detects the stimulus

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64
Q

What is the role of an effector in a coordinated response?

A

brings about the response (muscle of gland)

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65
Q

Why is it important to control body temperature?

A

enzymes denature at high temperatures and reactions too slow at low temperatures

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66
Q

Why is it important to control the water potential of the blood?

A

cells would shrivel if the water potential was too low, or swell and burst if the water potential is too high

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67
Q

How do plant shoots respond to light?

A

bend towards light (positive phototropism)

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68
Q

What general term describes a plant’s growth response to a stimulus?

A

tropism

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69
Q

How do plant shoots respond to gravity?

A

bend away from gravity (negative geotropism)

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70
Q

How do plant roots respond to light?

A

bend away from light (negative phototropism)

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71
Q

How do plant roots respond to gravity?

A

bend towards gravity (positive geotropism)

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72
Q

Explain how auxins cause the phototropic response in shoots

A

auxins accumulate on the shaded side of the shoot
higher auxin concentration causes greater cell elongation
so shoot bends towards light

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73
Q

What is a hormone?

A

chemical messenger, produced in glands and transported in bloodstream to target cells

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74
Q

Information in the nervous system is transmitted as…

A

electrical impulses

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75
Q

Describe three differences between nervous and hormonal communication

A

nervous system is faster
nervous system uses electrical signals and hormonal chemical
nervous system transmits messages along neurones, hormonal transmits messages in blood
hormonal message effects are longer lasting
nervous system messages are to a specific area, hormonal messages are more widespread

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76
Q

What are the two organs in the central nervous system?

A

brain, spinal cord

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77
Q

What links the sense organs to the central nervous system?

A

sensory neurones

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78
Q

What links the central nervous system to the muscles?

A

motor neurones

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79
Q

Name, in order, the three nerves which connect a receptor to an effector.

A

sensory neurones, relay neurones, motor neurones

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80
Q

Describe the sequence of events in a reflex arc, when you touch a hot pan.

A

heat detected by temperature receptors in skin
electrical impulse transmitted along sensory neurone to spinal cord
neurotransmitter released at synapse
electrical impusle transmitted along relay neurone in spinal cord
neurotransmitter released at synapse
electrical impulse transmitted along motor neurone to muscle (effector)
muscles in arm contract, pulling hand away

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81
Q

What is the job of a neurotransmitter?

A

transmit message across the synapse

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82
Q

Describe what hapepns at a synapse?

A

neurotransmitter released from first neurone
diffuses across
binds to second neurone, triggering an electrical impulse

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83
Q

What is the function of the lens?

A

changes shape to focus the light on the retina

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84
Q

What is the function of the cornea?

A

refracts light (does most of the focusing)

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85
Q

What is the function of the retina?

A

contains receptors (rods and cones) to detect light and generate electrical impulses

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86
Q

What is the function of the iris?

A

changes size of pupil, to control amount of light entering the eye

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87
Q

What is the function of the pupil?

A

allows light to enter the eye

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88
Q

What is the function of the ciliary muscles and the suspensory ligaments?

A

change the shape of the lens

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89
Q

Describe the changes to the iris and pupil when you enter a bright room

A

circular muscles contract in iris
radial muscles relax in iris
pupil constricts

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90
Q

Describe the changes to the iris and pupil when you enter a dark room

A

circular muscles relax in iris
radial muscles contract in iris
pupil dilates (widens)

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91
Q

Describe how the eye focuses on nearby objects

A

ciliary muscles contract
suspensory ligaments slacken
lens becomes rounder
light refracted more

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92
Q

Describe how the eye focuses on distant objects

A

ciliary muscles relax
suspensory ligaments ticghten
lens becomes flatter
light refracted less

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93
Q

Describe the events in vasodilation

A

arterioles supplying surface skin capillaries widen
more blood flows through capillaries near skin surface
more heat lost by radiation

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94
Q

Describe the events in vasoconstriction

A

arterioles supplying surface skin capillaries narrow
less blood flows through capillaries near skin surface
less heat lost by radiation

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95
Q

Describe the how sweat glands reduce the body temperature when it is too high

A

more sweat released
more evaporation of sweat
more heat loss

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96
Q

What gland produces the hormone adrenaline?

A

adrenal gland

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97
Q

What gland produces the hormone insulin?

A

pancrease

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98
Q

What gland produces the hormone testosterone?

A

testes

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99
Q

What gland produces the hormone oestrogen?

A

ovaries

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100
Q

What gland produces the hormone progesterone?

A

ovaries

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101
Q

What gland produces the hormone ADH?

A

pituitary gland

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102
Q

What gland produces the hormone FSH?

A

pituitary gland

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103
Q

What gland produces the hormone LH?

A

pituitary gland

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104
Q

What are the effects of the hormone adrenaline?

A

increased heart rate
increased breathing rate
increased blood flow to the muscles
pupils dilate

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105
Q

What are the effects of the hormone insulin?

A

increased absorption of glucose by liver and muscles
extra glucose stored as glycogen
reduces blood glucose concentration

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106
Q

What are the effects of the hormone testosterone?

A

causes sperm production
causes development of male secondary sexual characteristics

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107
Q

What are the effects of the hormone oestrogen?

A

causes uterus lining to develop
causes development of female secondary sexual characteristics

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108
Q

What are the effects of the hormone progesterone?

A

causes uterus lining to be maintained
causes development of female secondary sexual characteristics

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109
Q

What are the effects of the hormone ADH?

A

increases reabsorption of water from the collecting duct into the blood, resulting in concentrated urine

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110
Q

What are the effects of the hormone FSH?

A

causes egg to mature in the follicle
stimulates oestrogen production

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111
Q

What are the effects of the hormone LH?

A

causes ovulation
stimulates progesterone production

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112
Q

What are the key features of sexual reproduction?

A

2 parent cells required
requires gametes (haploid)
involves fertilisation
produces genetically different offspring

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113
Q

What are the key features of asexual reproduction?

A

1 parent cell required
no gametes (no meiosis)
no fertilisation
produces genetically identical offspring

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114
Q

What is fertilisation?

A

fusion of male and female gametes

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115
Q

What happens immediately after fertilisation?

A

the zygote divides by mitosis to form an embryo

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116
Q

Give three differences between the structure of an insect pollinated and a wind pollinated flower.

A

insect pollinated have larger, more colourful petals
insect pollinated have sticky stigma, wind pollinated have feathery stigma
insect pollinated have enclosed stigma, wind pollinate have stigma which hang outside the flower
insect pollinated have enclosed anthers, wind pollinate have anthers which hang outside the flower
only insect pollinated contain nectaries

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117
Q

What is the function of the anther?

A

where pollen (male gamete) is produced

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118
Q

What is the role of the stigma?

A

pollen sticks to it

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119
Q

What is the role of the style?

A

connects the stigma and ovary - the pollen tube grows down it

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120
Q

What is the role of the ovary?

A

contains the ovules, which contain ova (egg cells)
forms the fruit after fertilisation

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121
Q

What is pollination?

A

transfer of pollen from the anthers to the stigma

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122
Q

What is self-pollination?

A

when the pollen from the anthers of a plant is transferred to stigmas on the same plant

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123
Q

Describe the events from pollination to fertilisation in a plant

A

pollen grain releases enzymes
the enzymes digest the style to form a pollen tube to the ovary
pollen grain nucleus travels down the pollen tube to the ovary, into the ovule and to the ovum
the pollen grain nucleus fertilises (fuses with) the ovum

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124
Q

What happens to the egg, ovule and ovary after fertilisation in plants?

A

fertilised egg divided by mitosis to form the embryo
the ovule forms the seed
the ovary forms the fruit

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125
Q

Why do seeds need to contain a food store?

A

to provide glucose, etc. for cell division and growth until the plant can photosynthesise

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126
Q

What three conditions are needed for seeds to germinate?

A

warmth, water, oxygen

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127
Q

Why is warmth needed for seeds to germinate?

A

to provide optimum conditions for enzyme activity

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128
Q

Why is oxygen needed for seeds to germinate?

A

to allow aerobic respiration to occur

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129
Q

Why is water needed for seeds to germinate?

A

to allow the enzymes to function

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130
Q

How can plants reproduce asexually?

A

runners, tubers, bulbs

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131
Q

What is the role of oestrogen in the menstrual cycle?

A

causes the uterus lining to thicken
inhibits (stops) FSH production
stimulates LH production

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132
Q

What is the role of progesterone in the menstrual cycle?

A

maintains a thick uterus lining
inhibits FSH production

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133
Q

What is the role of FSH in the menstrual cycle?

A

causes the follicle and egg to mature
stimulates oestrogen production

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134
Q

What is the role of LH in the menstrual cycle?

A

causes the egg to be released (ovulation)
inhibits oestrogen production
stimulates progesterone production

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135
Q

What is the role of the amniotic fluid during pregnancy?

A

protects the fetus from knocks and bumps

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136
Q

What is the role of the placenta during pregnancy?

A

allows exchange of substances between fetal and maternal blood
oxygen, glucose, amino acids and fats diffuse from maternal blood into fetal blood
urea and carbon dioxide diffuse from fetal blood into maternal blood

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137
Q

What happens to females during puberty?

A

breasts develop
hips widen
pubic and underarm hair grows
menstrual cycle begins

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138
Q

What happens to males during puberty?

A

voice breaks and deepens
facial, pubic and underarm hair grows
increased muscle mass
growth of penis and testicles

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139
Q

What controls the changes which take place during puberty?

A

hormones - testosterone in males; oestrogen and progesterone in females

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140
Q

What is the function of the testes?

A

sperm production

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141
Q

What are the functions of the urethra in males?

A

carries urine and semen out of the body

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142
Q

What is the function of the sperm duct?

A

carries sperm to the glands and urethra

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143
Q

What is the function of the seminal vesicles and glands in males?

A

produce a fluid which mixes with sperm, producing semen

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144
Q

What happens in the oviduct in females?

A

transports egg from ovary to uterus; fertilisation occurs here

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145
Q

What is the function of the ovaries?

A

contains follicles, which mature and produce the mature egg

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146
Q

What is the function of the uterus?

A

lining grows and is shed; where the fetus develops

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147
Q

What is the function of the cervix?

A

narrow opening to the uterus - widens to allow the baby to be born

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148
Q

What is the function of the vagina?

A

baby passes down it during birth; penis is inserted during intercourse, to allow sperm to enter the uterus via the cervix

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149
Q

What is the function of the penis?

A

contains the urethra. Can become filled with blood and erect, allowing internal fertilisation to occur

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150
Q

When is carbon dioxide the excretory (waste) product from plants?

A

At night time, when respiration occurs at a faster rate than photosynthesis

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151
Q

When is oxygen the excretory (waste) product from plants?

A

In the day time, when photosynthesis occurs at a faster rate than respiration

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152
Q

How are oxygen and carbon dioxide excreted from plants?

A

diffuses out of the stomata

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153
Q

What excretory product is released via the lungs?

A

carbon dioxide, from respiration

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154
Q

What excretory product is released via the skin and kidneys?

A

urea

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155
Q

What is urea made from?

A

breakdown (deamination) of excess amino acids

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156
Q

Where is urea made?

A

liver

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157
Q

What blood vessel supplies the kidneys with oxygenated blood?

A

renal artery

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158
Q

What blood vessel removes deoxygenated blood from the kidneys?

A

renal vein

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159
Q

What tubes connect the kidneys to the bladder?

A

ureters

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160
Q

What tube transports urine from the bladder and out of the body?

A

urethra

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161
Q

What structure is labelled B?

A

Bowman’s capsule

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162
Q

What structure is labelled E?

A

Proximal convoluted tubule

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163
Q

What structure is labelled F and G?

A

Loop of Henle

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164
Q

What is the name of the bundle of capillaries inside B?

A

Glomerulus

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165
Q

What structure is labelled H?

A

Distal convoluted tubule

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166
Q

What structure is labelled I?

A

Collecting duct

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167
Q

What happens in ultrafiltration?

A

High pressure in glomerulus
(caused by afferent arteriole being wider than efferent arteriole)
Forces small molecules from the blood into the Bowman’s capsule

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168
Q

What substances are in the filtrate in the Bowmans capsule?

A

water, glucose, amino acids, salts, urea

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169
Q

Why aren’t there any proteins in the filtrate?

A

proteins are too big
to cross the basement membrane of the glomerulus

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170
Q

What happens in selective reabsorption?

A

all glucose and amino acids are reabsorbed into the blood
by active transport, using ATP
some water and salts are also reabsorbed

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171
Q

Where does ultrafiltration happen?

A

glomerulus and Bowman’s capsule

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172
Q

Where does selective reabsorption happen?

A

Proximal convoluted tubule

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173
Q

What substances are in the filtrate at the end of the proximal convoluted tubule?

A

water, salts, urea

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174
Q

Why is all the glucose reabsorbed in the proximal convoluted tubule?

A

glucose is needed for respiration

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175
Q

How is water reabsorbed in the collecting duct?

A

diffuses from collecting duct into medulla by osmosis
due to low water potential (high salt concentration) in medulla
water diffuses into capillaries

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176
Q

What effect does ADH have on the collecting duct?

A

increases the permeability of the collecting duct to water, so more water reabsorbed

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177
Q

Describe what happens when you are dehydrated.

A

low water potential detected by medulla in the brain
signals to the pituitary gland to release MORE ADH
ADH travels to kidneys in the blood
more ADH binds to the collecting duct, making it more permeable to water
more water reabsorbed into the blood
leaving a small volume of concentrated urine

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178
Q

Describe what happens when you drink too much water.

A

high water potential detected by medulla in the brain
signals to the pituitary gland to release LESS ADH
ADH travels to kidneys in the blood
less ADH binds to the collecting duct, making it less permeable to water
less water reabsorbed into the blood
leaving a large volume of dilute urine

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179
Q

What substances are found in the urine?

A

water, urea, salts

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180
Q

Where is ADH produced?

A

pituitary gland

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181
Q

What is excretion?

A

Removal of metabolic waste products from the body

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182
Q

What are the levels of organisations in organisms?

A

Organelles, cells, tissues, organs, organ systems and organism

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183
Q

What is the smallest subunit in all living organisms?

A

Cells

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184
Q

What are cells made up of?

A

Organelles

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185
Q

What is the definition of a tissue?

A

A collection of similar/identical cells grouped together to perform a specific function

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186
Q

What is the definition of an organ?

A

A collection of different tissues working together to perform a more complex function

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187
Q

What is the definition of an organ system?

A

A collection of different organs grouped together to perform a complex function essential for life

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188
Q

What components can animal cells have?

A

Cell membrane, cytoplasm, mitochondria, ribosomes and nucleus

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189
Q

What components do plant cells have?

A

Cell membrane, cytoplasm, mitochondria, ribosomes, nucleus, chloroplasts, vacuole and cell wall

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190
Q

What components can plant cells have that animal cells cannot?

A

Cell wall, chloroplasts and vacuole

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191
Q

What is the function of the nucleus?

A

Controls the activities of the cell (by making proteins). Stores the DNA as chromosomes which contains genes that code for proteins.

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192
Q

What is the function of the cell membrane?

A

Controls what goes in and out of the cell (selectivly permeable)

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193
Q

What is the function of the cytoplasm?

A

Holds the shape of the cell and site of metabolic reactions like anaerobic respiration

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194
Q

What is the function of the mitochondria?

A

Site of aerobic respiration, producing ATP

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195
Q

What is the function of the ribosomes?

A

Site of protein synthesis

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196
Q

What is the function of the chloroplasts?

A

Site of photosynthesis, absorbing light energy, producing glucose

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197
Q

What is the function of the cell wall?

A

Made of cellulose in plants, chitin in fungi and peptidoglycan in bacteria, holds the cells shape and stops it from bursting

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198
Q

What is the function of the vacuole?

A

Stores dissolved sugars and other minerals, holds the cells shape

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199
Q

How do you calculate the actual size of an image if you have the magnification and image size?

A

Image size / magnification

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200
Q

How many micrometers (um) are in 1mm?

A

1000

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201
Q

How many mm are in 1 micrometer (um)?

A

0.001

202
Q

How many nanometers (nm) are in 1mm?

A

1,000,000

203
Q

How many mm are in 1 nanometer (nm)?

A

0.00001

204
Q

What is a stem cell?

A

A non-speacialised cell that can differentiate (develop) into a specialised cell that carries out a specific function

205
Q

How is a red blood cell specialised for its function?

A

Contains haemoglobin that transports oxygen, no nucleus to store more haemoglobin and therefore carry more oxygen and biconcave shape for a larger surface area so more oxygen can enter and leave the cell quicker

206
Q

How is a sperm cell specialised for its function?

A

Contains a flagellum (tail) to aid movement, lots of mitochondria for more respiration and more energy released to aid movement/swimming and enzymes in its head to allow it to penetrate/enter the egg

207
Q

How is a palisade mesophyll cell specialised for its function?

A

Lots of chloroplasts to absorb more sunlight for photosynthesis and cells tightly packed together for larger surface area and for more light to be absorbed for more photosynthesis

208
Q

How do stem cells divide?

A

By mitosis

209
Q

What are the two types of stem cells?

A

Embryonic stem cells - can differentiate into any type of cell and adult stem cells - can only differentiate into specific cells, e.g. stem cells in the bone marrow can differentiate into blood cells

210
Q

What are the applications for stem cells?

A

Can be used to treat diseases, repair tissues and grow new organs

211
Q

How are adult stem cells used in medicine?

A

Bone marrow transplants for leukemia patients

212
Q

What are the problems with using embryonic stem cells?

A

Moral/ethical objections - the embryonic stem cells could be used in IVF to create a new organism

213
Q

What is a gene?

A

A section of DNA on a chromosome that codes for a protein

214
Q

What is the genome?

A

All of the DNA in an organism

215
Q

What shape is DNA said to have?

A

Double helix

216
Q

Where is DNA found?

A

Nucleus

217
Q

What is a DNA nucleotide made up of?

A

A deoxyribose sugar, a phosphate group and 1 of 4 nitrogenous bases

218
Q

What does the sugar and phosphate group of a DNA nucleotide make up?

A

Sugar-phosphate backbone

219
Q

What are the 4 bases in DNA?

A

Adenine (A), Thymine (T), Cytosine (C) and Guanine (G)

220
Q

What are the complementary base pairs?

A

A-T and C-G

221
Q

How does a RNA nucleotide differ from a DNA nucleotide?

A

RNA contains a ribose sugar, DNA a deoxyribose sugar and RNA contains uracil, DNA contains thymine

222
Q

How does RNA differ from DNA?

A

Same as the difference between the nucleotides as well as RNA is single stranded, short and linear, DNA is double stranded in a helix and much longer

223
Q

What is mRNA?

A

Messenger RNA, a copy of a gene produced in transcription that codes for a protein

224
Q

What is tRNA?

A

Transfer RNA, brings amino acids to the ribosome as it has a complementary anticodon to a codon on mRNA and helps form a protein in translation

225
Q

What happens in transcription?

A

Occurs in the nucleus, DNA helicase breaks the double helix of DNA, RNA nucleotides attach to the exposed DNA nucleotides according to the complementary base pairing rule (A-U, T-A, C-G and G-C), RNA polymerase then joins these RNA nucleotides together to form mRNA

226
Q

What happens in translation?

A

Occurs in the ribosome, mRNA attaches to the ribosome and reads the first codon (3 bases on mRNA), a tRNA molecule with a complementary anticodon to the codon on mRNA attaches to the strand, bringing an amino acid with it, the same thing happens with the second codon and a peptide bond forms between the two amino acids, the process continues until all of the codons have been read

227
Q

What is an allele?

A

An alternative version of a gene

228
Q

How are organisms of the same species different?

A

Different alleles

229
Q

What is a dominant allele?

A

An allele that is expressed in the phenotype when present in the genotype

230
Q

What is a recessive allele?

A

An allele that is expressed in the phenotype when present in the genotype with another recessive allele

231
Q

What does the term homozygous mean?

A

Both contain the same allele (TT or tt)

232
Q

What does the term heterozygous mean?

A

Contains different alleles, one dominant and one recessive (Tt)

233
Q

What is the genotype?

A

Genetic make up of an organism, the alleles it contains

234
Q

What is the phenotype?

A

The visual characteristics of an organism (e.g. hair colour) determined by the organisms genotype and the environment

235
Q

What is codominance?

A

When two alleles are equally dominant and both expressed in the phenotype when present in the genotype together

236
Q

If CR (red) is codomiant to CW (white), if an organism with the genotype of CRCR is bred with an organism who has the genotype of CWCW, what offspring could be produced?

A

All offspring would have the genotype CRCW (pink)

237
Q

If an individual had the genotype IAIB what would their phenotype be?

A

Blood group AB

238
Q

If an individual had the genotype IAIo what would their phenotype be?

A

Blood group A

239
Q

If an individual had the genotype IBIo what would their phenotype be?

A

Blood group B

240
Q

If an individual had the genotype IoIo what would their phenotype be?

A

Blood group o

241
Q

What does polygenic mean?

A

Most phenotypes are a result of multiple genes interacting with one another rather than a phenotype being controlled by a single gene

242
Q

For the allele T (tall) and t (short). If a parent who is homozygous dominant is crossed with a homozygous recessive parent, what would the genotypes of the offspring be?

A

All Tt (heterozygous)

243
Q

If two heterozygous parents (T - tall and t - short) are crossed together, what ratio of offspring could we expect to see?

A

3:1, the 3 being tall and 1 being short

244
Q

From the picture, how can we tell the parents at the top are carriers/heterozygous? For a disease that is caused by a recessive allele

A

They are unaffected but produce an offspring that is affected

245
Q

What must you ensure you do when drawing a genetic cross?

A

Dominant alleles are expressed using a capital letter, recessive with a lower case letter, alleles circled at the top to represent them being in an allele and the same letter being used, so T for dominant and t for recessive

246
Q

What is the genotype for males?

A

XY

247
Q

What is the genotype for females?

A

XX

248
Q

If a male is crossed with a female, what is the ratio/probabilities of their offspring?

A

50% XX (female) and 50% male (XY), 1:1

249
Q

What does diploid mean?

A

Cell that contains the full set of genetic information, in humans this is 46

250
Q

What does haploid mean?

A

Cells that contain half the set of genetic information, in humans this is 23

251
Q

What is mitosis?

A

Method of cellular division, used for growth, repair and replacement of cells/tissues

252
Q

What is produced in mitosis?

A

2 cells, genetically identical to one another and the parent cell, diploid cells, involving 1 cell division, used in asexual reproduction

253
Q

What is produced in meiosis?

A

4 cells, genetically different to one another and the parent cell, haploid, involving 2 cell divisions, used in sexual reproduction

254
Q

What produces variation?

A

Genetic variation in gametes and the random fertilisation of gametes and environmental factors

255
Q

What scientist bred peas together which helped us understand what we know about inheritance?

A

Gregor Mendel

256
Q

What is a mutation?

A

A rare, random change in the base sequence of DNA

257
Q

Give example of a chromosome mutation?

A

Down syndrome, an extra chromosome 21

258
Q

What impact can mutations have?

A

No effect (no change to the protein), a positive effect and negative effect due to changes to the protein being coded for

259
Q

When can a mutation be passed to the offspring of an organism?

A

If the mutation occurred in gamete formation

260
Q

What can cause mutations?

A

Ionising radiation (X-rays), chemicals (like in tobacco smoke) and faulty DNA replication

261
Q

If a mutation causes a change in the triplet which results in a different amino acid being transcribed, what might happen to the protein being translated?

A

Could be a positive change, amino acid sequence forms a new protein that performs its function better (enzyme with a more complementary active site) or a negative change where the protein is so different it cannot perform its job (denatured active site)

262
Q

Who proposed the model of evolution by natural selection?

A

Charles Darwin

263
Q

Outline the process of natural selection by using antibiotic resistance in bacteria as an example

A

Random mutation causes bacteria to be resistant to antibiotic, causes variation in the population, when exposed to antibiotic, bacteria with the mutated gene survive, reproduce and pass on mutated resisted allele to next generation, allele increases within population

264
Q

What is the purpose of photosynthesis?

A

to make glucose, which is used to make other biological molecules for growth

265
Q

In photosynthesis ________ energy is transferred to ______________ energy

A

light to chemical

266
Q

Write the word equation for photosynthesis

A

carbon dioxide + water –> glucose + oxygen

267
Q

Write the balanced chemical equation for photosynthesis

A

6CO2 + 6H2O –> C6H12O6 + 6O2

268
Q

Explain the effect of increasing carbon dioxide concentration on the rate of photosynthesis

A

Increases rate, as there is more reactant available
At high concentrations rate will stay constant. This is because light intensity or temperature is limiting the rate of reaction.

269
Q

Explain the effect of increasing light intentisty on the rate of photosynthesis

A

Increases rate, as there is more energy available
At high concentrations rate will stay constant. This is because carbon dioxide concentration or temperature is limiting the rate of reaction.

270
Q

Explain the effect of increasing temperature on the rate of photosynthesis

A

Increases rate, as reactants have more kinetic energy and there are more successful collisions with enzymes.
At high temperatures rate decreases, because enzymes are denatured.

271
Q

Where does photosynthesis take place in a plant cell?

A

Chloroplasts

272
Q

What is the function of chlorophyll?

A

To absorb light energy required for photosynthesis

273
Q

How is the palisade mesophyll adapted for photosynthesis?

A

many chloroplasts to absorb light energy
tall and thin, and tightly packed, to maximise light absorption

274
Q

How is the epidermis adapted for photosynthesis?

A

transparent - to allow light to pass through to palisade layer

275
Q

How is the spongy mesophyll adapted for photosynthesis?

A

air spaces - allow carbon dioxide to diffuse to cells
chloroplasts - absorb light energy passing through the palisade mesophyll

276
Q

Why do plants need magnesium ions?

A

to make chlorophyll

277
Q

Why do plants need nitrate ions?

A

to make amino acids (and proteins)

278
Q

How can you use pond weed to measure the rate of photosynthesis?

A

count the number of bubbles released per minute - or collect gas and measure volume per minute

279
Q

When testing a leaf for starch, why do you boil the leaf in water?

A

kill cells and break down cell walls

280
Q

When testing a leaf for starch, why do you place the leaf in hot ethanol?

A

to dissolve the chlorophyll

281
Q

When testing a leaf for starch, how do you heat the ethanol safely?

A

in a water bath (no lit Bunsens as flammable)

282
Q

When testing a leaf for starch, how do you check if starch is present?

A

add iodine solution - turns blue/black if starch is present and stays orange if starch is absent

283
Q

What is the function of carbohydrates in a balanced diet?

A

sugars used in respiration to release energy; starch and glycogen are insoluble and store glucose (without affecting water potential of cells)

284
Q

What is the function of fats in a balanced diet?

A

Energy storage; electrical insulation round nerves; thermal insulation; protects organs

285
Q

What is the function of protein in a balanced diet?

A

Enzymes; antibodies in immune system; hormones; transport proteins (E.g. haemoglobin); muscle

286
Q

What is the function of dietary fibre in a balanced diet?

A

keeps food moving through digestive system and prevents constipation

287
Q

What is the function of vitamin A in a balanced diet?

A

used to make rod cells in retina

288
Q

What is the function of vitamin C in a balanced diet?

A

helps form connective tissue, holding organs together

289
Q

What is the function of vitamin D in a balanced diet?

A

helps with absorption of calcium

290
Q

What is the function of iron in a balanced diet?

A

used to make haemoglobin

291
Q

What is the function of calcium in a balanced diet?

A

used to make bones (as calcium phosphate)

292
Q

What deficiency disease is caused by a lack of vitamin A?

A

night blindness

293
Q

What deficiency disease is caused by a lack of vitamin C?

A

scurvy

294
Q

What deficiency disease is caused by a lack of vitamin D?

A

Ricketts

295
Q

What deficiency disease is caused by a lack of iron?

A

anaemia

296
Q

What deficiency disease is caused by a lack of calcium?

A

osteoporosis

297
Q

How do you test the energy content of a food sample?

A

Measure out 25cm3 of water into a boiling tube
Measure mass of food
Measure starting temperature of food
Set light to food using Bunsen burner and hold under boiling tube of water until it goes out. Relight and repeat until it won’t catch fire
Measure finishing temperature of water and calculate temperature change
Energy content = (volume of water x temperature change x 4.2)/ mass of food

298
Q

What is the function of the mouth in the digestive system?

A

chews food to break it into smaller pieces
produces saliva which makes it easier to swallow food.
Saliva contains amylase

299
Q

What is the function of the oesophagus in the digestive system?

A

moves food from mouth to stomach through waves of muscular contraction (peristalsis)

300
Q

What is the function of the stomach in the digestive system?

A

Produces protease (pepsin) which digests protein
Produces hydrochloric acid, which provides optimum conditions for the enzyme and kills bacteria

301
Q

What is the function of the duodenum in the digestive system?

A

Final site of digestion of carbohydrates, fats and proteins - produces the enzyme maltase

302
Q

What is the function of the ileum in the digestive system?

A

absorption of small, soluble molecules from the small intestine into the blood

303
Q

What is the function of the pancreas in the digestive system?

A

produces the enzymes trypsin (protease), lipase and amylase

304
Q

What is the function of the colon in the digestive system?

A

absorbs water into the blood

305
Q

What is the function of the rectum in the digestive system?

A

stores the feces before egestion

306
Q

What enzyme digests starch to maltose?

A

amylase

307
Q

What enzyme digests maltose to glucose?

A

maltase

308
Q

What enzymes digest proteins to amino acids?

A

proteases (pepsin and trypsin)

309
Q

What enzymes digest fats to fatty acids and glycerol?

A

lipase

310
Q

Where in the digestive system is amylase produced?

A

salivary glands and pancreas

311
Q

Where in the digestive system is maltase produced?

A

duodenum

312
Q

Where in the digestive system are proteases produced?

A

stomach lining and pancreas

313
Q

Where in the digestive system is lipase produced?

A

pancreas

314
Q

Where is bile made and stored?

A

made in liver and stored in gall bladder

315
Q

What is the function of bile?

A

emulsifys fats - breaks large droplets into smaller droplets, increasing surface area and rate of digestion by lipase
neutralises stomach acid

316
Q

How is the ileum specialised for absorption?

A

Villi on the ileum wall - increase surface area
Microvilli on the surface of the villi - increase surface area
Villi wall one cell thick - short diffusion distance
Capillaries in villi - maintain high concentration gradient
Lacteal in villi - absorption of fats

317
Q

What is digestion?

A

breakdown of large, insoluble molecules into small, soluble molecules

318
Q

What is egestion?

A

removal of undigested food via the anus

319
Q

Why can single-celled organisms rely on diffusion for transport of substances in and out of cells?

A

large surface area to volume ratio

320
Q

Why do multicellular organisms require transport systems?

A

small surface area to volume ratio
large diffusion distance

321
Q

What is the function of the phloem?

A

transport a solution of sucrose and amino acids from the leaves to other parts of the plant

322
Q

What is the function of the xylem?

A

transport water and mineral ions from the roots to other parts of the plant

323
Q

How is water absorbed by root hair cells?

A

By osmosis
Active transport of mineral ions into the root hair cells reduces the water potential of the cytoplasm and increases the rate of osmosis

324
Q

How are root hair cells specialised for the absorption of water and mineral ions?

A

Thin cell wall - short diffusion distance
Root hair - large surface area
Many mitochondria - provide ATP for active transport

325
Q

What is transpiration?

A

evaporation of water from the surface of leaves

326
Q

Explain how the rate of transpiration is affected by higher temperatures

A

increased - water molecules have more kinetic energy, so diffuse faster (out of the stomata)

327
Q

Explain how the rate of transpiration is affected by higher light intensity

A

increased - stomata open wider due to faster rate of photosynthesis

328
Q

Explain how the rate of transpiration is affected by higher humidity

A

decreased - reduced concentration gradient between the air spaces and the atmosphere

329
Q

Explain how the rate of transpiration is affected by higher wind speeds

A

increased - water vapour blown away from leaf surface, increasing concentration gradient, increasing rate of diffusion

330
Q

How do you measure rate of transpiration with a potometer?

A

measure distance bubble travels per minute / measure mass loss per hour

331
Q

Why is it important to set up a potometer underwater?

A

to prevent any air bubbles entering the equipment, which could block the xylem

332
Q

What is the function of the blood plasma?

A

transports carbon dioxide, glucose, amino acids, salts, urea, hormones and heat energy

333
Q

What is the function of red blood cells?

A

transport oxygen

334
Q

How are red blood cells specialised to their function?

A

biconcave shape - increased surface area for oxygen to diffuse
contains haemoglobin - binds and transports oxygen
no nucleus - more space for haemoglobin

335
Q

How do platelets help blood clot formation?

A

platelets trigger formation of a mesh of insoluble fibrin
platelets and red blood cells are trapped in the fibrin mesh, forming a clot

336
Q

Why is clotting important?

A

prevents blood loss
prevents entry of pathogens

337
Q

What is the function of a phagocyte?

A

phagocytosis of pathogens
cell membrane extends around pathogen, engulfing them in a vesicle
inside the cell, enzymes are added to the vesicle to digest the pathogen

338
Q

What is the function of a lymphocyte?

A

detects antigens (marker proteins) on the surface of the pathogen
makes specific antibodies which are complementary to the antigen
antibodies disable pathogen, causing them to clump together
memory cells made on first infection, allowing for quicker antibody production in future

339
Q

How does vaccination protect against disease?

A

vaccine contains dead or weakened pathogen, or antigens
lymphocytes make specific antibodies which are complementary to the antigen
memory cells made, allowing for quicker antibody production in future if infected by the actual pathogen

340
Q

Why does heart rate increase during exercise?

A

increased blood flow to muscles
providing more oxygen and glucose
faster rate of aerobic respiration
to provide energy for muscle contraction
prevent anaerobic respiration and production of lactic acid

341
Q

Describe the events in the heart which pump blood around the body

A

atria contract, pushing blood into ventricles
ventricles contract, pushing blood into arteries
atria and ventricles relax, allowing the heart to fill with blood

342
Q

What is the function of the tricuspid and bicuspid valves?

A

prevent blood flowing backwards from ventricles into atria during ventricular contraction

343
Q

What is the function of the semi-lunar valves?

A

prevent blood flowing backwards from the arteries into the ventricles

344
Q

What is the function of the septum?

A

divides the left and right side of the heart, preventing mixing of oxygenated and deoxygenated blood

345
Q

Why is the left ventricle wall thicker than the right ventricle wall?

A

to generate a higher pressure on the left side, to push blood round the entire body

346
Q

What factors increase the risk of developing coronary heart disease?

A

smoking,
diet high in saturated fat and cholesterol,
lack of exercise
obesity
high blood pressure
high salt levels in diet

347
Q

What happens to the heart when a coronary artery is blocked by a plaque and a clot?

A

stops blood flow to the heart muscle
no oxygen for aerobic respiration
muscle respires anaerobically
lactic acid builds up and kills cells

348
Q

How does the structure of arteries relate to their function?

A

transport blood at high pressure
thick muscle layer in wall - can contract to maintain pressure
thick elastic layer in wall - can stretch and recoil to prevent bursting

349
Q

How does the structure of veins relate to their function?

A

transport blood at low pressure
wide lumen - low resistance to blood flow
valves - prevent the backflow of blood
thin muscle layer in wall - contracts to keep blood flowing

350
Q

How does the structure of capillaries relate to their function?

A

exchange molecules between plasma and cells
one cell thick wall - short diffusion distance

351
Q

What is structure A?

A

aorta

352
Q

What is structure B?

A

pulmonary artery

353
Q

What is structure C?

A

left ventricle

354
Q

What is structure D?

A

tricuspid valve

355
Q

What are structures E and I?

A

semi-lunar valves

356
Q

What is structure F?

A

pulmonary veins

357
Q

What are structures G and H?

A

vena cava

358
Q

What is structure J?

A

bicuspid valve

359
Q

What is structure K?

A

right ventricle

360
Q

What is structure L?

A

right atrium

361
Q

What is structure M?

A

left atrium

362
Q

What is the purpose of respiration?

A

The oxidation of glucose to release energy in the form of ATP

363
Q

What is the word equation for aerobic respiration?

A

Glucose + oxygen –> carbon dioxide + water

364
Q

What is the symbol equation for aerobic respiration?

A

C6H12O6 + 6O2 –> 6CO2 + 6H2O

365
Q

What is the difference between anaerobic and aerobic respiration in animals?

A

Aerobic - mitochondria, anaerobic - cytoplasm, aerobic - releases a lot of ATP, anaerobic - much less, aerobic - complete oxidation of glucose, anaerobic, partial breakdown of glucose due to lack of or no oxygen

366
Q

What is the word equation for anaerobic respiration in animals and bacteria?

A

Glucose –> Lactic acid

367
Q

What is the word equation for aerobic respiration in plants and fungi?

A

Glucose –> ethanol + carbon dioxide

368
Q

How have we used anaerobic respiration in bacteria to help us?

A

Production of yoghurt

369
Q

How have we used anaerobic respiration in plants/fungi to help us?

A

Production of bread and beer

370
Q

Why is lactic acid a bad waste product in animals?

A

It is poisinous and can cause cramps

371
Q

What is oxygen debt?

A

The extra oxygen needed to oxidise the lactic acid to break it down

372
Q

Looking at the diagram, what might we expect to see with the flask containing the germinating seeds?

A

An increase in temperature due to respiration being an exothermic reaction

373
Q

Why would we soak the peas in the flask with bleach?

A

To kill any microorganisms that could contaminate the flask and contribute to heat change

374
Q

What colour does limewater turn when bubbled through carbon dioxide?

A

Turns cloudy

375
Q

What colour does hydrogencarbonate indicator turn when bubbled through carbon dioxide?

A

Turns yellow

376
Q

What colour does hydrogencarbonate indicator turn with decreased carbon dioxide levels?

A

Turns purple

377
Q

What colour does hydrogencarbonate indicator turn when exposed to atmospheric carbon dioxide levels?

A

Turns red

378
Q

Using the picture, how could we measure the rate of anaerobic respiration in yeast?

A

Count the number of bubbles released in a minute

379
Q

Structure and function of the trachea

A

Contains C-rings of cartilage to ensure trachea is open during pressure changes, it connects the mouth to the lungs

380
Q

What tubes branch off from the trachea?

A

Bronchi/bronchus

381
Q

What tubes contain alveoli at the end of them?

A

Bronchioles

382
Q

Function of the alveoli?

A

Site of gas exchange

383
Q

Function of the pleural membrane?

A

Ensure thorax is air tight to allow pressure changes

384
Q

Function of the pleural fluid?

A

Stop lungs from sticking to the ribcage

385
Q

Function of the ribcage?

A

Protects the lungs

386
Q

Function of the intercostal muscles

A

contract and relax to increase or decrease the volume of the thorax to aid inhalation and exhalation

387
Q

Function of the diaphragm?

A

Contracts and relaxes to decrease and increase the volume of the thorax to aid pressure changes

388
Q

Outline what happens in inhalation?

A

Diaphragm contracts and flattens, and intercostal muscles contracts, ribcage moving up and out, both increasing the volume of the thorax and decreasing its pressure, pressure falls below atmospheric pressure, air is drawn into the lungs

389
Q

Outline what happens in exhalation?

A

Diaphragm relaxes and arches up, intercostal muscles relaxes, ribcage moves down and in, volume decreases in the thorax, pressure increases, to higher than atmospheric pressure and air is drawn out

390
Q

What are the 3 limiting factors of photosynthesis?

A

Carbon dioxide, light and temperature.

391
Q

How does temperature affect plant growth?

A

Optimum temperature needed for correct amount of kinetic energy,. Most successful collisions between active site and substrate. Leading to lots of photosynthesis.

392
Q

How can you increase co2 in a polytunnel/greenhouse?

A

Combustion- burn wood/fuel to release co2.

393
Q

How can you reduce transpiration in a polytunnel/greenhouse?

A

Increase the humidity, this reduces the water concentration gradient. Less water evaporates.

394
Q

Give an example of a organic fertiliser?

A

Faeces

395
Q

Advantages of organic fertilisers?

A

Improves soil structure, cheap, slow release of minerals, range of minerals.

396
Q

Disadvantages of inorganic fertilisers?

A

Can cause eutrophication and needs regular application.

397
Q

Advantages of inorganic fertilisers?

A

Mineral content known, fast release of minerals, easy to apply.

398
Q

Disadvantages of organic fertilisers?

A

Slow acting, harder to apply, may contain pests.

399
Q

What is a pest?

A

Organism which reduces the yield of crop plants or animals.

400
Q

What is a biological control?

A

Introducing another organism to reduce pest numbers.

401
Q

What does yeast produce when it anaerobically respires?

A

carbon dioxide and ethanol

402
Q

What gas makes bread rise?

A

carbon dioxide produced by yeast

403
Q

When yeast respires, it turns limewater?

A

Cloudy

404
Q

When yeast respires, it turns hydrogen carbonate indicator?

A

Yellow

405
Q

What is the bacteria called which can help make yoghurt?

A

Lactobacillus bulgaricus

406
Q

How is yoghurt made?

A

Lactobacillus bulgaricus uses the lactose in milk, to produce lactic acid. This happens at 46degrees and coagulates the milk.

407
Q

What do you have to do to milk before it is turned into yoghurt?

A

Pasteurise (heat) the milk to kill any unwanted bacteria.

408
Q

What does the air filter do in a fermenter?

A

Filters the air, stoppping bacteria and dirt from entering

409
Q

What does the stirrers/paddles do in a fermenter?

A

Mix the contents to oxygenate all parts and maintain the temperature, stops microorganisms from settling

410
Q

What does the cooling jacket do in a fermenter?

A

Removes heat energy, stopping enzymes from denaturing.

411
Q

How do you clean the fermenter before you use it?

A

Steam clean, kills microorganisms making it sterile and leaves no residue.

412
Q

In fish farming, why do you add antibiotics?

A

To kill bacteria that will cause disease or infection.

413
Q

In fish farming, why do you add nets?

A

To stop interspecific predation from birds and to stop intraspecific from other fish of the same species.

414
Q

In fish farming, what type of food do you give the fish?

A

High in protein and lipid, for growth/repair and insulation.

415
Q

In fish farming, why do you give small amounts of food often?

A

Less wastage so all is eaten. Less bacterial growth from waste.

416
Q

What conditions do you want to keep the same in a fermenter?

A

Temperature and pH. Oxygen if aerobic conditions are needed.

417
Q

What is selective breeding?

A

A type of artificial selection. Choose the individuals with the desired characteristic and breed them. They will hopefully pass on their desirable alleles to their offspring. Repeat, choosing the offspring with desired characteristics over many generations.

418
Q

What are the disadvantages with selective breeding?

A

Reduced variation in the population. Inbreeding can increase chances of recessive condition.

419
Q

Why do selective breeding?

A

Increased yield of crops, produce animals with lots of meat or milk, produce crops that are less prone to disease or pests.

420
Q

How can you do selective breeding in cows?

A

Give a female cow lots of FSH to mature lots of eggs. Use artificial insemination with the chosen bull sperm.

421
Q

What is genetic engineering?

A

Transferring genes from one organism to another

422
Q

In genetic engineering, which enzyme cuts DNA?

A

Restriction enzymes

423
Q

In genetic engineering, which enzyme bonds the chosen gene to the plasmid?

A

DNA ligase

424
Q

Which organism is used most in genetic engineering?

A

Bacteria, as they divide quickly and no ethics are involved.

425
Q

What is a plasmid?

A

A circular piece of DNA

426
Q

Once you have genetically modified bacteria, where do you put them?

A

In a fermenter, so the bacteria can divide in constant optimum conditions.

427
Q

What is a transgenic organism?

A

The organism that has received DNA from another organism.

428
Q

What is recombinant DNA?

A

DNA from 2 different organisms

429
Q

What is a vector?

A

A plasmid- It can be used to carry the DNA of one organism into another.

430
Q

What can be made in the process of genetic engineering?

A

Insulin, antibiotics, growth hormones for example.

431
Q

Which process produces whole plants from just a few plant cells?

A

Tissue culture

432
Q

What is the name of the bacteria which inserts plasmids into plant cells?

A

Agrobacterium tumefaciens

433
Q

What are some disadvantages of genetically modifying plants?

A

It is not accepted by the public, long term effects are unknown, it reduces variation and may affect food chains.

434
Q

What is micropropagation?

A

A way to clone plants on mass

435
Q

During micropropagation, what is the small cutting of a plant called?

A

explant

436
Q

During micropropagation, what is the small ball of plant cells called?

A

callus

437
Q

During micropropagation, what hormones do you add?

A

Shoot and root stimulating hormones

438
Q

What is a clone?

A

Genetically identical organism

439
Q

During mammal cloning, where does the nucleus come from?

A

Normal body cell. It is diploid.

440
Q

During mammal cloning, what happens to the donor egg cell?

A

Its nucleus is removed (enucleated)

441
Q

How is the donor nucleus put into the donor cell?

A

Electric shock

442
Q

What gas has a net movement into the alveoli?

A

Carbon dioxide

443
Q

What gas has a net movement out of the alveoli?

A

Oxygen

444
Q

How is the alveoli specialised for gas exchange?

A

Folded walls and lots of alveoli for a high surface area, network of capillaries for maintenance of a high concentration gradient, walls are one cell thick for a short diffusion distance, moist walls to make it easier for gases to diffuse in and out of the alveoli

445
Q

Looking at the diagram, what would the limewater do for inhaled air?

A

Stay colourless as little Carbon dioxide in inhaled air

446
Q

Looking at the diagram, what would the limewater do for exhaled air?

A

Turn cloudy as exhaled air has a lot of carbon dioxide due to it being produced via respiration

447
Q

Looking at the diagram, if we switched to hydrogencarbonate indicator, what would the left and right test tubes change to?

A

Left would stay red and the right would turn yellow due to an increase in carbon dioxide

448
Q

What happens to breathing rate during exercise and why?

A

It increases, as we need more oxygen for more aerobic respiration to release more energy for more muscle contraction

449
Q

What are the limitations of the bell jar model?

A

Sometimes only one balloon - we have two lungs, glass tube is rigid which the trachea isnt, intercostal muscles not modelled, ribcage doesn’t move and it does

450
Q

How is nicotine from cigarettes dangerous?

A

Increases heart rate and is addictive

451
Q

How are the carcinogens in cigarette smoke dangerous?

A

Increases the risk of mutations and cancer

452
Q

How is the carbon monoxide in cigarette smoke dangerous?

A

Binds irreversibly to haemoglobin and reduces the amount of oxygen carried by red blood cells

453
Q

How does smoking lead to bronchitis?

A

Tar covers the cilia and smoke destroys it, meaning more mucus is present in the lungs which damages and inflames the bronchus and bronchioles

454
Q

How does smoking lead to emphysema?

A

Cigarette smoke damages the elasticated walls of the alveoli, reducing its surface area and making gas exchange harder

455
Q

What is excretion?

A

The removal of metabolic waste

456
Q

What is excreted from the leaf at night?

A

Carbon dioxide from respiration

457
Q

What is excreted from the leaf during the day?

A

Carbon dioxide from respiration and oxygen from photosynthesis

458
Q

When is the rate of photosynthesis higher than respiration?

A

At mid day, around 10am-4pm

459
Q

When is the rate of respiration higher than photosynthesis?

A

Early morning (before 10am) and at night (after 4pm)

460
Q

When is the net movement of oxygen out of the leaf?

A

In light

461
Q

When is the net movement of carbon dioxide out of the leaf?

A

In dark

462
Q

How is carbon dioxide and oxygen excreted from the leaf

A

Diffuses through the air spaces in the spongy mesophyll and then out of the stomata

463
Q

How is the leaf specialised for gas exchange?

A

Thin for a short diffusion distance, large surface area and lots of stomata, air spaces in the spongy mesophyll layer for quicker diffusion, stomata open and close to control the loses of gases and water,

464
Q

Looking at the diagram, explain what happens in 1

A

Stays red as it’s the control

465
Q

Looking at the diagram, explain what happens in 2

A

Goes purple as more carbon dioxide is taken into the leaf due to photosynthesis occuring faster than respiration

466
Q

Looking at the diagram, explain what happens in 3

A

Goes yellow as more carbon dioxide is produced due to respiration occuring faster than photosynthesis

467
Q

What is an ecosystem?

A

System or area where organisms interact with their physical environment

468
Q

What are producers?

A

Organisms which make their own food, e.g. plants

469
Q

What are consumers?

A

Organisms which eat other living things e.g. animals

470
Q

What are decomposers?

A

Organisms which secrete digestive enzymes to decay (break down) dead organic matter to obtain their food e.g. fungi and bacteria

471
Q

What does abiotic mean? Give an example of an abiotic factor

A

Non-living factor - e.g. light, temperature, pH, humidity, wind speed

472
Q

What does biotic mean? Give an example of a biotic factor

A

Living factor - e.g. competition, predation, food availability

473
Q

What is a habitat?

A

The place an organism lives

474
Q

Define population

A

Total number of individuals of ONE species that live in a particular area at a given time

475
Q

Define community

A

Total number of individuals of ALL species that live in a particular area at a given time

476
Q

What is a quadrat?

A

A piece of equipment to measure population size. You place this on the ground and count the number of individuals in it / estimate % cover

477
Q

How do you work out population size?

A

Calculate area of a habitat. Count number of individuals in 1 quadrat. Repeat this 10x. Calculate average. Calculate how many quadrats fit into total area. Multiple the number of quadrats by the number of individuals in one.

478
Q

How do you do random sampling?

A

Lay out 2 tape measures on ground with measurements e.g. 10m x 10m. Calculate random numbers using random number generator. Use these numbers of coordinats to place quadra

479
Q

Why do you do random sampling?

A

To make sure there is no bias so the data is valid.

480
Q

What is a transect?

A

Line across a habitat which is placed to pass through a range of abiotic conditions (e.g. from the shaded area under a tree outwards to the light). Place quadrat at regular intervals along the transect and measure the % cover or number of individuals.

481
Q

What are trophic levels?

A

Stages in a food chain or web (e.g. primary consumer, secondary consumer)

482
Q

What is a primary consumer?

A

An organism which eats the producer (e.g. a cow that eats grass)

483
Q

What is a secondary consumer?

A

An organism which eats the primary consumer (e.g. an owl that eat a mouse)

484
Q

What is a food web?

A

A diagram that shows all the food chains linked together. It is useful to understand the links between species in a community

485
Q

What is a pyramid of numbers?

A

A digram that shows the relative numbers of organisms at each trophic level. They are drawn to scale.

486
Q

What is a pyramid of biomass?

A

A diagram which shows the total mass of organisms in each trophic level (mass of an individual x the total number of individuals). It is a more accurate way of looking at relative amounts of organisms

487
Q

How is energy available at each trophic level in a particular area expressed?

A

kilojoules per square metre per year

488
Q

Why is not all energy passed from the sun to a producer?

A

Some light will miss the plant or chloroplasts. Some light is reflected by the cuticle. Some light has wrong wavelength to be absorbed by chlorophyll.

489
Q

Why is only about 10% of energy transferred from one trophic level to the next?

A

Some parts of organism is not eaten. Some parts are not digested or absorbed (they are egested as faeces). Some materials are respired to release energy - this energy is used for movement (muscle contraction) and maintaining a constant body temp. Some is lost from excretion (urine)

490
Q

How do you calculate % energy transferred?

A

Energy transferred to next level divided by Energy received during transfer. Multiple by 100

491
Q

Explain what happens to carbon atoms during photosynthesis

A

Carbon dioxide is converted into Glucose (and stored as starch)

492
Q

Explain what happens with carbon atoms during respiration

A

Glucose will be used to provide energy for the organism, carbon dioxide will be given off

493
Q

How do non-photosynthesising organisms gain carbon compounds such as glucose

A

Animals eat plants, bacteria and fungi decompose

494
Q

Fossil fuels (coal, oil, gas) lock in carbon, how does this happen

A

Fossilisation, when living things do not decay fully when they die in the soil

495
Q

How do fossil fuels release carbon

A

In combustion carbon dioxide is released

496
Q

Where would you find mutualistic nitrogen fixing bacteria

A

In the root nodules of leguminous plants, and feely living in the soil

497
Q

What do nitrogen fixing bacteria do

A

Absorb nitrogen and make ammonia

498
Q

What do nitrifying bacteria do

A

convert ammonia to nitrites and nitrates

499
Q

Plants absorb nitrates via their roots, what do they then do with them?

A

Make plant amino acids and put these together to make plant proteins, DNA and RNA

500
Q

How do animals get amino acids (which contain nitrates)

A

Eating plants, they digest the plant protein, giving amino acids

Biology (22 decks)

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